JP2003159676A - Control method for leg type moving robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for a leg type moving robot that can control a body attitude stability by using a ZMP stability judging model with a comparatively slow sampling cycle. <P>SOLUTION: A ZMP position where both a pitch axis moment and a roll axis moment of a body are zero and a ZMP moving space defined by a floor reaction force that the body receives from a floor surface are defined. A ZMP stable position is obtained on the basis of the definition of the ZMP moving space. Transformation quantity or momentum of the body is produced so that the ZMP position is always made moved toward the center of a ZMP stable range by dynamically controlling a space distortion applied to the ZMP moving space according to contact conditions with a road surface. Consequently the attitude stabilizing control of the body can be made easily. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a legged mobile robot having at least a plurality of movable legs,
In particular, the present invention relates to a control method for a legged mobile robot that walks or performs other legged work with movable legs.

More specifically, the present invention relates to so-called ZMP.
The present invention relates to a control method of a legged mobile robot that performs posture stability control of a body during legged work while using (Zero Moment Point) as a stability determination criterion, and particularly uses a ZMP stability determination criterion at a relatively slow sampling cycle. However, the present invention relates to a control method for a legged mobile robot that performs posture stability control of a body.

[0003]

2. Description of the Related Art A mechanical device that makes a motion similar to a human motion by using an electrical or magnetic action is called a "robot". The origin of the robot is the Slavic word "ROBO".
It is said that it is derived from "TA (slave machine)." In Japan, robots began to be popular since the end of the 1960s, but most of them are automation of production work in factories.
It was an industrial robot such as a manipulator and a transfer robot for the purpose of unmanned operation.

In recent years, research and development of legged mobile robots imitating the body mechanism and motions of animals such as humans and monkeys that perform upright bipedal walking have progressed, and expectations for their practical application are increasing. The leg-type movement with two feet upright is more unstable than the crawler type, four-legged or six-legged type because posture control and walking control are difficult, but walking with unevenness on the work route such as uneven terrain or obstacles It is excellent in that it can realize flexible moving work such as being able to deal with discontinuous walking surfaces such as surfaces and stairs and ladders going up and down.

A legged mobile robot that reproduces the human biological mechanism and motion is called a "humanoid" or "humanoid" robot. The humanoid robot can perform, for example, life support, that is, support for human activities in various scenes in daily life such as a living environment.

Most of the working space and living space for humans are
It is formed according to the human body mechanism and behavior that two-leg upright walking has. In other words, in the human living space, there are many obstacles for the movement of the current mechanical system using wheels or other driving devices as a moving means.
Therefore, in order for the mechanical system, that is, the robot to perform various human tasks on behalf and further penetrate deep into the living space of the human, it is preferable that the movable range of the robot is substantially the same as that of the human. This is why there are great expectations for the practical use of legged mobile robots.
It can be said that biped upright walking is indispensable for the robot to improve affinity with the human living environment.

A number of techniques have already been proposed for posture control and stable walking for a two-legged mobile robot. Stable “walking” can be defined as “moving with legs without falling”. Posture stability control of the robot is very important for avoiding the fall of the robot. This is because the fall means that the robot interrupts the work being performed, and that considerable effort and time are spent to get up from the fall state and restart the work. Above all, there is a risk that the fall may cause fatal damage to the robot body itself or an object on the other side that collides with the falling robot.

Most of the proposals regarding the posture stability control of legged mobile robots and the fall prevention during walking are made by ZMP (Zero Momen).
t Point) is used as a criterion for gait stability determination. The stability discrimination criterion by ZMP is "Durhamber's principle" that gravity and inertial force from the walking system to the road surface, and these moments balance with the floor reaction force and floor reaction force moment as a reaction from the road surface to the walking system. based on. As a result of the mechanical reasoning, the point where the pitch axis and roll axis moments become zero on or inside the side of the supporting polygon formed by the plantar ground contact point and the road surface (that is, the ZMP stable area), that is, "ZMP (Zero Moment Point) "
Exists.

In summary, the ZMP norm means that "at every moment of walking, the ZMP exists inside the supporting polygon formed by the foot and the road surface, and the force exerted by the robot on the road surface acts. By doing so, the robot can walk stably without tipping (rotating motion of the aircraft). "

According to the bipedal walking pattern generation based on the ZMP standard, it is possible to set a foot sole landing point in advance and it is easy to consider a kinematic constraint condition of the toes according to a road surface shape. . Further, using ZMP as the stability determination criterion means that the trajectory is treated as the target value for motion control, not the force, so that technical feasibility is enhanced.

Incidentally, regarding the concept of ZMP and the point of applying ZMP to the stability determination standard of a walking robot, Miom
It is described in "LEGGED LOCOMOTION ROBOTS" by ir Vukobratovic ("Walking Robots and Artificial Feet" by Ichiro Kato (Nikkan Kogyo Shimbun)).

Conventionally, in the posture stability control and the walking control of the robot using ZMP as the stability determination criterion, the ZMP position is ZMP.
It is general to perform correction control so as to return to the stable region once it deviates from the stable region. In other words,
During the normal operation period, the ZMP can move freely, but when the amount of movement exceeds a certain area, the drive of each joint such as the leg is controlled and the ZMP position is controlled after the fact.

For example, the legged mobile robot described in Japanese Patent Laid-Open No. 5-305579 is designed to perform stable walking by matching a point on the floor surface where ZMP becomes zero with a target value.

Further, in the legged mobile robot described in JP-A-5-305581, the ZMP has at least a predetermined margin from the end of the supporting polygon inside the supporting polyhedron (polygon), or when landing or leaving the floor. It is configured to be in a position having. In this case, the ZMP has a margin for a predetermined distance even when subjected to a disturbance or the like, and the stability of the airframe during walking is improved.

Further, Japanese Patent Laid-Open No. 5-305583 discloses that the walking speed of a legged mobile robot is controlled by the ZMP target position. That is, using the walking pattern data set in advance, ZMP
The leg joint is driven so as to match the target position, the inclination of the upper body is detected, and the discharge speed of the walking pattern data set according to the detected value is changed.
For example, when the robot leans forward by stepping on an unknown unevenness,
The posture can be recovered by increasing the discharge speed. Further, since the ZMP is controlled to the target position, there is no problem even if the discharge speed is changed during the both-leg supporting period.

Further, Japanese Patent Laid-Open No. 5-305585 discloses that the landing position of the legged mobile robot is controlled by the ZMP target position. That is, the legged mobile robot described in the publication detects a deviation between the ZMP target position and the actual measurement position and drives one or both of the legs so as to eliminate it, or a moment around the ZMP target position. Is detected and the legs are driven so that it becomes zero, thereby achieving stable walking.

Further, Japanese Laid-Open Patent Publication No. 5-305586 discloses that the tilted posture of the legged mobile robot is controlled by the ZMP target position. That is, ZM
A moment around the P target position is detected, and when a moment is generated, the legs are driven so that the moment becomes zero, so that stable walking is performed.

The above-described posture stability control of the robot is performed by searching for a point where the pitch and roll moments are zero on or inside the side of the supporting polygon formed by the foot contact point and the road surface, that is, the ZMP stable area. Is the basic operation. Further, when the ZMP position deviates from the ZMP stable region, correction control is performed so as to return to the stable region again.

However, the ZMP norm is premised on that it can be assumed that the robot body and road surface are as close as possible to a rigid body (that is, they do not deform or move whatever force or moment acts). It is just a norm that can be applied. In other words, when it cannot be assumed that the robot or the road surface is as close as possible to a rigid body, for example, the force (translation) acting on the ZMP due to the high speed movement of the robot and the impact force at the time of switching the standing leg become large, and the robot itself When deformation or motion occurs in the robot, unless the amount of deformation of the robot with respect to the applied force is properly managed, the space itself in which the ZMP exists becomes unstable and the posture of the robot is temporarily changed. Even if the ZMP criterion is satisfied (the ZMP exists inside the supporting polygon and the robot exerts a force in the direction of pushing on the road surface), an unstable Z
The posture of the robot becomes unstable in order to stabilize the MP. In particular, the lower the center of gravity of the robot, the faster the rotational motion of the body occurs, which makes it difficult to achieve stable walking.

1 and 2 show the relationship between the ZMP position and the deformation amount (or momentum) of the robot in the case of an ideal model in which the robot or the road surface is as close as possible to a rigid body and in the case of not being a rigid body in reality. (That is, the ZMP behavior space of the robot) is shown.

In the ideal case where the robot and the road surface are as close to a rigid body as possible, in the ZMP behavior space, as shown in FIG. 1, any Z in the calculated ZMP stable region is obtained.
No deformation amount (or momentum) is generated in the robot even at the MP position. In other words, the robot does not lose its attitude stability at any ZMP position.

However, ZMP in the actual system
In the behavior space, the robot or road surface is not a rigid body, and even if it is within the calculated ZMP stable region, a deformation amount (or momentum) occurs in the robot depending on the ZMP position. In the example shown in FIG. 2, a deformation amount (or momentum) does not occur in the robot in the vicinity of the center in the ZMP stable region, so that the robot does not lose the posture stability of the machine body as it is. However, as the ZMP position moves away from the center of the ZMP stable region, the deformation amount (or momentum) of the robot increases in the negative direction.

The ZMP behavior space as shown in FIGS. 1 and 2 is defined by the ZMP position and the floor reaction force received from the floor surface by the airframe. Positive or negative of the amount of deformation (or momentum) of the robot in this ZMP behavior space is a direction in which negative causes a spatial distortion that tends to move the ZMP to the edge of the stable region, and positive moves the ZMP to the center of the stable region. This is the direction of causing the spatial distortion. Therefore, as shown in FIG. 2, the deformation amount (or momentum) of the robot increases in the negative direction as the ZMP position moves away from the center of the ZMP stable region. It deforms toward the edge of the ZMP stable region, and eventually the aircraft falls.

Therefore, in view of calculation, the ZMP position of the robot must be always within the ZMP stable region, but the attitude control of the body must always be performed so as to return it to the center of the ZMP stable region. A typical example of the control method for continuously returning the ZMP position to the center is the "inverted pendulum". However, in this case, high-speed control (that is, an extremely short sampling period) must be performed, and the computer load for attitude control increases.

In other words, the ZMP stability criterion is a stability criterion aimed at realizing walking in an ideal environment including a prerequisite that is difficult to meet in reality, that is, the robot and the road surface are rigid bodies. It is just a norm. Therefore, in order to autonomously continue stable dynamic walking in a human living environment, it is important to devise a robot system configuration method that considers the stability of the ZMP existence space.

[0026]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent attitude stability control of a body during leg work while using so-called ZMP (Zero Moment Point) as a stability determination standard. It is to provide a control method for a legged mobile robot.

A further object of the present invention is to provide an excellent legged mobile robot control method capable of suitably performing attitude stability control of an airframe while using the ZMP stability criterion in a relatively slow sampling period. Especially.

A further object of the present invention is to provide an excellent control method for a legged mobile robot capable of forming a ZMP behavior space that autonomously continues stable dynamic walking in a human living environment. Especially.

[0029]

The present invention has been made in consideration of the above problems, and a first aspect thereof is a control method for a legged mobile robot having two or more movable legs. The ZM that controls the ZMP behavior space defined by the ZMP position where the pitch axis moment and roll axis moment of the airframe are zero and the floor reaction force received from the floor surface by the airframe
A legged mobile robot control method comprising: a P behavior space control step, wherein the ZMP behavior space control step applies a predetermined distortion to the ZMP behavior space in advance.

As already described in the section "Prior Art", the ZMP stability determination criterion is only a criterion that can be applied only when it can be assumed that the robot body and road surface are as close as possible to a rigid body. In other words, it cannot be assumed that the robot or the road surface is as close as possible to a rigid body, and therefore the space itself in which the ZMP exists is unstable unless the deformation amount of the robot with respect to the applied force is properly managed at a relatively short sampling period. Even if the posture of the robot satisfies the ZMP stability determination standard, the posture of the robot becomes unstable in order to stabilize the unstable ZMP.

Therefore, a method for controlling a legged mobile robot according to the first aspect of the present invention is based on a ZMP (Zero Moment Poin).
t) is adopted as a criterion for posture stability determination, but a stable ZMP is performed in consideration of the deformation amount and the momentum of the robot body.
Adopt a method of controlling the operation of the aircraft with the existence space of.

In the ZMP behavior space control step, Z
The MP position of the airframe that is to be moved to the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region formed of the supporting polygon formed by the sole of the movable leg and the road surface. Spatial distortion is applied to the ZMP behavior space so that a deformation amount or a momentum is generated. Alternatively, in the ZMP behavior space control step, the ZMP behavior space is provided with a predetermined characteristic such that the deformation amount, the momentum, or the direction of the robot changes according to the floor reaction force.

That is, according to the control method for a legged mobile robot according to the first aspect of the present invention, the posterior correction control is not started until the movement amount of the ZMP position exceeds a predetermined region. Since a space distortion that stabilizes the posture of the robot is given in advance, high robustness against external disturbances can be obtained even when the control mechanism of the airframe does not have a sufficient response speed. .

Here, in the ZMP behavior space control step, a minimum point of the deformation amount or the momentum of the airframe may be set at substantially the center of the ZMP stable region. In such a case, since the deformation amount and the momentum of the body always occur in the direction in which the posture is stable, it becomes easy to maintain the posture stability. Also, even if the sampling period is relatively low,
Sufficient posture stability control can be performed.

In the ZMP behavior space control step, the minimum point of the deformation amount or the momentum of the airframe is set at the approximate center of the ZMP stable region, and the deformation amount or the momentum of the airframe is set near the boundary of the ZMP stable region. You may make it set a maximum point.

In such a case, in the region sandwiched between the maximum points, the amount of deformation or momentum of the robot body is generated so that the ZMP position always faces the center of the ZMP stable region.
It becomes easy to maintain posture stability, and sufficient posture stability control can be performed even with a relatively low sampling cycle. On the other hand, from the time when the maximum point is exceeded, a deformation amount or a momentum that causes the ZMP position to move to the outside of the ZMP stable region occurs, so that the robot shifts from the “posture stable mode” to the “falling mode”.

Further, in the ZMP behavior space control step, the first coordinate axis having the ZMP position outwardly of the machine body as a positive direction and the deformation amount of the robot for directing the ZMP position toward the center of the ZMP stable region or In the ZMP behavior space consisting of the second coordinate axis with the momentum in the positive direction, the deformation amount or momentum of the robot has a maximum value in the negative region with respect to the standing leg in the latter stage of single-leg support, and as the floor reaction force increases, Spatial distortion may be given to move the ZMP position having the maximum value of the deformation amount or the momentum in the positive direction.

In such a case, in the standing stance in the latter half of the monopod support, the bending amount decreases almost linearly with the moving amount of the ZMP position in the Y direction. When the floor reaction force is small, ZMP
When the position moves to the inside of the machine, the standing leg bends inward, and when the ZMP position moves to the outside of the machine, the standing leg bends to the outside, but the ZMP position increases as the floor reaction force increases. Even if the stance leg moves to the outside of the machine body, the stance leg does not easily bend to the outside.

When the total weight of the robot is 100, the floor reaction force is "large" when the floor reaction force is 100 or more. When the floor reaction force is about 20 to 100, the floor reaction force is The term "medium" is used, and the floor reaction force is "small" when the floor reaction force is 20 or less (the same applies hereinafter). However, these are only a guideline and may be changed depending on the robot body structure and weight. In particular, if you express qualitatively that "the floor reaction force is small", it is
It is the floor reaction force that is applied to the other leg while supporting the whole body with one leg.

Further, in the ZMP behavior space control step, the first coordinate axis having the ZMP position in the forward direction of the machine body as a positive direction and the deformation amount of the robot for directing the ZMP position toward the center of the ZMP stable region or In the ZMP behavior space consisting of the second coordinate axis with the momentum in the positive direction, the deformation amount or the momentum of the robot has a maximum value in the vicinity of the center of the ZMP stable region in the negative region with respect to the standing leg in the latter stage of the monopod support In addition, a spatial distortion may be applied such that the change in the deformation amount or the momentum decreases as the floor reaction force increases.

In such a case, in the standing leg in the latter half of the single-leg support, the bending amount decreases almost linearly with the moving amount of the ZMP position in the X direction. When the floor reaction force is small, ZMP
When the position moves to the front of the aircraft, the standing leg bends forward, and when the ZMP position moves to the rear of the aircraft, the standing leg bends backward, but as the floor reaction force increases, the ZMP position changes. The stance leg is difficult to bend regardless of whether it moves forward or backward.

In the ZMP behavior space control step, the ZMP position is set to the ZMP position when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the standing stance in the latter stage of single-leg support.
The ZMP position becomes ZMP as it deviates from the center of the stable region.
Deformation or momentum of the robot is generated so as to move away from the center of the stable region, but as the floor reaction force increases, the ZMP position becomes closer to the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. It is also possible to give a spatial distortion that causes a deformation amount or a momentum of the robot to move toward. When the floor reaction force is small in the traveling direction, the ZMP position is ZM
The ZMP position becomes ZM as it deviates from the center of the P stable region.
A deformation amount or momentum of the robot is generated so as to move away from the center of the P stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion may be applied such that a deformation amount or a momentum amount of the robot that moves toward

In such a case, when the floor reaction force is small, when the ZMP position moves to the inside of the machine body, the standing leg in the latter stage of single-leg support bends inward, and when the ZMP position moves to the outside of the machine body, Bends outward, but as the floor reaction force increases, conversely, ZM
When the P position moves inside the machine, the standing leg bends outward, and when the ZMP position moves outside the machine, the standing leg bends inward. Further, when the floor reaction force is small, the standing leg bends forward when the ZMP position moves to the front of the aircraft, and the standing leg bends backward when the ZMP position moves to the rear of the aircraft. Conversely, as the force increases, when the ZMP position moves to the front of the aircraft, the standing leg bends rearward and the ZMP
When the position moves to the rear of the body, the standing leg bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

In the ZMP behavior space control step, the ZMP position is deviated from the center of the ZMP stable region when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the trunk of the latter stage of monopod support. A deformation amount or a momentum of the robot is generated such that the position moves away from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position becomes the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. It is also possible to give a spatial distortion that causes a deformation amount or a momentum of the robot that moves toward the center of the. Further, when the floor reaction force is small in the traveling direction, as the ZMP position deviates from the center of the ZMP stable region, a deformation amount or a momentum of the robot is generated such that the ZMP position deviates from the center of the ZMP stable region. As the floor reaction force increases, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Good.

In such a case, when the floor reaction force is small, the trunk portion bends inward when the ZMP position moves inside the machine body, and the trunk portion moves outward when the ZMP position moves outside the machine body. However, as the floor reaction force increases, the trunk bends outward when the ZMP position moves to the inside of the airframe, and the trunk moves inward when the ZMP position moves to the outside of the airframe. It is configured to bend. Also, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the airframe, and the trunk bends backward when the ZMP position moves rearward of the airframe. As the force increases, conversely, when the ZMP position moves to the front of the body, the trunk bends rearward, and when the ZMP position moves to the rear of the body, the trunk bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

Further, in the ZMP behavior space control step, the first coordinate axis whose ZMP position is directed to the outside of the machine body is a positive direction and the deformation amount of the robot or the ZMP position is directed to the center of the ZMP stable region or In the ZMP behavior space composed of the second coordinate axis with the momentum in the positive direction, the robot's deformation amount or momentum has a maximum value near the center of the ZMP stable region in the negative region with respect to the standing leg in the two-leg supporting period, and Alternatively, spatial distortion may be applied so that the change in the deformation amount or the momentum decreases as the floor reaction force increases.

In such a case, the amount of bending of the standing leg decreases almost linearly with the amount of movement of the ZMP position to the outside of the body. When the floor reaction force is small, the stance leg bends inward when the ZMP position moves inside the aircraft, and
When the ZMP position moves to the outside of the aircraft, the standing leg bends outward, but as the floor reaction force increases,
The stance leg is configured to be difficult to bend regardless of whether the ZMP position moves inward or outward. In the two-leg supporting period, the amount of bending of the legs is smaller than that in the single-leg supporting period in which one leg is used to support the two legs.

In the ZMP behavior space control step, the first coordinate axis having the ZMP position in the forward direction of the machine body as the forward direction and the deformation amount of the robot or the ZMP position directed to the center of the ZMP stable region or In the ZMP behavior space composed of the second coordinate axis with the momentum in the positive direction, the robot's deformation amount or momentum has a maximum value near the center of the ZMP stable region in the negative region with respect to the standing leg in the two-leg supporting period, and Alternatively, spatial distortion may be applied so that the change in the deformation amount or the momentum decreases as the floor reaction force increases.

In such a case, the bending amount of the standing leg decreases almost linearly with the amount of movement of the ZMP position to the front of the airframe. When the floor reaction force is small, when the ZMP position moves to the front of the aircraft, the standing leg bends forward and
When the ZMP position moves to the rear of the aircraft, the standing leg bends rearward, but as the floor reaction force increases,
The stance leg is configured to be difficult to bend regardless of whether the ZMP position moves forward or backward. In the two-leg supporting period, the amount of bending of the legs is smaller than that in the single-leg supporting period in which one leg is used to support the two legs.

In the ZMP behavior space control step, the ZMP position is set to Z when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the standing leg in the two-leg supporting period.
The ZMP position becomes Z as it moves away from the center of the MP stable region.
Deformation or momentum of the robot is generated so as to move away from the center of the MP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion may be applied such that a deformation amount or a momentum amount of the robot that moves toward Further, when the floor reaction force is small in the traveling direction, as the ZMP position deviates from the center of the ZMP stable region, a deformation amount or a momentum of the robot is generated such that the ZMP position deviates from the center of the ZMP stable region. As the floor reaction force increases, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Good.

In such a case, when the floor reaction force is small, when the ZMP position moves to the inside of the machine, the standing leg in the two-leg supporting period bends inward, and when the ZMP position moves to the outside of the machine, the standing leg moves. It bends toward the outside, but as the floor reaction force increases, conversely, ZMP
The stance leg is configured to bend outward when the position is moved to the inside of the body, and the stance leg is configured to bend to the inside when the ZMP position is moved to the outside of the body. Further, when the floor reaction force is small, the standing leg bends forward when the ZMP position moves to the front of the aircraft, and the standing leg bends backward when the ZMP position moves to the rear of the aircraft. As the force increases, conversely, when the ZMP position moves to the front of the machine, the standing leg bends rearward, and when the ZMP position moves to the rear of the machine, the standing leg bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

In the ZMP behavior space control step, when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the torso during the two-leg supporting period, the ZMP position deviates from the center of the ZMP stable region. A deformation amount or a momentum of the robot is generated such that the position moves away from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position becomes the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. It is also possible to give a spatial distortion such that a deformation amount or a momentum of the robot toward the center of the robot is generated. Also,
When the floor reaction force is small in the traveling direction, a deformation amount or a momentum of the robot is generated such that the ZMP position deviates from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion may be applied such that the amount of robot deformation or the momentum such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region as the force increases.

In such a case, when the floor reaction force is small, the trunk portion bends inward when the ZMP position moves inside the machine body, and the trunk portion moves outward when the ZMP position moves outside the machine body. However, as the floor reaction force increases, the trunk bends outward when the ZMP position moves to the inside of the airframe, and the trunk moves inward when the ZMP position moves to the outside of the airframe. It is configured to bend. Also, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the airframe, and the trunk bends backward when the ZMP position moves rearward of the airframe. As the force increases, conversely, when the ZMP position moves to the front of the body, the trunk bends rearward, and when the ZMP position moves to the rear of the body, the trunk bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

In the ZMP behavior space control step, the first coordinate axis having a negative ZMP position toward the outside of the machine body and the amount of deformation of the robot or the ZMP position toward the center of the ZMP stable region. In the ZMP behavior space consisting of the second coordinate axis with the momentum in the positive direction, the deformation amount or the momentum of the robot has a maximum value in the negative region with respect to the standing leg in the first stage of the monopod support, and as the floor reaction force increases, Spatial distortion may be given to move the ZMP position having the maximum value of the deformation amount or the momentum in the positive direction.

In such a case, in the standing leg in the first half of the single-leg support, the bending amount decreases almost linearly with the moving amount of the ZMP position in the Y direction. When the floor reaction force is small, ZMP
When the position moves to the inside of the machine, the standing leg bends inward, and when the ZMP position moves to the outside of the machine, the standing leg bends to the outside, but the ZMP position increases as the floor reaction force increases. Even if the stance leg moves to the outside of the machine body, the stance leg does not easily bend to the outside.

In the ZMP behavior space control step, the first coordinate axis having the ZMP position in the forward direction of the machine body as the positive direction and the deformation amount of the robot or the ZMP position directed to the center of the ZMP stable region or In the ZMP behavior space consisting of the second coordinate axis with the momentum in the positive direction, the deformation amount or the momentum of the robot has a maximum value in the vicinity of the center of the ZMP stable region in the negative region with respect to the standing leg of the single-leg supporting period, In addition, a spatial distortion may be applied such that the change in the deformation amount or the momentum decreases as the floor reaction force increases.

In such a case, in the standing leg in the first half of the single-leg support, the bending amount decreases almost linearly with the moving amount of the ZMP position in the X direction. When the floor reaction force is small, ZMP
When the position moves to the front of the aircraft, the standing leg bends forward, and when the ZMP position moves to the rear of the aircraft, the standing leg bends backward, but as the floor reaction force increases, the ZMP position changes. The stance leg is difficult to bend regardless of whether it moves forward or backward.

In the ZMP behavior space control step, the ZMP position is set to Z when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the standing leg in the first stage of supporting the single leg.
The ZMP position becomes Z as it deviates from the center of the MP stable region.
Deformation or momentum of the robot is generated so as to move away from the center of the MP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. It is also possible to give a spatial distortion that causes a deformation amount or a momentum of the robot that moves toward the. Further, when the floor reaction force is small in the traveling direction, as the ZMP position deviates from the center of the ZMP stable region, a deformation amount or a momentum of the robot is generated such that the ZMP position deviates from the center of the ZMP stable region. As the floor reaction force increases, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Good. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

In such a case, when the floor reaction force is small, when the ZMP position moves to the outside of the machine body, the standing leg in the first leg of the single leg support bends outward, and when the ZMP position moves to the inside of the machine body, the standing leg moves. Bends inward, but as the floor reaction force increases, conversely, ZM
When the P position moves to the outside of the airframe, the standing leg bends inward, and when the ZMP position moves to the inside of the airframe, the standing leg bends outward. Further, when the floor reaction force is small, the standing leg bends forward when the ZMP position moves to the front of the aircraft, and the standing leg bends backward when the ZMP position moves to the rear of the aircraft. Conversely, as the force increases, when the ZMP position moves to the front of the aircraft, the standing leg bends rearward and the ZMP
When the position moves to the rear of the body, the standing leg bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

Further, in the ZMP behavior space control step, with respect to the torso in the first leg supporting period, when the floor reaction force is small in the direction orthogonal to the traveling direction, the ZMP position deviates from the center of the ZMP stable region. A deformation amount or a momentum of the robot is generated such that the position moves away from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position becomes the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. It is also possible to give a spatial distortion that causes a deformation amount or a momentum of the robot that moves toward the center of the. Further, when the floor reaction force is small in the traveling direction, as the ZMP position deviates from the center of the ZMP stable region, a deformation amount or a momentum of the robot is generated such that the ZMP position deviates from the center of the ZMP stable region. As the floor reaction force increases, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Good.

In such a case, when the floor reaction force is small, the trunk portion bends outward when the ZMP position moves to the outside of the machine body, and the trunk portion faces inward when the ZMP position moves to the inside of the machine body. However, as the floor reaction force increases, the trunk bends inward when the ZMP position moves to the outside of the fuselage, and the trunk moves outward when the ZMP position moves to the inside of the fuselage. It is configured to bend. Also, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the airframe, and the trunk bends backward when the ZMP position moves rearward of the airframe. As the force increases, conversely, when the ZMP position moves to the front of the body, the trunk bends rearward, and when the ZMP position moves to the rear of the body, the trunk bends forward. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

The second aspect of the present invention is a method of controlling a legged mobile robot having two or more movable legs, wherein the ZMP position where the pitch axis moment and the roll axis moment of the machine are zero. A step of defining a ZMP behavior space defined by the floor reaction force received from the floor surface of the airframe, a step of obtaining a ZMP stable position based on the definition of the defined ZMP behavior space, and a step of determining the ZMP stable position obtained. And a step of controlling the operation of the machine body based on the control method.

According to the legged mobile robot control method of the second aspect of the present invention, ZMP is adopted as a criterion for determining the stability of the posture, but it is stable in consideration of the deformation amount and the momentum of the robot body. It is possible to control the operation of the airframe having the ZMP existence space.

That is, the ZMP position is moved to the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region formed of the supporting polygon formed by the sole of the movable leg and the road surface. Spatial distortion can be given in advance to the ZMP behavior space so that the desired amount of deformation or momentum of the airframe is generated. As a result, even when the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against disturbance and the like.

The legged mobile robot control method according to the second aspect of the present invention further comprises the step of changing the definition of the ZMP behavior space according to the contact state between the legged mobile robot and the road surface. May be.

In such a case, the spatial strain applied to the ZMP behavior space can be dynamically controlled according to the contact situation with the road surface, such as when the floor reaction force received from the floor surface by the sole changes. In any situation, as the ZMP position deviates, the ZMP position is always moved to the center of the ZMP stable region so that the deformation amount or the momentum of the airframe is generated, and the attitude stability control of the aircraft is made easy. be able to.

In the step of defining the ZMP behavior space, the maximum points and // in the ZMP behavior space are defined.
Alternatively, the minimum point may be arbitrarily designated. Also,
The maximum point in the ZMP behavior space and /
Alternatively, the minimum point may be arbitrarily designated. Also,
The maximum point in the ZMP motion space and / or
Alternatively, the minimum point may be arbitrarily designated.

In such a case, when the robot performs legged work, it is possible to dynamically generate a ZMP behavior space having a spatial distortion in which stable posture control is easy according to a gait that changes from moment to moment. .

Further objects, features and advantages of the present invention are as follows.
It will be apparent from the embodiments of the present invention described later and the more detailed description based on the accompanying drawings.

[0070]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

A. Configuration of Robot FIGS. 3 and 4 show front and rear views of a "humanoid" or "humanoid" legged mobile robot 100 used in the practice of the present invention standing upright. Shows. As shown in the figure, the legged mobile robot 100 includes a trunk 1
01, the head 102, the left and right upper limbs 103, the left and right lower limbs 104 that perform legged movement, and the control unit 105 that totally controls the operation of the aircraft.

Each of the left and right lower limbs 104 is composed of a thigh, a knee joint, a shin, an ankle, and a foot, and they are connected by a hip joint at substantially the lowermost end of the trunk. Further, each of the left and right upper limbs is composed of an upper arm, an elbow joint, and a forearm,
The left and right lateral edges above the trunk are connected by shoulder joints. The head is connected to the center of the uppermost end of the trunk by a neck joint.

The control unit 105 controls the legged mobile robot 1
00 is a housing in which a controller (main control unit) that controls the drive of each joint actuator that constitutes 00 and external inputs from each sensor (described later), a power supply circuit, and other peripheral devices are mounted. The control unit may also include a communication interface and a communication device for remote operation. In the example shown in FIGS. 3 and 4, the legged mobile robot 10 is used.
0 wears the control part on his back,
The installation location of the control unit is not particularly limited.

The legged mobile robot 1 configured as described above
00 can realize bipedal locomotion by whole-body coordinated motion control by the control unit 105. Such bipedal walking is generally performed by repeating a walking cycle divided into the following operation periods. That is,

(1) Single leg support period with left leg with right leg lifted (2) Double leg support period with right leg grounded (3) Left leg with single leg support period with right leg (4) Left Both legs support period with the legs touching the ground

Walking control in the legged mobile robot 100 is realized by planning the target trajectory of the lower limb in advance and correcting the planned trajectory in each of the above periods. That is, in the two-leg support period, the correction of the lower limb trajectory is stopped, and the hip height is corrected to a constant value using the total correction amount for the planned trajectory. In the single-leg support period, a corrected trajectory is generated so that the corrected relative positional relationship between the ankle and the waist of the leg is returned to the planned trajectory. The specific correction is performed by interpolation calculation using a quintic polynomial so that the position, velocity, and acceleration are continuous in order to reduce the deviation with respect to ZMP.

FIG. 5 schematically shows the joint degree of freedom structure of the legged mobile robot 100. As shown in the figure, the legged mobile robot 100 connects an upper limb including two arms and a head 1, a lower limb composed of two legs for realizing a moving motion, and an upper limb and a lower limb. It is a structure having a plurality of limbs, which is composed of a trunk.

The neck joint that supports the head 1 is a neck joint yaw axis 2, a neck joint pitch axis 3, and a neck joint roll axis 4.
Have a degree of freedom.

Each arm has a shoulder joint pitch axis 8, a shoulder joint roll axis 9, an upper arm yaw axis 10, an elbow joint pitch axis 11, a forearm yaw axis 12, and a wrist joint pitch axis 13.
It is composed of a wrist joint roll shaft 14 and a hand portion 15. The hand portion 15 is actually a multi-joint / multi-degree-of-freedom structure including a plurality of fingers. However, the operation of the hand portion 15 is performed by the robot 10
Since 0 has little contribution to or influence on posture control or walking control, it is assumed in this specification that the degree of freedom is zero. Therefore,
Each arm has 7 degrees of freedom.

Further, the trunk has three degrees of freedom: trunk pitch axis 5, trunk roll axis 6, and trunk yaw axis 7.

Further, each leg constituting the lower limbs has a hip joint yaw axis 16, a hip joint pitch axis 17, a hip joint roll axis 18, a knee joint pitch axis 19, and an ankle joint pitch axis 2.
0, an ankle joint roll shaft 21, and a foot portion 22. The foot 22 of the human body is actually a structure including a multi-joint, multi-degree-of-freedom foot, but the foot of the legged mobile robot 100 according to this embodiment has zero degrees of freedom. Therefore,
Each leg has 6 degrees of freedom.

In summary, the legged mobile robot 100 according to this embodiment has a total of 3 + 7 × 2 + 3.
It will have + 6 × 2 = 32 degrees of freedom. However, the legged mobile robot 100 for entertainment is not necessarily limited to 32 degrees of freedom. It goes without saying that the degree of freedom, that is, the number of joints, can be appropriately increased or decreased in accordance with design / manufacturing constraints, required specifications, and the like.

Each degree of freedom of the legged mobile robot 100 as described above is actually implemented by using an actuator. It is preferable that the actuator be small and lightweight in view of demands such as eliminating extra bulges in appearance and approximating the shape of a natural human body, and performing posture control for an unstable structure such as bipedal walking. . In this embodiment, a small AC servo of the type directly connected to the gear and having a servo control system integrated into a motor unit and built in a motor unit.
We decided to install an actuator. An AC servo actuator of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-299970 (Japanese Patent Application No. 11-33386), which has already been assigned to the present applicant.

FIG. 6 schematically shows the control system configuration of the legged mobile robot 100 according to this embodiment.
As shown in the figure, the control system includes a thought control module 200 that dynamically reacts to user input and controls emotional judgment and emotional expression, and motion control that controls joint whole body motion of a robot such as driving joint actuators. Module 30
It is composed of 0 and.

The thought control module 200 is a CPU (Central Processing Unit) that executes arithmetic processing relating to emotional judgment and emotional expression.
Processing Unit) 211, RAM (Random Access M)
emory) 212, ROM (Read Only Memory) 213,
And external storage device (hard disk drive, etc.)
This is an independent drive type information processing device configured by 214 and capable of performing self-contained processing within a module.

The thought control module 200 is a CPU (Central Processing Unit) that executes arithmetic processing relating to emotional judgment and emotional expression.
Processing Unit) 211, RAM (Random Access M)
emory) 212, ROM (Read Only Memory) 213,
And external storage device (hard disk drive, etc.)
It is an independent information processing device configured by 214 and capable of performing self-contained processing within the module.

In the thought control module 200, the visual data input from the image input device 251 and the voice input device 2 are input.
The current emotions and intentions of the legged mobile robot 100 are determined according to stimuli from the outside world, such as auditory data input from 52. Furthermore, the motion control module 30 is configured to execute an action or action sequence (behavior) based on a decision, that is, a motion of a limb.
Issue a command to 0.

One of the motion control modules 300 is a central processing unit (CPU) that controls the whole body coordinated motion of the robot 100.
Processing Unit) 311 and RAM (Random Access M)
emory) 312, ROM (Read Only Memory) 313,
And external storage device (hard disk drive, etc.)
314 is an independent drive type information processing device capable of performing self-contained processing within a module. The external storage device 314 can store, for example, a walking pattern calculated offline, a ZMP target trajectory, and other action plans.

The motion control module 300 includes joint actuators (see FIG. 5) that realize joint degrees of freedom dispersed in the whole body of the robot 100, a posture sensor 351 that measures the posture and inclination of the trunk. Ground contact confirmation sensors 352 and 3 for detecting the leaving or landing of the left and right soles
53, various devices such as a power supply control device for managing the power supply such as a battery are connected via the bus interface 301.

Thought control module 200 and motion control module 300 are built on a common platform, and bus interfaces 201 and 301 are provided between them.
Are interconnected via.

The motion control module 300 controls the whole body coordinated motion by each joint actuator so as to embody the action instructed by the thought control module 200. That is, the CPU 311 takes out an operation pattern according to the action instructed from the thought control module 200 from the external storage device 314, or internally generates an operation pattern. Then, the CPU 311 sets the foot movement, the ZMP trajectory, the trunk movement, the upper limb movement, the waist horizontal position, the height, and the like according to the designated movement pattern, and
Command values for instructing operations according to these settings are transferred to each joint actuator.

Furthermore, the motion control module 300 determines how much the behavior as intended decided in the thought control module 200 is expressed, that is, the processing situation.
It is designed to be returned to the thought control module 200.

CPU 31 in motion control module 300
1 indicates the robot 10 according to the output signal of the posture sensor 351.
A legged mobile robot by detecting the posture and inclination of the trunk portion of 0 and detecting whether each movable leg is a free leg or a standing leg by the output signals of the ground contact confirmation sensors 352 and 353. 100 whole body coordinated movements can be adaptively controlled.

Further, the CPU 311 uses ZMP as a discriminant criterion for posture stability to perform arithmetic processing for controlling the posture and movement of the machine body. In this embodiment, the CPU 311 is the ZM of the machine body.
P behavior space is defined, ZMP stable position is obtained based on the definition of ZMP behavior space, and ZMP position is always ZM.
The attitude and movement of the airframe are controlled so as to move toward the center of the P stable region. Further, by sequentially redefining the ZMP behavior space according to the contact state with the road surface, the ZMP position is always relocated to the center of the ZMP stable region. By giving it to the behavior space, the attitude stability control of the airframe can be maintained in an easy state. ZMP
The behavior space and the mechanism of spatial distortion will be explained in detail in the next section.

B. Robot posture control Many legged mobile robots use ZMP (Zero Moment Poin).
t) is adopted as the criterion for determining the walking stability.

B-1. The stability determination criterion based on the ZMP behavior space ZMP is that gravity and inertial force from the walking system to the road surface, and these moments balance with the floor reaction force as a reaction from the road surface to the walking system and the floor reaction force moment. It is based on the d'Alembert's principle, and "at every moment of walking, if the ZMP exists inside the supporting polygon formed by the foot and the road surface, and if the force that the robot pushes on the road surface acts. , The robot can walk stably without tipping (rotation of the machine).

The posture stability control of the robot using ZMP as the stability determination criterion is to search for a point where the pitch and roll moments are zero inside the supporting polygon formed by the foot contact point and the road surface. Use as a base. According to the bipedal walking pattern generation based on the ZMP stability determination criterion, there is an advantage that it is possible to set a foot landing point in advance and it is easy to consider a kinematic constraint condition of the toes according to a road surface shape. . Further, using ZMP as the stability determination criterion means that the trajectory is treated as the target value for motion control, not the force, so that technical feasibility is enhanced.

However, as already described in the section of "Prior Art", the ZMP standard is only a standard applicable when it can be assumed that the body and road surface of the robot are as close as possible to a rigid body. That is, when it cannot be assumed that the robot or the road surface is as close as possible to a rigid body, for example, the force acting on the ZMP (translation) by the robot moving at high speed and the impact force at the time of switching the standing point become large, and If deformation or motion occurs, unless the amount of deformation of the robot with respect to the applied force is properly managed, the space itself in which the ZMP exists becomes unstable, and the posture of the robot is temporarily changed to ZMP. Even if the stability determination criterion is satisfied, the posture of the robot becomes unstable because it takes an unstable ZMP position.

Further, the posterior control in which the correction control is applied only when the ZMP position deviates from the ZMP stable region cannot respond at a sufficient speed, and the robustness against disturbances is not high.

Therefore, in this embodiment, a robot system configuration having a stable ZMP behavior space is adopted in consideration of the deformation amount and the momentum of the robot body. The ZMP behavior space is defined by the ZMP position and the floor reaction force that the aircraft receives from the floor surface. However, in the present embodiment, a predetermined distortion is generated in the ZMP behavior space so that a deformation amount and a momentum that stabilize the aircraft are generated. The operation control of the airframe is given in advance.

Therefore, instead of starting the posterior correction control only after the movement amount of the ZMP position exceeds a predetermined area, the body motion is controlled in advance so as to give a spatial distortion that stabilizes the robot posture. Therefore, even if the control mechanism of the airframe does not have a sufficient response speed, it is possible to obtain high robustness against a disturbance or the like.

Here, whether the deformation amount (or momentum) of the robot is positive or negative is a direction in which the negative direction causes a spatial distortion to move the ZMP to the edge of the stable region, and the positive direction is the ZMP.
It should be noted that this is the direction in which a spatial distortion that tends to move to the center of the stable region is generated.

FIG. 7 shows an example of the structure of the ZMP behavior space showing the relationship between the amount of deformation or momentum of the robot and the ZMP position.

In the example shown in the figure, the ZMP behavior space is composed of a non-linear curve represented by a parabola or an arc. Although not shown, it may include discontinuities or inflection points.

When the ZMP position is in the vicinity of the center of the ZMP stable region, a large amount of deformation (or momentum) does not occur in the robot, and therefore the robot does not lose the posture stability of the machine body as it is.

Further, as the ZMP position moves away from the center of the ZMP stable region, the deformation amount (or momentum) of the robot increases in the positive direction. Along with this, a function of causing a spatial distortion that tends to move the ZMP to the center of the stable region is exerted, so that it is also easy to maintain the attitude stability of the airframe.

FIG. 8 shows another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

In the example shown in the figure, the ZMP behavior space is Z
It is composed of a linear straight line near the center of the MP stable region and a non-linear curve connected at both left and right ends thereof, and includes a discontinuity between the straight line and the curve. Although not shown, an inflection point may be included.

When the ZMP position is near the center of the ZMP stable area, the robot is flat, that is, a large amount of deformation (or momentum) does not occur in the robot. Therefore, the robot does not lose the posture stability of the machine body as it is.

When the ZMP position deviates from the flat area, the deformation amount (or momentum) of the robot rapidly increases in the positive direction. Along with this, an action that causes a spatial distortion that attempts to move the ZMP to the center of the stable region is exerted, so that it becomes easy to maintain the attitude stability of the airframe without any subsequent motion control.

Further, FIG. 9 shows still another example of the ZMP behavior space showing the relation between the deformation amount or the momentum of the robot and the ZMP position.

In the example shown in the figure, the ZMP behavior space is formed by connecting a plurality of linear straight lines and includes a plurality of discontinuities.

When the ZMP position is substantially near the center of the ZMP stable region, the deformation amount (or momentum) of the robot gradually increases in the positive direction in accordance with the distance from the ZMP center position. A space is formed.
Further, when the distance from the ZMP center position reaches a predetermined value, the amount of deformation (or momentum) of the robot rapidly increases in the positive direction in accordance with the distance from the ZMP center position. The ZMP behavior space is formed by a straight line.

In the illustrated example, when the ZMP position is near the center of the ZMP stable region, there is a relatively weak action that causes a spatial distortion that tends to move the ZMP to the center of the stable region, and the ZMP position is at the ZMP center. At a point apart from a certain distance from the position, there is a relatively strong action that causes spatial distortion that tends to move the ZMP to the center of the stable region. Therefore, it becomes easy to maintain the attitude stability of the airframe even without the posterior motion control.

Further, FIG. 10 shows still another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

In the example shown in the figure, the ZMP behavior space is composed of a non-linear curve and has a local minimum point at the approximate center of the ZMP stable region and a local maximum point near the boundary of the ZMP stable region. There is.

In such a ZMP behavior space, Z
When the MP position is inside the left and right maxima, the amount of deformation (or momentum) of the robot depends on the distance from the ZMP center position.
Increases in the positive direction, so that the attitude stability mode in which the attitude stability of the airframe is easily maintained is formed.

On the other hand, when the ZMP position is outside the maximum points on the left and right, the deformation amount (or momentum) of the robot gradually decreases, and the spatial distortion for moving the ZMP to the center of the stable region decreases. Go. As a result, the aircraft tends to lose its posture stability and forms a fall mode.

Further, FIG. 11 shows still another example of the ZMP behavior space showing the relationship between the ZMP position and the deformation amount or the momentum of the robot.

In the example shown in the figure, a plurality of linear straight lines are connected to each other and a plurality of discontinuous points are included. Near the center of the ZMP stable region, the ZMP behavior space is formed by a straight line with a relatively gentle inclination in which the deformation amount (or momentum) of the robot gradually increases in the negative direction according to the distance from the ZMP center position. Further, it becomes flat when the distance from the ZMP center position reaches a predetermined value.

In the ZMP behavior space in this case, the deformation amount (or momentum) of the robot acts only in the negative direction at any position within the ZMP stable region, and when the ZMP position is separated from the central position by a certain amount or more, The spatial strain that tries to move the outside of the stable region becomes a constant amount.
Therefore, the ZM is unstable but relatively easy to control.
It can be said that it is a P behavior space.

B-2. Control of the ZMP behavior space By controlling the ZMP behavior space of the robot, a spatial distortion that causes a deformation amount or a momentum of the airframe to move the ZMP position to the center of the ZMP stable region is given, and Posture stability control can be maintained in an easy state. In this section, a method of controlling the ZMP behavior space for each operation phase will be described by taking as an example a case where a two-legged mobile robot performs a normal walking operation.

FIGS. 12 and 13 show the Y direction (direction orthogonal to the traveling direction) and X in the left standing leg in the latter half of the single-leg supporting period.
An example of a method of controlling the ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 12, when the floor reaction force is small, the ZMP behavior space in the left standing leg in the latter half of the single-leg supporting period has a negative direction, that is, a ZMP position as the ZMP position deviates from the center of the ZMP stable region. Deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the deformation or momentum of the robot occurs when the ZMP position moves toward the outside of the machine body. It gives a spatial distortion that disappears. As a result, in the left standing leg as the supporting leg, the bending amount decreases almost linearly with the moving amount of the ZMP position in the Y direction. When the floor reaction force is small,
The left standing leg bends inward when the ZMP position moves inside the aircraft, and the left standing leg bends outward when the ZMP position moves outside the aircraft,
As the floor reaction force increases, the left standing leg becomes difficult to bend outward even if the ZMP position moves to the outside of the aircraft.

When the total weight of the robot is 100, the floor reaction force is "large" when the floor reaction force is 100 or more. When the floor reaction force is about 20 to 100, the floor reaction force is The term "medium" is used, and the floor reaction force is "small" when the floor reaction force is 20 or less (the same applies hereinafter). However, these are only a guideline and may be changed depending on the robot body structure and weight. In particular, if you express qualitatively that "the floor reaction force is small", it is
It is the floor reaction force that is applied to the other leg while supporting the whole body with one leg.

Further, as shown in FIG. 13, the ZMP behavior space in the X direction in the left standing leg in the latter stage of the monopod support period is ZMP.
As the position deviates from the center of the ZMP stable region, the amount of robot deformation or momentum that moves in the negative direction, that is, the direction in which the ZMP position deviates from the center of the ZMP stable region, occurs, but occurs as the floor reaction force increases. Spatial distortion is applied so that the amount of deformation or momentum that gradually decreases is gradually reduced. As a result, in the left standing leg as the supporting leg, the bending amount decreases almost linearly with the moving amount of the ZMP position in the X direction. When the floor reaction force is small,
The left standing leg bends forward when the ZMP position moves to the front of the aircraft, and the left standing leg bends backward when the ZMP position moves to the rear of the aircraft.
As the floor reaction force increases, the left standing leg becomes difficult to bend regardless of whether the ZMP position moves forward or backward.

14 and 15, the Y direction (direction orthogonal to the traveling direction) and the X direction of the left standing leg in the latter half of the single-leg supporting period are shown in FIGS.
An example of the control method of the ideal ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 14, the ideal ZMP behavior space in the Y direction in the left standing leg in the latter half of the single-leg support period is in the negative direction as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. ZMP position is ZMP
The amount of deformation or momentum of the robot is generated so as to move away from the center of the stable region, but as the floor reaction force increases, the positive direction, that is, the ZMP position becomes the ZMP stable region, as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion that causes the amount of deformation or momentum of the robot toward the center of the robot is given. As a result, when the floor reaction force is small, when the ZMP position moves to the inside of the aircraft, the left standing leg bends inward and Z
When the MP position moves outside the aircraft, the left standing leg bends outward, but as the floor reaction force increases, conversely, when the ZMP position moves inside the aircraft, the left standing leg bends outward and When the ZMP position moves to the outside of the aircraft, the left standing leg bends inward.

Further, as shown in FIG. 15, the ideal ZMP behavior space in the X direction in the left standing leg in the latter half of the single-leg support period is as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. A deformation amount or a momentum of the robot occurs in a negative direction, that is, a direction in which the ZMP position deviates from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position deviates from the center of the ZMP stable region. Along with this, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region in the positive direction. As a result, when the floor reaction force is small, the left standing leg bends forward when the ZMP position moves toward the front of the aircraft, and the left standing leg bends backward when the ZMP position moves toward the rear of the aircraft. Conversely, as the reaction force increases, when the ZMP position moves to the front of the aircraft, the left standing leg bends backward and the ZM
When the P position moves to the rear of the body, the left standing leg bends forward.

16 and 17, the Y direction (direction orthogonal to the traveling direction) and the X direction in the trunk of the latter half of the monopod supporting period are shown.
An example of the control method of the ideal ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 16, the ideal ZMP behavior space in the Y direction in the trunk in the latter half of the single-leg supporting period is in the negative direction as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. ZMP position is ZMP
The amount of deformation or momentum of the robot is generated so as to move away from the center of the stable region, but as the floor reaction force increases, the positive direction, that is, the ZMP position becomes the ZMP stable region, as the ZMP position deviates from the center of the ZMP stable region. There is a spatial distortion that causes deformation or momentum of the robot that moves toward the center of the robot. As a result, when the floor reaction force is small, when the ZMP position moves inside the machine body, the trunk bends inward and Z
When the MP position moves to the outside of the aircraft, the trunk bends outward, but as the floor reaction force increases, conversely, when the ZMP position moves to the inside of the aircraft, the trunk bends outward and When the ZMP position moves to the outside of the body, the trunk portion bends inward.

Further, as shown in FIG. 17, the ideal ZMP behavior space in the X direction in the trunk in the latter half of the monopod support period is as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. A deformation amount or a momentum of the robot occurs in a negative direction, that is, a direction in which the ZMP position deviates from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position deviates from the center of the ZMP stable region. Along with this, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region in the positive direction. As a result, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the aircraft, and the trunk bends backward when the ZMP position moves backward of the aircraft. As the reaction force increases, conversely, when the ZMP position moves to the front of the aircraft, the trunk bends backward and ZM
When the P position moves to the rear of the body, the trunk portion bends forward.

FIGS. 18 and 19 show examples of the control method of the ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) and in the X direction (traveling direction) of the left standing leg in the two-leg supporting period.

As shown in FIG. 18, in the ZMP behavior space in the Y direction in the left standing leg during the two-leg supporting period, the ZMP position is ZM.
As it deviates from the center of the P stable region, the negative direction, that is, Z
A deformation amount or momentum of the robot is generated such that the MP position moves away from the center of the ZMP stable region, but as the floor reaction force increases, the deformation amount or momentum generated in the airframe gradually decreases. It gives a spatial distortion. Since it is supported by two legs in the two-leg supporting period, the ZMP behavior space has higher rigidity and less spatial distortion than the single-leg supporting period in which one leg is supporting. As a result, ZM
The amount of bending of the left standing leg decreases almost linearly with the amount of movement of the P position in the Y direction. When the floor reaction force is small, the left standing leg bends inward when the ZMP position moves inside the airframe, and the left standing leg bends outward when the ZMP position moves outside the airframe. Becomes larger, the left standing leg becomes more difficult to bend regardless of whether the ZMP position moves inward or outward. In the two-leg support period, the legs are supported by two legs, so the amount of bending of the legs is smaller than that in the single-leg support period in which one leg is supported.

Further, as shown in FIG. 19, the ZMP behavior space in the X direction in the left standing leg during the two-leg support period is in the negative direction as the ZMP position deviates from the center of the ZMP stable region, that is, the ZMP position deviates from the center of the ZMP stable region. A deformation amount or a momentum of the robot is generated so as to move toward the direction of deviating, but the deformation amount or the momentum generated in the airframe is gradually reduced as the floor reaction force increases. In the two-leg support period, the ZMP behavior space has higher rigidity and less spatial distortion than in the single-leg support period in which one leg is used to support the two-leg support period. As a result,
The amount of bending of the left standing leg decreases almost linearly with the amount of movement of the ZMP position in the X direction. When the floor reaction force is small, ZMP
When the position moves to the front of the aircraft, the left standing leg bends forward, and when the ZMP position moves to the rear of the aircraft, the left standing leg bends backward, but as the floor reaction force increases, the ZMP position changes. The left standing leg becomes difficult to bend regardless of whether it moves forward or backward.
In the two-leg support period, the legs are supported by two legs, so the amount of bending of the legs is smaller than that in the single-leg support period in which one leg is supported.

FIG. 20 and FIG. 21 respectively show examples of the ideal control method of the ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) and the X direction (travel direction) in the left standing leg during the two-leg supporting period. There is.

As shown in FIG. 20, when the floor reaction force is small, the ideal ZMP behavior space in the left standing leg in the two-leg support period is in the negative direction, that is, ZMP, as the ZMP position deviates from the center of the ZMP stable region. A deformation amount or a momentum of the robot is generated such that the position deviates from the center of the ZMP stable region, but as the floor reaction force increases, conversely, as the ZMP position deviates from the center of the ZMP stable region, the positive direction, that is, Spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region. Since it is supported by two legs in the two-leg supporting period, the ZMP behavior space has higher rigidity and less spatial distortion than the single-leg supporting period in which one leg is supporting. As a result, when the floor reaction force is small, Z
When the MP position moves to the inside of the aircraft, the left standing leg bends toward the inside, and when the ZMP position moves to the outside of the aircraft, the left standing leg bends toward the outside, but as the floor reaction force increases, conversely, When the ZMP position moves to the inside of the machine, the left standing leg bends outward, and when the ZMP position moves to the outside of the machine, the left standing leg bends to the inside. 2 for both legs
Since it is supported by the legs of a book, the amount of bending of the legs is smaller than that in the single-leg support period when the legs are supported by one leg.

Further, as shown in FIG. 21, the ideal ZMP behavior space in the X direction in the left standing leg during the two-leg support period is negative as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. That is, the ZMP position is Z
Deformation or momentum of the robot is generated so as to move away from the center of the MP stable region, but as the floor reaction force increases, conversely, as the ZMP position deviates from the center of the ZMP stable region, the positive direction, that is, the ZMP position. Is Z
Spatial distortion is generated such that a deformation amount or a momentum of the robot toward the center of the MP stable region is generated.
Since it is supported by two legs during the two-leg supporting period, the rigidity of the ZMP behavior space is higher than that in the single-leg supporting period in which it is supported by one leg, and the spatial distortion is small. As a result, when the floor reaction force is small, the left standing leg bends forward when the ZMP position moves toward the front of the aircraft, and the left standing leg bends backward when the ZMP position moves toward the rear of the aircraft. As the reaction force increases, conversely, when the ZMP position moves to the front of the aircraft, the left standing leg bends backward, and when the ZMP position moves to the rear of the aircraft, the left standing leg bends forward. . In the two-leg support period, the legs are supported by two legs, so the amount of bending of the legs is smaller than that in the single-leg support period in which one leg is supported.

22 and 23 show examples of the ideal control method of the ZMP behavior space in the Y direction (direction orthogonal to the advancing direction) and the X direction (direction of advancing) in the torso during both-leg support. There is.

As shown in FIG. 22, when the floor reaction force is small, the ideal ZMP behavior space in the trunk in the trunk during the two-leg supporting period becomes negative, that is, ZMP, as the ZMP position deviates from the center of the ZMP stable region. A deformation amount or a momentum of the robot is generated such that the position deviates from the center of the ZMP stable region, but as the floor reaction force increases, conversely, as the ZMP position deviates from the center of the ZMP stable region, the positive direction, that is, Spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region. Since it is supported by two legs in the two-leg supporting period, the ZMP behavior space has higher rigidity and less spatial distortion than the single-leg supporting period in which one leg is supporting. As a result, when the floor reaction force is small, Z
When the MP position moves to the inside of the airframe, the trunk bends inward, and when the ZMP position moves to the outside of the airframe, the trunk bends to the outside, but as the floor reaction force increases, conversely, When the ZMP position moves inside the body, the trunk bends outward, and when the ZMP position moves outside the fuselage, the trunk bends inward.

Further, as shown in FIG. 23, the ideal ZMP behavior space in the X direction in the torso during the two-leg support period is negative as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. That is, the ZMP position is Z
Deformation or momentum of the robot is generated so as to move away from the center of the MP stable region, but as the floor reaction force increases, conversely, as the ZMP position deviates from the center of the ZMP stable region, the positive direction, that is, the ZMP position. Is Z
Spatial distortion is generated such that a deformation amount or a momentum of the robot toward the center of the MP stable region is generated.
Since it is supported by two legs in the two-leg supporting period, the ZMP behavior space has higher rigidity and less spatial distortion than the single-leg supporting period in which one leg is supporting. As a result, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the aircraft, and the trunk bends backward when the ZMP position moves backward of the aircraft. As the reaction force increases, conversely, when the ZMP position moves to the front of the aircraft, the trunk bends backward, and when the ZMP position moves to the rear of the aircraft, the trunk bends forward. .

24 and 25, the Y direction (direction orthogonal to the traveling direction) and the X direction of the left standing leg in the first half of the single-leg supporting period are shown.
An example of a method of controlling the ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 24, the ZMP behavior space in the Y direction in the right standing leg in the first half of the single-leg supporting period has a negative direction, that is, a ZMP position as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. Deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the deformation or momentum of the robot occurs when the ZMP position moves toward the outside of the machine body. It gives a spatial distortion that disappears. As a result, in the right standing leg as the supporting leg, the bending amount decreases almost linearly with the movement amount of the ZMP position in the Y direction. When the floor reaction force is small,
The right standing leg bends inward when the ZMP position moves inside the aircraft, and the right standing leg bends outward when the ZMP position moves outside the aircraft,
As the floor reaction force increases, even if the ZMP position moves to the outside of the machine body, the right standing leg becomes difficult to bend outward.

Further, as shown in FIG. 25, the ZMP behavior space in the X direction in the right standing leg in the first half of the monopod supporting period is ZMP.
As the position deviates from the center of the ZMP stable region, the amount of robot deformation or momentum that moves in the negative direction, that is, the direction in which the ZMP position deviates from the center of the ZMP stable region, occurs, but occurs as the floor reaction force increases. Spatial distortion is applied so that the amount of deformation or momentum that gradually decreases is gradually reduced. As a result, in the right standing leg as the supporting leg, the amount of bending decreases almost linearly with the amount of movement of the ZMP position in the X direction. When the floor reaction force is small,
The right standing leg bends forward when the ZMP position moves to the front of the aircraft, and the right standing leg bends backward when the ZMP position moves to the rear of the aircraft.
As the floor reaction force increases, the right standing leg becomes difficult to bend regardless of whether the ZMP position moves forward or backward.

26 and 27, in the Y direction (direction orthogonal to the traveling direction) and X in the right standing leg in the first half of the single-leg supporting period.
An example of the control method of the ideal ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 26, the ideal ZMP behavior space in the Y direction in the right standing leg in the first half of the single-leg support period is negative in the negative direction as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. ZMP position is ZMP
The amount of deformation or momentum of the robot is generated so as to move away from the center of the stable region, but as the floor reaction force increases, the positive direction, that is, the ZMP position becomes the ZMP stable region, as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion that causes the amount of deformation or momentum of the robot toward the center of the robot is given. As a result, when the floor reaction force is small and the ZMP position moves to the outside of the aircraft, the right standing leg bends outward and Z
The right standing leg bends inward when the MP position moves to the inside of the aircraft, but as the floor reaction force increases, conversely, the right standing leg bends toward the inside when the ZMP position moves to the outside of the aircraft. When the ZMP position moves inside the body, the right standing leg bends outward.

Further, as shown in FIG. 27, the ideal ZMP behavior space in the X direction in the right standing leg in the first half of the monopod support period is as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. A deformation amount or a momentum of the robot occurs in a negative direction, that is, a direction in which the ZMP position deviates from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position deviates from the center of the ZMP stable region. Along with this, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region in the positive direction. As a result, when the floor reaction force is small, the right standing leg bends forward when the ZMP position moves to the front of the aircraft and the right standing leg bends backward when the ZMP position moves to the rear of the aircraft. As the reaction force increases, conversely, when the ZMP position moves forward of the aircraft, the right standing leg bends backward and ZM
When the P position moves to the rear of the body, the right standing leg bends forward.

28 and 29, the Y direction (the direction orthogonal to the traveling direction) and the X direction in the trunk of the single leg supporting period are shown.
An example of the control method of the ideal ZMP behavior space in the direction (traveling direction) is shown.

As shown in FIG. 28, the ideal ZMP behavior space in the Y direction in the torso during the first half of the monopod support period is negative in the negative direction as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. ZMP position is ZMP
The amount of deformation or momentum of the robot is generated so as to move away from the center of the stable region, but as the floor reaction force increases, the positive direction, that is, the ZMP position becomes the ZMP stable region, as the ZMP position deviates from the center of the ZMP stable region. Spatial distortion that causes the amount of deformation or momentum of the robot toward the center of the robot is given. As a result, when the floor reaction force is small, when the ZMP position moves to the outside of the machine body, the trunk bends outward and Z
When the MP position moves inside the airframe, the trunk bends inward, but as the floor reaction force increases, conversely, when the ZMP position moves outside the airframe, the trunk bends inward. When the ZMP position moves to the inside of the body, the trunk portion bends outward.

Further, as shown in FIG. 29, the ideal ZMP behavior space in the X direction in the trunk during the first half of the monopod support period is as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small. A deformation amount or a momentum of the robot occurs in a negative direction, that is, a direction in which the ZMP position deviates from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position deviates from the center of the ZMP stable region. Along with this, a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated such that the ZMP position moves toward the center of the ZMP stable region in the positive direction. As a result, when the floor reaction force is small, the trunk bends forward when the ZMP position moves forward of the aircraft, and the trunk bends backward when the ZMP position moves backward of the aircraft. As the reaction force increases, conversely, when the ZMP position moves to the front of the aircraft, the trunk bends backward and ZM
When the P position moves to the rear of the body, the trunk portion bends forward.

In the process of legged work, the legged mobile robot
The ZMP behavior space is defined by sequentially repeating the operation phases of the left leg single-leg supporting period, the left leg grounding both legs supporting period, the right leg single leg supporting period, and the right leg grounding both legs supporting period. By sequentially switching between the ZMP position and the ZMP position in any operation phase, a space distortion that causes a deformation amount or a momentum of the airframe that always attempts to move to the ZMP stable region is formed, and thus the attitude of the airframe is increased. The stable control can be maintained in an easy state.

C. ZMP Behavior Space Control System In the present embodiment, the ZMP is used in the motion control module 300 as a discriminant criterion for posture stability to control the posture and motion of the body. At this time, the ZMP behavior space of the airframe is defined, the ZMP stable position is obtained based on the definition of the ZMP behavior space, and the attitude and motion of the airframe are controlled so that the ZMP position always faces the center of the ZMP stable region. . Further, by sequentially redefining the ZMP behavior space according to the contact state with the road surface, the ZMP position is always relocated to the center of the ZMP stable region. By giving it to the behavior space, the posture stability control of the airframe can be maintained in an easy state.

In this section, the configuration of the control system for the ZMP behavior space will be described in detail.

FIG. 30 schematically shows a functional configuration of the ZMP behavior space control system 500. The control system 500 is actually a motion control module 300.
The CPU 311 therein implements a predetermined control program.

As shown in the figure, the ZMP behavior space control system 500 is composed of a ZMP behavior space definition unit 501 and a stable point calculation unit 502.

The ZMP behavior space definition unit 501 inputs the target value concerning the attitude of the machine body and the state value of the actual machine, and
Define the behavior space. In the defined ZMP behavior space,
Spatial distortion is formed such that the ZMP position is moved to the center of the ZMP stable region and the amount of deformation or momentum of the airframe is generated.

The target value is, for example, the rotation angle, angular velocity, angular acceleration, etc. of each joint actuator calculated from the planned trajectory. The state value of the actual machine is the rotation angle of the joint output from the encoder arranged in each joint actuator,
These are the angular velocity, the angular acceleration, other sensor inputs on the machine body, the ZMP actual measurement value, and the like.

The ZMP behavior space is defined, for example, by the following equation.

[0159]

[Equation 1]

Here, the vector T is a target value obtained from a planned trajectory or the like. Further, the matrices B, C, and D are matrices for spatial conversion.

However, the definition formula of the above ZMP behavior space is
The concept of the ZMP behavior space as described in the section B is described in the simplest form, and the gist of the present invention is not limited to this. Further, although the above equation is configured by adding the respective terms linearly independently, it is preferable to calculate in consideration of the interference term.

In this embodiment, the ZMP behavior space definition unit 5
In 01, the definition of the ZMP behavior space is dynamically switched according to the contact state with the road surface. For example, in a legged mobile robot, in the course of legged work, there are single-leg support periods with the left leg, double-leg support periods with the left leg grounded, single-leg support periods with the right leg, and double-leg support periods with the right leg grounded. The phases are repeated in order, but the contact situation with the road surface changes dramatically for each operation phase. Therefore, by sequentially switching the definition of the ZMP behavior space, in any operation phase, a spatial distortion that always causes the deformation amount or the momentum of the airframe to move the ZMP position to the center of the ZMP stable region is formed. To do so.

The stable point calculation unit 502 obtains the stable point by second-order differentiating the above-described ZMP behavior space definition equation. A command value for each joint actuator is generated based on the calculated stable point, and the operation of the machine can be servo-controlled. As a result, spatial distortion is realized such that the ZMP position moves to the center of the ZMP stable region.

According to this embodiment, the ZMP behavior space of the robot can be arbitrarily defined by the description of the control program executed by the CPU 311 in the motion control module 300.

For example, the maximum point and / or the minimum point in the ZMP behavior space may be arbitrarily designated. Further, the maximum point and / or the minimum point in the ZMP behavior space may be arbitrarily designated at any time. Further, the maximum point and / or the minimum point in the ZMP behavior space may be arbitrarily designated according to the supporting state of the leg such as the latter half of the single leg support period, the both legs support period, the first leg support period.

As described above, by setting the maximum point or the minimum point in the ZMP stable region, the space where the stable posture control can be easily performed according to the gait that changes from moment to moment when the robot performs legged work. A ZMP behavior space with distortion can be dynamically generated.

In each of the above-mentioned embodiments of the present invention,
The ZMP behavior space is defined by the ZMP position and the floor reaction force. However, in addition to the ZMP position and the floor reaction force, the ZMP behavior space is defined by further adding a component of the external force propulsion direction and its magnitude to the airframe. You can also

[Supplement] The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the scope of the present invention.

The subject matter of the present invention is not necessarily limited to products called “robots”. That is, as long as it is a mechanical device that performs a motion similar to a human motion by using an electric or magnetic action, even if it is a product belonging to another industrial field such as a toy, the present invention is similarly applied. Can be applied.

In short, the present invention has been disclosed in the form of exemplification, and the contents of this specification should not be construed in a limited manner. To determine the gist of the present invention,
The claims section mentioned at the beginning should be taken into consideration.

[0171]

As described above in detail, according to the present invention,
It is possible to provide an excellent control method for a legged mobile robot capable of suitably performing posture stability control of a body during legged work while using so-called ZMP (Zero Moment Point) as a stability determination criterion.

Further, according to the present invention, there is provided an excellent legged mobile robot control method capable of suitably carrying out posture stability control of an airframe while using the ZMP stability discrimination criterion at a relatively slow sampling period. be able to.

Further, according to the present invention, in order to autonomously continue stable dynamic walking in a human living environment, it is possible to control a ZMP behavior space given a spatial distortion in consideration of ZMP position stability. It is possible to provide an excellent legged mobile robot control method capable of performing the above.

According to the present invention, the ZMP behavior space defined by the ZMP position and the floor reaction force received by the airframe from the floor surface is defined, and the ZMP stable position is obtained based on the definition of the ZMP behavior space. A command value for keeping the posture stable can be issued to each movable part. In addition, depending on the contact situation with the road surface, Z
Dynamically controlling the spatial distortion applied to the MP behavior space so that the ZMP position is always displaced to the center of the ZMP stable region so that the deformation amount or the momentum of the airframe is generated, and the attitude stability control of the airframe is facilitated. Can be in a state.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a ZMP position and a deformation amount (or a momentum) of a robot (that is, a ZMP behavior space of the robot) in the case of an ideal model in which a robot or a road surface is as close to a rigid body as possible.

FIG. 2 is a diagram showing a relationship between a ZMP position and a deformation amount (or a momentum) of the robot (that is, a ZMP behavior space of the robot) when the robot is not actually a rigid body.

FIG. 3 is a diagram showing a state in which a “humanoid” or “humanoid” legged mobile robot 100 used for carrying out the present invention is upright as viewed from the front.

FIG. 4 is a diagram showing a state in which a “humanoid” or “humanoid” legged mobile robot 100 used for implementing the present invention is upright and viewed from the rear.

5 is a diagram schematically showing a joint degree-of-freedom configuration included in the legged mobile robot 100. FIG.

FIG. 6 is a legged mobile robot 1 according to an embodiment of the present invention.
It is the figure which showed typically the control system structure of 00.

FIG. 7 is a diagram showing a configuration example of a ZMP behavior space showing a relationship between a deformation amount or a momentum of a robot and a ZMP position.

FIG. 8 is a diagram showing another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

FIG. 9 is a diagram showing still another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

FIG. 10 is a diagram showing still another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

FIG. 11 is a diagram showing still another configuration example of the ZMP behavior space showing the relationship between the deformation amount or the momentum of the robot and the ZMP position.

FIG. 12 is a diagram showing a configuration example of a ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the left standing leg in the latter half of the single-leg supporting period.

FIG. 13 is a diagram showing a configuration example of a ZMP behavior space in the X direction (traveling direction) in the left standing leg in the latter half of the single-leg supporting period.

FIG. 14 is a diagram showing an ideal configuration example of a ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the left standing leg in the latter half of the single-leg supporting period.

FIG. 15 is a diagram showing an ideal configuration example of a ZMP behavior space in the X direction (traveling direction) in the left standing leg in the latter half of the single-leg supporting period.

FIG. 16 is a diagram showing an ideal configuration example of a ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the trunk of the latter half of the single-leg supporting period.

FIG. 17 is a diagram showing an ideal configuration example of a ZMP behavior space in the X direction (traveling direction) in the trunk of the latter half of the single-leg supporting period.

FIG. 18 is a diagram showing a configuration example of a ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the left standing leg in the two-leg supporting period.

FIG. 19 is a diagram showing a configuration example of a ZMP behavior space in the X direction (traveling direction) of the left standing leg in the two-leg supporting period.

FIG. 20 is a diagram showing a configuration example of an ideal ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the left standing leg during the two-leg supporting period.

FIG. 21 is a diagram showing a configuration example of an ideal ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the left standing leg in the both-leg supporting period.

FIG. 22 is a diagram showing a configuration example of an ideal ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the torso during both legs supporting period.

[Fig. 23] Fig. 23 is a diagram showing a configuration example of an ideal ZMP behavior space in the X direction (traveling direction) in the torso during the two-leg supporting period.

FIG. 24 is a diagram showing a configuration example of a ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the right standing leg in the first half of the single-leg supporting period.

FIG. 25 is a diagram showing a configuration example of a ZMP behavior space in the X direction (traveling direction) in the right standing leg in the first half of the single-leg supporting period.

FIG. 26 is a diagram showing a configuration example of an ideal ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the right standing leg in the first half of the single-leg supporting period.

FIG. 27 is a diagram showing a configuration example of an ideal ZMP behavior space in the X direction (traveling direction) of the right standing leg in the first half of the single-leg supporting period.

FIG. 28 is a diagram showing a configuration example of an ideal ZMP behavior space in the Y direction (direction orthogonal to the traveling direction) in the trunk of the first half of the single-leg supporting period.

FIG. 29 is a diagram showing a configuration example of an ideal ZMP behavior space in the X direction (traveling direction) in the trunk of the first half of the single-leg supporting period.

FIG. 30 is a diagram schematically showing a functional configuration of a ZMP behavior space control system 500.

[Explanation of symbols]

1 ... Head, 2 ... Neck joint yaw axis 3 ... Neck joint pitch axis, 4 ... Neck joint roll axis 5 ... Trunk pitch axis, 6 ... Trunk roll axis 7 ... Trunk yaw axis, 8 ... Shoulder joint pitch axis 9 ... Shoulder joint roll axis, 10 ... Upper arm yaw axis 11 ... Elbow joint pitch axis, 12 ... Forearm yaw axis 13 ... Wrist joint pitch axis, 14 ... Wrist joint roll axis 15 ... Hand, 16 ... Hip joint yaw axis 17 ... Hip pitch axis, 18 ... Hip roll axis 19 ... Knee joint pitch axis, 20 ... Ankle joint pitch axis 21 ... Ankle joint roll axis, 22 ... Foot 100 ... Legged mobile robot 200 ... Thought control module 201 ... Bus interface 211 ... CPU, 212 ... RAM, 213 ... ROM 214 ... External storage device 251 ... Image input device (CCD camera) 252 ... Voice input device (microphone) 253 ... Audio output device (speaker) 254 ... Communication interface 300 ... Motion control module 301 ... Bus interface 311 ... CPU, 312 ... RAM, 313 ... ROM 314 ... External storage device, 351 ... Attitude sensor 352, 353 ... Grounding confirmation sensor 354 ... Power supply control device 500 ... ZMP behavior space control system 501 ... ZMP behavior space definition unit 502 ... Stable point calculator

Continued front page    (72) Inventor Yuichi Hattori             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Jinichi Yamaguchi             5-14-38 Tamadaira, Hino City, Tokyo F-term (reference) 3C007 AS36 CS08 WA03 WA13 WB07

Claims (22)

[Claims] 1. A method for controlling a legged mobile robot having two or more movable legs, comprising a ZMP position at which a pitch axis moment and a roll axis moment of the machine body are zero, and a floor reaction force received from the floor surface by the machine body. The ZMP behavior space control step for controlling the ZMP behavior space defined by
A method for controlling a legged mobile robot, wherein a predetermined distortion or a predetermined characteristic is given to a behavior space. 2. In the ZMP behavior space control step, Z
The MP position of the airframe that is to be moved to the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region formed of the supporting polygon formed by the sole of the movable leg and the road surface. The method for controlling a legged mobile robot according to claim 1, wherein the ZMP behavior space is pre-distorted so that a deformation amount or a momentum amount is generated. 3. The method of controlling a legged mobile robot according to claim 1, wherein the predetermined characteristic is that the amount of deformation, the amount of movement, or the direction of the robot changes according to the floor reaction force. 4. The legged mobile robot according to claim 2, wherein in the ZMP behavior space control step, a minimum point of a deformation amount or a momentum of the airframe is set at substantially the center of the ZMP stable region. Control method. 5. In the ZMP behavior space control step, a minimum point of the deformation amount or momentum of the airframe is set at substantially the center of the ZMP stable region, and the deformation amount or momentum of the airframe is set near the boundary of the ZMP stable region. The method for controlling a legged mobile robot according to claim 2, wherein a maximum point is set. 6. In the ZMP behavior space control step, Z
The first direction in which the MP position is the direction toward the outside of the machine body is the positive direction
In the ZMP behavior space consisting of the second coordinate axis whose coordinate axis and the ZMP position are directed toward the center of the ZMP stable region, and the deformation amount or the momentum of the robot is the positive direction, the robot is The deformation amount or the momentum has a maximum value in the negative region, and a spatial distortion is given such that the ZMP position of the maximum value of the deformation amount or the momentum has a positive value in the positive direction as the floor reaction force increases. The control method for the legged mobile robot according to claim 1. 7. In the ZMP behavior space control step, Z
The first direction in which the MP position is in the forward direction of the aircraft
In the ZMP behavior space consisting of the second coordinate axis whose coordinate axis and the ZMP position are directed toward the center of the ZMP stable region, and the deformation amount or the momentum of the robot is the positive direction, the robot is ZM in the negative range of deformation or momentum
Has a maximum value near the center of the P stable region, and
The method for controlling a legged mobile robot according to claim 1, wherein spatial distortion is applied so that a change in the amount of deformation or a change in momentum becomes smaller as the floor reaction force increases. 8. In the ZMP behavior space control step, the ZMP position is increased as the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the standing leg in the latter half of the monopod support. Deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. When the ZMP position deviates from the center of the ZMP stable region in the traveling direction and the floor reaction force is small in the direction of travel, the ZMP position becomes the center of the ZMP stable region. Deformation or momentum of the robot is generated that goes away from As the floor reaction force increases, a spatial distortion that causes a deformation amount or a momentum of the robot such that the ZMP position moves toward the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region, The method for controlling a legged mobile robot according to claim 1, wherein 9. In the ZMP behavior space control step, the ZMP position is deviated from the center of the ZMP stable region when the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the trunk of the latter half of the monopod support. A deformation amount or a momentum amount of the robot is generated such that the position deviates from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position becomes ZM.
The ZMP position becomes ZM as it deviates from the center of the P stable region.
When the floor reaction force is small in the direction of travel, the ZMP position is deviated from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The method for controlling a legged mobile robot according to claim 1, wherein a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated toward 10. In the ZMP behavior space control step,
A ZMP consisting of a first coordinate axis whose positive direction is the direction in which the ZMP position is directed to the outside of the machine body, and a second coordinate axis whose positive direction is the amount of deformation or momentum of the robot that directs the ZMP position toward the center of the ZMP stable region. In the behavior space,
The robot's deformation amount or momentum is ZM in the negative region with respect to the stance while supporting both legs.
Has a maximum value near the center of the P stable region, and
The control method for a legged mobile robot according to claim 1, wherein spatial distortion is applied so that a change in the deformation amount or the momentum decreases as the floor reaction force increases. 11. The ZMP behavior space control step comprises:
A ZMP consisting of a first coordinate axis whose positive direction is the direction in which the ZMP position is forward of the machine body and a second coordinate axis whose positive direction is the amount of deformation or momentum of the robot that directs the ZMP position toward the center of the ZMP stable region. In the behavior space,
The robot's deformation amount or momentum is ZM in the negative region with respect to the stance while supporting both legs.
Has a maximum value near the center of the P stable region, and
The method for controlling a legged mobile robot according to claim 1, wherein spatial distortion is applied so that a change in the amount of deformation or a change in momentum becomes smaller as the floor reaction force increases. 12. In the ZMP behavior space control step,
When the floor reaction force is small in the direction orthogonal to the direction of travel with respect to the stance in the two-leg supporting period, the ZMP position deviates from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. Although the amount of deformation or momentum of the robot is generated, the ZMP position becomes Z as the floor reaction force increases.
The ZMP position becomes Z as it deviates from the center of the MP stable region.
When the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small in the direction of travel, the ZMP position deviates from the center of the ZMP stable region in addition to the spatial distortion that causes the deformation amount or the momentum of the robot to move toward the center of the MP stable region. A deformation amount or a momentum of the robot is generated such that the direction is deviated from the center of the ZMP stable region. However, as the floor reaction force becomes larger, the ZMP position becomes closer to the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The control method for a legged mobile robot according to claim 1, wherein a spatial distortion that causes a deformation amount or a momentum amount of the robot toward the center is generated. 13. The ZMP behavior space control step comprises:
When the floor reaction force is small in the direction orthogonal to the traveling direction with respect to the torso during the two-leg support period, the ZMP position moves away from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position becomes Z.
The ZMP position becomes Z as it deviates from the center of the MP stable region.
When the ZMP position deviates from the center of the ZMP stable region when the floor reaction force is small in the direction of travel, the ZMP position deviates from the center of the ZMP stable region in addition to the spatial distortion that causes the deformation amount or the momentum of the robot to move toward the center of the MP stable region. A deformation amount or a momentum of the robot is generated such that the direction is deviated from the center of the ZMP stable region. However, as the floor reaction force becomes larger, the ZMP position becomes closer to the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The control method for a legged mobile robot according to claim 1, wherein a spatial distortion that causes a deformation amount or a momentum amount of the robot toward the center is generated. 14. In the ZMP behavior space control step,
A ZMP comprising a first coordinate axis whose negative direction is the direction in which the ZMP position is directed to the outside of the machine body and a second coordinate axis whose positive direction is the amount of deformation or momentum of the robot that causes the ZMP position to be directed to the center of the ZMP stable region. In the behavior space,
Monopod support The maximum amount of deformation or momentum of the robot in the negative region with respect to the standing in the previous period, and the ZMP position of the maximum amount of deformation or momentum moves in the positive direction as the floor reaction force increases. The method for controlling a legged mobile robot according to claim 1, wherein the spatial distortion is given. 15. The ZMP behavior space control step comprises:
A ZMP consisting of a first coordinate axis whose positive direction is the direction in which the ZMP position is forward of the machine body and a second coordinate axis whose positive direction is the amount of deformation or momentum of the robot that directs the ZMP position toward the center of the ZMP stable region. In the behavior space,
Single-leg support When the amount of robot deformation or momentum is negative in the negative region, ZM
Has a maximum value near the center of the P stable region, and
The method for controlling a legged mobile robot according to claim 1, wherein spatial distortion is applied so that a change in the amount of deformation or a change in momentum becomes smaller as the floor reaction force increases. 16. The ZMP behavior space control step comprises:
In the direction orthogonal to the direction of travel, the ZMP position deviates from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region in the direction orthogonal to the direction of travel with respect to the standing leg in the first half of the single-leg support. The amount of deformation or momentum of the robot is generated, but as the floor reaction force increases, the ZMP position becomes ZM.
The ZMP position becomes ZM as it deviates from the center of the P stable region.
When the floor reaction force is small in the direction of travel, the ZMP position is deviated from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The amount of deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The method for controlling a legged mobile robot according to claim 1, wherein a spatial distortion is generated such that a deformation amount or a momentum of the robot is generated toward 17. The ZMP behavior space control step comprises:
When the floor reaction force is small in the direction orthogonal to the direction of movement with respect to the trunk of the first half of the single-leg support, as the ZMP position deviates from the center of the ZMP stable region, the ZMP position deviates from the center of the ZMP stable region. However, as the floor reaction force increases, the ZMP position changes to ZM.
The ZMP position becomes ZM as it deviates from the center of the P stable region.
When the floor reaction force is small in the direction of travel, the ZMP position is deviated from the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The amount of deformation or momentum of the robot is generated so as to move away from the center of the ZMP stable region, but as the floor reaction force increases, the ZMP position becomes the center of the ZMP stable region as the ZMP position deviates from the center of the ZMP stable region. The method for controlling a legged mobile robot according to claim 1, further comprising: applying a spatial distortion such that a deformation amount or a momentum amount of the robot is generated toward the direction. 18. A method for controlling a legged mobile robot having two or more movable legs, comprising a ZMP position at which a pitch axis moment and a roll axis moment of the machine body are zero, and a floor reaction force received from the floor surface by the machine body. Defining a ZMP behavior space defined by, a step of obtaining a ZMP stable position based on the definition of the defined ZMP behavior space, and a step of controlling an airframe operation based on the obtained ZMP stable position. A method for controlling a legged mobile robot, comprising: 19. The control method for a legged mobile robot according to claim 18, further comprising the step of changing the definition of the ZMP behavior space in accordance with the contact situation between the legged mobile robot and a road surface. . 20. The leg type according to claim 18, wherein in the step of defining the ZMP behavior space, a maximum point and / or a minimum point in the ZMP behavior space can be arbitrarily designated. Control method for mobile robot. 21. The maximum point and / or the minimum point in the ZMP behavior space can be arbitrarily designated at an arbitrary time in the step of defining the ZMP behavior space. A method for controlling the described legged mobile robot. 22. In the step of defining the ZMP behavior space, a maximum point and / or a minimum point in the ZMP behavior space can be arbitrarily designated according to a supporting state of a leg. Item 19. A method for controlling a legged mobile robot according to item 18.