JP2019037442A - Lower limb function assistance device - Google Patents

Abstract

To provide a lower limb function assistance device that can satisfactorily assist a daily lower limb operation to a person having a decline in a lower limb stretch function.SOLUTION: A lower limb function assistance device concerning one embodiment of the present invention includes: a hanging belt 2 having a circular portion 2a as a fixed portion for fixing to a sole or an ankle of a user at one end, and arranged so as to sequentially go from the sole to the front side and rear side of a lower limb in the lower limb of the user; a rotary motor 3 fixed in a vertical upward position from a hip joint in the user and used as a winding device for winding the hanging belt 2; a first supporting member 4 for slidably supporting the hanging belt 2 at a predetermined position between a thigh joint and an ankle joint of the user in the front side of the lower limb; and a second supporting member 5 for slidably supporting the hanging belt 2 at a predetermined position between the hip joint and the thigh joint of the user in the rear side of the lower limb.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lower limb function assisting device.

  In recent years, many robots have been developed to support lower limb movements. For example, Patent Literature 1 discloses a driving unit that is mounted on a user's lower limb and transmits a driving force to the lower limb, a centroid position detecting unit that detects a centroid position by a change in the load on the back of the user's foot, A wearable motion assisting device is described that includes a biological signal detection unit that detects a biological signal that accompanies a walking motion, and a control unit that controls driving of the driving unit based on the detected position of the center of gravity and the biological signal. .

International Publication No. 2009/084387

  By the way, in lower limb movements performed on a daily basis, such as walking and raising and lowering stairs, it is necessary to have an ability to generate a vertical reaction force from the ground to support the weight at the tip (foot tip) of the lower limbs. Even if it is possible to walk on its own, people with weak leg extension functions (such as elderly people whose knee extensors have weakened due to aging) who are required to produce vertical reaction force from the ground are long. Sometimes walking on time was difficult. In addition, the weakening of the knee extensor muscles makes it easier to fall during walking and increases the risk of injury during walking. For this reason, it is necessary to assist the operation of the knee extensor muscles in the daily lower limb movements for a person whose leg extension function has deteriorated.

  However, the wearable motion assist device described in Patent Document 1 is supposed to assist the standing motion and walking motion of a person who is difficult to walk on their own, such as a person with a disability in the lower limb motor function. This function is not suitable as a device for assisting the movement of the lower limbs performed on a daily basis. That is, the wearable movement assist device described in Patent Document 1 assists the user's walking movement itself, which is difficult to walk by himself / herself. If a person who can walk on is worn, the walking motion performed by himself / herself may be excessively restricted or inhibited.

  The present invention has been made in view of the background described above, and although it is possible to walk on its own, it is a leg function assisting device that can favorably assist daily leg movements for a person whose leg extension function has declined. The purpose is to provide.

  The lower limb function assisting device according to one aspect of the present invention has a fixing portion for fixing to a user's sole or ankle at one end, and the user's lower limb from the sole to the front side and the rear side of the lower limb. A suspension belt arranged so as to pass in order, a hoisting device for hoisting the suspension belt, and the suspension belt at a predetermined position between the user's thigh joint and ankle joint on the front side of the lower limb A first support member that slidably supports, and a second support member that slidably supports the suspension belt at a predetermined position between the hip joint and thigh joint of the user on the rear side of the lower limb. It is to be prepared.

  According to the present invention, it is possible to favorably assist daily leg movements for a person whose leg extension function has deteriorated.

It is a schematic diagram which shows schematic structure of the leg function assistance apparatus concerning this Embodiment. It is the arrow line view seen from the arrow A of FIG. It is a schematic diagram explaining the arrangement | sequence of the antagonistic muscle in a person's leg thigh. It is a schematic diagram which shows the test apparatus for evaluating the ability of the leg support apparatus concerning this Embodiment to generate | occur | produce the vertical reaction force from the ground on a toe. It is a table | surface which shows the angle (theta) 1 of the hip joint, and the angle (theta) 2 of the thigh joint in each attitude | position (position from which the bending condition of the joint of a leg is respectively different) evaluated by the said test. It is a graph which shows an experimental result.

Hereinafter, an embodiment of a lower limb function assisting device of the present invention will be described with reference to the drawings.
First, a schematic configuration of the lower limb function assisting apparatus according to the present embodiment will be described with reference to FIGS. 1 and 2. A user who is a wearing target of the lower limb function assisting device in the present embodiment, for example, a person who has a reduced leg extension function in at least one of the lower limbs even if he / she can walk by himself / herself. It is.

  FIG. 1 is a schematic diagram showing a schematic configuration of a lower limb function assisting apparatus 1 according to the present embodiment. FIG. 2 is a view as seen from an arrow A in FIG. As shown in FIGS. 1 and 2, the lower limb function assisting device 1 includes a suspension belt 2, a rotation motor 3 as a hoisting device, a first support member 4, a second support member 5, a control unit 6, It has.

  The suspension belt 2 is disposed on the left and right lower limbs Ufr and Ufl of the user. The suspension belt 2 disposed on the user's right lower limb Ufr and the suspension belt 2 disposed on the left lower limb Ufl have the same configuration. The suspension belt 2 plays a role of transmitting power from the directly connected rotary motor 3, and has a fixing portion for fixing to the position of the user's sole 51 or ankle joint 56 at one end. The suspension belt 2 and the ring-shaped portion 2a are formed of a material that has sufficient strength and does not have much stretchability, such as nylon, so that the power from the rotary motor 3 can be transmitted clearly. In the lower limb function assisting apparatus 1 according to the present embodiment, the fixed portion is a ring-shaped portion 2a for hooking on the sole 51 of the user. The position where the suspension belt 2 is hooked on the sole of the user is preferably as close to the heel as possible. This is because, as the position where the suspension belt 2 is hooked on the sole of the user is further away from the heel side, the extra rotational force is generated in the lower limbs, and the effect of assisting the lower limb function is diminished. Further, the user may wear the shoes 10 in a state where the ring-shaped portion 2a of the suspension belt 2 is hooked.

  The suspension belt 2 reaches the second support member 5 from the sole 51 via the lower leg thigh front side 52. The second support member 5 slidably supports the suspension belt 2 at a predetermined position between the user's thigh joint 54 and ankle joint 56 on the front side of the lower limb. The position at which the suspension belt 2 is supported by the second support member 5 is preferably as close to the user's thigh joint 54 as possible.

  Furthermore, the suspension belt 2 reaches the first support member 4 from the position supported by the second support member 5 via the lower leg thigh rear side 53. The first support member 4 slidably supports the suspension belt 2 at a predetermined position between the user's hip joint 55 and the thigh joint 54 on the rear side of the lower limb. Note that the position at which the suspension belt 2 is supported by the first support member 4 is preferably as close to the user's hip joint 55 as possible.

  Further, the suspension belt 2 is connected to the rotary motor 3 at the other end via the flange portion 57 from the first support member 4. The rotary motor 3 as a hoisting device is for hoisting the suspension belt 2 and is fixed at a position vertically above the hip joint 55 (or the heel portion 57) of the user. The rotary motor 3 is fixed to the position of the user's waist 58 with a weight belt, for example. In addition, in order to wind up separately the suspension belt 2 with which each was attached to the left and right leg, two rotation motors 3 are provided. It is desirable that the rotary motor 3 has a sufficient auxiliary force and a high back-drive property so as not to hinder the user's operation. For example, a high-output servo motor having an input current value of about 20 A can be used. As the weight belt, a commercially available training belt can be used. In this way, the weight of the rotary motor 3 can be dispersed by fixing the rotary motor 3 to the waist position of the user with the weight belt.

  The hoisting device for hoisting the suspension belt 2 is not limited to the rotary motor 3 shown in FIGS. The hoisting device may have any structure as long as the hoisting belt 2 arranged in the above-described path in the user's lower limb can be hoisted from above the hip joint 55. For example, the arrangement of the rotary motor 3 shown in FIGS. 1 and 2 can naturally be changed. Instead of fixing the rotary motor 3 to the position of the user's waist 58 with a weight belt, the user may carry a backpack on which the rotary motor 3 is installed. The rotary motor 3 may be installed on a frame installed outside the user instead of being carried by the user. The rotary motor 3 may use a direct acting motor instead of the servo motor.

  As the first support member 4 and the second support member 5, for example, a commercially available medical supporter can be used. That is, in a state where the suspension belt 2 is arranged on the lower limb, a predetermined position between the user's hip joint 55 and the thigh joint 54 and a predetermined position between the user's thigh joint 54 and the ankle joint 56 on the front side of the lower limb. The suspension belt 2 can be slidably fixed by winding the medical supporter as the first support member 4 and the second support member 5 at the position. In order to prevent the suspension belt 2 from being damaged by sliding, a buffer (cushion) or the like may be inserted between the lower limbs and the suspension belt 2.

  The control unit 6 controls driving of the rotary motor 3. A specific method for controlling the rotary motor 3 by the control unit 6 will be described later.

Next, the arrangement of antagonistic muscles in the human lower limb thigh will be described.
Since antagonistic muscles are unidirectional that generate force and displacement only in the contraction direction, there is always a pair of antagonistic muscles in the joint.

  FIG. 3 is a schematic diagram illustrating the arrangement of antagonistic muscles in the lower limb thigh of a person. As shown in FIG. 3, the array of antagonistic muscles in the lower limb thigh of a person has a configuration of 3 to 6 muscles. That is, the antagonist muscles in the lower limb thigh of a person are a pair of antagonist muscles of the hip joint 55 (rear side hip joint muscle f1, front side hip joint muscle e1) and a pair of antagonist muscles of the thigh joint 54 (rear side thigh joint muscle f2, front side). The thigh joint muscle e2) is composed of a pair of antagonistic muscles (rear biarticular muscle f3, front biarticular muscle e3) simultaneously involved in the hip joint 55 and the thigh joint 54.

The rear hip joint muscle f1 generates a torque τ _f1 in a direction to rotate the hip joint 55 rearward, and the front hip joint muscle e1 generates a torque τ _e1 in a direction to rotate the hip joint 55 forward. The rear thigh joint muscle f2 generates a torque τ _f2 in a direction to rotate the thigh joint 54 rearward, and the front thigh joint muscle e2 generates a torque τ _e2 in a direction to rotate the thigh joint 54 forward. The rear biarticular muscle f3 generates a torque τ _f3 in the direction of rotating the hip joint 55 and the thigh joint 54 rearward, and the front biarticular muscle e3 is a torque in the direction of rotating the hip joint 55 and the thigh joint 54 forward. τ _e3 is generated.

In order to support daily leg movements for those who have weakened leg extension functions, the leg function assisting device artificially replenishes the foot outputs F _f1 and F _e2 that generate a vertical reaction force from the ground. It is effective to do. A component perpendicular to the ground of the foot output F _f1 and F _e2 is a vertical reaction force from the ground. According to the effective muscular strength theory by function (FEMS [Functional Effective Muscle Strength] theory), the toe outputs F _f1 and F _e2 are expressed by the following formulas 1 and 2. Here, l1 is the length of the first link 22, l2 is the length of the second link 23, θ2 is the angle of the thigh joint 54, θ3 is the angle of the ankle joint 56 (note that θ1 in FIG. 3 is the hip joint) 55 angles).

As can be seen from Equations 1 and 2, in order to effectively assist the toe outputs F _f1 and F _e2 , it is necessary to increase the torque τ _f1 and the torque τ _e2 .

Further, the total torque τ _H in the direction in which the hip joint 55 is rotated rearward and the total torque τ _K in the direction in which the thigh joint 54 is rotated forward are expressed by the following equations (3) and (4).

As shown in Expression 3 and Expression 4, the total torque τ _H in the direction of rotating the hip joint 55 rearward includes the torque τ _f1 , and the total torque τ _K in the thigh joint 54 includes the torque τ _e2 . That is, by artificially increasing τ _H and τ _K , the generation of the toe outputs F _f1 and F _e2 can be assisted.

Next, a specific control method of the rotary motor 3 by the control unit 6 of the lower limb function assisting apparatus 1 will be described.
In the lower limb function assisting apparatus 1 shown in FIGS. 1 and 2, when the rotary motor 3 is operated by the control unit 6, the suspension belt 2 is wound up, and tension is generated in the suspension belt 2. As a result, as shown in FIG. 3, torque τ1 is generated in the direction of rotating the hip joint 55 rearward at the position of the first support member 4, and the thigh joint 54 is rotated forward at the position of the second support member 5. Torque τ2 in the direction of movement is generated. When the rotary motor 3 is operated to generate the torques τ1 and τ2, the total torque τ _H in the direction to rotate the hip joint 55 rearward and the total torque in the direction to rotate the thigh joint 54 forward τ _K is expressed by the following formulas 5 and 6.

As can be seen from Equations 5 and 6, by operating the rotary motor 3, the total torque τ _H in the direction of rotating the hip joint 55 rearward is increased by the torque τ1, and the thigh joint 54 is rotated forward. The total direction torque τ _K increases by the torque τ 2. That is, by operating the rotary motor 3, the foot output _Ff1 , _Fe2 can be effectively assisted. The torque τ1 and the torque τ2 can be increased according to the input current of the rotary motor 3. In other words, the lack of vertical reaction force from the ground, which is obtained by subtracting the vertical reaction force from the ground generated by the user from the vertical reaction force from the ground necessary for the user to normally perform lower limb movements such as walking. What is necessary is just to set the input current of the rotary motor 3 suitably so that a part may be supplemented.

  The control unit 6 may perform control (torque control) so that the drive torque of the rotary motor 3 is maintained at the control command value. In this way, it is possible to assist daily lower limb movements such as walking and raising and lowering stairs without excessively hindering the user's autonomous lower limb movements. When a DC servo motor is used as the rotary motor 3, the relationship between the input current and the drive torque in the rotary motor 3 is proportional, so that the torque control of the rotary motor 3 can be performed relatively easily in the control unit 6. .

  When the user bends the lower limb, the control unit 6 may control the rotary motor 3 so that the drive torque of the rotary motor 3 is smaller than the control command value. For example, the control unit 6 sets the driving torque of the rotary motor 3 to zero when the user bends the lower limb. In this way, when the user bends the lower limb, the torque τ1 in the direction of rotating the hip joint 55 rearward at the position of the first support member 4 and the thigh at the position of the second support member 5 It is possible to prevent the generation of torque τ2 in the direction in which the joint 54 is rotated forward. That is, when the user bends the lower limb, the driving torque of the rotary motor 3 is set to zero, so that the torque τ1 and the torque τ2 that prevent the lower limb from being bent are not generated, and the user can perform more daily lower limb movements. It can be done smoothly.

Next, a test that evaluates the ability of the lower limb function assisting apparatus 1 according to the present embodiment to generate a vertical reaction force from the ground on the toe will be described.
FIG. 4 is a schematic diagram showing a test apparatus 20 for evaluating the ability of the lower limb function assisting apparatus 1 to generate a vertical reaction force from the ground on the toes. As shown in FIG. 4, the test apparatus 20 includes a grounding portion 21, a first link 22, a second link 23, a fixing plate 24, an upper pulley 25, a lower pulley 26, and a load cell 27. ing.

  The test apparatus 20 simulates a human lower limb. That is, the contact portion 21 simulates the toe, the first link 22 simulates the thigh, the second link 23 simulates the lower leg, the fixing plate 24 simulates the torso, the upper pulley 25 simulates the hip joint, and the lower pulley 26 simulates the thigh joint. doing. These pulleys and links are designed to weigh as much as the average human limb of an average adult male, and the radius of each pulley is designed to the size of a human foot. The corresponding link and pulley slide freely with low friction. The lengths of the first link 22 and the second link 23 are both 40 cm.

  The fixed plate 24 is fixed to a frame as a base (not shown). The suspension belt 2 passes from the rotary motor 3 to the rear side via the upper pulley 25 and then passes to the front side via the lower pulley 26 to hook the ring-shaped portion 2 a on the ground contact surface of the ground contact portion 21. The load cell 27 is provided between the grounding surface of the grounding part 21 and the ground, and measures the vertical reaction force from the ground. The rotary motor 3 is fixed to the back surface of the fixed plate 24.

  This test was performed for three postures (postures with different bending degrees of the lower limb joints). FIG. 5 is a table showing the hip joint angle θ1 and the thigh joint angle θ2 in each posture. As shown in FIG. 5, the posture “Low” is a substantially upright state, the posture “Middle” is a middle waist state, and the posture “High” is a substantially seated posture. The rotary motor 3 used for the test is a servo motor having an input current value of about 4A. In the test, the input current to the rotary motor 3 was changed, and the vertical reaction force from the ground was measured by the load cell 27. The input current was changed between 0 and -4.0 [A] every 1.0 [A].

  FIG. 6 is a graph showing the test results. Here, the horizontal axis represents the input current, and the vertical axis represents the vertical reaction force from the ground as Output. As shown in FIG. 6, in the posture “Low” and the posture “Middle”, the vertical reaction force from the ground increased as the input current to the rotary motor 3 increased. That is, it was confirmed that a sufficient vertical reaction force from the ground can be generated by driving the rotary motor 3 in the lower limb function assisting device 1 and winding up the suspension belt 2. That is, it has been confirmed that the lower limb function assisting apparatus 1 is useful for assisting daily leg motion.

  On the other hand, in the posture “High”, it has not been confirmed that the lower limb function assisting device 1 generates a vertical reaction force from the ground. In a substantially seated posture with respect to the almost upright state, in order to generate the vertical reaction force from the same ground, it is necessary to increase the torque τ1 for extending the hip joint and the torque τ2 for extending the thigh joint. For this reason, it is considered that the ability of the rotary motor 3 was insufficient in the posture “High”. That is, in the posture “High”, it is considered that a vertical reaction force from the ground can be sufficiently generated by using a servo motor having an input current value of about 20 A and increasing the input current to 4 A or more.

  Conversely, in order to assist the operation when standing up from the sitting posture, it is necessary to use a large motor as the rotary motor 3. A relatively small one can be used. Therefore, when the lower limb function assisting apparatus 1 is used for the purpose of assisting walking, the weight of the apparatus can be suppressed, so that it is more preferable as an assisting tool for daily use by the user.

  When the control unit 6 performs control so that the drive torque of the rotary motor 3 is maintained at the control command value, the control command value may be changed according to the angle of the user's hip joint and thigh joint. In this case, the lower limb function assisting apparatus 1 further includes an angle sensor that detects the angles of the user's hip joint and thigh joint. Accordingly, an appropriate vertical reaction force from the ground can be generated regardless of the bending angle of the joints of the user's lower limbs.

  The lower limb function assisting device according to one aspect of the present invention has, at one end, a ring-shaped portion 2a as a fixing portion for fixing to the user's sole or ankle. In the user's lower limb, from the sole to the front side of the lower limb, A suspension belt 2 arranged so as to pass through in order with the rear side, a rotation motor 3 as a hoisting device for lifting the suspension belt 2 fixed at a position vertically above the hip joint in the user, and a front side of the lower limb A first support member 4 that slidably supports the suspension belt 2 at a predetermined position between the user's thigh joint and ankle joint, and a predetermined position between the user's hip joint and thigh joint on the rear side of the lower limb. And a second support member 5 that slidably supports the suspension belt 2. When the suspension belt 2 arranged in this way is wound up by the rotary motor 3, tension is generated in the suspension belt 2. As a result, in the lower limbs, torque in a direction for rotating the hip joint to the rear and torque in a direction for rotating the thigh joint to the front can be generated, and a vertical reaction force from the ground can be generated in the lower limbs. Therefore, it is possible to favorably assist daily leg movements for a person whose leg extension function that generates a vertical reaction force from the ground has deteriorated.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, the lower limb function assisting device has the suspension belts disposed on the left and right lower limbs of the user, but the present invention is not limited to this, and the suspension belt 2 is disposed only on one of the lower limbs. There may be. This is a preferable configuration when, for example, the affected leg of the user is either the left or right. In the case of the configuration in which the suspension belt 2 is disposed only on one of the lower limbs, the device configuration can be simplified, for example, by only one rotation motor for winding up the suspension belt.

  In the above embodiment, the drive of the rotary motor is controlled by the control unit. However, the user may adjust the timing for driving the rotary motor and the input current of the rotary motor. That is, in the lower limb function assisting device, an operation switch capable of turning on / off the rotary motor and adjusting the input current is provided instead of the control unit, and the user operates the operation switch to control the drive of the rotary motor. Also good. For example, when performing an operation of extending the lower limb from a state in which the bending angle of the hip joint and the thigh joint is relatively large, such as when climbing stairs or standing up from a chair, the user turns on the operation switch to drive the rotation motor. Thereby, extension of a user's leg is assisted and the above-mentioned operation can be performed easily.

  The fixed portion provided at one end of the suspension belt is not limited to the ring-shaped portion 2a shown in FIGS. The fixing portion may be formed by any fixing method as long as one end of the suspension belt can be fixed to the sole or ankle of the user. For example, the fixing portion may be one in which one end of the suspension belt is fixed to the user's ankle via a band, or one that is sewn to a shoe.

  In the above-described embodiment, the process for controlling the hoisting apparatus can be realized by causing a computer to execute a control program.

DESCRIPTION OF SYMBOLS 1 Lower limb function assistance apparatus 2 Suspension belt 2a Ring-shaped part 3 Rotary motor 4 1st support member 5 2nd support member 6 Control part 20 Test apparatus 21 Grounding part 22 1st link 23 2nd link 24 Fixing plate 25 Upper pulley 26 Lower pulley 27 Load cell

Claims (10)

A suspension belt that has a fixing portion for fixing to the sole or ankle of the user at one end, and is arranged so as to pass in order from the sole to the front side and the rear side of the lower limb in the lower limb of the user,
A hoisting device for hoisting the suspension belt;
A first support member that slidably supports the suspension belt at a predetermined position between the user's thigh joint and ankle joint on the front side of the lower limb;
A lower limb function assisting device, comprising: a second support member that slidably supports the suspension belt at a predetermined position between the hip joint and thigh joint of the user on the rear side of the lower limb.   The lower limb function according to claim 1, further comprising a control unit that controls driving of the hoisting device, wherein the control unit controls the hoisting device such that a driving torque is maintained at a control command value. Auxiliary device.   The lower limb function assistance according to claim 2, wherein the control unit controls the hoisting device so that a driving torque of the hoisting device becomes smaller than the control command value when the user bends the lower limb. apparatus.   An angle sensor that detects angles of the hip and thigh joints of the user is further provided, and the control command value is changed according to the angles of the hip and thigh joints of the user detected by the angle sensor. 3. Lower limb function assisting device according to 3. A suspension belt that has a fixing portion for fixing to the sole or ankle of the user at one end, and is arranged so as to pass in order from the sole to the front side and the rear side of the lower limb in the lower limb of the user,
A hoisting device for hoisting the suspension belt;
A first support member that slidably supports the suspension belt at a predetermined position between the user's thigh joint and ankle joint on the front side of the lower limb;
And a second support member that slidably supports the suspension belt at a predetermined position between the hip and thigh joints of the user on the rear side of the lower limbs. ,
A control method for a lower limb function assisting device, wherein the hoisting device is controlled such that the driving torque of the hoisting device is maintained at a control command value.   The method for controlling a lower limb function assisting device according to claim 5, wherein when the user bends the lower limb, the hoisting device is controlled such that a driving torque of the hoisting device is smaller than the control command value.   The lower limb function assisting device further includes an angle sensor that detects angles of the hip and thigh joints of the user, and changes the control command value according to the angles of the hip and thigh joints of the user detected by the angle sensor. A method for controlling a lower limb function assisting device according to claim 5 or 6. A suspension belt that has a fixing portion for fixing to the sole or ankle of the user at one end, and is arranged so as to pass in order from the sole to the front side and the rear side of the lower limb in the lower limb of the user,
A hoisting device for hoisting the suspension belt;
A first support member that slidably supports the suspension belt at a predetermined position between the user's thigh joint and ankle joint on the front side of the lower limb;
A second support member that slidably supports the suspension belt at a predetermined position between the hip and thigh joints of the user on the rear side of the lower limb, and controls for controlling the lower limb function assisting device A program,
A control program for causing a computer to execute processing for controlling the hoisting device such that the driving torque of the hoisting device is maintained at a control command value.   9. The control program according to claim 8, wherein when the user flexes the lower limb, the computer executes a process of controlling the hoisting device so that a driving torque of the hoisting device becomes smaller than the control command value. .   The lower limb function assisting device further includes an angle sensor that detects angles of the hip and thigh joints of the user, and changes the control command value according to the angles of the hip and thigh joints of the user detected by the angle sensor. The control program according to claim 8 or 9, which causes a computer to execute processing.

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