JP2019198960A - Articulated robot using link operation device - Google Patents

Abstract

To provide an articulated robot using a link operation device which is compact in a size of a joint part, can perform a fine and quick motion, is high in the safety of the motion, and suitable for use in a working site in which the robot coexists with people.SOLUTION: An articulated robot 1 has a base unit 2 and an articulated arm 3. In the articulated arm 3, a plurality of arm parts 11 to 14 are aligned toward a tip side from a base end side, and the base-end side arm part 11 which is the nearest base unit 2, and the adjacent arm parts 11 to 14 are connected to each other via joint parts 21 to 24. The joint part 24 includes a link operation device for relatively rotating the arm parts 13, 14 at both sides around orthogonal two axes. A posture control drive source 31 for arbitrarily changing a position of a link hub 33 at a tip side with respect to a base-end side link hub 32 is arranged at a link mechanism 34, and there is used the link operation device including load estimation means 79 for estimating a load acting on the tip-side link hub 33 from a detection result of torque detection means 78 which is arranged at each posture control drive source 31.SELECTED DRAWING: Figure 1

Description

  The present invention is a multi-joint robot having a degree of freedom of 6 degrees or more using a link actuating device used for medical equipment, industrial equipment, etc. that require high speed, high accuracy, and a robot that coexists with a wide working range. About.

  Patent Documents 1 and 2 propose articulated robots used for devices that require high speed, high accuracy, and a wide operating range, such as medical devices and industrial devices, and robots that coexist with humans. The articulated robot of Patent Document 1 is configured by combining a mechanism with one degree of freedom of rotation. The articulated robot of Patent Document 2 uses a link actuator with two degrees of freedom of rotation.

JP 2005-329521 A US Pat. No. 6,658,962

  Since all the articulated robots of Patent Document 1 are composed of a combination of joint portions with one degree of freedom of rotation, for example, when an articulated robot collides with a person or an object, there is a direction in which the collision is difficult to detect and is safe. There is a problem in terms. In addition, it is necessary to drive a plurality of motors even by slightly changing the attitude of the end effector mounted on the tip, and there is a problem that fine work cannot be performed. Furthermore, as a control problem, there may be a plurality of solutions for one posture of the end effector, and there is a possibility that the operation cannot be determined. As an operation problem, it is difficult to imagine in which direction the tip moves even if each axis is moved during teaching, so knowledge and experience are required to perform the operation.

  The articulated robot of Patent Document 2 can solve the safety problem by providing a link actuating device capable of a smooth two-degree-of-freedom motion. However, when moving the end effector (for example, the hand) on the central axis of the link hub on the proximal end side of the link actuator, it is necessary to move and adjust both the posture of the link actuator and the elbow joint. Requires knowledge and experience. In addition, it is expected that the load on the link actuating device is large and fine work cannot be performed.

  An object of the present invention is to provide an articulated robot using a link actuator suitable for use in a work site where a joint portion is compact, quick and fine movement is possible, operation safety is high, and coexist with humans. Is to provide.

An articulated robot using the link actuator of the present invention has a base unit and an articulated arm installed on the base unit, and the articulated arm has a plurality of arm portions from the base end side to the distal end side. Are arranged in series, and the base unit, the most proximal arm part, and the adjacent arm parts are connected to each other via a joint part so as to be relatively displaceable from each other, and are mounted on the most distal arm part. An articulated robot with 6 degrees of freedom or more that works using
Of the plurality of joint portions, the joint portion that connects the most distal arm portion and one proximal end arm portion from the arm portion is configured such that the arm portions on both sides are mutually orthogonally around two axes. It consists of a link actuator that rotates relatively,
The link actuating device comprises three sets of link hubs on the distal end side fixed to the arm portion on the distal end side with respect to the link hub on the proximal end side fixed to the arm portion on the proximal end side among the arm portions on both sides. The above-mentioned link mechanisms are connected so that their postures can be changed, and the respective link mechanisms are respectively connected to the base end side link hub and the front end side link hub so that one end is rotatably connected to the base end side and the front end. Side end link members, and central link members whose both ends are rotatably connected to the other ends of the base end side and distal end side end link members, respectively, of the three or more sets of link mechanisms A posture control drive source that arbitrarily changes the posture of the distal end side link hub with respect to the proximal end side link hub in the two or more sets of link mechanisms;
Each of the attitude control drive sources is provided with torque detection means for detecting torque applied to the attitude control drive source, and load estimation means for estimating a load acting on the link hub on the distal end side from the detection result of the torque detection means. The link actuating device provided with was used.

  The link actuating device is composed of a link hub on the base end side, a link hub on the front end side, and three or more sets of link mechanisms. The link hub on the front end side is rotatable about two orthogonal axes with respect to the link hub on the base end side. A two-degree-of-freedom mechanism. Although this two-degree-of-freedom mechanism is compact, the movable range of the link hub on the distal end side can be widened. For example, the maximum bending angle between the central axis of the link hub on the proximal end side and the central axis of the link hub on the distal end side is about ± 90 °, and the swivel angle of the link hub on the distal end side with respect to the link hub on the proximal end side is It can be set in the range of 0 ° to 360 °.

  By using the link actuating device for at least one of the plurality of joints, a smooth operation without a singular point is possible in the operating range of the bending angle of 90 ° and the turning angle of 360 °, and fine-grained operation is possible. realizable. In addition, by using a linear motion mechanism for at least one of the remaining joints, it is possible to perform a straight-ahead operation with a single actuator. Can be operated.

In the present invention, when the attitude control drive source is a rotary actuator that generates a rotational force, each attitude control drive source is provided with torque detection means for detecting the torque applied to the attitude control drive source. You may provide the load estimation means which estimates the load which acts on the link hub of the said front end from the detection result of a means.
Thereby, when an unusual load is applied to the articulated robot, for example, when it collides with a person or an object, this can be detected. For this reason, when an abnormal load is applied, an avoidance operation such as stopping the operation can be performed, which is safe.
By providing torque detection means in the attitude control drive source, the load acting on the link hub on the tip side can be estimated without providing a separate load detection sensor, making the articulated robot more compact and reducing cost. It leads to. In addition, there is no singular point within the operating range of the link actuator, and it can be moved smoothly in all directions, so even if a load is applied to the link hub on the tip side from various directions, the posture control drive source can be reliably Torque is transmitted and an accurate load can be estimated.

In this invention, the linear motion mechanism is configured such that when the arm portions on both sides are moved relative to each other in one direction of the linear direction, either one of the arm portions is housed inside the other arm portion. And good.
With this configuration, when the articulated robot is not used, it can be made compact, and a storage space can be reduced. In addition, since the movable range of the entire articulated robot, particularly the movable range of the articulated arm between the base unit and the end effector can be minimized, the occupied space can be reduced.

In this invention, the joint unit that includes the basic configuration and connects the base unit and the most proximal arm part is provided on both sides of the base unit around a rotation axis that is orthogonal to the installation surface of the base unit. And a rotation mechanism that relatively rotates the arm portion, and the joint portion that connects the arm portion closest to the base end side and the second arm portion from the base end side rotates in parallel with the installation surface of the base unit. A rotation mechanism that relatively rotates the respective arm portions on both sides around an axis, and a joint portion that connects the second arm portion from the base end side and the third arm portion from the base end side, The joint portion that connects the third arm portion from the base end side to the fourth arm portion from the base end side includes the linear motion mechanism that relatively moves the arm portions relative to each other in the linear direction. Made to each other from the link actuator to rotate relative to each other in two orthogonal axes around a joint portion connecting the end effector from the proximal end side and the fourth of the arm portion may be the rotating mechanism.
With this configuration, when the multi-joint arm of this multi-joint robot is regarded as a human arm, the fourth joint corresponding to the wrist joint can be operated close to the wrist joint so that the link can be operated with two degrees of freedom. Since the apparatus is configured, it is easy to imagine the relationship between the movement of each joint and the movement of the end effector, and the operability is good. Further, since the link actuating device is arranged in the joint portion near the tip of the multi-joint arm corresponding to the wrist joint in the human arm, the load acting on the link actuating device is small, and a finer operation can be performed at higher speed. Furthermore, since the rotation mechanism that can twist the cable is arranged on the tip side of the multi-joint arm with respect to the link operation device, the linear motion mechanism, etc., the wiring of the link operation device, the linear motion mechanism, etc. can be easily handled.

In the present invention, two articulated arms may be installed in one base unit.
As a result, it is possible to perform an operation that a person performs with both hands.

In the two articulated arms, it is preferable that the arm portion on the most proximal side is installed on the surfaces of the base unit that are symmetrical to each other.
By adopting this configuration, the shape of a double-armed robot similar to that of a person is obtained, and work similar to that of a person can be performed. Further, when the articulated robot becomes malfunctioning, it is possible to perform work by replacing a person who has entered the space where the articulated robot has been removed.

  An articulated robot using the link actuator of the present invention has a base unit and an articulated arm installed on the base unit, and the articulated arm has a plurality of arm portions from the base end side to the distal end side. Are arranged in series, and the base unit, the most proximal arm part, and the adjacent arm parts are connected to each other via a joint part so as to be relatively displaceable from each other, and are mounted on the most distal arm part. A multi-joint robot with a degree of freedom of 6 or more that uses the robot to connect the most distal arm part and one proximal end arm part of the plurality of joint parts The joint portion comprises a link actuating device that relatively rotates the arm portions on both sides around two orthogonal axes, and the link actuating device comprises a base end side arm portion of the arm portions on both sides. The distal end side link hub fixed to the distal end side arm portion is connected to the fixed proximal end side link hub so that the posture can be changed via three or more sets of link mechanisms. A proximal end and a distal end end link member, one end of which is rotatably connected to the proximal end link hub and the distal end link hub, respectively, and the proximal end and distal end end link members; A central link member having both ends rotatably coupled to the other end, and the distal-side link with respect to the proximal-side link hub is connected to two or more sets of the three or more sets of link mechanisms. An attitude control drive source for arbitrarily changing the attitude of the hub is provided, and each of the attitude control drive sources is provided with a torque detection means for detecting torque applied to the attitude control drive source. From the detection result of the torque detection means Previous Because the link actuator equipped with load estimation means for estimating the load acting on the link hub on the distal end side is used, fine and quick operation is possible, the operation is safe, and it can be used at work sites where people coexist. Suitable for.

It is a figure which shows schematic structure of the articulated robot concerning one Embodiment of this invention. It is the figure which abbreviate | omitted a part of link operating device of the same articulated robot. It is a perspective view of one state of the parallel link mechanism of the link actuator. It is a perspective view of a different state of the parallel link mechanism. It is sectional drawing of the link hub of the base end side of the parallel link mechanism, the edge part link member of a base end side, etc. It is the figure which expressed one link mechanism of the parallel link mechanism with a straight line. It is a figure which shows schematic structure of the articulated robot concerning other embodiment of this invention. It is a figure which shows schematic structure of the articulated robot concerning further another embodiment of this invention. It is a figure which shows schematic structure of the articulated robot concerning further another embodiment of this invention.

An articulated robot using a link actuator according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of this articulated robot. The multi-joint robot 1 includes a base unit 2 and a multi-joint arm 3 installed on the base unit 2, and an end that performs work on a workpiece (not shown) at the tip of the multi-joint arm 3. An effector 4 is mounted. In this example, the base unit 2 is installed on an installation surface 5 formed of a horizontal plane. A controller 6 that controls the operation of the articulated robot 1 is built in the base unit 2. The controller 6 may be installed outside the base unit 2.

  The articulated arm 3 includes a plurality of (four in the illustrated example) arm portions 11 to 14 arranged in series from the proximal end side to the distal end side, and the base unit 2 and the most proximal arm portion 11, and Adjacent arm portions 11 to 14 are connected to each other so as to be relatively displaceable via joint portions 21 to 24, respectively. The end effector 4 is installed on the most distal end arm portion 14. In the following description, the arm portions 11 to 14 will be referred to as “first arm portion 11”, “second arm portion 12”,. The first joint portion 21, the second joint portion 22,...

The first joint portion 21 that connects the base unit 2 and the first arm portion 11 moves the first arm portion 11 relative to the base unit 2 around the rotation axis 7 orthogonal to the installation surface 5. It consists of a rotating mechanism that rotates. The first arm portion 11 is rotationally driven by a drive source 21 a such as a motor provided in the base unit 2.

  The second joint portion 22 that connects the first arm portion 11 and the second arm portion 12 is a second arm with respect to the first arm portion 11 around the rotation axis 8 parallel to the installation surface 5. It consists of a rotation mechanism that relatively rotates the part 12. The second arm unit 12 is rotationally driven by a drive source 22 a such as a motor provided in the first arm unit 11.

  The third joint portion 23 that connects the second arm portion 12 and the third arm portion 13 includes a linear motion mechanism that moves the third arm portion 13 in the linear direction with respect to the second arm portion 12. Become. The movement of the third arm unit 13 is performed by a drive source 23 a such as a linear actuator provided in the second arm unit 12. The second arm portion 12 and the third arm portion 13 are provided on the same axis, and the second arm portion 12 and the third arm portion 13 are moved when the third arm portion 13 moves closer to the base end of the second arm portion 12. The third arm portion 13 is housed inside the arm portion 12, and the third arm portion 13 projects from the inside of the second arm portion 12 when the arm portion 12 moves away.

  The fourth joint portion 24 that connects the third arm portion 13 and the fourth arm portion 14 is a link with two degrees of freedom for rotating the fourth arm portion 14 with respect to the third arm portion 13. It consists of an actuator.

  The link actuator which is the 4th joint part 24 is demonstrated. As shown in FIG. 2, the link actuating device includes a parallel link mechanism 30 and a posture control drive source 31 that operates the parallel link mechanism 30. 3 and 4 are perspective views showing only the parallel link mechanism 30 taken out and showing different states. As shown in FIGS. 2 to 4, the parallel link mechanism 30 is formed by connecting the link hub 33 on the distal end side to the link hub 32 on the proximal end side through three sets of link mechanisms 34 so that the posture can be changed. . In FIG. 2, only one set of link mechanisms 34 is shown. The number of link mechanisms 34 may be four or more.

  Each link mechanism 34 is composed of a base end side end link member 35, a front end side end link member 36, and a central link member 37, and forms a four-joint link mechanism including four rotating pairs. The end link members 35 and 36 on the proximal end side and the distal end side are L-shaped, and one ends thereof are rotatably connected to the link hub 32 on the proximal end side and the link hub 33 on the distal end side, respectively. The central link member 37 has both ends connected to the other ends of the end link members 35 and 36 on the proximal end side and the distal end side in a freely rotatable manner.

  The parallel link mechanism 30 has a structure in which two spherical link mechanisms are combined, and each rotation pair of the link hubs 32 and 33 and the end link members 35 and 36, and the end link members 35 and 36 and the central link member 37. The center axis of each rotation pair intersects with the spherical link centers PA and PB (FIG. 2) on the proximal end side and the distal end side. Further, on the proximal end side and the distal end side, the distances from the rotary pairs of the link hubs 32, 33 and the end link members 35, 36 and the respective spherical link centers PA, PB are the same, and the end link members 35, The distances from the rotary pairs of 36 and the central link member 37 and the spherical link centers PA and PB are the same. The central axis of each rotational pair of the end link members 35 and 36 and the central link member 37 may have a certain crossing angle γ (FIG. 2) or may be parallel.

  FIG. 5 is a cross-sectional view of the base end side link hub 32, the base end side end link member 35, and the like. In FIG. 5, the base end side link hub 32 and the base end side end link member 35 are shown. The relationship between the center axis O1 of each rotation pair and the spherical link center PA is shown. The positional relationship between the distal end side link hub 33 and the distal end side end link member 36 is also the same as that in FIG. 5 (not shown). In the illustrated example, the central axis O1 of each rotational pair of the link hubs 32, 33 and the end link members 35, 36, and the central axis O2 of each rotational pair of the end link members 35, 36 and the central link member 37 are illustrated. Is 90 degrees, but the angle α may be other than 90 degrees.

  The three sets of link mechanisms 34 have the same geometric shape. As shown in FIG. 6, the geometrically identical shape is represented by a geometric model in which each link member 35, 36, 37 is represented by a straight line, that is, each rotational pair and a straight line connecting these rotational pairs. A model says that the base end side part and front end side part with respect to the center part of the center link member 37 are symmetrical shapes. FIG. 6 is a diagram representing a set of link mechanisms 34 by straight lines. The parallel link mechanism 30 of this embodiment is a rotationally symmetric type, and includes a proximal end side link hub 32 and a proximal end side end link member 35, a distal end side link hub 33 and a distal end side end link member 36. The positional relationship is such that the positional relationship is rotationally symmetric with respect to the center line C of the central link member 37. The central part of each central link member 37 is located on a common track circle D.

  The link hub 32 on the proximal end side, the link hub 33 on the distal end side, and the three sets of link mechanisms 34 allow the link hub 33 on the distal end side to rotate about two orthogonal axes with respect to the link hub 32 on the proximal end side. A degree mechanism is configured. In other words, the position of the link hub 33 on the distal end side with respect to the link hub 32 on the proximal end side is a mechanism whose posture can be freely changed with two degrees of freedom. Although this two-degree-of-freedom mechanism is compact, the movable range of the link hub 33 on the distal end side with respect to the link hub 32 on the proximal end side can be widened.

  For example, a straight line that passes through the spherical link centers PA and PB and intersects the link hubs 32 and 33 and the center axis O1 (FIG. 5) of each rotation pair of the end link members 35 and 36 at right angles is the center axis of the link hubs 32 and 33. In the case of QA and QB, the maximum value of the bending angle θ (FIG. 6) between the central axis QA of the link hub 32 on the proximal end side and the central axis QB of the link hub 33 on the distal end side may be about ± 90 °. it can. Further, the turning angle φ (FIG. 6) of the distal end side link hub 33 with respect to the proximal end side link hub 32 can be set in a range of 0 ° to 360 °. The bending angle θ is a vertical angle in which the central axis QB of the distal end side link hub 33 is inclined with respect to the central axis QA of the proximal end side link hub 32, and the turning angle φ is the proximal end side link hub. This is a horizontal angle at which the central axis QB of the link hub 33 on the distal end side is inclined with respect to the central axis QA of 32.

  The posture change of the distal end side link hub 33 with respect to the proximal end side link hub 32 is performed with an intersection O between the central axis QA of the proximal end side link hub 32 and the central axis QB of the distal end side link hub 33 as a rotation center. Is called. 3 shows a state in which the central axis QA of the link hub 32 on the proximal end side and the central axis QB of the link hub 33 on the distal end side are on the same line, and FIG. 4 shows the central axis QA of the link hub 32 on the proximal end side. In contrast, a state in which the central axis QB of the link hub 33 on the distal end side takes a certain operating angle is shown. Even if the posture changes, the distance L (FIG. 6) between the spherical link centers PA and PB on the proximal end side and the distal end side does not change.

  In this parallel link mechanism 30, the angle of the central axis O1 of the rotation pair of the link hubs 32, 33 and the end link members 35, 36 in each link mechanism 34 and the length from the spherical link centers PA, PB are equal to each other, and The center axis O1 of the rotation pair of the link hubs 32, 33 and the end link members 35, 36 of each link mechanism 34 and the center axis O2 of the rotation pair of the end link members 35, 36 and the center link 7 are the base ends. The end link member 35 crosses the spherical link centers PA and PB on the side and the front end side, the geometrical shapes of the end link member 35 on the base end side and the end link member 36 on the front end side are equal, and the central link member 37 is also based on When the shape is the same on the end side and the front end side, the angular position relationship between the central link member 37 and the end link members 35 and 36 with respect to the symmetry plane of the central link member 37 And the distal end side link hub 32 and the proximal end side end link member 35, the distal end side link hub 33 and the distal end side end link member 36 in view of geometric symmetry. Moves the same way.

  As shown in FIGS. 2 to 4, the base-side link hub 32 includes a base end member 40 fixed to the third arm portion 13 and three rotations provided integrally with the base end member 40. It is comprised with the shaft connection member 41. FIG. The base end member 40 has a circular through hole 40a at the center, and three rotary shaft coupling members 41 are arranged at equal intervals in the circumferential direction around the through hole 40a. The center of the through hole 40a is located on the central axis QA of the link hub 32 on the proximal end side. A rotating shaft 42 whose shaft center intersects the central axis QA of the link hub 32 on the proximal end side is rotatably connected to each rotating shaft connecting member 41. One end of an end link member 35 on the base end side is connected to the rotating shaft 42.

  As shown in FIG. 5, the rotating shaft 42 is rotatably supported by the rotating shaft connecting member 41 via two bearings 43. The bearing 43 is a ball bearing such as a deep groove ball bearing or an angular ball bearing. These bearings 43 are installed in an inner diameter hole 44 provided in the rotary shaft connecting member 41 in a fitted state, and are fixed by a method such as press fitting, bonding, or caulking. The same applies to the types and installation methods of the bearings provided in other rotating pairs.

  One end of an end link member 35 on the base end side and a fan-shaped bevel gear 45 described later are coupled to the rotation shaft 42 so as to rotate integrally with the rotation shaft 42. Specifically, a notch 46 is formed at one end of the base end side end link member 35, and the rotation shaft connecting member is provided between the inner and outer rotation shaft support portions 47 and 48, which are both sides of the notch 46. 41 is arranged. The bevel gear 45 is disposed in contact with the inner surface of the inner rotary shaft support portion 47. Then, from the inside, the rotation shaft 42 has a through hole formed in the bevel gear 45, a through hole formed in the inner rotation shaft support portion 47, an inner ring of the bearing 43, and a through hole formed in the outer rotation shaft support portion 48. The bevel gear 45, the inner and outer rotary shaft support portions 47 and 48, and the inner ring of the bearing 43 are inserted by the nut 50 that is inserted in the order of the holes and screwed into the head portion 42 a of the rotary shaft 42 and the screw portion 42 b of the rotary shaft 42. These are sandwiched and joined together. Spacers 51 and 52 are interposed between the inner and outer rotary shaft support portions 47 and 48 and the bearing 43, and a preload is applied to the bearing 43 when the nut 50 is screwed.

  The rotation shaft 55 is coupled to the other end of the proximal end side end link member 35. The rotary shaft 55 is rotatably connected to one end of the central link member 37 via two bearings 53. Specifically, a notch 56 is formed at the other end of the base end side end link member 35, and a central link member is provided between the inner and outer rotary shaft support portions 57 and 58 that are both side portions of the notch 56. One end of 37 is arranged. Then, the rotating shaft 55 is inserted from the outside through the through hole formed in the outer rotating shaft support portion 58, the inner ring of the bearing 53, and the through hole formed in the inner rotating shaft support portion 57 in this order. The inner and outer rotary shaft support portions 57 and 58 and the inner ring of the bearing 53 are sandwiched between the head portion 55a and the nut 60 screwed to the screw portion 55b of the rotary shaft 55, and these are coupled to each other. Spacers 61 and 62 are interposed between the inner and outer rotary shaft support portions 57 and 58 and the bearing 53, and a preload is applied to the bearing 53 when the nut 60 is screwed.

  As shown in FIG. 3 and FIG. 4, the link hub 33 on the distal end side is provided with a distal end member 70 fixed to the fourth arm portion 14, and 3 provided on the inner surface of the distal end member 70 at equal intervals in the circumferential direction. It is comprised with the one rotating shaft connection member 71. FIG. The center of the circumference where each rotary shaft connecting member 71 is arranged is located on the central axis QB of the link hub 33 on the distal end side. Each rotating shaft connecting member 71 is rotatably connected to a rotating shaft 73 whose axis intersects the link hub central axis QB. One end of the end link member 36 on the front end side is connected to the rotation shaft 73 of the link hub 33 on the front end side. A rotating shaft 75 that is rotatably connected to the other end of the central link member 37 is connected to the other end of the end-side end link member 36. The rotary shaft 73 of the link hub 33 on the distal end side and the rotary shaft 75 of the central link member 37 are respectively connected to the rotary shaft connecting member 71 and two rotary shafts (not shown) in the same manner as the rotary shafts 42 and 55. The other end of the central link member 37 is rotatably connected.

As shown in FIG. 2, the attitude control drive source 31 for operating the parallel link mechanism 30 is installed on the base end member 40 and is arranged inside the third arm portion 13. The number of posture control drive sources 31 is three, which is the same as the number of link mechanisms 34. The attitude control drive source 31 is composed of a rotary actuator, and a bevel gear 76 attached to the output shaft thereof meshes with the fan-shaped bevel gear 45 attached to the rotary shaft 42 of the link hub 32 on the proximal end side.
In this example, the same number of attitude control drive sources 31 as the link mechanisms 34 are provided, but if at least two of the three sets of link mechanisms 34 are provided with the attitude control drive sources 31, The posture of the distal end side link hub 33 with respect to the proximal end side link hub 32 can be determined.

  The fourth joint unit 24 including the link actuating device activates the parallel link mechanism 30 by rotationally driving each posture control drive source 31. Specifically, when the attitude control drive source 31 is rotationally driven, the rotation is transmitted to the rotary shaft 42 via the pair of bevel gears 76 and 45, and the proximal end side link with respect to the proximal end side link hub 32. The angle of the member 35 changes. Accordingly, the position and posture of the link hub 33 on the distal end side with respect to the link hub 32 on the proximal end side are determined. Here, the angle of the end link member 35 on the base end side is changed using the bevel gears 76 and 45, but other mechanisms (for example, a spur gear or a worm mechanism) may be used.

  In FIG. 1, each attitude control drive source 31 is provided with torque detection means 78 for detecting torque applied to the attitude control drive source 31. The detection signal of the torque detection means 78 is sent to the load estimation means 79 in the controller 6. The load estimating means 79 estimates the load acting on the distal end side link hub 33 from the detection results of the torque detecting means 78.

  The fourth arm portion 14 is provided with a rotation mechanism 80 (hereinafter referred to as “tip rotation mechanism 80”), and supports the end effector 4 via the tip rotation mechanism 80. The tip rotation mechanism 80 is obtained by attaching an end effector installation member 80b to a rotation shaft of a rotational drive source 80a such as a motor, and the end effector 4 is fixed to the end effector installation member 80b. As the end effector 4, for example, a hand, a welding machine, a coating machine, or the like is used, but the end effector 4 is not limited to these.

  This multi-joint robot 1 has one degree of freedom of the first joint portion 21 composed of a rotation mechanism, one degree of freedom of the second joint portion 22 composed of a rotation mechanism, and one of the third joint portion 23 composed of a linear motion mechanism. The configuration is a total of 6 degrees of freedom, including a degree of freedom, 2 degrees of freedom of the fourth joint portion 24 formed of a link actuator, and 1 degree of freedom of the tip rotation mechanism 80 provided in the fourth arm portion 14. With a 6-degree-of-freedom configuration, motion close to that of a human hand is possible.

  In particular, by using a link actuator for one of the plurality of joints 21 to 24, a smooth operation without a singular point is possible within the operating range of a bending angle of 90 ° and a turning angle of 360 °. This makes it possible to achieve fine-grained operation. The fine-grained motion is, for example, a motion that moves around a human wrist joint, such as a character writing motion or a motion using a snap, but is not limited to these motions. By using the link actuating device, the joint portion 24 can be made compact while having two degrees of freedom of rotation.

  Further, by using a linear motion mechanism for one joint portion 23, it is possible to perform an operation in a straight traveling direction by operating one drive source 23a. Therefore, it can be easily operated even if it has little knowledge and little experience.

  Torque detection means 78 for detecting the torque applied to each posture control drive source 31 and load estimation means 79 for estimating the load acting on the distal end side link hub 33 from the detection result of the torque detection means 78 are provided. Therefore, when an abnormal load is applied to the articulated robot 1, for example, when it collides with a person or an object, this can be detected. For this reason, when an abnormal load is applied, an avoidance operation such as stopping the operation can be performed, which is safe.

  By providing the torque detection means 78 in the posture control drive source 31, it is possible to estimate the load acting on the link hub 33 on the distal end side without providing a load detection sensor separately. Leads to cost reduction and cost reduction. In addition, since there is no singular point and the structure can be moved smoothly in all directions within the operating range of the fourth joint portion 24 composed of the link operating device, when a load acts on the link hub 33 on the distal end side from various directions However, torque is reliably transmitted to the attitude control drive source 31, and an accurate load can be estimated.

  When the articulated arm 3 of the articulated robot 1 is regarded as a human arm, the fourth joint portion 24 corresponding to the wrist joint is a link actuating device with two degrees of freedom capable of rotating close to the wrist joint. Since it comprised, it became easy to imagine the relationship between the motion of each joint part 21-24 and the motion of the end effector 4, and operativity is good. Further, since the fourth joint portion 24 composed of the link actuator is disposed near the tip of the multi-joint arm 3, the load acting on the link actuator is small, and a finer operation can be performed at a higher speed. Further, since the distal end rotating mechanism 80 that may twist the cable is arranged on the distal end side with respect to the fourth joint portion 24 formed of the link operating device and the third joint portion 23 formed of the linear motion mechanism, the link operating device. Wiring such as a linear motion mechanism is easy.

  The third joint portion 23 composed of the linear motion mechanism is configured such that the third arm portion 13 is housed inside the second arm portion 12, so that it is compact when the articulated robot 1 is not used. And storage space is small. Further, since the movable range of the entire articulated robot 1, particularly the movable range of the articulated arm 3 between the base unit 2 and the end effector 4 can be minimized, the occupied space can be reduced.

  FIG. 7 shows another embodiment. In this multi-joint robot 1, the third joint portion 23 formed of a linear motion mechanism is different from the embodiment of FIG. 1 in that the third joint portion 23 extends along the linear stage 23 b installed on the side surface of the second arm portion 12. In this configuration, the arm unit 13 is moved. The third arm unit 13 is driven by a drive source 23c such as a linear actuator provided in the second arm unit 12. Others are the same as the articulated robot 1 of FIG.

  FIG. 8 shows still another embodiment. This articulated robot 1 is configured by installing two articulated arms 3 on one base unit 2. Specifically, the first arm portions 11 of the two articulated arms 3 are installed on side surfaces of the base unit 2 that are symmetrical to each other. Each articulated arm 3 has the same configuration as the articulated arm 3 of the articulated robot 1 of FIG.

  In this way, by providing two multi-joint arms 3, it is possible to perform an operation that a person performs with both hands. In particular, by arranging the two multi-joint arms 3 on a symmetrical surface in the base unit 2, a double-armed robot shape similar to that of a person is obtained, and work similar to that of a person can be performed. In addition, when the articulated robot 1 becomes malfunctioning, a person can enter the space where the articulated robot 1 has been removed to perform the work, so that the productivity can be prevented from being significantly reduced.

  FIG. 9 shows still another embodiment. This articulated robot 1 has a configuration in which the second joint portion 22 of the articulated arm 3 is replaced with a rotation mechanism of the articulated robot 1 shown in FIG. The other joint parts 21, 23, and 24 have the same configuration as the articulated robot of FIG. Therefore, since the second joint portion 22 has two degrees of freedom, the multi-joint arm 3 itself has a configuration of six degrees of freedom. When the tip arm rotation mechanism (not shown) is provided on the fourth arm portion 14, the entire articulated robot 1 has a configuration of 7 degrees of freedom. As described above, by configuring the second joint portion 22 corresponding to a human elbow joint with a link actuating device having two degrees of freedom of rotation, it is possible to perform a more complicated operation.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Articulated robot 2 ... Base unit 3 ... Articulated arm 4 ... End effector 5 ... Installation surface 11 ... 1st arm part 12 ... 2nd arm part 13 ... 3rd arm part 14 ... 4th arm part 21 ... 1st joint part (rotation mechanism)
22 ... Second joint (rotating mechanism)
23 ... Third joint (linear motion mechanism)
24 ... Fourth joint (link actuating device)
DESCRIPTION OF SYMBOLS 30 ... Parallel link mechanism 31 ... Attitude control drive source 32 ... Base end side link hub 33 ... Front end side link hub 34 ... Link mechanism 35 ... Base end side end link member 36 ... Front end side end link member 37 ... Center link member 78 ... Torque detection means 79 ... Load estimation means

Claims (1)

A base unit and a multi-joint arm installed on the base unit. The multi-joint arm has a plurality of arms arranged in series from the base end side to the tip end side. 6-degree-of-freedom or more articulated robot in which the arm part and adjacent arm parts are connected to each other via joint parts so as to be relatively displaceable, and work is performed using an end effector mounted on the arm part on the most distal side. Because
Of the plurality of joint portions, the joint portion that connects the most distal arm portion and one proximal end arm portion from the arm portion is configured such that the arm portions on both sides are mutually orthogonally around two axes. It consists of a link actuator that rotates relatively,
The link actuating device comprises three sets of link hubs on the distal end side fixed to the arm portion on the distal end side with respect to the link hub on the proximal end side fixed to the arm portion on the proximal end side among the arm portions on both sides. The above-mentioned link mechanisms are connected so that their postures can be changed, and the respective link mechanisms are respectively connected to the base end side link hub and the front end side link hub so that one end is rotatably connected to the base end side and the front end. Side link member and a central link member having both ends rotatably connected to the other ends of the proximal and distal end link members, of the three or more sets of link mechanisms A posture control drive source that arbitrarily changes the posture of the distal end side link hub with respect to the proximal end side link hub in the two or more sets of link mechanisms;
Each of the attitude control drive sources is provided with torque detection means for detecting torque applied to the attitude control drive source, and load estimation means for estimating the load acting on the distal end side link hub from the detection result of the torque detection means. An articulated robot using a link actuating device provided.

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