JP2005271183A - Articulated drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an articulated drive device capable of realizing the miniaturization without causing a torque loss of a direct-acting actuator. <P>SOLUTION: The articulated drive device is provided with rotating parts 6-8 for freely rotatably supporting each frame 3-5 about supporting shafts 11-13, a pair of first or third direct-acting actuators 61a, 61b, 71a, 71b, 81a, and 81b, in which each one end is connected so as to bend each frame in the normal/reverse directions to each rotating part, and a controller 10 to which the other end of each direct-acting actuator is connected and which bends each frame in the normal/reverse directions by controlling a contraction amount of each direct-acting actuator. The contraction amount control of each direct-acting actuator is executed by the controller. Each slackened direct-acting actuator is respectively stretched between the rotating part and the controller. After that, one frame is bent by controlling so as to release the contraction of the other direct-acting actuator by an amount corresponding to the contraction amount of one direct-acting actuator while further contracting the one direct-acting actuator. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multi-joint drive device that is driven by a linear actuator, and particularly relates to a multi-joint drive device that is used for a robot hand or the like that exhibits a movement similar to a human hand.

  In recent years, a robot hand having a movement similar to that of a human hand and realized by a plurality of fingers composed of a multi-joint mechanism has been developed.

  As means for moving the joint part of this multi-joint mechanism independently, there are those using a link mechanism and those using a ball screw, etc., because these are complicated and there is a problem in miniaturization. A method of driving each joint with a wire is employed. As described above, in the method of driving the joint portion with the wire, the wire is routed between the joint and the driving motor by the guide pulley, the wire is pulled in the desired direction by the driving motor, and the joint is driven via the guide pulley or the like. (For example, refer to Patent Document 1).

  However, the method of driving the joint portion with a wire requires a motor having a certain size in order to obtain an appropriate generated force. Further, since the number of motors corresponding to the number of joints is required, there is a limit to downsizing the robot hand, and it is very difficult to make it equal to the size of a human.

  In recent years, therefore, the development of artificial muscles has become active. This is a direct acting actuator, and a typical example thereof is a shape memory alloy or the like (for example, see Non-Patent Document 1).

  Specifically, when converting the driving force of the direct acting actuator into a unidirectional rotational motion, as shown in FIG. 4, the rotational direction (in the figure, relative to the rotating part b rotating around the fulcrum a). One end of the direct acting actuator c is coupled to the upper end side), while one end of the spring d is coupled to the rotating portion b in the reverse rotation direction (the lower end side in the drawing) opposite to the rotation direction. The other end of c and the other end of the spring d are connected to the base body e. When the current is applied to the direct acting actuator c and contracted, the rotating part b rotates in the direction of the arrow around the fulcrum a while pulling the spring d, while the current supply to the direct acting actuator c is cut off. Thus, when the direct acting actuator c returns to its original length, the rotating portion b rotates reversely due to the contraction force of the spring d and returns to its original state.

Further, when the driving force of the direct acting actuator is converted into rotational motion in both directions (forward and reverse rotation directions), as shown in FIG. 5, the rotating part b ′ rotating around the fulcrum a ′ is rotated forward and backward One end of one linear motion actuator f is connected to the forward rotation direction (upper end side in the figure) of the rotation part b ′, while the other in the reverse rotation direction (lower end side in the figure) of the rotation part b ′. One end of each of the direct acting actuators g is connected, and the other ends of the two direct acting actuators f and g are attached to an intermediate operation portion h having a spring structure. When a current is applied to one linear actuator f and contracted, the rotating part b 'rotates around one fulcrum a' toward the one linear actuator f (clockwise in the figure), while the other When a current is applied to the direct acting actuator g to cause it to contract, the rotating part b 'rotates around the fulcrum a' toward the other direct acting actuator g (counterclockwise in the figure). At this time, the load acting on the other direct acting actuator g (or f) when the one direct acting actuator f (or g) contracts is absorbed by the intermediate operation portion h.
JP-A-6-8178 "Frequently asked questions about biometal" HP of Toki Corporation (http://www.toki.co.jp/BioMetal/index.html)

  However, those using the above-described direct acting actuators have the following problems.

  That is, in the case of using the single direct acting actuator c like the former, the rotation is performed when the rotating part b is rotated in one direction by the driving force (contraction force) of the direct acting actuator c. Since the part b tries to rotate in the reverse direction by the biasing force (tensile force) of the spring d, the driving force (torque) of the direct acting actuator c is reduced by the biasing force of the spring d. Therefore, even if the motion of the multi-joint drive device such as the fingertip of the robot hand is to be reproduced by the direct-acting actuator c, if the driving force (torque) of the direct-acting actuator c is reduced, the articulated drive device has a large effect. A force cannot be generated, and the performance of the multi-joint drive device is significantly reduced.

  Further, in the case of using the two direct acting actuators f and g as in the latter case, the rotating part b ′ is rotated in one direction by the driving force of one of the direct acting actuators f (or g). In this case, since the load acting on the other direct acting actuator g (or f) is absorbed by the intermediate operation portion h, the driving force (torque) of the one direct acting actuator is reduced by the intermediate operation portion h. It will be. Therefore, even if the movement of the multi-joint drive device is to be reproduced by the direct acting actuators f and g, if the driving force (torque) of the direct acting actuators f and g is reduced, a large force is applied to the multi-joint drive device. It cannot be generated and the performance of the multi-joint drive device will be significantly reduced as well. Moreover, when a structure such as the intermediate operation portion h is attached to the other end side of each of the direct acting actuators f and g, it is necessary to secure a space for accommodating the intermediate operation portion h. This is a factor that hinders downsizing of the driving device.

  The present invention has been made in view of such points, and an object of the present invention is to provide a multi-joint drive device that can be reduced in size without incurring torque loss of a direct acting actuator. It is aimed.

  In order to achieve the above object, the present invention is based on the premise of a multi-joint drive device in which a plurality of frames sequentially connected via a plurality of joints are rotationally driven by a drive unit around each joint as a fulcrum. And a pair of linear motions, each end being connected to bend the frame in the forward / reverse direction with respect to the rotating part. And a controller that bends each frame in the forward and reverse directions by controlling the amount of contraction of each linear actuator relative to the rotating portion. Then, when the controller is in a state before the contraction amount control is performed by the controller, each of the above-described components is provided between the rotating unit and the controller with a slack longer than the shortest distance connecting the rotating unit and the controller. Connect a direct acting actuator. Further, the controller controls the amount of contraction of each linear actuator when the frame is bent in one of the forward and reverse directions, and each linear actuator is stretched between the rotating portion and the controller. In this state, one linear motion actuator in the bending direction is further contracted, while the contraction of the other linear motion actuator is released by an amount corresponding to the contraction amount of the linear motion actuator. .

  Due to this specific matter, when each frame is bent in one of the forward and reverse directions, the amount of contraction of each linear actuator is controlled, and each linear actuator is stretched between the rotating part and the controller. In this state, one linear motion actuator in the bending direction is further contracted, and the contraction of the other linear motion actuator is canceled and extended by an amount corresponding to the contraction amount of the one linear motion actuator. Therefore, the driving force (torque) when contracting one of the linear actuators in the bending direction of each frame is not reduced by the other linear actuator, and the movement of the fingertip of the robot hand etc. is straightforward. A multi-joint drive device that is reproduced smoothly by a dynamic actuator and applied to the fingertips of such robot hands. It is possible to generate a large force, it is possible to improve the performance of the multi-joint drive.

  In addition, the intermediate operation unit has a structure in which an intermediate operation unit having a spring that absorbs a load acting on the other direct acting actuator when one of the direct acting actuators contracts is attached to each direct acting actuator. Therefore, it is not necessary to secure a space for housing the multi-joint drive device without the need for an intermediate operation portion.

  In particular, the following configurations are listed as specifying the linear motion actuators.

  That is, at least a part of each direct acting actuator is made of a material that can be expanded and contracted.

  Due to this specific matter, it is not necessary to configure the whole of each direct acting actuator with a material that can be expanded and contracted, and the production cost of each direct acting actuator can be reduced.

  In addition, when shape memory alloy is applied as a material that can be expanded and contracted, the shape memory alloy contracts due to the heat generated by energization of current by the controller, and the contraction control of each linear actuator is smoothly performed. Is possible.

  On the other hand, when a conductive polymer is used as a stretchable material, the conductive polymer contracts when a voltage is applied by the controller, and each linear motion is not affected by the ambient temperature. It becomes possible to perform the contraction control of the type actuator more smoothly.

  In particular, the following configurations are listed as specifying the length of each linear motion actuator.

That is, the shortest distance H connecting the rotating unit and the controller, the radius r of the rotating unit, the rotation angle range 2θ (rad) of the rotating unit, and the length L of each linear actuator,
L ≧ r · θ + H
It is set to satisfy the relationship.

  With this specific matter, the length L of each linear actuator is logically determined based on the shortest distance H between the rotating part and the controller, the radius r of the rotating part, and the rotation angle range 2θ (rad) of the rotating part. Therefore, it is possible to reliably improve the performance of the multi-joint drive device and reduce the size of the multi-joint drive device. In addition, it is possible to provide an articulated drive device in which the length of each linear motion actuator is appropriately set and has an arbitrary rotation angle. In addition, it can be applied to various linear motion actuators, and the usage can be diversified.

Furthermore, the rotation angle range 2θ (rad) of the rotating part, the radius r of the rotating part, and the contraction amount m of each direct acting actuator,
m ≧ 2r · θ
Is set so as to satisfy the relationship, the contraction amount m of each direct acting actuator is logically set based on the rotation angle range 2θ of the rotating part and the radius r of the rotating part. The contraction control of the direct acting actuator can be performed more reliably.

  In short, the amount of contraction of each direct acting actuator is controlled and each direct acting actuator is stretched between the rotating part and the controller, and then one of the direct acting actuators is further contracted. By releasing the contraction of the other direct acting actuator and extending it by the amount corresponding to the contraction amount of one direct acting actuator, the torque loss when contracting one of the direct acting actuators is suppressed. The performance of the multi-joint drive device can be improved, and the multi-joint drive device can be downsized.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of an articulated drive device according to the present invention. In FIG. 1, an articulated drive device 1 includes a base 2 and a plurality of first to third frames 3, which are sequentially connected to the tip thereof. 4 and 5 are provided.

  The base 2 and the first frame 3 on the base end side connected to the base 2 are rotatably connected by a first disk-shaped first rotating portion 6. Further, the first frame 3 and the central second frame 4 connected to the first frame 3 are rotatably connected by a substantially disc-shaped second rotating portion 7. Further, the second frame 4 and the third frame 5 on the distal end side connected to the second frame 4 are rotatably connected by a substantially disc-shaped third rotating portion 8. Specifically, the first rotating portion 6 is connected to the base end (base 2 side end) of the first frame 3 so as to rotate together, and rotates to the first support shaft 11 as a rotation fulcrum erected on the base 2. It is supported freely. The second rotating portion 7 is integrally connected to the base end (first frame 3 side end) of the second frame 4 and is erected on the tip end (second frame 4 side end) of the first frame 3. The second support shaft 12 as a rotation fulcrum is rotatably supported. Further, the third rotating portion 8 is integrally connected to the base end (second frame 4 side end) of the third frame 5 and is erected on the tip end (third frame 5 side end) of the second frame 4. The third support shaft 13 as a rotation fulcrum is rotatably supported.

  A pair of first linear motions, which are entirely composed of a string-like shape memory alloy, on the outer peripheral surface of the first rotating portion 6 located on the central axis of the first frame 3 passing through the first support shaft 11. A first fixing member 61c for fixing one end of each of the type actuators 61a and 61b is fixed. Further, on the outer peripheral surface of the second rotating portion 7 positioned on the central axis of the second frame 4 passing through the second support shaft 12, a pair of second members are formed entirely of string-like shape memory alloy. A second fixing member 71c for fixing one end of each of the direct acting actuators 71a and 71b is fixed. Further, on the outer peripheral surface of the third rotating portion 8 located on the center axis of the third frame 5 passing through the third support shaft 13, a pair of third parts are formed entirely by a string-like shape memory alloy. A third fixing member 81c for fixing one end of each of the direct acting actuators 81a and 81b is fixed. In this case, on the outer peripheral surfaces of the first to third rotating parts 6-8, linear motion actuators 61a, 61b, one ends of which are connected to the fixing members 61c, 71c, 81c of the rotating parts 6-8, Guide grooves (not shown) for guiding 71a, 71b, 81a, 81b are provided.

  On the other hand, the other ends of the first to third linear motion actuators 61a, 61b, 71a, 71b, 81a, 81b are respectively connected to the controller 10 housed in the base 2. The controller 10 individually controls the amount of current applied to each of the first to third linear actuators 61a, 61b, 71a, 71b, 81a, 81b, and controls each of the linear actuators 61a, 61b, 71a. , 71b, 81a, 81b generate heat to control the amount of contraction. For example, as shown in FIG. 2, when the third frame 5 is rotated in the direction of arrow B (upward in FIG. 2) with respect to the second frame 4, the one in the direction of arrow B (upward in FIG. 2) This is done by energizing the third direct acting actuator 81a to cause the actuator 81a to generate heat and contracting it, and rotating the third rotating portion 8 around the third support shaft 13. On the other hand, when the third frame 5 is rotated relative to the second frame 4 in the direction of arrow A (downward in FIG. 2), the other third linear actuator 81b in the direction of arrow A (downward in FIG. 2). The current is supplied to the actuator 81b to generate heat, causing the actuator 81b to contract, and the third rotating portion 8 is rotated about the third support shaft 13. The same control is performed when the first frame 3 is rotated with respect to the base 2 and when the second frame 4 is rotated with respect to the first frame 3.

  Each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b can be controlled to contract from the original length by controlling the amount of current applied by the controller 10, but extends beyond the original length. Therefore, when connecting between the fixing members 61c, 71c, 81c of the rotating parts 6-8 and the controller 10, the fixing members 61c, 71c, 81c of the rotating parts 6-8 and the controller 10 are connected. 3 is longer than the shortest distance between the fixing members 61c, 71c, 81c of the rotating portions 6-8 and the controller 10, as shown in FIG. In a state where the slack is provided, the fixing members 61 c, 71 c, 81 c of the rotating parts 6 to 8 are connected to the controller 10. Specifically, the length L1 of the first linear actuators 61a and 61b is set such that the shortest distance between the first fixing member 61c of the first rotating unit 6 and the controller 10 is H1, and the length of the first rotating unit 6 is Assuming that the radius is r1 and the rotation angle range of the first rotating unit 6 is 2θ (rad), it is set so as to satisfy the relationship of L1 ≧ r1 · θ + H1. The length L2 of the second linear actuators 71a and 71b is such that the shortest distance between the second fixed member 71c of the second rotating part 7 and the controller 10 is H2, and the radius of the second rotating part 4 is r2. Assuming that the rotation angle range of the second rotating unit 7 is 2θ (rad), it is set so as to satisfy the relationship of L2 ≧ r2 · θ + H2. Furthermore, the length L3 of the third linear actuators 81a and 81b is set such that the shortest distance between the third fixing member 81c of the third rotating portion 8 and the controller 10 is H3, and the radius of the third rotating portion 8 is r3. Assuming that the rotation angle range of the third rotating unit 8 is 2θ (rad), it is set so as to satisfy the relationship of L3 ≧ r3 · θ + H3. In this case, the length of each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b may be set to be longer than L1, L2, L3, respectively. Therefore, it is desirable to match the lengths L1, L2, and L3 as much as possible.

  Further, the contraction amount m1 of the first linear actuators 61a and 61b is such that m1 ≧ 2r1 · θ, where 2θ (rad) is the rotation angle range of the first rotation unit 6 and r1 is the radius of the first rotation unit 6. It is set to satisfy the relationship. The contraction amount m2 of the second linear motion actuators 71a and 71b is such that m2 ≧ 2r2 · θ, where 2θ (rad) is the rotation angle range of the second rotation unit 7 and r2 is the radius of the second rotation unit 7. It is set to satisfy the relationship. Further, the contraction amount m3 of the third linear actuators 81a and 81b is such that m3 ≧ 2r3 · θ where the rotation angle range of the third rotation unit 8 is 2θ (rad) and the radius of the third rotation unit 8 is r3. It is set to satisfy the relationship.

  Here, control by the controller 10 when the first to third frames 3 to 5 are rotated will be described with reference to FIGS. 2 and 3. Note that the same control is performed when the first frame 3 is rotated with respect to the base 2 and when the second frame 4 is rotated with respect to the first frame 3. Only the case of rotating will be described.

  First, when the third frame 5 is bent in the direction of the arrow B (upward in FIGS. 2 and 3), the contraction amount control of the third linear actuators 81a and 81b is performed as shown in FIG. The third linear motion type actuators 81a and 81b are stretched between the third fixing member 81c of the third rotating portion 8 and the controller 10, respectively. In this state, as indicated by a two-dot chain line in FIG. 2, a current is further supplied to one of the linear actuators 81a in the bending direction (the upper side in FIGS. 2 and 3) to further contract, Control is performed by the controller 10 so as to release the contraction of the other direct acting actuator 81b (the lower side in FIGS. 2 and 3) corresponding to the amount of contraction of the direct acting actuator 81a. As a result, one third linear motion actuator 81a stretched between the third fixing member 81c of the third rotating portion 8 and the controller 10 starts to contract further, and the other third linear motion is moved accordingly. The actuator 81b starts to return to the original length. Therefore, the third rotating portion 8 rotates in the direction of arrow B around the support shaft 13 at the tip of the second frame 4, and the third frame 5 rotates to the rotation angle range θ (rad) that is the limit in the direction of arrow B. It is supposed to be.

  On the other hand, when the third frame 5 is bent by rotating in the arrow A direction (downward in FIGS. 2 and 3), the contraction amount control of the third linear actuators 81a and 81b is performed as shown in FIG. From the state where the third linear motion type actuators 81a and 81b are stretched between the third fixing member 81c of the third rotating portion 8 and the controller 10 after removing the slack, as shown by a solid line in FIG. In addition, the other direct acting actuator 81b in the bending direction (the lower side in FIGS. 2 and 3) is further shrunk by applying a current to the other, and the amount corresponding to the shrinkage amount of the other direct acting actuator 81b. Only one (the upper side in FIGS. 2 and 3) is controlled by the controller 10 so as to release the contraction of the direct acting actuator 81 a. As a result, the other third linear actuator 81b stretched between the third fixing member 81c of the third rotating portion 8 and the controller 10 starts to further contract, and one of the third linear actuators moves accordingly. The actuator 81a starts to return to the original length. Therefore, the third rotating portion 8 rotates in the direction of arrow A around the support shaft 13 at the tip of the second frame 4, and the third frame 5 rotates to the rotation angle range θ (rad) that is the limit in the direction of arrow A. It is supposed to be.

  As described above, in the above embodiment, when the third frame 5 is bent in either the arrow A direction or the arrow B direction, the contraction amount control of the third linear motion actuators 81a and 81b is performed, respectively. From the state in which the third linear actuators 81a and 81b are stretched between the fixed member 13 of the rotating unit 8 and the controller 10, one third linear actuator 81a (or 81b) in the bending direction is further moved. While contracting, the contraction of the other third linear actuator 81b (or 81a) is canceled by an amount corresponding to the contraction amount of one third linear actuator 81a (or 81b) to the original length. Since it is made to return, the driving when the third linear actuator 81a (or 81b) on one side in the bending direction of the third frame 8 is contracted. The force (torque) is not reduced by the other third direct acting actuator 81b (or 81a), and the movement of the fingertip of the robot hand is caused by each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b. It can be reproduced smoothly and a large force can be generated in the multi-joint drive device 1 when applied to the fingertip of such a robot hand, and the performance of the multi-joint drive device 1 can be improved.

  In addition, each linear operation type is provided with an intermediate operation portion having a spring that absorbs a load acting on the other third linear motion actuator 81b (or 81a) when the one third linear motion actuator 81a (or 81b) contracts. It is not necessary to attach to the actuators 61a, 61b, 71a, 71b, 81a, 81b, and it is not necessary to secure a space for accommodating the intermediate operation unit, so that the articulated drive device 1 can be reduced in size.

  Further, since the shape memory alloy is applied as a material that can control the compression of each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b, the shape memory is generated by the heat generated by the current supply by the controller 10. The alloy contracts and the contraction control of each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b can be smoothly performed.

  And the shortest distance which connects between each fixed member 11-13 of the 1st thru / or the 3rd rotation parts 6-8 and controller 10 is H1, H2, H3, and the radius of each rotation parts 6-8 is r1, r2, r3. When the rotation angle range of each of the rotating units 6 to 8 is 2θ (rad), the lengths L1, L2, and L3 of the respective direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b are set to L1 (or L2 or L3) ≧ r1 (or r2 or r3) · θ + H1 (or H2 or H3) is set so as to satisfy the relationship of each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b. The lengths L1, L2, and L3 are the shortest distances H1, H2, and H3 that connect the fixing members 11 to 13 of the first to third rotating parts 6 to 8 and the controller 10, and the radii of the rotating parts 6 to 8 r1 , R2, r3, and the rotation angle range 2θ (rad) of each of the rotating units 6 to 8, which are logically set to reliably improve the performance of the multi-joint drive 1 and reduce the size of the multi-joint drive 1 Can be made. In addition, it is possible to provide the multi-joint drive device 1 in which the length of each of the linear motion actuators 61a, 61b, 71a, 71b, 81a, 81b is appropriately set and has an arbitrary rotation angle. Moreover, it can be applied to various linear motion actuators 61a, 61b, 71a, 71b, 81a, 81b, and the usage can be diversified.

  Furthermore, the rotation angle range 2θ (rad) of the first to third rotating parts 6 to 8, the radii r1, r2, and r3 of the rotating parts 6 to 8, the direct acting actuators 61a, 61b, 71a, 71b, 81a, Since the contraction amounts m1, m2, and m3 of 81b are set so as to satisfy the relationship of m1 (or m2 or m3) ≧ 2r1 (or 2r2 or 2r3) · θ, each of the direct acting actuators 61a, 61b, 71a , 71b, 81a, 81b, the contraction amounts m1, m2, m3 are logically set based on the rotation angle range 2θ of each of the rotating parts 6-8 and the radii r1, r2, r3 of each of the rotating parts 6-8, The contraction control of each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b by the controller 10 can be performed more reliably.

  In addition, this invention is not limited to the said embodiment, The other various modifications are included. For example, in the above embodiment, each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b is made of a string-like shape memory alloy, but each of the direct acting actuators is made of a conductive polymer that contracts when a voltage is applied. May be configured. In this case, the conductive polymer contracts due to the application of voltage by the controller, and the contraction control of each direct acting actuator can be performed more smoothly without being affected by the ambient temperature.

  Furthermore, in the above-described embodiment, each of the direct acting actuators 61a, 61b, 71a, 71b, 81a, 81b is made of a string-like shape memory alloy, but only a part of the shape memory alloy, a conductive polymer, etc. It may be made of a shrinkable material, and the remaining portion may be made of a non-stretchable material such as a metal wire or a non-bendable metal rod. In this case, the portion corresponding to the non-stretchable material such as a non-bendable metal rod is not wound around the outer peripheral surface of the rotating part, so it needs to be positioned in the base, but the shape memory alloy, conductive polymer, etc. The parts corresponding to non-stretchable materials and the parts corresponding to non-stretchable materials such as metal wires can be positioned in each frame and in the base, and it is possible to constitute a direct acting actuator of various materials Become.

It is sectional drawing explaining the outline of the internal structure of the articulated drive device concerning embodiment of this invention. It is sectional drawing explaining the outline of the internal structure of a multi joint drive device in the bending state of a 3rd frame. It is sectional drawing explaining the outline of the internal structure of a multi joint drive device in the state before contraction | shrinkage amount control of each linear actuator. It is sectional drawing explaining the outline which implement | achieved the rotational drive by the linear motion type actuator concerning a prior art example. It is sectional drawing explaining the outline which implement | achieved the rotational drive by the linear motion type actuator concerning another prior art example.

Explanation of symbols

1 Articulated Drive Device 3 First Frame (Frame)
4 Second frame (frame)
5 Third frame (frame)
11 First spindle (rotating fulcrum)
12 Second spindle (rotating fulcrum)
13 Third spindle (rotating fulcrum)
6 1st rotation part (rotation part)
61a, 61b
First direct acting actuator (direct acting actuator)
7 Second rotating part (rotating part)
71a, 71b
Second direct acting actuator (direct acting actuator)
8 Third rotating part (rotating part)
81a, 81b
Third direct acting actuator (direct acting actuator)
10 Controller

Claims (6)

In the multi-joint drive device that is configured to rotationally drive a plurality of frames sequentially connected via a plurality of joints with each joint as a fulcrum by a drive unit,
The drive unit is
A rotating part that rotatably supports each frame around the rotation fulcrum of each joint;
A pair of direct acting actuators, each end of which is connected to bend each frame in the forward and reverse directions with respect to each rotating part;
A controller that bends each frame in the forward / reverse direction by controlling the amount of contraction of each linear actuator relative to the rotating portion, the other end of each linear actuator being connected to each other;
When each of the linear motion actuators is in a state before the contraction amount control by the controller, the rotation unit and the controller are in a state of having a slack longer than the shortest distance connecting the rotation unit and the controller. Is connected between and
The controller controls the amount of contraction of each direct acting actuator when each frame is bent in either the forward or reverse direction, and each direct acting actuator is stretched between the rotating part and the controller. The one direct acting actuator in the bending direction is further contracted while the other direct acting actuator is controlled to release the contraction by an amount corresponding to the contraction amount of the one direct acting actuator. A multi-joint drive device. In the multi-joint drive device according to claim 1,
Each of the linear motion actuators is constituted by a material that can be expanded and contracted, at least a part of which is an articulated drive device. In the multi-joint drive device according to claim 2,
An articulated drive device characterized in that a shape memory alloy is applied as the stretchable material. In the multi-joint drive device according to claim 2,
An articulated drive device characterized in that a conductive polymer is applied as the stretchable material. In the articulated drive device according to any one of claims 1 to 4,
The shortest distance H between the rotating part and the controller, the radius r of the rotating part, the rotation angle range 2θ (rad) of the rotating part, and the length L of each linear actuator are:
L ≧ r · θ + H
An articulated drive device characterized by being set so as to satisfy the above relationship. In the articulated drive device according to any one of claims 1 to 5,
The rotation angle range 2θ (rad) of the rotating part, the radius r of the rotating part, and the contraction amount m of each direct acting actuator are:
m ≧ 2r · θ
An articulated drive device characterized by being set so as to satisfy the above relationship.

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