JP4397805B2 - Joint structure and robot arm - Google Patents

Description

  The present invention relates to a joint structure of a mechanical device such as a robot arm and a robot arm including the joint structure.

  Conventionally, a multi-joint robot arm usually has a structure in which an actuator for driving the joint is arranged at or near the joint. However, in such a structure, a portion close to the hand, such as a wrist of a humanoid arm, is heavy. Since a motor or the like is disposed, the inertia of the hand increases, which impedes improvement of the position control performance of the hand, or gives a large impact at the time of a collision, which must be considered in terms of safety.

  In order to solve such problems, a wire-driven robot arm has been developed in which an actuator is disposed apart from a joint to be driven and is located near the base, and a driving force is transmitted by a wire. The wire-driven robot arm has excellent features such as high-speed driving because the hand can be made lightweight.

  However, in a wire-driven robot arm, in order to reduce the inertia on the hand side, an actuator is arranged on the body, which is the base to which the arm is attached, and the wire is routed when driving the wrist. When the distance is increased, it is necessary to dispose the wire across the joint on the way, such as the elbow of a humanoid arm. In this case, when the motion of the joint in the middle is driven, the path length of the wire changes, and the problem arises that the motion of the joint of the tip part such as the wrist driven by the wire is affected. .

  For this problem, Patent Document 1 discloses a configuration having a pair of guide pulleys disposed so as to deviate from the rotation center of the joint. Patent Document 2 discloses a configuration having a wire guide pulley whose center of rotation rotates with the movement of a joint.

Japanese Patent No. 3290709 Japanese Patent Publication No. 6-77914

  However, since the configurations of Patent Document 1 and Patent Document 2 both have a structure in which a wire passes near the joint axis, the gear for operating the joint and the joint angle are measured near the joint axis. These structures cannot be adopted when an encoder or the like must be installed.

  An object of the present invention is to solve the above-mentioned problems of the conventional joint mechanism, and to provide a joint structure capable of transmitting a driving force without being affected by joint movement without passing a wire near the joint shaft and the joint It is to provide a robot arm provided with a structure.

  In order to achieve the above object, the present invention is configured as follows.

According to the aspect of the present invention, the first structure, the second structure, the third structure, the first rotary joint that connects the first structure and the second structure so as to be relatively rotatable, interlinked rotary shaft and the rotation shaft of the first rotating joint is straight, a second rotary joint that relatively rotatably connecting the second structure and the third structure, (each) end of the first structure body and is relatively rotatably connected, and the second structure and the (respectively) disposed in a flat row (of the pair) and the first parallel link, (each) end rotates relative and the second structure is connected, the (each) the other end is connected rotatably other end relative to the first parallel link, and disposed on said first structure and (respectively) flat row (a pair of) 2 parallel links, and a relatively rotatable (respectively) disposed on the connecting portion of the first structure and the first parallel link. (A pair of) first rotation guide pulleys, (a pair of) second rotation guide pulleys (respectively) disposed so as to be relatively rotatable at a connection portion between the first parallel link and the second parallel link, The first rotation guide pulley, the second rotation guide pulley, and the third structure are passed (respectively) in this order, and (a pair of) wires each having one end fixed to the third structure, Provided in one structure, the (respective) other ends of the (pair) wires are fixed and the wires can be driven (respectively), and the second structure can be driven by driving the wires. And a wire driving device for rotating the third structure relative to each other.

  According to the present invention, the wire is guided by the first rotation guide pulley and the second rotation guide pulley, so that the wire is arranged on the first structure without being affected by the rotational motion of the first rotation joint. It becomes possible to transmit the driving force of the wire driving device, for example, the actuator, to the tip side of the robot arm (for example, the tip of the wrist (for example, the hand)) beyond the first rotary joint.

  Therefore, a wire driving device, for example, an actuator for driving the movement around the second rotary joint can be disposed on the base side of the robot arm, and the inertia on the tip side of the robot arm is reduced, and control relating to position control and force control is performed. In addition to improved performance, it is possible to operate at high speed. Further, since the inertia is small, the kinetic energy is also reduced, and the safety at the time of collision is improved.

  Further, since the parallel link structure is constituted by the first parallel link, the second parallel link, the first structure, and the second structure, the wire does not pass through the vicinity of the first rotary joint, and the joint structure can be simplified. This makes it easy to dispose an encoder or the like that detects the rotation angle of a rotating part such as a joint.

  Before describing embodiments of the present invention in detail based on the drawings, various aspects of the present invention will be described below.

According to the first aspect of the present invention, the first rotary joint that connects the first structure, the second structure, the third structure, and the first structure and the second structure so as to be relatively rotatable. When, the rotation axis and the rotation axis of the first rotating joint is interlinked straight, a second rotary joint for connecting the second structure and the third structure relatively rotatably, is the first (respectively) at one end 1 structure and is relatively rotatably connected, and the second structure and is disposed in the (each) flat row (of the pair) and the first parallel link, and (each) end the second structural member is relatively rotatably connected, the (each) the other end rotatably connected to the other end relative to the first parallel link, and said first structure and (respectively) disposed in a flat row (the pair ) The second parallel link and the connecting portion of the first structure and the first parallel link are arranged to be relatively rotatable (respectively). A pair of first rotation guide pulleys, and a pair of second rotation guide pulleys (respectively) disposed so as to be rotatable relative to the connecting portions of the first parallel link and the second parallel link; The first rotation guide pulley, the second rotation guide pulley, and the third structure in order (respectively), and (a pair of) wires each having one end fixed to the third structure; Provided in the first structure, the (respectively) other ends of the (pair of) wires are fixed, the wires can be driven (respectively), and the second structure is achieved by driving the wires. There is provided a joint structure having a wire driving device for rotating the third structure relative to the body.

According to the second aspect of the present invention, the (respective) wires are hung from the side on which the first parallel link of the first rotation guide pulley is disposed, with respect to the first rotation guide pulley. The second rotary guide pulley is passed to the second rotary guide pulley from the side far from the second structure of the first rotary guide pulley, and the second structure of the second rotary guide pulley is passed to the second rotary guide pulley. The joint structure according to the first aspect is provided such that the joint structure is hung from a side far from the first side and passed from the side farther from the first structure of the first rotation guide pulley to the third structure. .

According to a third aspect of the present invention, the joint structure according to the first or second aspect;
A hand disposed at the tip of the third structure opposite to the second rotary joint side;
A robot arm is provided in which the third structure and the hand rotate relative to the second structure by driving the wire driving device.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
1A and 1B are general views showing a joint structure according to a first embodiment of the present invention. In FIGS. 1A and 1B, the structure is shown by way of example in which the joint structure according to the first embodiment is applied to the robot arm 100.

  1A and 1B, reference numeral 1 denotes a rod-shaped first structure, which forms the upper arm of the robot arm 100. Reference numeral 2 denotes a rod-shaped second structure that forms part of the forearm of the robot arm 100. The first structure 1 and the second structure 2 are connected by a first rotary joint 3, and the first structure 1 and the second structure 2 are relatively centered on the joint axis 3 a of the first rotary joint 3. Forward and reverse rotation is possible. As an example, as shown in FIG. 1B, the first rotary joint side end of the second structure 2 is formed in a bifurcated branch 2a, and the lower end of the first structure 1 is formed in the branch 2a. The portion is sandwiched so as to be relatively rotatable with respect to the joint shaft 3a.

  Reference numerals 4-1 and 4-2 denote two first linear actuators, such as pneumatic artificial muscles, which can constitute a first linear actuator as an example of the first driving device. The upper end portions of the two first linear actuators 4-1 and 4-2 are fixed to the support plate 1 a fixed to the upper end portion. The lower ends of the two first linear actuators 4-1 and 4-2 are respectively connected to the rotating ends of the rotary joints 5-1 and 5-2 whose base ends are fixed to the second structure 2. Two first linear actuators 4-1 and 4-2 are connected to the first structure body 1 and the second structure body 2 by being rotatably connected, and the first structure body 1 and the second structure body The forward / reverse rotational motion of the second first rotational joint 3 is driven. That is, the base end portions of the rod-shaped rotary joints 5-1 and 5-2 are fixed to the second structure 2, and the first linear motion actuator 4-1 is attached to the front ends of the joints 5-1 and 5-2. The lower end of 4-2 is rotatably connected. As a result of the rotary joint 5-1 and the joint 5-2 being arranged symmetrically with respect to the rotary shaft 3a of the first rotary joint 3, the lower end of the first linear actuator 4-1 is raised and the first When the lower end portion of the linear actuator 4-2 is lowered, the second structure 2 rotates clockwise around the rotation axis 3a of the first rotary joint 3. On the other hand, when the lower end portion of the first linear motion actuator 4-1 is lowered and the lower end portion of the first linear motion actuator 4-2 is raised, the second structure 2 is rotated by the rotation shaft 3 a of the first rotary joint 3. Rotate counterclockwise.

  6-1, 6-2 (although they are overlapped in FIG. 1A, the second linear actuator on the front side is 6-1 and the second linear actuator on the back side is 6-2). Each of the second linear actuators can be configured as an example of a second driving device (wire driving device), for example, two second linear actuators such as pneumatic artificial muscles, motors, and cylinders. The arm bending wires 7-1 and 7-2 having their respective ends fixed to the lower ends of the second linear motion actuators 6-1 and 6-2 are pulled and driven by the moving actuators 6-1 and 6-2.

  As shown in FIG. 2, the pneumatic artificial muscles constituting the linear actuators 4-1, 4-2, 6-1, 6-2 are formed on the outer surface of the tubular elastic body 15 made of a rubber material. A restraining member 16 composed of a fiber cord is provided, and both ends of the tubular elastic body 15 are hermetically sealed with a sealing member 17. By supplying a compressive fluid such as air into the tubular elastic body 15 through a fluid injecting member 18 provided on the sealing member 17 at one end of the tubular elastic body 15, the internal pressure of the tubular elastic body 15 is increased. , The tubular elastic body 15 tends to expand mainly in the radial direction, but is converted into a movement in the central axis direction of the tubular elastic body 15 by the action of the restraining member 16, and the entire length of the tubular elastic body 15 contracts. . Conversely, when the pressure in the inner space of the tubular elastic body 15 is lowered by discharging a compressive fluid such as air from the tubular elastic body 15 through the fluid injecting member 18, the tubular elastic body 15 contracts mainly in the radial direction. However, due to the action of the restraining member 16, the tubular elastic body 15 is converted into movement in the central axis direction, and the entire length of the tubular elastic body 15 is extended. Since this pneumatic artificial muscle is mainly composed of an elastic body, it has a feature that it is a flexible, safe and lightweight actuator.

  Reference numerals 8-1 and 8-2 denote first rotation guide pulleys with guide grooves 8a, which are opposed to each other with the first structure 1 interposed therebetween, and the rotation shaft 3a of the first rotation joint 3 along the longitudinal direction of the first structure 1. Further, they are arranged at positions shifted to the upper end side of the first structure 1, and can freely rotate around the rotation shafts 8-1a and 8-2a fixed to the first structure 1. is there. In FIG. 1A, the first rotation guide pulley 8-2 on the back side is not shown because it is a shadow of the first rotation guide pulley 8-1 on the near side, but is shown in FIG. 1B.

  Reference numerals 9-1 and 9-2 denote first parallel links arranged in parallel to the second structure 2, respectively, and one end of each of the first rotation guide pulleys 8-1 and 8-2 via a bearing is a rotating shaft 8- It is rotatably connected to the first structure 1 by being rotatably supported by 1a and 8-2a, with respect to the first structure 1 and the first rotation guide pulleys 8-1 and 8-2. A relatively swinging motion is possible. In FIG. 1A, the first parallel link 9-2 on the back side is not shown because it is a shadow of the first parallel link 9-1 on the near side, but is shown in FIG. 1B.

  Reference numerals 10-1 and 10-2 are second rotation guide pulleys having a diameter substantially equal to that of the first rotation guide pulley and having a guide groove 10a. The first structure 1 of the first parallel links 9-1 and 9-2 A rotating shaft 10-1a, 10-2a is rotatably connected to the end opposite to the connected end through a bearing, and the first parallel link around the rotating shaft 10-1a, 10-2a. Rotation is possible relative to 9-1 and 9-2. In FIG. 1A, the second rotation guide pulley 10-2 on the back side is not shown because it is a shadow of the second rotation guide pulley 10-1 on the near side, but is shown in FIG. 1B.

  Reference numerals 11-1 and 11-2 denote second parallel links arranged in parallel to the first structure 1, respectively, and one ends of the rotation shafts 10- of the second rotation guide pulleys 10-1 and 10-2 via bearings. The first parallel links 9-1 and 9-2 are rotatably connected by being rotatably supported by 1a and 10-2a. Therefore, the second parallel links 11-1 and 11-2 can swing relative to the first parallel links 9-1 and 9-2 and the second rotation guide pulleys 10-1 and 10-2. is there.

  Further, the other ends of the second parallel links 11-1 and 11-2 are rotatably connected to a fulcrum shaft as an example of the fulcrums 11-1a and 11-2a with respect to the second structure 2 via bearings. Thus, it can swing relative to the second structure 2. In FIG. 1A, the second parallel link 11-2 on the back side is not shown because it is a shadow of the second parallel link 11-1 on the near side, but is shown in FIG. 1B.

  The first parallel links 9-1 and 9-2 and the second parallel links 11-1 and 11-2 described above and the first structure 1 and the second structure 2 constitute a parallel link structure.

  Reference numeral 12 denotes a rod-shaped third structure, which is connected to the second structure 2 by the second rotary joint 13, and the rotation shaft 13 a protruding from the end of the second structure 2 is the third structure 2. By being rotatably connected to and supported by a bearing 13b disposed in the recess, the second structure 2 can be rotated relative to the rotation axis 13a along the longitudinal direction of the second structure 2. is there. In addition, one end of the arm bending wires 7-1 and 7-2 is fixed to the end of the third structure 12 on the second structure side at wire fixing points 12a-1 and 12a-2, respectively. In FIG. 1A, the wire fixing point 12a-2 on the back side is illustrated on the opposite side of the wire fixing point 12a-1 on the near side across the third structure 12 and is a shadow of the third structure 12. Although not shown in FIG. 1B.

  Reference numeral 14 denotes a hand for gripping an article or the like, and is disposed at the tip of the third structure 12.

  Next, the path of the arm bending wire 7-1 with respect to the first rotation guide pulley 8-1 and the second rotation guide pulley 10-1 will be described with reference to FIG. In addition, although it is hung so that a wire may be accommodated in each guide groove with respect to each pulley (refer FIG. 1B), description is abbreviate | omitted about the guide groove in the following description.

  The arm bending wire 7-1 having one end fixed to the lower end of the second linear motion actuator 6-1 is led to the first rotation guide pulley 8-1 and the first parallel link 9-1 is disposed. From the side to the first rotation guide pulley 8-1 (see arrow (1)), the first rotation guide pulley 8-1 is rotated about three quarters, and then the second rotation guide pulley 10-1 (See arrow (2)).

  The arm bending wire 7-1 is hung from the side far from the second structure 2 with respect to the second rotation guide pulley 10-1 (see arrow (3)), and the direction is bent, and then the third structure After being guided toward 12, the wire fixing point 12a-1 is fixed to the third structure 12 by a wire fixing pin or the like.

  The path of the arm bending wire 7-2 with respect to the first rotation guide pulley 8-2 and the second rotation guide pulley 10-2 is the same as the path of the arm bending wire 7-1. Omitted.

  FIG. 3 is a diagram showing a configuration of a pneumatic supply driving system for driving the pneumatic artificial muscle. In FIG. 3, 19 is an air pressure source such as a compressor, and 20 is an air pressure adjusting unit in which an air pressure filter 20a, an air pressure reducing valve 20b, and an air pressure lubricator 20c are combined. Reference numeral 21 denotes a 5-port flow rate control electromagnetic valve that controls the flow rate by driving a spool valve or the like with the force of an electromagnet, for example. Reference numeral 22 denotes a control computer constituted by, for example, a general personal computer, which is equipped with a D / A board 22a, and outputs a voltage command value to the 5-port flow rate control solenoid valve 21 so that each fluid can be injected and discharged. The flow rate of each air flowing through the member 18 can be controlled.

  According to the air pressure supply drive system shown in FIG. 3, the high pressure air generated by the air pressure source 19 is depressurized by the air pressure adjusting unit 20, adjusted to a constant pressure of, for example, 600 kPa, and supplied to the 5-port flow control electromagnetic valve 21. The The opening degree of the 5-port flow rate control solenoid valve 21 is controlled in proportion to the voltage command value output from the control computer 22 via the D / A board 22a. A fluid injecting member 18 of a tubular elastic body 15 of a pair of pneumatic artificial muscles 201-1 and 201-2 is connected to the 5-port flow rate control electromagnetic valve 21, respectively. The pair of pneumatic artificial muscles 201-1 and 201-2 are arranged substantially parallel along the support rod 203, and the end of each tubular elastic body 15 on the fluid injection member 18 side is fixed to the end of the support rod 203. The support plate 202 is fixed. On the other end side of the tubular elastic body 15 of the pair of pneumatic artificial muscles 201-1 and 201-2, a T-shaped rotating member 204 that is rotatably supported by the support rod 203 with the rotary joint shaft 200 is provided. The other end of the tubular elastic body 15 of the pair of pneumatic artificial muscles 201-1 and 201-2 is rotatably supported by the rotating member 204. Therefore, as described below, when the tubular elastic bodies 15 of the pair of pneumatic artificial muscles 201-1 and 201-2 expand and contract, the rotating member 204 is driven to rotate forward and backward around the rotary joint axis 200. .

  When a positive voltage command value is input from the control computer 22 to the 5-port flow rate control solenoid valve 21 from the D / A board 22a, the air pressure circuit symbol A is entered as shown in FIG. The flow path from the source 21 side to the fluid injecting member 18 side of the tubular elastic body 15 of the pneumatic artificial muscle 201-1 is opened through the 5-port flow rate control electromagnetic valve 21, and the flow rate is proportional to the absolute value of the voltage command value. Is supplied to the pneumatic artificial muscle 201-1 side. On the pneumatic artificial muscle 201-2 side, the flow path from the fluid injection member 18 of the tubular elastic body 15 to the atmospheric pressure side is opened via the 5-port flow control solenoid valve 21, and the absolute value of the voltage command value is set. A proportional air flow is exhausted from the pneumatic artificial muscle 201-2 side to the atmosphere. Therefore, as shown in FIG. 3, the total length of the pneumatic artificial muscle 201-1 is reduced and the total length of the pneumatic artificial muscle 201-2 is extended, so that the joint shaft 200 is indicated by an arrow at a speed proportional to the absolute value of the voltage command value. Perform a clockwise rotation as shown.

  On the other hand, when a negative voltage command value is input from the D / A board 22a to the 5-port flow control solenoid valve 21 from the control computer 22, the 5-port flow control solenoid valve 21 is switched, and the pneumatic circuit symbol B , The operation of the pneumatic artificial muscle 201-2 is reversed, and the joint shaft 200 performs a counterclockwise rotation. That is, the flow path from the air pressure source 19 side to the fluid injecting member 18 side of the tubular elastic body 15 of the pneumatic artificial muscle 201-2 is opened via the 5-port flow rate control electromagnetic valve 21, and the absolute value of the voltage command value is set. A proportional flow rate of air is supplied to the pneumatic artificial muscle 201-1 side. On the pneumatic artificial muscle 201-1 side, the flow path from the fluid injection member 18 of the tubular elastic body 15 to the atmospheric pressure side is opened via the 5-port flow control solenoid valve 21, and the absolute value of the voltage command value is set. A proportional air flow is exhausted from the pneumatic artificial muscle 201-1 side into the atmosphere. Accordingly, when the total length of the pneumatic artificial muscle 201-2 is reduced and the total length of the pneumatic artificial muscle 201-1 is extended, the joint axis 200 is shown in the direction opposite to the arrow at a speed proportional to the absolute value of the voltage command value. Perform a rotational motion.

  The operation of the joint structure having the above configuration will be described.

  4A and 4B are views showing the operation of the joint structure according to the first embodiment of the present invention.

  As described above, the two first linear actuators 4-1 and 4-2 include the first linear actuator 4-1 on the left side of FIG. 1A and another first linear actuator 4- on the right side of FIG. 1A. 2 is connected to the second structure 2 by rotary joints 5-1 and 5-2 so as to face each other with respect to the first rotary joint 3 across the first structure 1. Accordingly, if the first linear actuator 4-1 on the left side of FIG. 1A (or FIG. 4A) expands and the other first linear actuator 4-2 on the right side of FIG. 1A (or FIG. 4A) contracts, As shown in 4A, a counterclockwise rotational motion around the rotational axis 3a of the first rotational joint 3 occurs. Conversely, if the first linear actuator 4-1 on the left side of FIG. 1A (or FIG. 4A) contracts and another first linear actuator 4-2 on the right side of FIG. 1A (or FIG. 4A) expands, A clockwise rotational movement of the first rotary joint 3 around the rotation axis 3a occurs.

  Here, the feature of the first embodiment of the present invention is that the first rotation guide pulleys 8-1 and 8-2, the second rotation guide pulleys 10-1 and 10-2, and the first parallel links 9-1 and 9-. 2. The arm bending wires 7-1 and 7-2 are guided by a mechanism constituted by the second parallel links 11-1 and 11-2. The operation will be described with reference to FIGS. 5A and 5B.

  As described above, by the operation of the first linear actuators 4-1 and 4-2, as shown in FIG. 4A, the counterclockwise rotational motion around the rotational axis 3 a of the first rotary joint 3 of the second structure 2. When this occurs, the second rotation guide pulley 10-1 moves to the position indicated by the dotted line of the arrow A in FIG. 5A. At this time, the amount of contact between the arm bending wire 7-1 and the first rotation guide pulley 8-1 decreases by the circumference corresponding to the angle α, but the arm bending wire 7-1 becomes the second rotation guide. Since the amount of contact with the pulley 10-1 increases by the circumference corresponding to the angle α, they cancel each other.

  The above wire guiding operation is the same for guiding the arm bending wire 7-2 by the first rotating guide pulley 8-2 and the second rotating guide pulley 10-2. Therefore, there is little change in the path length of the arm bending wires 7-1 and 7-2 due to the rotational movement of the first rotary joint 3 around the rotation axis 3a, and the arm bending wires are formed by the wire fixing points 12a-1 and 12a-2. The influence on the motion around the rotation axis 13a of the second rotary joint 13 of the third structure 12 connected to the 7-1 and 7-2 is small.

  On the other hand, when the second linear motion actuator 6-1 is contracted and the second linear motion actuator 6-2 is extended, the arm bending wire 7-1 is pulled as shown by an arrow B in FIG. The one-rotation guide pulley 8-1 performs a counterclockwise rotational movement as indicated by an arrow C, and the second rotational guide pulley 10-1 performs a counterclockwise rotational movement as indicated by an arrow D to The bending wire 7-1 is sent out to the second linear actuator 6-1 side. Therefore, the arm bending wire 7-1 generates a driving force that pulls the wire fixing point 12a-1 of the third structure as indicated by an arrow E.

  At this time, since the second linear actuator 6-2 is extended on the second linear actuator 6-2 side, the arm is bent by the first rotary guide pulley 8-2 and the second rotary guide pulley 10-2. In the induction of the wire 7-2, the operation of the arm bending wire 7-2 is opposite to that of the arm bending wire 7-1, and the wire 7-2 is loosened with respect to the wire fixing point 12a-2. Become.

  Therefore, as shown in FIG. 4B and FIG. 5B, the third structure 12 is second to the second structure 2 by the arm bending wire 7-1 and the arm bending wire 7-2 as shown by the arrow F. A relative rotational movement around the rotary joint 13 is performed counterclockwise as viewed from the hand 14 side.

  On the other hand, when the second linear actuator 6-2 is contracted and the second linear actuator 6-1 is extended, the arm bending wire 7-2 is similar to the previous case in FIG. Pulled as indicated by arrow B, the first rotating guide pulley 8-2 rotates counterclockwise as indicated by arrow C, and the second rotating guide pulley 10-2 as indicated by arrow D. A counterclockwise rotational movement is performed, and the arm bending wire 7-2 is sent to the second linear actuator 6-2 side. Therefore, the arm bending wire 7-2 generates a driving force that pulls the wire fixing point 12a-2 of the third structure as indicated by an arrow E.

  At this time, since the second linear actuator 6-1 is extended on the second linear actuator 6-1 side, the arm is bent by the first rotary guide pulley 8-1 and the second rotary guide pulley 10-1. In the induction of the wire 7-1, the operation of the arm bending wire 7-1 is opposite to that of the arm bending wire 7-2, and the wire 7-1 is loosened with respect to the wire fixing point 12a-1. Become.

  Therefore, contrary to FIGS. 4B and 5B, the arm bending wire 7-2 and the arm bending wire 7-1 cause the third structure 12 to move in the direction opposite to the arrow F with respect to the second structure 2. A relative rotational movement around the second rotary joint 13 in the clockwise direction as viewed from the hand 14 side is performed.

  As described above, according to the joint structure of the first embodiment of the present invention, the arm bending wire is formed by the first rotation guide pulleys 8-1 and 8-2 and the second rotation guide pulleys 10-1 and 10-2. By adopting a configuration in which 7-1 and 7-2 are guided, the second straight line disposed in the first structure 1 is not affected by the rotational motion of the first rotary joint 3 around the rotation axis 3a. The driving force of the dynamic actuators 6-1 and 6-2 can be transmitted to the hand side on the distal end side of the robot arm 100 beyond the first rotary joint 3.

  Therefore, the actuator that drives the movement around the second rotary joint 13 can be disposed on the base side of the robot arm 100 like the second linear actuators 6-1 and 6-2. The inertia on the front end side is reduced, the control performance relating to position control and force control is improved, and it is possible to operate at high speed. Further, since the inertia is small, the kinetic energy is also reduced, and the safety at the time of collision is improved.

  Moreover, according to the joint structure of the first embodiment of the present invention, the first parallel links 9-1 and 9-2, the second parallel links 11-1 and 11-2, the first structure 1, and the second structure. Since the parallel link structure is constituted by the body 2, the arm bending wire 7-1 and the arm bending wire 7-2 do not pass through the vicinity of the first rotary joint 3, and the joint structure can be simplified. And the like are easily arranged.

  In the first embodiment, as an example, the second structure 2 rotates about 60 degrees clockwise and counterclockwise around the rotation axis 3a from the posture of FIG. 1A with respect to the first structure 1. The third structure 3 and the hand 12 can also rotate about the rotation axis 13a clockwise and counterclockwise by about 60 degrees with respect to the second structure 2 from the posture of FIG. 1A. .

  In the above-described embodiment, the actuator that drives the robot arm 100 is a direct-acting actuator. However, the present invention is not limited to this. For example, even a rotary electric motor has a pulley on the rotation shaft of the motor. The same effect is exhibited even in a structure in which the wire is wound and wound by rotating the motor.

  In the above embodiment, the linear actuator is a pneumatic artificial muscle. However, the present invention is not limited to this, and other linear actuators such as a pneumatic cylinder, a hydraulic cylinder, and an electric linear actuator also exhibit the same effect. To do.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced.

  The joint structure of the present invention is useful as a joint structure of an articulated robot arm and a robot arm including the joint structure. Further, the present invention is not limited to a robot arm, and can be applied as a joint structure in a joint mechanism of a mechanical device such as a joint mechanism for a rotation mechanism in a production facility or the like.

It is a top view which shows the substantially whole structure of the joint structure in 1st Embodiment of this invention. It is a bottom view which shows the substantially whole structure of the joint structure in 1st Embodiment of this invention. It is a figure which shows the structure of the pneumatic artificial muscle which can comprise a linear motion actuator as an example of the drive device of the joint structure body in 1st Embodiment of this invention. It is a figure which shows the structure of the air pressure supply drive system for driving the said pneumatic artificial muscle. It is a figure which shows operation | movement of the joint structure in 1st Embodiment of this invention. It is a figure which shows operation | movement of the joint structure in 1st Embodiment of this invention. It is a figure which shows the joint structure wire guidance operation | movement in 1st Embodiment of this invention. It is a figure which shows the wire guidance operation | movement of the joint structure in 1st Embodiment of this invention. It is explanatory drawing for demonstrating the wiring of the wire to the pulley of the joint structure body in 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st structure 1a Support plate 2 2nd structure 3 1st rotation joint 3a Rotating shaft of 1st rotation joint 4-1, 4-2 1st linear motion actuator 5-1, 5-2 Joint 6-1, 6-2 Second linear actuator 7-1, 7-2 Arm bending wire 8-1, 8-2 First rotating guide pulley 8-1a, 8-2a Rotating shaft 9-1 of first rotating guide pulley 9-1, 9-2 First parallel links 10-1, 10-2 Second rotation guide pulleys 10-1a, 10-2a Rotating shafts 11-1, 11-2 of second rotation guide pulleys 11-1a, 11 -2a Support point of second parallel link 12 Third structure 12a-1, 12a-2 Wire fixing point of third structure 13 Second rotation joint 13a Rotation shaft of second rotation joint 13b Bearing 14 Hand 15 Tubular elastic body 16 Restraint member 17 Sealing member 18 Fluid inlet / outlet member 19 Air pressure source 20 Air pressure adjusting unit 20a Air pressure filter 20b Air pressure reducing valve 20c Air pressure lubricator 21 5 port flow control solenoid valve 22 Control computer 22a D / A board

DESCRIPTION OF SYMBOLS 100 Robot arm 200 Joint axis 201-1 and 201-2 Pneumatic artificial muscle 202 Support plate 203 Support rod 204 Rotating member

Claims (3)

A first structure;
A second structure;
A third structure;
A first rotary joint that connects the first structure and the second structure so as to be relatively rotatable;
Interlinked rotary shaft and the rotation shaft of the first rotating joint is straight, a second rotary joint that relatively rotatably connecting the second structure and the third structure,
One end connected rotatably relative to the aforementioned first structure, and a first parallel links that are disposed in the second structure and the flat row,
One end connected rotatably relative and the second structure, the other end is connected rotatably other end relative to the first parallel link, and a second disposed on the first structure and the flat ascending Parallel links,
A first rotation guide pulley disposed in a relatively rotatable manner at a connection portion between the first structure and the first parallel link;
A second rotation guide pulley disposed in a relatively rotatable manner at a connection portion between the first parallel link and the second parallel link;
The first rotary guide pulley, the second rotating guide pulleys, is passed in the order of the third structure, a wire having one end fixed to the third structure,
Provided in the first structure, the other end of the wire is fixed and the wire can be driven, and by driving the wire, the third structure is attached to the second structure. A joint structure characterized by having a wire drive device for relative rotation. The wire is hooked to the first rotation guide pulley from the side where the first parallel link of the first rotation guide pulley is disposed, and is far from the second structure of the first rotation guide pulley. From the side to the second rotation guide pulley. The second rotation guide pulley is hung from a side farther from the second structure of the second rotation guide pulley, and the first rotation guide pulley The joint structure according to claim 1, wherein the joint structure is passed from the side far from the first structure to the third structure . The joint structure according to claim 1 or 2,
A hand disposed at the tip of the third structure opposite to the second rotary joint side;
A robot arm characterized in that the third structure and the hand rotate relative to the second structure by driving the wire driving device.

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