JP2010025218A - Compressible fluid pressure actuator and joint drive unit using the same - Google Patents

Abstract

A compressible fluid pressure actuator excellent in operation efficiency and a joint drive unit using the same are provided.
A swing member that is held by a universal joint mechanism on a base member and is swingable with respect to each of two of three orthogonal axes including the center of the mechanism, and first and second A rotating member, a pressure source for replenishing the compressive fluid to the tank member that stores the compressible fluid, and a base member and the swing member connected to each other and driven by the compressive fluid in the tank member to swing relative to the swing member A plurality of swing torque generating mechanisms for generating torque, a control valve device for controlling the connection of the compressible fluid in the tank member, and a swing angle adjusting means for changing the relative angle between the two rotating members.
[Selection] Figure 1A

Description

  The present invention relates to a compressible fluid pressure actuator excellent in operation efficiency and a joint drive unit using the same.

  In recent years, there are increasing expectations for robots that operate in areas close to humans, such as medical robots, home service robots, and work support robots in factories. In such robots, unlike industrial robots, it is important to ensure safety when in contact with people. For this purpose, the joint driving actuator is required to be lightweight and to change the joint rigidity as necessary. One example of an actuator that meets such a requirement is a pneumatic actuator (see, for example, Non-Patent Document 1 and Non-Patent Document 2). The pneumatic actuator can be easily reduced in weight because it is driven using gas pressure, and the rigidity can be changed by controlling the internal pressure.

Published by IEICE, “Journal of IEICE A”, 2005, Vol. J88-A, no. 11 pages 1318-1325 Published by the Robotics Society of Japan, “Advanced Robotics”, 2002, Vol. 20, no. 2 pages 213-232

  When the pneumatic actuator is used as a joint driving actuator, it is necessary to frequently change the internal pressure in order to control the joint torque or the joint rigidity according to the operation state. Therefore, in the pneumatic actuator, the pressure of the compressed air supplied from the pressure source is frequently reduced or the compressed air in the actuator is exhausted as it is, so that a large amount of compressed air is consumed. For this reason, the use of pneumatic actuators for applications such as joint drive is less efficient than the energy contained in the compressed air that is consumed, resulting in less work efficiency and lower operating efficiency. Will have.

  Accordingly, an object of the present invention is to provide a compressible fluid pressure actuator excellent in operation efficiency and a joint drive unit using the same in view of the above point.

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

According to a first aspect of the present invention, a base member;
A swing member that is held with respect to the base member via a universal joint mechanism and is swingable with respect to a first axis including a joint center of the universal joint mechanism with respect to the base member;
A first rotating member that is rotatably held with respect to the swinging member around a second axis including the joint center of the universal joint mechanism with respect to the swinging member;
The first rotating member is held so as to be rotatable about a third axis perpendicular to the second axis and including the joint center of the universal joint mechanism, and also to the base member. A second rotating member held rotatably about the first axis;
A tank member for storing a compressible fluid;
A pressure source connected to the tank member to replenish the compressive fluid in the tank member;
The base member and the swing member are coupled, connected to the tank member, and driven by the compressive fluid in the tank member, thereby generating swing torque on the swing member. A swing torque generating mechanism;
A control valve device for controlling connection of the compressive fluid between the swing torque generating mechanism and the tank member;
Rocking angle adjusting means for changing a relative angle of the first rotating member and the second rotating member around the third axis;
The control valve device controls the swing torque generation mechanism to generate swing torque for the swing member about a fourth axis perpendicular to the first shaft and the third shaft. A compressible fluid pressure actuator capable of rotating operation is provided.

  According to an eleventh aspect of the present invention, there is provided a joint drive unit driven by the compressive fluid pressure actuator according to any one of the first to tenth aspects.

  Therefore, according to the present invention, it is possible to obtain a compressible fluid pressure actuator excellent in operation efficiency and a joint drive unit using the same. That is, the rotational torque that acts on the second rotating member includes the swinging torque about the fourth axis that acts on the swinging member, and the first and second rotating members that are adjusted by the swinging angle adjusting means. Since the pressure is determined by the relative angle to the member, the pressure of the compressive fluid in the tank member is directly applied to the swing torque generating mechanism to continuously generate the swing torque around the fourth axis with respect to the swing member. Even in this state, the rotational torque acting on the second rotating member can be controlled by the swing angle adjusting means regardless of the swing torque around the fourth axis. At this time, except for a part of the oscillating torque generating mechanism used for adjusting the oscillating torque around the third axis acting on the oscillating member, it can be directly driven by the compressive fluid in the tank member, The energy lost by the compressive fluid and the energy generated outside the compressive fluid pressure actuator are linked to improve the operation efficiency. Furthermore, when work is performed from the outside on the compressive fluid pressure actuator according to the present invention, the energy is regenerated with respect to the compressive fluid in the tank member. It will be planned.

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

  DESCRIPTION OF EMBODIMENTS Hereinafter, various embodiments of the present invention will be described before detailed description of embodiments of the present invention with reference to the drawings.

According to a first aspect of the present invention, a base member;
A swing member that is held with respect to the base member via a universal joint mechanism and is swingable with respect to a first axis including a joint center of the universal joint mechanism with respect to the base member;
A first rotating member that is rotatably held with respect to the swinging member around a second axis including the joint center of the universal joint mechanism with respect to the swinging member;
The first rotating member is held so as to be rotatable about a third axis perpendicular to the second axis and including the joint center of the universal joint mechanism, and also to the base member. A second rotating member held rotatably about the first axis;
A tank member for storing a compressible fluid;
A pressure source connected to the tank member to replenish the compressive fluid in the tank member;
The base member and the swing member are coupled, connected to the tank member, and driven by the compressive fluid in the tank member, thereby generating swing torque on the swing member. A swing torque generating mechanism;
A control valve device for controlling connection of the compressive fluid between the swing torque generating mechanism and the tank member;
Rocking angle adjusting means for changing a relative angle of the first rotating member and the second rotating member around the third axis;
The control valve device controls the swing torque generation mechanism to generate swing torque for the swing member about a fourth axis perpendicular to the first shaft and the third shaft. A compressible fluid pressure actuator capable of rotating operation is provided.

  According to such a configuration, the rotational torque acting on the second rotating member is the first rotation adjusted by the swinging torque around the fourth axis acting on the swinging member and the swinging angle adjusting means. Since it is determined by the relative angle between the member and the second rotating member, the pressure of the compressive fluid in the tank member is applied to the swing torque generating mechanism as it is, and the swing torque about the fourth axis with respect to the swing member. Even in a state where the maximum rotation is continuously generated, the rotational torque acting on the second rotating member can be controlled by the swing angle adjusting means regardless of the swing torque around the fourth axis. At this time, except for a part of the oscillating torque generating mechanism used for adjusting the oscillating torque around the third axis acting on the oscillating member, it can be directly driven by the compressive fluid in the tank member, The energy lost by the sexual fluid and the energy made outside are linked to improve the operating efficiency. Furthermore, when work is performed from the outside on the compressive fluid pressure actuator according to the present invention, the energy is regenerated with respect to the compressive fluid in the tank member. It will be planned. Therefore, a compressible fluid pressure actuator having excellent operating efficiency can be obtained.

  According to a second aspect of the present invention, there is provided the compressible fluid pressure actuator according to the first aspect, wherein the universal joint mechanism is a constant velocity joint mechanism.

  According to such a configuration, variation in characteristics due to the angle of the second rotating member is reduced, and the control of the rotational torque acting on the second rotating member by the swing angle adjusting means, or the third by the control valve device. Therefore, it is possible to obtain a compressible fluid pressure actuator with better controllability.

  According to the third aspect of the present invention, each of the plurality of swing torque generating mechanisms is arranged at equal intervals on a circumference around the second axis. A compressible fluid pressure actuator according to any one aspect is provided.

  According to such a configuration, variation in characteristics due to the angle of the second rotating member is reduced, and the control of the rotational torque acting on the second rotating member by the swing angle adjusting means, or the third by the control valve device. Therefore, it is possible to obtain a compressible fluid pressure actuator with better controllability.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the swing torque generating mechanism applies a bidirectional swing torque to the swing member. A compressible fluid pressure actuator is provided.

  According to such a configuration, any of a region where the torque around the fourth axis acting on the swinging member can be generated by pressing the swinging member and a region where the torque can be generated by pulling the swinging member is selected. Therefore, it is possible to generate the compressive fluid pressure actuator with higher output.

  According to a fifth aspect of the present invention, there is provided the compressible fluid pressure actuator according to the fourth aspect, wherein the swing torque generating mechanism is provided with an odd number of three or more.

  According to such a configuration, each swing torque generating mechanism can be disposed at an asymmetric position with respect to the joint center without increasing the variation in the interval at which the swing torque generating mechanism is disposed. As a result, variation in the swinging torque due to the angle of the second rotating member can be reduced, and a compressible fluid pressure actuator with more stable performance can be obtained.

  According to the sixth aspect of the present invention, the pressure of the compressive fluid acting on the swing torque generating mechanism is the tank member except for the swing torque generating mechanism closest to the fourth shaft. A compressible fluid pressure actuator according to a fifth aspect is provided, wherein the compressive fluid pressure is a pressure of a compressive fluid or a pressure around the oscillation torque generating mechanism.

  According to such a configuration, the pressure of the compressible fluid in the tank member can be directly applied to the oscillation torque generating mechanism except for one, so that the energy change of the compressive fluid and the external energy transfer And a compressible fluid pressure actuator having more excellent operation efficiency can be obtained.

  According to a seventh aspect of the present invention, there is provided the compressible fluid pressure actuator according to any one of the first to sixth aspects, wherein the swing torque generating mechanism is a piston cylinder mechanism.

  According to such a configuration, since the generated force of the swing torque generating mechanism can be made constant regardless of the displacement, a compressible fluid pressure actuator with more stable performance can be obtained.

  According to an eighth aspect of the present invention, there is provided the compressible fluid pressure actuator according to the seventh aspect, wherein the piston cylinder mechanism is a mechanism using a double rod type piston.

  According to such a configuration, when the swing torque generating mechanism is operated by the pressure of the compressive fluid in the tank member, the difference in swing torque depending on the piston operating direction can be suppressed. A compressible fluid pressure actuator having stable performance can be obtained.

  According to a ninth aspect of the present invention, the swing torque generating mechanism and the swing member are connected by a ball joint mechanism, and the joint center of the ball joint mechanism is perpendicular to the second axis and the third shaft. The compressible fluid pressure actuator according to any one of the first to eighth aspects is provided on a plane including an axis.

  According to such a configuration, since the work performed by the swing angle adjusting means when changing the relative angle between the first rotating member and the second rotating member can be reduced, the controllability is further improved. A compressible fluid pressure actuator can be obtained.

  According to a tenth aspect of the present invention, a plurality of the compressible fluid pressure actuators according to any one of the first to ninth aspects are provided, and the tank member and the pressure source of each compressive fluid pressure actuator are shared with each other. A multi-axis compressible fluid pressure actuator is provided.

  According to such a configuration, the pressure fluctuations in the tank members used by the plurality of compressible fluid pressure actuators are averaged. And a multiaxial compressible fluid pressure actuator with more stable performance can be obtained.

  According to an eleventh aspect of the present invention, the compressive fluid pressure actuator according to any one of the first to tenth aspects is disposed at the joint portion of two arms connected via a joint portion, and the compression There is provided a joint drive unit in which the other arm is driven with respect to one of the two arms by a sexual fluid pressure actuator.

  According to such a configuration, the joint drive unit driven by the compressible fluid pressure actuator according to any one of the first to tenth aspects can be configured, and the action of the compressible fluid pressure actuator can be configured. It is possible to obtain a joint drive unit capable of producing an effect.

  Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1A is a front sectional view showing an outline of a rotary actuator 1 as an example of a compressible fluid pressure actuator according to a first embodiment of the present invention, and a partially enlarged view thereof is FIG. 1B. 1C shows a right side cross-sectional view of the rotary actuator 1, and FIG. 1D shows a cross-sectional view taken along line AA in FIG. 1A. As the orthogonal coordinate axes in the rotary actuator of the first embodiment, the upward direction in FIG.

  1A to 1D, a fixed shaft 12 whose center axis functions as an example of a first axis (virtual axis) is fixed to a central portion of an upper surface of a cylindrical frame 11 that is an example of a base member. A rocking shaft 14 whose central axis functions as an example of a second axis (virtual axis) is connected to the fixed shaft 12 via a constant velocity joint 13 which is an example of a universal joint mechanism. As the constant velocity joint 13, for example, a constant velocity joint as disclosed in JP-A-2002-349593 can be used. Use of such a constant velocity joint is desirable because there is no difference depending on the direction in which the swing shaft 14 is inclined. Furthermore, an opening 15b of a central plate portion 15a of a bowl-shaped member 15 which is an example of a swinging member and has a pentagonal planar shape is fixed to the lower end of the swinging shaft 14, and the joint of the constant velocity joint 13 is fixed. With the center as a reference, the swing shaft 14 and the bowl-shaped member 15 can swing integrally. Further, the bowl-shaped member 15 is a circular plate that is an example of a first rotating member via a bearing mechanism 16 that is disposed on the upper surface of the central plate portion 15a of the bowl-shaped member 15 and can hold a radial load and a thrust load. The plate-like member 17 is held in parallel with the central plate portion 15 a, and the plate-like member 17 can rotate relative to the flange-like member 15 coaxially with the central axis of the swing shaft 14. . As the bearing mechanism 16, for example, a cross roller bearing or a combined angular ball bearing can be used. The plate-like member 17 has two plate-like protrusions 38a and 38b spaced by 180 degrees around the central axis of the swing shaft 14, and the plate-like protrusions 38a and 38b have shafts 18a and 18b, respectively. It is fixed. The shafts 18 a and 18 b are disposed on the same axis, and the central axes of the shafts 18 a and 18 b are disposed at positions that pass through the joint center of the constant velocity joint 13.

  On the other hand, the rotating body 20, which is an example of a second rotating member, is connected to the fixed shaft 12 via a bearing mechanism 21 that is disposed at the intermediate step portion and can hold a radial load and a thrust load. It is held so that it can rotate around the central axis. The bearing mechanism 21 is fixed to the rotating body 20 by a bearing retainer 22. The rotating body 20 is also connected to shafts 18a and 18b via radial bearings 19a, 19b, 19c and 19d. The rotating body 20 has a central axis with respect to the bowl-shaped member 15 and a third axis ( It can be relatively rotated around the central axis (around the X axis) of the axes 18a and 18b functioning as an example of the (virtual axis). Furthermore, the rotation of the rotating body 20 is transmitted to a rotating shaft 28 that rotates integrally with the bevel gear 27 via a bevel gear 27 that is meshed with the bevel gear portion 39 provided at the upper end of the rotating body 20. It has become so. The rotary shaft 28 is held on the upper surface of the frame 11 via bearing mechanisms 29a and 29b so as to freely rotate through the through hole 11b of the upper end protrusion 11a of the frame 11 and to rotate around the X axis. The rotation angle of the rotary shaft 28 with respect to the frame 11 is measured by the encoder 57. The encoder 57 is connected to a control controller (an example of a control means or a control unit) 52 to be described later, and the rotating body interlocked with the rotation shaft 28 from the rotation angle of the rotation shaft 28 measured by the encoder 57 with the control controller 52. The rotation angle of 20 is obtained.

  Further, gears 23a and 23b are fixed to the end surfaces of the shafts 18a and 18b, respectively. Servo motors 25a and 25b, which are examples of swing angle adjusting means, are respectively held at the other ends of L-shaped support members 26a and 26b whose one ends are fixed to the side surfaces of the rotating body 20. The gears 24a and 24b fixed to the rotation shafts of the servo motors 25a and 25b respectively mesh with the gears 23a and 23b. Accordingly, the relative angle between the rotating body 20 and the bowl-shaped member 15 is changed by driving the servo motors 25a and 25b to rotate the respective rotation shafts and the gears 24a and 24b with respect to the gears 23a and 23b. Is possible. When the relative angle between the rotating body 20 and the bowl-shaped member 15 changes, the state shown in FIG. 1C (the state where the rotation axis of the rotating body 20 and the rotation axis of the plate-like member 17 are parallel (that is, the bowl-shaped member) 15 is a state in which the central plate portion 15a is positioned along the horizontal plane), for example, as shown in FIG. 1E (the state in which the rotational axis of the plate member 17 is inclined with respect to the rotational axis of the rotating body 20 (that is, The central plate portion 15a of the bowl-shaped member 15 is changed to an inclined state in which the central plate portion 15a is inclined along the horizontal plane)). The rotation information of the servo motors 25a and 25b is input to the controller 52.

  Further, the bowl-shaped member 15 includes spherical joints 32a, 32b arranged on the side surface of the bowl-shaped member 15 on the circumference around the rotation axis of the bowl-shaped member 15 at equal intervals (positions every 72 degrees), Double rod-shaped pistons 31a, 31b, 31c, 31d of air cylinders 30a, 30b, 30c, 30d, 30e as an example of a piston cylinder mechanism which is an example of a swing torque generating mechanism through 32c, 32d, 32e, Positions at which the upper ends of the upper rods of 31e are rotationally symmetric with respect to the central axis of the fixed shaft 12 (specifically, at positions of 72 degrees on the same circumference around the central axis of the fixed shaft 12) Is pivotally connected to the motor. The air cylinder is desirable in that the force does not change with respect to the displacement. Furthermore, it is desirable to use a double rod type piston in that a difference in generated force does not occur depending on the driving direction, and disposing it at a rotationally symmetric position causes variations in characteristics when the angle of the rotating body 20 changes. This is desirable because it can be minimized. The joint centers of the ball joints 32a, 32b, 32c, 32d, and 32e are located on a plane that is perpendicular to the central axis of the swing shaft 14 and includes the central axes of the shafts 18a and 18b. In this way, even if the inclination of the rotational axis of the plate-like member 17 changes with respect to the rotational axis of the rotating body 20, a circle that passes through the joint centers of the ball joints 32 a, 32 b, 32 c, 32 d, and 32 e. This is desirable because the center position of the head is constant, and no excessive imbalance occurs in the bowl-shaped member 15. Further, the lower portions of the air cylinders 30a, 30b, 30c, 30d, and 30e are provided with spherical portions 33q at the respective lower end portions, and the lower rods of the pistons 31a, 31b, 31c, 31d, and 31e pass through the central portions. Are fixed to the upper ends of cylinder support members 33a, 33b, 33c, 33d, and 33e each having a through hole 33p. The spherical portion 33q at the lower ends of the cylinder support members 33a, 33b, 33c, 33d, and 33e The ball holders 34a, 34b, 34c, 34d, and 34e fixed to the bottom surface of the lower end of each of them are rotatably supported and constitute a ball joint.

  On the other hand, upper connection pipes 36a, 36b, 36c, 36d, 36e for supplying dry air, which is an example of a compressive fluid, are provided on the upper and lower side surfaces of the air cylinders 30a, 30b, 30c, 30d, 30e. And the lower connection pipes 37a, 37b, 37c, 37d, and 37e are respectively connected, and the valve mechanism 35 that is an example of the control valve device and the air cylinders 30a, 30b, 30c, 30d, and 30e are connected to the upper connection pipe 36a, 36b, 36c, 36d, 36e and lower connection pipes 37a, 37b, 37c, 37d, 37e are connected. The internal structure of the valve mechanism 35 is as shown in the piping diagram shown in FIG. Further, the valve mechanism 35 is provided with a control controller 52, and the control controller 52 and each element shown in FIG. 2 are connected as shown in FIG.

  In FIG. 2, the upper connection pipes 36a, 36b, 36c, 36d, and 36e and the lower connection pipes 37a, 37b, 37c, 37d, and 37e have 5-port valves 41a, 41b, 41c, 41d, and 41e, respectively. The air cylinders 30a, 30b, 30c, 30d, and 30e are connected to the pneumatic tank 40, which is an example of a tank member, and the atmosphere release unit 48. An air pressure source 53, which is an example of a pressure source, is connected to the air pressure tank 40, and high-pressure dry air supplied from the air pressure source 53 is stored in the air pressure tank 40. Further, the upper connection pipes 36a, 36b, 36c, 36d, and 36e are connected to the low-pressure pipe 51 that reaches the atmosphere opening section 48 via ON-OFF valves 42a, 42b, 42c, 42d, and 42e, respectively. In addition, the high-pressure pipe 50 reaching the pneumatic tank 40 is also connected through ON-OFF valves 43a, 43b, 43c, 43d, 43e and check valves 46a, 46b, 46c, 46d, 46e, respectively. ing. Similarly, the lower connection pipes 37a, 37b, 37c, 37d, and 37e are respectively connected to the low-pressure pipe 51 that reaches the atmosphere opening portion 48 via ON-OFF valves 44a, 44b, 44c, 44d, and 44e. The high-pressure pipe 50 connected to the pneumatic tank 40 is also connected to the high-pressure pipes 50 through ON-OFF valves 45a, 45b, 45c, 45d, 45e and check valves 47a, 47b, 47c, 47d, 47e, respectively. It is connected. The low pressure pipe 51 is filled with dry air held at a lower pressure than the dry air in the high pressure pipe 50. The controller 52 includes 5-port valves 41a, 41b, 41c, 41d, 41e, ON-OFF valves 42a, 42b, 42c, 42d, 42e, ON-OFF valves 43a, 43b, 43c, 43d, 43e, and ON. -Connected to the OFF valves 44a, 44b, 44c, 44d, 44e and the ON-OFF valves 45a, 45b, 45c, 45d, 45e, respectively, the operation of each ON-OFF valve can be controlled by the controller 52, respectively. I am doing so.

  Further, the high-pressure pipe 50 is connected to the low-pressure pipe 51 via a relief valve 49, and protects the pneumatic tank 40 so that the pressure of the pneumatic tank 40 does not exceed a certain pressure. Further, pressure sensors 54a, 54b, 54c, 54d, and 54e are provided in the middle of the upper connection pipes 36a, 36b, 36c, 36d, and 36e, respectively, so that the pressure in the upper connection pipe can be measured. Yes. Similarly, pressure sensors 55a, 55b, 55c, 55d, and 55e are respectively provided in the middle of the lower connection pipes 37a, 37b, 37c, 37d, and 37e, and a pressure sensor 56 is also provided in the middle of the high-pressure pipe 50. Therefore, the pressure in each pipe can be measured. The controller 52 is connected to the pressure sensors 54a, 54b, 54c, 54d, 54e, the pressure sensors 55a, 55b, 55c, 55d, 55e, and the pressure sensor 56, and the respective sensors measured by the respective sensors. Information on the pressure in the pipe is input to the controller 52.

  Next, the operation of the rotary actuator 1 performed under the control controller 52 provided in the valve mechanism 35 will be described.

  The force acting on the rotary shaft 28 of the rotary actuator 1 includes the generated force of the air cylinders 30 a, 30 b, 30 c, 30 d, 30 e and the magnitude of the inclination of the rotary shaft core of the plate member 17 with respect to the rotary shaft core of the rotating body 20. Determined by. That is, in FIG. 1C, when the generated force of the air cylinders 30a, 30b, 30c, 30d, and 30e acts on the bowl-shaped member 15, the displacement in each direction of the X axis, the Y axis, and the Z axis and the rotation around the Z axis Since the hook-shaped member 15 is connected to the fixed shaft 12 via the swing shaft 14 and the constant velocity joint 13, it is restricted. Regarding the rotational torque around the X-axis acting on the bowl-like member 15, the bearing mechanism 16, the plate-like member 17, the plate-like protrusions 38a and 38b that rotate integrally with the plate-like member 17, the shafts 18a and 18b, and the gears 23a, 23b, and the servo motors 25a, 25b via the gears 24a, 24b. Further, the rotational torque about the Y axis acting on the bowl-shaped member 15 is transmitted to the rotating body 20 via the bearing mechanism 16, the plate-shaped member 17, and the shafts 18a and 18b. In the state of FIG. 1C, since the central plate portion 15a of the bowl-shaped member 15 is maintained in a horizontal state, only the rotational torque around the Y axis acts on the rotating body 20. Since the rotation of the rotating body 20 around the Y axis is restrained by the bearing mechanism 21, the state of the rotating body 20 does not change in the state of FIG. 1C.

  On the other hand, in the inclined state of FIG. 1E in which the central plate portion 15a of the bowl-shaped member 15 is tilted from the horizontal state, the rotational torque around the Y-axis (torque as an example of the swinging torque) acting on the bowl-shaped member 15 is rotated. That is, the body 20 is decomposed into a rotational torque about the Y axis and a rotational torque about the Z axis. The hook-shaped member 15 can only swing about the joint center of the constant velocity joint 13 as a swing center. As shown in FIG. 1E, the hook-shaped member 15 rotates around the Y axis from the tilted state. Giving this rotation is equivalent to rotating the tilting direction of the bowl-shaped member 15 around the Z axis. On the other hand, since the central axes of the shafts 18a and 18b can only exist on the XY plane including the joint center of the constant velocity joint 13 due to the restraint by the rotating body 20, the tilting direction of the bowl-shaped member 15 changes. Accordingly, the shafts 18a and 18b and the rotating body 20 rotate around the Z axis. Therefore, the rotational torque about the Z axis with respect to the rotating body 20 can be obtained by the rotational torque about the Y axis acting on the bowl-shaped member 15. That is, the inclination of the plate member 17 is fixed by the servo motors 25a and 25b, and the axis perpendicular to the central axis of the shafts 18a and 18b on the XY plane (as an example of the fourth axis perpendicular to the third axis). The valve mechanism 35 generates each of the air cylinders 30a, 30b, 30c, 30d, and 30e so that a constant torque is generated in the bowl-shaped member 15 around the imaginary axis) (hereinafter referred to as the Y ′ axis). By controlling the force, the rotating body 20 generates a constant torque around the Z axis. The torque around the Z-axis acting on the rotating body 20 changes depending on the inclination of the plate-like member 17, and becomes 0 in the horizontal state where there is no inclination as shown in FIG. 1C, and the plate-like state in the inclined state as shown in FIG. 1E. As the inclination of the member 17 increases, it will increase. Incidentally, the torque around the Z-axis acting on the rotating body 20 is transmitted to the rotating shaft 28 via the bevel gear portion 39 of the rotating body 20 and the bevel gear 27, and this is the torque generated by the rotary actuator 1. It becomes.

  Next, the operation of the valve mechanism 35 will be described. As shown in FIG. 3, the valve mechanism 35 is a mechanism that controls the valve based on information from a plurality of sensors and controls the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e. In the controller 52, the rotation angle of the rotating body 20 interlocked with the rotation shaft 28 is obtained from the rotation angle of the rotation shaft 28 measured by the encoder 57, and the plate member 17 and the bowl-shaped member are obtained from the rotation information of the servo motors 25a and 25b. Information on the inclination of the member 15 is obtained. 4A to 4E show examples of the relationship between the angle of the rotating body 20 and the generated force of the air cylinders 30a, 30b, 30c, 30d, and 30e, which are controlled by the control controller 52, respectively. 4A to 4E, the angle θ on the horizontal axis indicates the rotation angle of the rotating body 20 in units of degrees (°). The state of FIG. Yes. The vertical axis indicates the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e, and the Z-axis direction is positive. Further, “+ F” on the vertical axis means a state in which the pressure of the pneumatic tank 40 is applied to each of the lower connection pipes 37a, 37b, 37c, 37d, and 37e, that is, the 5-port valves 41a and 41b in FIG. , 41c, 41d, and 41e each represent a state of moving leftward. Similarly, “−F” on the vertical axis means a state in which the pressure of the pneumatic tank 40 is applied to each of the upper connection pipes 36a, 36b, 36c, 36d, and 36e, that is, in FIG. Each of 41b, 41c, 41d, and 41e represents a state of moving in the right direction. Further, when the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e is between “+ F” and “−F”, each of the 5-port valves 41a, 41b, 41c, 41d, and 41e is illustrated in FIG. The pressure control is performed by the ON-OFF valves 42a, 42b, 42c, 42d, and 42e, and the ON-OFF valves 43a, 43b, 43c, 43d, and 43e, respectively. In the state of FIG. 1E, when the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e changes as shown in FIGS. 4A to 4E, the rotating body 20 has a rotational torque around the left-hand screw in the Z-axis direction. Will work. When the inclination of the hook-shaped member 15 is constant, the torque around the Y ′ axis acting on the hook-shaped member 15 varies approximately by 5%, but is substantially constant regardless of the angle of the rotating body 20. On the other hand, the torque around the central axis of the shafts 18a and 18b acting on the bowl-shaped member 15 is substantially zero, so that no load is applied to the servo motors 25a and 25b. The torque around the central axis of the shafts 18a and 18b may be changed linearly as shown in FIGS. 4A to 4E, but ± F × tan (Δθ) / tan (180 ° / (n × 2)) It is desirable to change the angle because the torque around the central axis of the shafts 18a and 18b can be made closer to zero. However, Δθ is a difference from an angle at which the generated force becomes 0 in FIGS. 4A to 4E, n is the number of cylinders, and n = 5 in the first embodiment. The sign is + when the generated force changes to the right in FIGS. 4A to 4E, and − when the generated force changes to the right. Incidentally, in the case of the air cylinder 30a in FIG. 4A, it is desirable that −F × tan (θ−90 °) / tan (18 °) in the range of θ = 72 ° to 108 °, and θ = 252 ° to 288. F × tan (θ-270 °) / tan (18 °) in the range of °. In this first embodiment, an odd number of air cylinders with n = 5 are operated bidirectionally, which generates bidirectional torque (bidirectional swing torque) in five directions with respect to the bowl-shaped member 15. This is desirable because it can be done. For example, in the case of six air cylinders arranged evenly, even if they are operated bidirectionally, only bidirectional torque from three directions can be generated. Further, in the first embodiment, n = 5, but by increasing this, torque fluctuation around the Y ′ axis can be further reduced. However, since the structure becomes complicated if the numerical value of n is too large, an odd number of 3 or more, preferably an odd number of about n = 5, 7, 9, 11 is desirable.

  As described above, in the state where the valve mechanism 35 controls the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e, the servo motors 25a and 25b are operated to change the inclination of the plate member 17. Thus, the torque generated by the rotary actuator 1 can be freely changed including the direction change. The torque required for the operation of the servo motors 25a, 25b is affected by the torque around the central axis of the shafts 18a, 18b due to the generated force of the air cylinders 30a, 30b, 30c, 30d, 30e, but is controlled by the valve mechanism 35. By suppressing the torque around the central axis of the shafts 18a, 18b, the required torque of the servo motors 25a, 25b is reduced (that is, the operating load of the servo motors 25a, 25b, which is an example of the swing angle adjusting means). )be able to. In addition, when the angle of the rotating body 20 is an angle at which the pressure control by the valve mechanism 35 is not performed, such as 36 °, 72 °, and 108 ° in FIGS. 4A to 4E, the servo motors 25a and 25b Since energy consumption associated with pressure control is not required even when the actuator is operated, it is desirable in terms of operating efficiency of the rotary actuator 1 to operate the servo motors 25a and 25b at such an angle as much as possible.

  On the other hand, the torque generated by the rotary actuator 1 depends on the torque around the Y ′ axis acting on the bowl-shaped member 15, but most of the torque around the Y ′ axis is directly from the pressure of the pneumatic tank 40. It will be generated by the added air cylinder. That is, when the generated force of each of the air cylinders 30a, 30b, 30c, 30d, and 30e changes as shown in FIGS. 4A to 4E, the pressure controlled state is that the air cylinder closest to the Y ′ axis (For example, in the case of θ = 0 ° to 36 °, the air cylinder 30e) only, and the influence of the force generated by the air cylinder on the torque around the Y ′ axis is also because it is closest to the Y ′ axis. Slightly. Therefore, when the rotary actuator 1 rotates in the direction of torque generation (the rotary shaft 28 rotates around the left-hand screw in the X-axis direction) and performs work outside the rotary actuator 1, the energy equivalent to the energy output to the outside remains as it is. The energy contained in the pressure tank 40 is consumed. Conversely, when the rotation actuator 1 rotates in the direction opposite to the direction of torque generation (the rotation shaft 28 rotates around the right screw in the X-axis direction) and work is performed from the outside of the rotation actuator 1, it is equivalent to the energy input from the outside. The energy is replenished to the energy contained in the pneumatic tank 40 as it is. As described above, the rotary actuator 1 can automatically switch between driving and regeneration in accordance with the direction of rotation thereof, and thus can achieve driving with high operating efficiency. Further, energy lost from the pneumatic tank 40 due to the operation of the rotary actuator 1 is supplemented from the pneumatic source 53. At this time, in the operation of the rotary actuator 1, when the regeneration works effectively and the average power is greatly reduced compared to the peak power of the output, it is time to replenish the energy in the pneumatic tank 40 released in a short time. Therefore, the capacity required for the air pressure source 53 may be small.

  Therefore, according to the first embodiment, it is possible to obtain a compressible fluid pressure actuator excellent in operation efficiency and a joint drive unit using the same. That is, the rotational torque that acts on the rotating body 20 that is an example of the second rotating member is the swing torque about the fourth axis that acts on the bowl-shaped member 15 that is an example of the swing member, and the swing angle adjustment. Since it is determined by the relative angle between the plate member 17 as an example of the first rotating member adjusted by the servo motors 25a and 25b as an example of the means and the rotating body 20, it is an example of the swing torque generating mechanism. The air cylinders 30 a, 30 b, 30 c, 30 d, and 30 e are subjected to the pressure of dry air, which is an example of a compressible fluid in the pneumatic tank 40, which is an example of a tank member, as it is, and the fourth axis with respect to the bowl-shaped member 15 It is possible to control the rotational torque acting on the rotating body 20 by the servo motors 25a and 25b regardless of the swing torque around the fourth axis even when the maximum swing torque is continuously generated. It made. At this time, except for some of the air cylinders 30a, 30b, 30c, 30d, and 30e used for adjusting the swing torque around the third shaft (for example, the central axis of the shafts 18a and 18b) acting on the bowl-shaped member 15. Can be directly driven by the dry air in the pneumatic tank 40, the energy lost from the pneumatic tank 40 and the energy made outside are linked to improve the operating efficiency. Furthermore, when work is performed from the outside on the compressible fluid pressure actuator 1 according to the first embodiment, the energy is regenerated as the energy contained in the dry air in the pneumatic tank 40. Thus, the operation efficiency can be further improved.

  In the first embodiment, the servo motors 25a and 25b are used as the swing angle adjusting means. However, the present invention is not limited to this, and other types of motors and encoders such as ordinary electromagnetic motors or ultrasonic motors are used. A rotary actuator that can be operated in an open loop such as a stepping motor or the like can also be used. Further, instead of angle measurement by the encoder, a measured value of torque acting on the rotating body 20 or the rotating shaft 28 may be used. This is desirable in that the influence of the pressure fluctuation in the pneumatic tank 40 or the torque fluctuation around the Y ′ axis on the output torque of the rotary actuator 1 can be reduced.

  In addition, in the first embodiment, the rotation angle of the rotating body 20 is obtained from the rotation angle of the rotating shaft 28 by the controller 52. However, the rotation angle of the rotating body 20 may be directly measured. Furthermore, in the first embodiment, the torque around the central axis of the shafts 18a and 18b is always close to 0. However, when there is a margin in the capacity of the servo motors 25a and 25b, an angle range for performing pressure control is illustrated. You may narrow rather than the case of 4A-FIG. 4E. This is desirable because energy consumption accompanying pressure control can be suppressed.

  Furthermore, the structural example of the joint drive unit 71 using the rotary actuator 1 in 1st Embodiment is shown to FIGS. 5-6B. A first arm 60 is disposed below the rotary actuator 1, a second arm 61 is disposed above the rotary actuator 1, and the frame 11 of the rotary actuator 1 is fixed to the first arm 60, and The two arms 61 are directly fixed (specifically, both end portions of the rotating shaft 28 are fixed to the overhanging portion 61a of the second arm 61). That is, the joint drive unit 71 is used as a drive unit for rotating the second arm 61, which is the upper arm, by the rotary actuator 1 with respect to the first arm 60, which is the lower arm.

  With such a configuration, the rotary actuator 1 is operated from the state shown in FIG. 6A (the state where the central axis of the first arm 60 and the central axis of the second arm 61 are positioned substantially on the same straight line), and the rotational axis By rotating 28 in the counterclockwise direction, the second arm 61 rotates counterclockwise with respect to the first arm 60, and is in the state of FIG. 6B (the first arm 60 with respect to the central axis of the first arm 60). The central axis of the two arms 61 is inclined). Conversely, by rotating the rotating shaft 28 in the clockwise direction, the second arm 61 can be rotated in the opposite direction to the first arm 60 (that is, in the clockwise direction).

  Therefore, with such a configuration, a joint drive unit 71 that inherits the characteristics of the rotary actuator 1, that is, the characteristics of excellent operation efficiency, can be obtained, and the joint drive unit in a robot arm particularly suitable for home use can be obtained. Can be realized. That is, in the example of FIG. 5, the two arms of the robot arm connected via the joint portion are the first arm 61 and the second arm 60, and the compressive fluid pressure actuator 1 is disposed at the joint portion. The compressible fluid pressure actuator 1 drives the other arm (for example, the first arm 61) by the joint drive unit 71 with respect to one arm (for example, the second arm 60) of the two arms. I try to do it.

  In addition, as shown in FIG. 7, a plurality of (for example, four) rotary actuators 1a, 1b, 1c, and 1d have a single pneumatic tank 40 and a single pneumatic pressure source. 53 may be shared. By doing so, it is possible to reduce fluctuations in the internal pressure of the pneumatic tank 40 especially when the operations of the rotary actuators 1a, 1b, 1c, and 1d are performed in an interlocked manner, and the pneumatic pressure source 53 is shared. By doing so, it becomes possible to make the whole structure compact.

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

  The compressible fluid pressure actuator according to the present invention and the joint drive unit using the compressive fluid pressure actuator are easy in force control and excellent in operation efficiency, such as a joint drive actuator for a robot, a joint drive unit using the actuator, and the like Useful as.

It is a front sectional view showing the outline of the rotation actuator by a 1st embodiment of the present invention. It is the elements on larger scale of the front sectional view showing the outline of the rotation actuator by the 1st embodiment of the present invention. FIG. 3 is a right side cross-sectional view schematically showing the rotary actuator according to the first embodiment of the present invention. It is the sectional view on the AA line of FIG. 1A which shows the outline of the said rotation actuator by the said 1st Embodiment of this invention. FIG. 3 is a right side cross-sectional view showing an outline at the time of driving the rotary actuator according to the first embodiment of the present invention. It is a piping diagram which shows the internal structure of the valve mechanism of the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the connection relation of the controller and each part in the said valve mechanism of the said rotary actuator by the said 1st Embodiment of this invention. It is a figure which shows the generated force change of the air cylinder 30a controlled by the said controller of the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the generated force change of the air cylinder 30b controlled by the said controller of the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the generated force change of the air cylinder 30c controlled by the said controller of the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the generated force change of the air cylinder 30d controlled by the said controller of the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the generated force change of the air cylinder 30e controlled by the said controller of the said rotation actuator by the said 1st Embodiment of this invention. It is a perspective view which shows the outline of the joint drive unit using the said rotation actuator by the said 1st Embodiment of this invention. It is a side view which shows the outline of the joint drive unit using the said rotation actuator by the said 1st Embodiment of this invention. It is a side view which shows the outline of the joint drive unit using the said rotation actuator by the said 1st Embodiment of this invention. It is a figure which shows the structure which uses the said rotary actuator by the said 1st Embodiment of this invention in multiple numbers, and shares a pneumatic tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d Rotary actuator 11 Frame 11a Upper end protrusion part 11b Through-hole 12 Fixed shaft 13 Constant velocity joint 14 Oscillating shaft 15 Gutter-shaped member 16 Bearing mechanism 17 Plate-shaped member 18a, 18b Shaft 19a, 19b, 19c, 19d Radial bearing 20 Rotating body 21 Bearing mechanism 22 Bearing retainer 23a, 23b Gear 24a, 24b Gear 25a, 25b Servo motor 26a, 26b Support member 27 Bevel gear 28 Rotating shaft 29a, 29b Bearing mechanism 30a, 30b, 30c, 30d , 30e Air cylinder 31a, 31b, 31c, 31d, 31e Double rod type piston 32a, 32b, 32c, 32d, 32e Ball joint 33a, 33b, 33c, 33d, 33e Cylinder support member 33p Cylinder support Through-hole of material 33q Spherical portion of lower end of cylinder support member 34a, 34b, 34c, 34d, 34e Ball holder 35 Valve mechanism 36a, 36b, 36c, 36d, 36e Upper connection piping 37a, 37b, 37c, 37d, 37e Bottom Side connection piping 38a, 38b Plate-like projection 39 Bevel gear 40 Pneumatic tank 41a, 41b, 41c, 41d, 41e 5 port valve 42a, 42b, 42c, 42d, 42e ON-OFF valve 43a, 43b, 43c, 43d, 43e ON-OFF valve 44a, 44b, 44c, 44d, 44e ON-OFF valve 45a, 45b, 45c, 45d, 45e ON-OFF valve 46a, 46b, 46c, 46d, 46e Check valve 47a, 47b, 47c 47d, 47e Check valve 48 Air release part 49 Relief valve 50, 0a, 50b, 50c, 50d High pressure piping 51 Low pressure piping 52 Control controller 53 Air pressure source 54a, 54b, 54c, 54d, 54e Pressure sensor 55a, 55b, 55c, 55d, 55e Pressure sensor 56 Pressure sensor 57 Encoder 60, 60a, 60b, 60c, 60d Arm 61, 61a, 61b, 61c, 61d Arm 71 Joint drive unit

Claims (11)

A base member;
A swing member that is held with respect to the base member via a universal joint mechanism and is swingable with respect to a first axis including a joint center of the universal joint mechanism with respect to the base member;
A first rotating member that is rotatably held with respect to the swinging member around a second axis including the joint center of the universal joint mechanism with respect to the swinging member;
The first rotating member is held so as to be rotatable about a third axis perpendicular to the second axis and including the joint center of the universal joint mechanism, and also to the base member. A second rotating member held rotatably about the first axis;
A tank member for storing a compressible fluid;
A pressure source connected to the tank member to replenish the compressive fluid in the tank member;
The base member and the swing member are coupled, connected to the tank member, and driven by the compressive fluid in the tank member, thereby generating swing torque on the swing member. A swing torque generating mechanism;
A control valve device for controlling connection of the compressive fluid between the swing torque generating mechanism and the tank member;
Rocking angle adjusting means for changing a relative angle of the first rotating member and the second rotating member around the third axis;
The control valve device controls the swing torque generation mechanism to generate swing torque for the swing member about a fourth axis perpendicular to the first shaft and the third shaft. A compressible fluid pressure actuator capable of rotating operation.   The compressible fluid pressure actuator according to claim 1, wherein the universal joint mechanism is a constant velocity joint mechanism.   The compressibility according to any one of claims 1 to 2, wherein each of the plurality of swing torque generating mechanisms is arranged at equal intervals on a circumference around the second axis. Fluid pressure actuator.   The compressible fluid pressure actuator according to any one of claims 1 to 3, wherein the swing torque generating mechanism applies a bidirectional swing torque to the swing member.   The compressible fluid pressure actuator according to claim 4, comprising an odd number of three or more swinging torque generating mechanisms.   The pressure of the compressive fluid or the swing torque in the tank member, except for the swing torque generation mechanism where the pressure of the compressive fluid acting on the swing torque generation mechanism is closest to the fourth shaft. 6. The compressible fluid pressure actuator according to claim 5, wherein the compressive fluid pressure actuator is a pressure around the generating mechanism.   The compressible fluid pressure actuator according to claim 1, wherein the swing torque generation mechanism is a piston cylinder mechanism.   8. The compressible fluid pressure actuator according to claim 7, wherein the piston cylinder mechanism is a mechanism using a double rod type piston.   The swing torque generating mechanism and the swing member are connected by a ball joint mechanism, and a joint center of the ball joint mechanism is on a plane perpendicular to the second axis and including the third axis. The compressible fluid pressure actuator according to any one of claims 1 to 8.   A plurality of the compressible fluid pressure actuators according to any one of claims 1 to 9, wherein the tank member and the pressure source of each compressive fluid pressure actuator are shared with each other. Axial compressible fluid pressure actuator.   The compressible fluid pressure actuator according to any one of claims 1 to 10 is arranged at the joint portion of two arms connected via a joint portion, and the two arms are formed by the compressible fluid pressure actuator. A joint drive unit in which the other arm is driven with respect to one of the arms.

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