Variable-cavity pneumatic robot joint and its driving system and control method

Abstract

The application discloses a variable-cavity pneumatic robot joint, a driving system and a control method thereof. The variable-cavity pneumatic robot joint comprises a robot joint body, a variable-cavity single-acting cylinder group, a steel wire rope group and a gear hob, wherein the single-acting cylinder group is symmetrically arranged about the gear hob and is installed on the robot joint body. The linear motion of the single-acting cylinder is converted into the rotation of the gear hob through the steel wire rope group, so that the rotational motion of the robot joint is realized. According to the load feedback, the variable-cavity pneumatic robot joint selectively provides an effective acting area through the control of a two-position two-way electromagnetic reversing valve and a three-position five-way electromagnetic reversing valve, so that the output torque of the robot joint is matched with the actual load torque, and the driving efficiency of the robot joint system is greatly improved.

Description

Technical fields:

[0001] This invention relates to a variable cavity pneumatic robot joint, its drive system, and control method. Technical background:

[0002] With the development of science and technology, the performance of mobile robots has been greatly improved, and they have been widely used in fields such as medical health, industrial manufacturing, and military equipment. Currently, however, energy and drive technologies have not yet achieved breakthroughs, limiting the load capacity and endurance of mobile robots and severely hindering their promotion and application. Therefore, constructing a drive system with high power density and improving energy utilization efficiency are bottleneck problems that need to be solved for mobile robots to become practical. Currently, researchers are attempting to use pneumatic drive systems for robot joints, taking exoskeleton robots as an example, such as the BONES exoskeleton robot developed by Julius Klein et al. at the University of California, Irvine, and the PNEU-WREX cylinder-driven robot developed by the University of California. These robots use cylinders as actuators to drive the movement of each joint, but the drive structure is relatively simple, and the effective working area of ​​the cylinder cavity is fixed, unable to be adjusted in real time according to changes in joint load. When the load changes, the drive system can only change the output force and speed through pneumatic valve throttling. Because the joint load of such robots varies greatly, throttling adjustment results in significant pressure loss, leading to high energy consumption in the pneumatic system and low overall robot drive efficiency. Therefore, researching high-energy-efficiency robot joints and their drive systems and control methods is of great significance for improving the efficiency of mobile robot systems. Summary of the Invention:

[0003] The purpose of this invention is to provide a drive system and control method that can improve the driving efficiency of robot joints, addressing the shortcomings of existing technologies. It can achieve real-time matching with variable loads by selecting different single-acting cylinder cavities and high-pressure air circuits. This invention is applicable to robot joints with large load variations and has good social value and economic benefits.

[0004] The present invention achieves the above objectives through the following technical solutions:

[0005] First, the present invention provides a variable cavity pneumatic robot joint, including a single-acting cylinder assembly, a cylinder fixing plate, a lifting eye nut assembly, a wire rope locking assembly, a screw assembly, a lower forearm, a wire rope assembly, a guide wheel assembly, a guide wheel shaft assembly, a wire rope connecting key assembly, a sleeve assembly, a bearing assembly, a gear hobbing assembly, a round nut with a hole on the side, and a joint connector.

[0006] The single-acting cylinder assembly is mounted on the upper end of the cylinder mounting plate via an external thread connection. The lower forearm is mounted on the lower end of the cylinder mounting plate via a screw assembly. The sleeve assembly is mounted on the lower forearm extension shaft via a clearance fit. The bearing assembly is mounted on the lower forearm extension shaft via an interference fit. The gear hobbing assembly is mounted on the bearing assembly via an interference fit. The round nut with a hole on the side is mounted on the end of the lower forearm extension shaft via an internal thread connection. The joint connector is mounted on the lower end of the gear hobbing assembly via a screw assembly.

[0007] The eye nut assembly is installed on the end of the piston rod of the single-acting cylinder assembly via an internal thread connection. The guide wheel assembly is installed on the lower forearm support hole via a guide wheel shaft assembly. The guide wheel and the guide wheel shaft form a clearance fit, and the guide wheel shaft and the support hole form an interference fit.

[0008] The upper end of the wire rope assembly is connected to the eye nut assembly via the wire rope lock assembly. The lower end of the wire rope assembly passes around the guide wheel assembly and is then wound into the gear hobbing groove. The end of the wire rope assembly is welded to the wire rope connecting key assembly, which is installed on the gear hobbing keyway via an interlocking fit.

[0009] The gear hobbing teeth are provided with grooves A, B, C and D, as well as keyways A, B, C and D. The lower forearm is provided with support holes A, B, C and D.

[0010] By adopting the above installation method, the initial states of the piston rods of the single-acting cylinders are set as follows: the piston rods of single-acting cylinders 11 and 12 are in the fully extended state, and the piston rods of single-acting cylinders 13 and 14 are in the fully retracted state.

[0011] Secondly, the present invention also provides a drive system for a variable cavity pneumatic robot joint, for driving the variable cavity pneumatic robot joint, including a single-acting cylinder 11, a single-acting cylinder 12, a single-acting cylinder 13, a single-acting cylinder 14, a three-position five-way solenoid valve I, a three-position five-way solenoid valve II, an adjustable flow valve I, an adjustable flow valve II, an adjustable flow valve III, a two-position two-way solenoid valve I, a two-position two-way solenoid valve II, a muffler I, and a muffler II.

[0012] The rod chamber of the single-acting cylinder 11 is connected to port A of the three-position five-way solenoid valve I; the rod chamber of the single-acting cylinder 12 is connected to port A of the three-position five-way solenoid valve II; the rod chamber of the single-acting cylinder 13 is connected to port B of the three-position five-way solenoid valve I; and the rod chamber of the single-acting cylinder 14 is connected to port B of the three-position five-way solenoid valve II.

[0013] The P port of the adjustable flow valve I is connected to the R port of the three-position five-way solenoid directional valve I. The P port of the adjustable flow valve I is connected to the R port of the three-position five-way solenoid directional valve II. The P port of the adjustable flow valve II is connected to the S port of the three-position five-way solenoid directional valve I. The P port of the adjustable flow valve II is connected to the S port of the three-position five-way solenoid directional valve II. The A port of the adjustable flow valve I is connected to the atmosphere through silencer I. The A port of the adjustable flow valve II is connected to the atmosphere through silencer II.

[0014] The A port of the two-position two-way solenoid valve I is connected to the P port of the three-position five-way solenoid valve I, and the A port of the two-position two-way solenoid valve II is connected to the P port of the three-position five-way solenoid valve II.

[0015] The A port of the adjustable flow valve III is connected to the P port of the two-position two-way solenoid directional valve I, the A port of the adjustable flow valve III is connected to the P port of the two-position two-way solenoid directional valve II, and the P port of the adjustable flow valve III is connected to the high-pressure gas circuit.

[0016] Here, the present invention provides a control method for a variable cavity pneumatic robot joint, used to control the drive system of the variable cavity pneumatic robot joint:

[0017] When one or both piston rods of the single-acting cylinder 11 and single-acting cylinder 12 retract, the hobbing gear rotates clockwise. Based on the actual load on the robot joint, the rod chambers of one or two single-acting cylinders whose output torque is closest to the actual load are selected and combined. Then, the corresponding position of the three-position five-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, connecting the rod chamber of the selected single-acting cylinder to the P port of the corresponding three-position five-way solenoid valve. Finally, the left position of the two-position two-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. The rod chamber of the cylinder is connected to the high-pressure air circuit, thereby achieving the matching of the output torque of the joint connector with the actual load torque. At the same time, under the control of its corresponding three-position five-way solenoid directional valve, the rod chamber of the unselected single-acting cylinder 13 is connected to the P port of the adjustable flow valve II, the rod chamber of the unselected single-acting cylinder 14 is connected to the P port of the adjustable flow valve II, the rod chamber of the unselected single-acting cylinder 11 is connected to the P port of its corresponding three-position five-way solenoid directional valve, and the rod chamber of the unselected single-acting cylinder 12 is connected to the P port of its corresponding three-position five-way solenoid directional valve.

[0018] When one or both piston rods of the single-acting cylinders 13 and 14 retract, the hobbing gear rotates counterclockwise. Based on the actual load on the robot joint, the rod chambers of one or two single-acting cylinders whose output torque is closest to the actual load are selected and combined. Then, the corresponding position of the three-position five-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, connecting the rod chamber of the selected single-acting cylinder to the P port of the corresponding three-position five-way solenoid valve. Finally, the left position of the two-position two-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. The rod chamber of the cylinder is connected to the high-pressure air circuit, thereby achieving the matching of the output torque of the joint connector with the actual load torque. At the same time, under the control of its corresponding three-position five-way solenoid directional valve, the rod chamber of the unselected single-acting cylinder 11 is connected to the P port of the adjustable flow valve I, the rod chamber of the unselected single-acting cylinder 12 is connected to the P port of the adjustable flow valve I, the rod chamber of the unselected single-acting cylinder 13 is connected to the P port of its corresponding three-position five-way solenoid directional valve, and the rod chamber of the unselected single-acting cylinder 14 is connected to the P port of its corresponding three-position five-way solenoid directional valve.

[0019] The piston area of ​​the rod chamber of the single-acting cylinder group is determined, so the output force of each single-acting cylinder can be determined. Moreover, the piston rods do not interfere with each other during extension and retraction, and can be independently controlled under the control of the three-position five-way solenoid valve. When performing variable load conditions, the effective working area of ​​the single-acting cylinder group is selected according to the load change through the control of the two-position two-way solenoid valve and the three-position five-way solenoid valve, so as to match the robot joint output torque with the actual load torque.

[0020] In summary, this invention has robot load matching capability, which can improve the driving efficiency of robot joint system. When performing variable load conditions, it can achieve real-time matching with the robot's variable load by selecting different single-acting cylinder cavities and high-pressure air circuits, thereby improving the driving efficiency of robot joint system. This invention is suitable for robots with large load variations, such as walking robots and exoskeleton robots, and has good social value and economic benefits. Attached image description:

[0021] Figure 1 This is an overall structural diagram of the joint of the variable cavity pneumatic robot, an example of the present invention.

[0022] Figure 2 This is a front view of the joint of the variable cavity pneumatic robot, an example of the present invention.

[0023] Figure 3 This is a cross-sectional view of the joint of the variable cavity pneumatic robot, an example of the present invention.

[0024] Figure 4 This is a structural diagram of the lower forearm of the joint of the variable cavity pneumatic robot, an example of the present invention.

[0025] Figure 5 This is a front view of the gear hobbing of the variable cavity pneumatic robot joint, an example of the present invention.

[0026] Figure 6 This is a rear view of the gear hobbing of the joint of the variable cavity pneumatic robot, an example of the present invention.

[0027] Figure 7 This is a structural diagram of the joint drive system of the variable cavity pneumatic robot, an example of the present invention. Detailed implementation method:

[0028] The specific embodiments of this patent will be further described in detail below with reference to the accompanying drawings:

[0029] like Figures 1 to 6 As shown, the variable cavity pneumatic robot joint consists of a single-acting cylinder assembly 1, a cylinder fixing plate 2, a lifting eye nut assembly 3, a wire rope locking assembly 4, a screw assembly 5, a lower forearm 6, a wire rope assembly 7, a guide wheel assembly 8, a guide wheel shaft assembly 9, a wire rope connecting key assembly 10, a sleeve assembly 15, a bearing assembly 16, a gear hobbing assembly 17, a round nut with a hole on the side 18, a screw assembly 19, and a joint connector 20.

[0030] The single-acting cylinder assembly 1 includes single-acting cylinders 11, 12, 13, and 14. The single-acting cylinder assembly 1 is mounted on the upper end of the cylinder fixing plate 2 via external thread connection and is symmetrically arranged about the gear hobbing 17. The lower end arm 6 is mounted on the lower end of the cylinder fixing plate 2 via the screw assembly 5. The sleeve assembly 15 includes sleeve 151 and sleeve 152. Sleeve 151 is mounted on the top end of the protruding shaft of the lower end arm 6 via clearance fit, and sleeve 152 is mounted between bearing 161 and bearing 162 via clearance fit. The bearing assembly 16 includes bearing 16... 1. Bearing 161 is installed between sleeve 151 and sleeve 152 by interference fit. Bearing 162 is installed between sleeve 152 and the side-hole round nut 18 by interference fit. The hobbing gear 17 is installed on bearing 161 and bearing 162 by interference fit. The upper end of the hobbing gear 17 is flush with the upper end of bearing 161, and the lower end of the hobbing gear 17 is flush with the lower end of bearing 162. The side-hole round nut 18 is installed at the end of the lower forearm 6 extension shaft by internal thread connection. The joint connector 20 is installed at the lower end of the hobbing gear 17 by the screw group 19 connection.

[0031] The eye nut assembly 3 includes eye nut 31, eye nut 32, eye nut 33, and eye nut 34. Eye nut 31 is installed at the end of the piston rod of single-acting cylinder 11 via an internal thread connection. Eye nut 32 is installed at the end of the piston rod of single-acting cylinder 12 via an internal thread connection. Eye nut 33 is installed at the end of the piston rod of single-acting cylinder 13 via an internal thread connection. Eye nut 34 is installed at the end of the piston rod of single-acting cylinder 14 via an internal thread connection. The guide wheel shaft assembly 9 includes a guide wheel shaft 91 and a guide wheel. The guide wheel assembly 8 includes guide wheels 81, 82, 83, and 84, connected by shaft 92, guide wheel shaft 93, and guide wheel shaft 94. Guide wheel 81 is mounted on the support hole A of the lower forearm 6 via guide wheel shaft 91, guide wheel 82 is mounted on the support hole B of the lower forearm 6 via guide wheel shaft 92, guide wheel 83 is mounted on the support hole C of the lower forearm 6 via guide wheel shaft 93, and guide wheel 84 is mounted on the support hole D of the lower forearm 6 via guide wheel shaft 94.

[0032] The guide wheel and the guide wheel shaft form a clearance fit, while the guide wheel shaft and the support hole form an interference fit.

[0033] The wire rope locking assembly 4 includes wire rope locking 41, wire rope locking 42, wire rope locking 43 and wire rope locking 44. The wire rope assembly 7 includes wire rope 71, wire rope 72, wire rope 73 and wire rope 74. Wire rope 71 is connected to the upper end of the eye nut 31 by wire rope locking 41. Wire rope 72 is connected to the upper end of the eye nut 32 by wire rope locking 42. Wire rope 73 is connected to the upper end of the eye nut 33 by wire rope locking 43. Wire rope 74 is connected to the upper end of the eye nut 34 by wire rope locking 44.

[0034] The lower end of wire rope 71 passes over guide wheel 81 and then winds into groove A of the toothed roller 17. The lower end of wire rope 72 passes over guide wheel 82 and then winds into groove B of the toothed roller 17. The lower end of wire rope 73 passes over guide wheel 83 and then winds into groove C of the toothed roller 17. The lower end of wire rope 74 passes over guide wheel 84 and then winds into groove D of the toothed roller 17.

[0035] The wire rope connecting key assembly 10 includes wire rope connecting key 101, wire rope connecting key 102, wire rope connecting key 103, and wire rope connecting key 104. Wire rope connecting key 101 is welded to the end of wire rope 71 and then installed on the keyway A of the hobbing gear 17 through a transition fit. Wire rope connecting key 102 is welded to the end of wire rope 72 and then installed on the keyway B of the hobbing gear 17 through a transition fit. Wire rope connecting key 103 is welded to the end of wire rope 73 and then installed on the keyway C of the hobbing gear 17 through a transition fit. Wire rope connecting key 104 is welded to the end of wire rope 74 and then installed on the keyway D of the hobbing gear 17 through a transition fit.

[0036] By adopting the above installation method, the initial states of the piston rods of the single-acting cylinders are set as follows: the piston rods of single-acting cylinders 11 and 12 are in the fully extended state, and the piston rods of single-acting cylinders 13 and 14 are in the fully retracted state.

[0037] like Figure 7 As shown, the drive system of the variable cavity pneumatic robot joint consists of single-acting cylinder 11, single-acting cylinder 12, single-acting cylinder 13, single-acting cylinder 14, three-position five-way solenoid valve I, three-position five-way solenoid valve II, adjustable flow valve I, adjustable flow valve II, adjustable flow valve III, two-position two-way solenoid valve I, two-position two-way solenoid valve II, muffler I and muffler II.

[0038] The specific working method and principle of this invention are as follows:

[0039] Let the control signals of the two-position two-way solenoid valve I, the two-position two-way solenoid valve II, the three-position five-way solenoid valve I and the three-position five-way solenoid valve II be X1, X2, X3 and X4 respectively, which are composed of the control signals [X1 X2 X3 X4].

[0040] (1) The gear hobbing rotates clockwise.

[0041] a) The piston rod of the single-acting cylinder 11 retracts;

[0042] When the piston rod of the single-acting cylinder 11 retracts, the hobbing gear 17 rotates clockwise. Its working principle is as follows: both the two-position two-way solenoid directional valve I and the three-position five-way solenoid directional valve I are energized in the left position. At this time, the rod chamber of the single-acting cylinder 11 is connected to the high-pressure air circuit, and the rod chamber of the single-acting cylinder 13 is connected to the P port of the adjustable flow valve II. Simultaneously, the two-position two-way solenoid directional valve II is not energized in the left position, and the three-position five-way solenoid directional valve II is energized in the left position. At this time, the rod chamber of the single-acting cylinder 12 is connected to the P port of the three-position five-way solenoid directional valve II, and the rod chamber of the single-acting cylinder 14 is connected to the P port of the adjustable flow valve II. The directional valve control signal [X1 X2 X3 X4] = [1 0 1] [1] In summary, when the piston rod of single-acting cylinder 11 retracts and the piston rod of single-acting cylinder 12 extends, after the adjustable flow valve II throttles and regulates the speed, the extension of the piston rods of single-acting cylinders 13 and 14 is obstructed. At this time, the hobbing gear 17 rotates clockwise, and the output torque of the joint connector 20 is:

[0043] T 11 =F 11 ·R=P·S 11 ·R

[0044] b) The piston rod of the single-acting cylinder 12 retracts;

[0045] When the piston rod of the single-acting cylinder 12 retracts, the hobbing gear 17 rotates clockwise. Its working principle is as follows: both the two-position two-way solenoid directional valve II and the three-position five-way solenoid directional valve II are energized in the left position. At this time, the rod chamber of the single-acting cylinder 12 is connected to the high-pressure air circuit, and the rod chamber of the single-acting cylinder 14 is connected to the P port of the adjustable flow valve II. Simultaneously, the two-position two-way solenoid directional valve I is not energized in the left position, and the three-position five-way solenoid directional valve I is energized in the left position. At this time, the rod chamber of the single-acting cylinder 11 is connected to the P port of the three-position five-way solenoid directional valve I, and the rod chamber of the single-acting cylinder 13 is connected to the P port of the adjustable flow valve II. The directional valve control signal [X1 X2 X3 X4] = [0 1 1] [1] In summary, when the piston rod of single-acting cylinder 12 retracts and the piston rod of single-acting cylinder 11 extends, after the adjustable flow valve II throttles and regulates the speed, the extension of the piston rods of single-acting cylinders 13 and 14 is obstructed. At this time, the hobbing gear 17 rotates clockwise, and the output torque of the joint connector 20 is:

[0046] T 12 =F 12 ·R=P·S 12 ·R

[0047] c) The piston rods of both single-acting cylinder 11 and single-acting cylinder 12 are retracted;

[0048] When the piston rods of single-acting cylinders 11 and 12 are both retracted, the hobbing gear 17 rotates clockwise. Its working principle is as follows: the two-position two-way solenoid directional valve I, the two-position two-way solenoid directional valve II, the three-position five-way solenoid directional valve I, and the three-position five-way solenoid directional valve II are all energized in the left position. At this time, the rod chamber of single-acting cylinder 11 is connected to the high-pressure air circuit, the rod chamber of single-acting cylinder 12 is connected to the high-pressure air circuit, the rod chamber of single-acting cylinder 13 is connected to the P port of the adjustable flow valve II, and the rod chamber of single-acting cylinder 14 is connected to the P port of the adjustable flow valve II. The directional valve control signal [X1X2X3X4] = [1 1 1] [1] In summary, the piston rods of both single-acting cylinder 11 and single-acting cylinder 12 retract. After the adjustable flow valve II throttles and regulates the speed, the piston rods of single-acting cylinder 13 and single-acting cylinder 14 are obstructed from extending. At this time, the hobbing gear 17 rotates clockwise, and the output torque of the joint connector 20 is:

[0049] T 11+12 =T 11 +T 12 =(F 11 +F 12 )·R=P·(S 11 +S 12 )·R

[0050] (2) The gear hobbing rotates counterclockwise.

[0051] a) The piston rod of the single-acting cylinder 13 retracts;

[0052] When the piston rod of the single-acting cylinder 13 retracts, the hobbing gear 17 rotates counterclockwise. Its working principle is as follows: the two-position two-way solenoid valve I is energized in the left position, and the three-position five-way solenoid valve I is energized in the right position. At this time, the rod chamber of the single-acting cylinder 11 is connected to the P port of the adjustable flow valve I, and the rod chamber of the single-acting cylinder 13 is connected to the high-pressure air circuit. Simultaneously, the two-position two-way solenoid valve II is not energized in the left position, and the three-position five-way solenoid valve II is energized in the right position. At this time, the rod chamber of the single-acting cylinder 12 is connected to the P port of the adjustable flow valve I, and the rod chamber of the single-acting cylinder 14 is connected to the P port of the three-position five-way solenoid valve II. The directional valve control signal [X1 X2 X3 X4] = [1 0 -1 -1] In summary, the piston rod of single-acting cylinder 13 retracts, and the piston rod of single-acting cylinder 14 is extended. After the speed regulation action of the adjustable flow valve I, the extension of the piston rods of single-acting cylinders 11 and 12 is blocked. At this time, the hobbing gear 17 rotates counterclockwise, and the output torque of the joint connector 20 is:

[0053] T 13 =F 13 ·R=P·S 13 ·R

[0054] b) The piston rod of the single-acting cylinder 14 retracts;

[0055] When the piston rod of the single-acting cylinder 14 retracts, the hobbing gear 17 rotates counterclockwise. Its working principle is as follows: the left position of the two-position two-way solenoid valve II is energized, and the right position of the three-position five-way solenoid valve II is energized. At this time, the rod chamber of the single-acting cylinder 12 is connected to the P port of the adjustable flow valve I, and the rod chamber of the single-acting cylinder 14 is connected to the high-pressure air circuit. Simultaneously, the left position of the two-position two-way solenoid valve I is not energized, and the right position of the three-position five-way solenoid valve I is energized. At this time, the rod chamber of the single-acting cylinder 11 is connected to the P port of the adjustable flow valve I, and the rod chamber of the single-acting cylinder 13 is connected to the P port of the three-position five-way solenoid valve I. The directional valve control signal [X1 X2 X3 X4] = [0 1 -1 -1] In summary, when the piston rod of single-acting cylinder 14 retracts and the piston rod of single-acting cylinder 13 extends, after the speed regulation effect of the adjustable flow valve I, the extension of the piston rods of single-acting cylinders 11 and 12 is blocked. At this time, the hobbing gear 17 rotates counterclockwise, and the output torque of the joint connector 20 is:

[0056] T 14 =F 14 ·R=P·S14 ·R

[0057] c) The piston rods of both single-acting cylinder 13 and single-acting cylinder 14 are retracted;

[0058] When the piston rods of single-acting cylinders 13 and 14 are both retracted, the hobbing gear 17 rotates counterclockwise. Its working principle is as follows: both the two-position two-way solenoid directional valve I and II are energized to the left, and both the three-position five-way solenoid directional valve I and II are energized to the right. At this time, the rod chamber of single-acting cylinder 11 is connected to the P port of adjustable flow valve I, the rod chamber of single-acting cylinder 12 is connected to the P port of adjustable flow valve I, the rod chamber of single-acting cylinder 13 is connected to the high-pressure air circuit, and the rod chamber of single-acting cylinder 14 is connected to the high-pressure air circuit. The directional valve control signal [X1 X2 X3 X4] = [1 1 -1 -1] In summary, the piston rods of both single-acting cylinder 13 and single-acting cylinder 14 retract. After the adjustable flow valve I throttles and regulates the speed, the piston rods of single-acting cylinder 11 and single-acting cylinder 12 are obstructed from extending. At this time, the hobbing gear 17 rotates counterclockwise, and the output torque of the joint connector 20 is:

[0059] T 13+14 =T 13 +T 14 =(F 13 +F 14 )·R=P·(S 13 +S 14 )·R

[0060] (3) Rotation of the hobbing gear after the antagonistic action of the single-acting cylinder

[0061] a) After the single-acting cylinder 12 and the single-acting cylinder 13 act in opposition, the piston rod of the single-acting cylinder 12 retracts.

[0062] When single-acting cylinders 12 and 13 act in opposition, the piston rod of single-acting cylinder 12 retracts, and the hobbing gear 17 rotates clockwise. Its working principle is as follows: both the two-position two-way solenoid valve I and the two-position two-way solenoid valve II are energized in the left position; the three-position five-way solenoid valve I is energized in the right position; and the three-position five-way solenoid valve II is energized in the left position. At this time, the rod chamber of single-acting cylinder 12 is connected to the high-pressure air circuit; the rod chamber of single-acting cylinder 13 is connected to the high-pressure air circuit; the rod chamber of single-acting cylinder 11 is connected to the P port of the adjustable flow valve I; and the rod chamber of single-acting cylinder 14 is connected to the P port of the adjustable flow valve II. The directional valve control signal [X1 X2 X3 X4] = [1 1 -1 [1] In summary, when the piston rod of single-acting cylinder 12 retracts and the piston rod of single-acting cylinder 11 extends, after the throttling and speed regulation by the adjustable flow valve I and the adjustable flow valve II, the extension of the piston rods of single-acting cylinders 13 and 14 is obstructed. At this time, the hobbing gear 17 rotates clockwise, and the output torque of the joint connector 20 is:

[0063] T 12-13 =T 12 -T 13 =(F 12 -F 13 )·R=P·(S 12 -S 13 )·R

[0064] b) After the single-acting cylinder 14 and the single-acting cylinder 11 act in opposition, the piston rod of the single-acting cylinder 14 retracts.

[0065] When single-acting cylinders 14 and 11 act in opposition, the piston rod of single-acting cylinder 14 retracts, and the hobbing gear 17 rotates counterclockwise. Its working principle is as follows: both the two-position two-way solenoid valve I and the two-position two-way solenoid valve II are energized in the left position; the three-position five-way solenoid valve I is energized in the left position; and the three-position five-way solenoid valve II is energized in the right position. At this time, the rod chamber of single-acting cylinder 11 is connected to the high-pressure air circuit; the rod chamber of single-acting cylinder 14 is connected to the high-pressure air circuit; the rod chamber of single-acting cylinder 12 is connected to the P port of the adjustable flow valve I; and the rod chamber of single-acting cylinder 13 is connected to the P port of the adjustable flow valve II. The directional valve control signal [X1 X2 X3 X4] = [1 1 1] -1] In summary, when the piston rod of single-acting cylinder 14 retracts and the piston rod of single-acting cylinder 13 extends, after the throttling and speed regulation by the adjustable flow valve I and the adjustable flow valve II, the extension of the piston rods of single-acting cylinders 11 and 12 is obstructed. At this time, the hobbing gear 17 rotates counterclockwise, and the output torque of the joint connector 20 is:

[0066] T14-11 =T 14 -T 11 =(F 14 -F 11 )·R=P·(S 14 -S 11 )·R

[0067] In summary, when the reversing valve is under different control signals, the corresponding single-acting cylinder operates, the hobbing gear 17 rotates, and the output torque of the joint connector 20 are as shown in the table below.

[0068]

[0069] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A variable cavity pneumatic robot joint, characterized in that: Includes a single-acting cylinder assembly, cylinder mounting plate, eye nut assembly, wire rope lock assembly, screw assembly, lower end forearm, wire rope assembly, guide wheel assembly, guide wheel shaft assembly, wire rope connecting key assembly, sleeve assembly, bearing assembly, gear hobbing, side-hole round nut, and joint connector; The single-acting cylinder assembly is installed on the upper end of the cylinder mounting plate via an external thread connection. The lower arm is installed on the lower end of the cylinder mounting plate via a screw assembly. The sleeve assembly is installed on the lower arm extension shaft via a clearance fit. The bearing assembly is installed on the lower arm extension shaft via an interference fit. The gear hobbing assembly is installed on the bearing assembly via an interference fit. The round nut with a hole on the side is installed on the end of the lower arm extension shaft via an internal thread connection. The joint connector is installed on the lower end of the gear hobbing assembly via a screw assembly. The eye nut assembly is installed on the end of the piston rod of the single-acting cylinder assembly via an internal thread connection. The guide wheel assembly is installed on the lower forearm support hole via a guide wheel shaft assembly. The guide wheel and the guide wheel shaft form a clearance fit, and the guide wheel shaft and the support hole form an interference fit. The upper end of the wire rope assembly is connected to the eye nut assembly via the wire rope lock assembly. The lower end passes around the guide wheel assembly and is then wound into the hobbing groove. The end of the wire rope assembly is welded to the wire rope connecting key assembly, which is installed on the hobbing key groove via an transition fit. The hobbing gear is provided with grooves A, B, C and D, as well as keyways A, B, C and D. The lower forearm is provided with support holes A, B, C and D. It also includes a drive system, which includes a single-acting cylinder I (11), a single-acting cylinder II (12), a single-acting cylinder III (13), a single-acting cylinder IV (14), a three-position five-way solenoid valve I, a three-position five-way solenoid valve II, an adjustable flow valve I, an adjustable flow valve II, an adjustable flow valve III, a two-position two-way solenoid valve I, a two-position two-way solenoid valve II, a muffler I and a muffler II; The rod chamber of the single-acting cylinder I (11) is connected to port A of the three-position five-way solenoid valve I; the rod chamber of the single-acting cylinder II (12) is connected to port A of the three-position five-way solenoid valve II; the rod chamber of the single-acting cylinder III (13) is connected to port B of the three-position five-way solenoid valve I; the rod chamber of the single-acting cylinder IV (14) is connected to port B of the three-position five-way solenoid valve II; the P port of the adjustable flow valve I is connected to port R of the three-position five-way solenoid valve I; the P port of the adjustable flow valve I is connected to port R of the three-position five-way solenoid valve II; the P port of the adjustable flow valve II is connected to port S of the three-position five-way solenoid valve I. The adjustable flow valve II has its port P connected to the three-position five-way solenoid valve II. The adjustable flow valve I has its port A connected to the atmosphere through silencer I. The adjustable flow valve II has its port A connected to the atmosphere through silencer II. The two-position two-way solenoid valve I has its port A connected to the three-position five-way solenoid valve I. The two-position two-way solenoid valve II has its port A connected to the three-position five-way solenoid valve II. The adjustable flow valve III has its port A connected to the two-position two-way solenoid valve I. The adjustable flow valve III has its port A connected to the two-position two-way solenoid valve II. The adjustable flow valve III has its port P connected to the high-pressure gas circuit.

2. A control method for a variable cavity pneumatic robot joint, used to control the variable cavity pneumatic robot joint as described in claim 1, characterized in that: When one or both piston rods of the single-acting cylinder I (11) and single-acting cylinder II (12) retract, the hobbing gear rotates clockwise. Based on the actual load on the robot joint, the rod chambers of one or two single-acting cylinders whose output torque is closest to the actual load are selected for combination. Then, the corresponding position of the three-position five-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. Finally, the left position of the two-position two-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. The rod chamber is connected to the high-pressure air circuit, thereby achieving the matching of the output torque of the joint connector with the actual load torque. At the same time, under the control of its corresponding three-position five-way solenoid directional valve, the rod chamber of the unselected single-acting cylinder III (13) is connected to the P port of the adjustable flow valve II, the rod chamber of the unselected single-acting cylinder IV (14) is connected to the P port of the adjustable flow valve II, the rod chamber of the unselected single-acting cylinder I (11) is connected to the P port of its corresponding three-position five-way solenoid directional valve, and the rod chamber of the unselected single-acting cylinder II (12) is connected to the P port of its corresponding three-position five-way solenoid directional valve. When one or both piston rods of the single-acting cylinder III (13) and single-acting cylinder IV (14) retract, the hobbing gear rotates counterclockwise. Based on the actual load of the robot joint, the rod chambers of one or two single-acting cylinders whose output torque is closest to the actual load are selected for combination. Then, the corresponding position of the three-position five-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. Finally, the left position of the two-position two-way solenoid valve corresponding to the rod chamber of the selected single-acting cylinder is energized, realizing the connection between the rod chamber of the selected single-acting cylinder and the P port of the corresponding three-position five-way solenoid valve. The rod chamber is connected to the high-pressure air circuit, thereby achieving the matching of the output torque of the joint connector with the actual load torque. At the same time, under the control of its corresponding three-position five-way solenoid directional valve, the rod chamber of the unselected single-acting cylinder I (11) is connected to the P port of the adjustable flow valve I, the rod chamber of the unselected single-acting cylinder II (12) is connected to the P port of the adjustable flow valve I, the rod chamber of the unselected single-acting cylinder III (13) is connected to the P port of its corresponding three-position five-way solenoid directional valve, and the rod chamber of the unselected single-acting cylinder IV (14) is connected to the P port of its corresponding three-position five-way solenoid directional valve.

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