Nested rotating type inverse stiffness rope-driven manipulator

Abstract

The invention discloses a nested rotating type inverse stiffness rope-driven manipulator which comprises a driving mechanism, a nested rotating type differential mechanism, a transmission mechanism and an encoder. The driving mechanism is used for driving the outer driving wheel of the nested rotary differential mechanism to rotate; the nested rotary differential mechanism, the transmission mechanism and the encoder are matched to realize differential control of the manipulator; according to the mechanical arm, the two clamping jaw fingertips drive the inner adaptive wheel of the nested rotary differential mechanism to rotate through differential power, the fingertip contact force is reduced, inverse stiffness self-adaptive motion is achieved, differential state reading can be achieved by reading an encoder on the inner adaptive wheel, and a grabbed object can be positioned in the mechanical arm.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and in particular to a nested rotary inverse stiffness rope-driven manipulator. Background Art

[0002] A manipulator is typically the end effector of a robotic arm. Due to factors such as the arm's motion errors and sensor recognition errors of the grasped object, it is difficult to perfectly align the center of the manipulator with the center of the grasped object. Therefore, adaptive grasping tasks are extremely important.

[0003] Adaptive manipulators can be divided into shape adaptation based on soft materials and position adaptation based on differential mechanisms. Currently, the main problems are as follows:

[0004] (1) Operational requirements

[0005] The research focus of these adaptive manipulators is on how to achieve adaptive motion. However, the manipulator not only includes grasping, but more importantly, it is to complete the operation. The most important thing in the operation is to ensure the relative position of the target and the manipulator, which is exactly the research content that has been ignored after the adaptive motion. It is difficult to establish the material contact deformation law for the shape adaptation of flexible materials, and thus it is difficult to estimate the relative state of the grasped target in the manipulator, so feedback guidance is required to compensate for the position error. However, this method has a high application cost and is difficult to apply to the dynamic grasping of fast-moving targets. This article focuses on the research of differential mechanism position adaptive manipulators, and analyzes the shortcomings of differential mechanisms to achieve shape adaptive grasping of targets under small displacements.

[0006] (2) Response and travel requirements

[0007] In the differential position adaptation category, the differential force of a gear differential mechanism is used to drive the rotation of the planetary gears. The minimum differential force is the sum of the gear meshing friction and the rotational friction of the planetary gear shafts. This type of mechanism can only be used for differential control of relatively large loads. When the load is small, the reaction force cannot overcome the friction to achieve differential control. This means that the minimum stiffness of the mechanism is greater than the static friction of the grasped object, and the manipulator pushes the grasped object, which means that adaptive motion under low contact forces cannot be achieved. Lever differential mechanisms are typically used for travel expansion and contraction. However, when the travel is expanded, the error is also amplified, making it difficult to achieve both a large travel and high precision. In a rope differential mechanism, the differential force is used to drive the translational friction of the movable pulley. Like gear differential mechanisms, adaptive grasping under low contact forces is also difficult. This paper proposes a nested rotational differential mechanism that converts the differential force into rotational motion. The minimum differential force is a smaller rotational friction, thus enabling movement with low contact forces and large travel.

[0008] (3) Mechanism stability and status reading requirements

[0009] In a rope-driven differential mechanism, the rope only transmits force in one direction (it can only withstand tension, not compression). Therefore, the rope is often tensioned by a spring. However, after the differential mechanism's adaptive motion, the springs deform to varying lengths. As a result, after the manipulator closes, the non-uniform spring force causes the grasped object to reciprocate within the gripper, making it difficult to maintain a stable state. This paper utilizes mutually tensioned ropes to avoid the instability introduced by the springs. This allows the differential state to be read using an encoder, enabling accurate reading of the grasped object's state within the manipulator.

[0010] Specifically, the existing technologies can be roughly divided into two categories, as follows:

[0011] Prior art 1

[0012] (1) Single-drive four-finger adaptive gripper / CN 117506991 A

[0013] (2) Underactuated traction device and hand exoskeleton based on planetary gear differential mechanism / CN 116587249A

[0014] (3) Rope-driven robot, rope differential, and rope-driven robot rope tension detection method / CN 116652920A

[0015] (4) A flexible arm segment and flexible robotic arm based on differential gears / CN 108189018 A

[0016] (5) A clamp capable of adaptively adjusting the clamping position / CN 118617334 A

[0017] (6) A two-speed shunting winch with a planetary speed change mechanism / CN 101234733 A

[0018] (7) Underactuated manipulator for training cricket serve / CN 116549950A

[0019] (8) Variable stiffness rope-driven three-finger adaptive manipulator and method / CN 115946104A

[0020] (9) An adaptive manipulator with adjustable gripping range / CN 115741750A

[0021] (10) A rope-driven underactuated adaptive suction cup manipulator / CN 115870964A

[0022] The prior art can be roughly divided into three categories according to the principle: gear-type differential mechanisms, slider-type differential mechanisms, and other gear-type differential mechanisms.

[0023] For gear-type differential mechanisms (bevel gears, planetary gears), when the differential output shaft is subjected to different loads, the planetary gears rotate due to the force difference, achieving differential motion between the two grippers. The large moment of inertia of the gears that create the force difference and the significant friction between the gears result in a large force differential required for differential motion. Furthermore, the gears are heavy, making integration into the end-of-machine interface difficult.

[0024] A slider-type differential mechanism consists of two transmission lines, driven by their intersection. The different tensions in the ropes at different sliders cause the different sliders to move in sequence. The essence of differential motion is that the ropes overcome the force difference between the moving pairs formed by the guide rails and sliders. Compared to gear-type differential mechanisms, this mechanism overcomes more friction, resulting in a greater force difference in differential motion and a larger overall footprint.

[0025] As for other gear-type differential mechanisms, this type of differential mechanism is mostly used in scenarios with large loads. The overall size is relatively large and the mass is very large, making it difficult to apply to the robot end gripper.

[0026] That is, the prior art 1 has the following problems:

[0027] (1) Currently, gear-type adaptive grippers are only suitable for large load scenarios. They require a large force difference to achieve differential motion, and it is difficult to achieve fast and sensitive response with a small force difference. In addition, the gear-type adaptive gripper itself has a large mass.

[0028] (2) Currently, the minimum cable force of the slider-type adaptive gripper needs to be greater than the maximum static friction force of the slider, which makes it difficult to achieve rapid response and adaptive grasping through a small force difference.

[0029] (3) The gripper that meets the requirements of posture adaptation cannot meet the large load requirements due to the influence of the material, and is constrained by feedback control and has difficulty in grasping fast-moving targets in real time.

[0030] Prior Art 2

[0031] [1]On the Design of a Mechanically Programmable UnderactuatedAnthropomorphic Prosthetic Gripper,10.1115 / 1.4025493

[0032] [2]Static Analysis of Single-Input / Multiple-Output Tendon-DrivenUnderactuated Mechanisms for Robotic Hands,10.1115 / DETC2010-28933

[0033] [3]Force Analysis of Connected Differential Mechanisms:Application toGrasping,10.1177 / 0278364906068942

[0034] [4]MOGrip:Gripper for multiobject grasping in pick-and-place tasksusing translational movements offingers,10.1126 / scirobotics.ado3939

[0035] [5]Exo-Glove:A Wearable Robot for the Hand with a Soft Tendon RoutingSystem,10.1109 / MRA.2014.2362863

[0036] The second prior art belongs to a rope-driven differential manipulator, which can be roughly divided into a full-joint serial rope-driven differential manipulator, a lever-rotation differential manipulator, and a spring-tensioned rope-driven differential manipulator according to the principle.

[0037] For fully jointed serial rope-driven differential manipulators, the essence of this mechanism's differential motion is to use ropes to connect all joints in series. When the joints are subjected to uneven forces, the sliding of the ropes drives the joints toward equilibrium, thereby achieving adaptive enveloping motion. However, the rope path is too long. As the rope path grows, force transmission attenuates significantly, and friction has a significant impact. Essentially, this is translational friction, making adaptive motion difficult to achieve under low contact forces.

[0038] For lever-rotating differential manipulators, this type of differential mechanism adapts to load differences by lever rotation. However, the rotational stroke is small and the differential law is highly nonlinear, making it difficult to meet differential requirements over a large stroke.

[0039] For spring-tensioned rope-driven differential manipulators, this type of manipulator requires spring-assisted tensioning to meet the manipulator's bidirectional movement. However, when the two fingertips of the manipulator move unevenly, the spring tension is different, making it difficult for the two fingers to remain stable, and the position of the grasped object in the manipulator oscillates.

[0040] That is, the second prior art has the following problems:

[0041] (1) The minimum cable force difference of the fully jointed serial rope-driven differential manipulator needs to be greater than the maximum static friction of the rope. At the same time, the force transmission is significantly attenuated, and the friction force has a large influence. It is essentially a translational friction, which makes it difficult to achieve adaptive motion under small contact force. This also makes it difficult to achieve rapid response and adaptive grasping through a small force difference.

[0042] (2) The differential stroke of the lever-rotating differential manipulator is limited, and the differential motion is highly nonlinear.

[0043] (3) The spring tensioned rope-driven differential manipulator is difficult to maintain stability after the manipulator is closed.

[0044] In summary, the existing adaptive gripper has the following problems:

[0045] (1) Currently, gear-type adaptive grippers are only suitable for large load scenarios. They require a large force difference to achieve differential motion, and it is difficult to achieve fast and sensitive response with a small force difference. In addition, the gear-type adaptive gripper itself has a large mass.

[0046] (2) Currently, the minimum cable force of the slider-type adaptive gripper needs to be greater than the maximum static friction force of the slider, which makes it difficult to achieve rapid response and adaptive grasping through a small force difference.

[0047] (3) The gripper that meets the requirements of posture adaptation cannot meet the large load requirements due to the influence of the material, and is constrained by feedback control and has difficulty in grasping fast-moving targets in real time. Summary of the Invention

[0048] The object of the present invention is to provide a nested rotary inverse stiffness rope-driven manipulator to solve the problem in the prior art that it is difficult to achieve complete alignment between the center of the manipulator and the center of the grasped object.

[0049] In order to solve the above technical problems, the present invention provides a nested rotary inverse stiffness rope-driven manipulator, comprising a drive mechanism, a nested rotary differential mechanism, a transmission mechanism, and an encoder; the drive mechanism is used to drive the outer drive wheel of the nested rotary differential mechanism to rotate; the nested rotary differential mechanism comprises a differential frame, the outer drive wheel rotatably arranged in the differential frame, and an inner adaptive wheel rotatably arranged in a space surrounded by the outer drive wheel; the inner peripheral wall of the differential frame is provided with a first frame guide wheel, a second frame guide wheel, a third frame guide wheel, and a fourth frame guide wheel arranged in sequence along the central axis thereof; the peripheral wall of the outer drive wheel is provided with a The first wheel mounting groove, the second wheel mounting groove, the third wheel mounting groove, and the fourth wheel mounting groove are arranged in sequence and separated along the central axis thereof, and the inner and outer walls thereof are penetrated by the first wheel mounting groove, the second wheel mounting groove, the third wheel mounting groove, and the fourth wheel mounting groove, respectively, wherein the first guide movable pulley, the second guide movable pulley, the third guide movable pulley, and the fourth guide movable pulley are rotatably installed in the first wheel mounting groove, the second wheel mounting groove, the third wheel mounting groove, and the fourth wheel mounting groove; the outer peripheral wall of the outer driving wheel is provided with a first outer annular groove, a second outer annular groove, a third outer annular groove, and a fourth outer annular groove, which are arranged in sequence and separated along the central axis thereof; the outer peripheral wall of the inner adaptive wheel is provided with a first inner annular groove, a second inner annular groove, a third inner annular groove, and a fourth inner annular groove, which are arranged in sequence and separated along the central axis thereof shaped groove; the transmission mechanism includes a transmission frame, and a linear guide rail, a first guide wheel group, a second guide wheel group, a third guide wheel group, and a fourth guide wheel group arranged on the transmission frame; a first clamping jaw and a second clamping jaw are slidably mounted on the linear guide rail; a surface of the first clamping jaw away from the second clamping jaw is connected to a first rope, the first rope passes through the first guide wheel group, the first frame guide wheel, the first outer annular groove, the first guide movable pulley, and the first inner annular groove in sequence and is connected and fixed to the inner adaptive wheel; a surface of the second clamping jaw away from the first clamping jaw is connected to a second rope, and the second rope passes through the second guide wheel group, the second frame guide wheel, the second outer annular groove, the second guide movable pulley in sequence, and is fixed to the inner adaptive wheel and the second inner annular groove and then is connected and fixed to the inner adaptive wheel; the surface of the second clamp facing the first clamp is connected with a third rope, and the third rope passes through the first clamp and then bypasses the third guide wheel group, the third frame guide wheel, the third outer annular groove, the third guide movable pulley, and the third inner annular groove in sequence and is then connected and fixed to the inner adaptive wheel; the surface of the first clamp facing the second clamp is connected with a fourth rope, and the fourth rope passes through the second clamp and then bypasses the fourth guide wheel group, the fourth frame guide wheel, the fourth outer annular groove, the fourth guide movable pulley, and the fourth inner annular groove in sequence and is then connected and fixed to the inner adaptive wheel; the encoder is used to detect the output shaft rotation information of the inner adaptive wheel.

[0050] In one embodiment, the driving mechanism includes a driving bracket and a driving motor arranged in the space surrounded by the driving bracket; the driving bracket is connected and fixed to the differential bracket; the output shaft of the driving motor is fixedly connected to a motor connecting flange, the motor connecting flange is connected and fixed to one end of the outer driving wheel, the other end of the outer driving wheel is fixedly connected to an encoding fixing seat, the encoding fixing seat is provided with the encoder, and the output shaft of the inner adaptive wheel extends into the detection area of the encoder.

[0051] In one embodiment, the two ends of the inner adaptive wheel are respectively covered with a first inner bearing and a second inner bearing; the first inner bearing is arranged between the motor connecting flange and the inner adaptive wheel; the second inner bearing is arranged between the encoder fixing seat and the inner adaptive wheel.

[0052] In one embodiment, the encoder fixing seat is outer-mounted with an outer bearing, and the outer bearing is arranged between the encoder fixing seat and the differential frame.

[0053] In one embodiment, the rotational center axes of the first frame guide wheel, the second frame guide wheel, the third frame guide wheel, and the fourth frame guide wheel are perpendicular to the central axis of the differential frame.

[0054] In one embodiment, the rotation center axis of the first guide movable pulley, the second guide movable pulley, the third guide movable pulley, and the fourth guide movable pulley is consistent with the rotation center axis of the outer drive wheel.

[0055] In one embodiment, on one side of the nested rotating differential mechanism, the differential frame is provided with the first frame guide wheel and the fourth frame guide wheel, the outer drive wheel is provided with the second guide movable pulley and the third guide movable pulley, and the inner adaptive wheel is fixedly connected to the first rope and the fourth rope; on the other side opposite to the nested rotating differential mechanism, the differential frame is provided with the second frame guide wheel and the third frame guide wheel, the outer drive wheel is provided with the first guide movable pulley and the fourth guide movable pulley, and the inner adaptive wheel is fixedly connected to the second rope and the third rope.

[0056] In one embodiment, the transmission frame is provided with the first guide wheel group adjacent to the connection between the first jaw and the first rope; the transmission frame is provided with the second guide wheel group adjacent to the connection between the second jaw and the second rope; the transmission frame is provided with the third guide wheel group adjacent to the first jaw for the third rope to pass through; and the transmission frame is provided with the fourth guide wheel group adjacent to the first jaw for the fourth rope to pass through.

[0057] In one embodiment, the first guide wheel group includes a first long-wall guide wheel provided at the long side wall of the transmission frame, a first corner guide wheel provided at the corner of the transmission frame, and a first short-wall guide wheel provided at the short side wall of the transmission frame, the first rope is connected to the first clamping claw after passing through the first long-wall guide wheel, the first corner guide wheel, and the first short-wall guide wheel in sequence; the second guide wheel group includes a second long-wall guide wheel provided at the long side wall of the transmission frame, a second corner guide wheel provided at the corner of the transmission frame, and a second short-wall guide wheel provided at the short side wall of the transmission frame, the second rope is connected to the second long-wall guide wheel, the second corner guide wheel, and the second short-wall guide wheel in sequence The third guide wheel group includes a third long-wall guide wheel provided at the long side wall of the transmission frame, a third corner guide wheel provided at the corner of the transmission frame, and a third short-wall guide wheel provided at the short side wall of the transmission frame, and the third rope is connected to the second clamping jaw after passing through the third long-wall guide wheel, the third corner guide wheel, and the third short-wall guide wheel in sequence; the fourth guide wheel group includes a fourth long-wall guide wheel provided at the long side wall of the transmission frame, a fourth corner guide wheel provided at the corner of the transmission frame, and a fourth short-wall guide wheel provided at the short side wall of the transmission frame, and the fourth rope is connected to the first clamping jaw after passing through the fourth long-wall guide wheel, the fourth corner guide wheel, and the fourth short-wall guide wheel in sequence.

[0058] In one embodiment, the rotation axes of the first long-wall guide wheel, the second long-wall guide wheel, the third long-wall guide wheel, and the fourth long-wall guide wheel are all perpendicular to the long side wall of the transmission frame; the rotation axes of the first corner guide wheel, the second corner guide wheel, the third corner guide wheel, and the fourth corner guide wheel are all consistent with the rotation axis of the inner adaptive wheel; the rotation axes of the first short-wall guide wheel, the second short-wall guide wheel, the third short-wall guide wheel, and the fourth short-wall guide wheel are all consistent with the rotation axis of the inner adaptive wheel.

[0059] The beneficial effects of the present invention are as follows:

[0060] (1) The present invention utilizes the rope drive principle to reduce the high contact stiffness corresponding to factors such as large inertia and large friction of the gear differential, and large translational friction. It utilizes extremely small rotational friction to constrain the differential contact stiffness, and the portion of the contact force that is greater than the rotational friction is converted into the rotational motion of the inner adaptive wheel, thereby achieving an inverse stiffness manipulator design that is much smaller than the rope stiffness and the gripper stiffness.

[0061] (2) The present invention utilizes a nested rotary design to increase the driving stroke by r2 / r1 times.

[0062] (3) The present invention uses rope antagonistic force instead of spring tension to ensure the stability of the manipulator after closing, and reads the relative state of the grasped target on the manipulator through the encoder, thereby improving the operating accuracy of the manipulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] Figure 1 It is a structural diagram provided by an embodiment of the present invention;

[0065] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure;

[0066] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure of the driving mechanism;

[0067] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure of the nested rotating differential mechanism;

[0068] Figure 5 yes Figure 4 Schematic diagram of the outer drive wheel structure;

[0069] Figure 6 yes Figure 4 Schematic diagram of the inner adaptive wheel structure;

[0070] Figure 7 yes Figure 4 Schematic diagram of the differential rack structure in FIG;

[0071] Figure 8 yes Figure 1 Schematic diagram of the transmission mechanism structure;

[0072] Figure 9 yes Figure 8 Schematic diagram of the cross-sectional structure.

[0073] The reference numerals are as follows:

[0074] 10. Driving mechanism; 11. Driving bracket; 12. Driving motor;

[0075] 20. Nested Rotary Differential Mechanism; 21. Outer Drive Wheel; 2111. First Wheel-Mounting Groove; 2112. Second Wheel-Mounting Groove; 2113. Third Wheel-Mounting Groove; 2114. Fourth Wheel-Mounting Groove; 2121. First Guide Movable Pullway; 2122. Second Guide Movable Pullway; 2123. Third Guide Movable Pullway; 2124. Fourth Guide Movable Pullway; 2131. First Outer Annular Groove; 2132. Second Outer Annular Groove; 2133. Third Outer Annular Groove; 2134. Fourth Outer Annular Groove; 22. Inner Adaptive Wheel; 221. First Inner Annular Groove; 222. Second Inner Annular Groove; 223. Third Inner Annular Groove; 224. Fourth Inner Annular Groove; 23. Differential Frame; 231. First Frame Guide Wheel; 232. Second Frame Guide Wheel; 233. Third Frame Guide Wheel; 234. Fourth Frame Guide Wheel;

[0076] 30. Transmission mechanism; 31. First guide wheel assembly; 311. First long-wall guide wheel; 312. First corner guide wheel; 313. First short-wall guide wheel; 32. Second guide wheel assembly; 321. Second long-wall guide wheel; 322. Second corner guide wheel; 323. Second short-wall guide wheel; 33. Third guide wheel assembly; 331. Third long-wall guide wheel; 332. Third corner guide wheel; 333. Third short-wall guide wheel; 34. Fourth guide wheel assembly; 341. Fourth long-wall guide wheel; 342. Fourth corner guide wheel; 343. Fourth short-wall guide wheel; 35. Transmission frame; 36. Linear guide rail; 371. First clamp; 372. Second clamp; 381. First rope; 382. Second rope; 383. Third rope; 384. Fourth rope.

[0077] 40. Encoder;

[0078] 51. Motor connection flange; 52. Encoding fixing seat;

[0079] 61. First inner bearing; 62. Second inner bearing; 63. Outer bearing. DETAILED DESCRIPTION

[0080] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0081] The present invention provides a nested rotary inverse stiffness rope-driven manipulator, which is implemented as follows: Figure 1 and Figure 4 As shown, it includes a driving mechanism 10 , a nested rotary differential mechanism 20 , a transmission mechanism 30 , and an encoder 40 .

[0082] Regarding the driving mechanism 10, Figures 1 to 4As shown, the driving mechanism 10 of this embodiment is used to drive the outer driving wheel 21 of the nested rotary differential mechanism 20 to rotate. Specifically, the driving mechanism 10 at this time includes a driving bracket 11 and a driving motor 12 arranged in a space surrounded by the driving bracket 11.

[0083] The driving bracket 11 is mainly used to wrap and protect the driving motor 12 and to realize the connection with the nested rotating differential mechanism 20. For example, in this embodiment, screws are used to pass through the driving bracket 11 and connect with the nested rotating differential mechanism 20, thereby realizing the connection and fixation between the driving mechanism 10 and the nested rotating differential mechanism 20.

[0084] The main function of the drive motor 12 is to provide the outer drive wheel 21 with power for self-rotation. Therefore, to achieve this purpose, the output shaft of the drive motor 12 can be directly or indirectly connected to the outer drive wheel 21.

[0085] For example, from Figure 3 and Figure 4 It can be seen that in this embodiment, a motor connecting flange 51 is fixedly connected to the output shaft of the drive motor 12, and the motor connecting flange 51 is fixedly connected to one end of the outer drive wheel 21. The other end of the outer drive wheel 21 is fixedly connected to an encoding fixing seat 52, and an encoder 40 is provided on the encoding fixing seat 52. The output shaft of the inner adaptive wheel 22 of the nested rotary differential mechanism 20 extends into the detection area of the encoder 40, so that the encoder 40 can be used to detect the output shaft rotation information of the inner adaptive wheel 22.

[0086] Regarding the nested rotary differential mechanism 20, Figure 4 As shown, the nested rotary differential mechanism 20 of this embodiment includes a differential carrier 23 , an outer drive wheel 21 rotatably disposed in the differential carrier 23 , and an inner adaptive wheel 22 rotatably disposed in a space surrounded by the outer drive wheel 21 .

[0087] The differential frame 23 is mainly used to realize the wrapping and surrounding of the outer driving wheel 21 and the inner adaptive wheel 22, and to realize the connection and fixation with the driving mechanism 10 and the transmission mechanism 30; for example, this embodiment uses the driving bracket 11 to connect and fix with the differential frame 23, so that Figures 2 to 4 As shown, at this time, the upper portion of the figure can be connected to the differential frame 23 by passing screws through the drive bracket 11, so that the drive bracket 11 and the differential frame 23 can form a closed space, and the lower portion can be connected and fixed to the transmission mechanism 30 by passing screws through the differential frame 23.

[0088] And from Figure 7 It can be seen that in this embodiment, the inner peripheral wall of the differential frame 23 is provided with a Figure 7The first frame guide wheel 231, the second frame guide wheel 232, the third frame guide wheel 233, and the fourth frame guide wheel 234 are arranged in sequence (in the vertical direction of the direction shown), and the rotation center axis of the first frame guide wheel 231, the second frame guide wheel 232, the third frame guide wheel 233, and the fourth frame guide wheel 234 is axially (i.e. Figure 7 The horizontal direction shown in the figure is perpendicular to the central axis of the differential frame 23.

[0089] For the outer drive wheel 21, Figure 5 As shown, in this embodiment, the peripheral wall of the outer driving wheel 21 is provided with a Figure 5 The first wheel mounting groove 2111, the second wheel mounting groove 2112, the third wheel mounting groove 2113, and the fourth wheel mounting groove 2114 are arranged in sequence and separated from each other in the vertical direction of the direction shown, and the inner and outer walls thereof are penetrated. The first guide movable pulley 2121, the second guide movable pulley 2122, the third guide movable pulley 2123, and the fourth guide movable pulley 2124 are rotatably installed in the first wheel mounting groove 2111, the second wheel mounting groove 2112, the third wheel mounting groove 2113, and the fourth wheel mounting groove 2114, respectively. The rotation center axis of the first guide movable pulley 2121, the second guide movable pulley 2122, the third guide movable pulley 2123, and the fourth guide movable pulley 2124 (i.e. Figure 5 The vertical direction of the direction shown) is consistent with the rotation center axis of the outer drive wheel 21; and the outer peripheral wall of the outer drive wheel 21 is provided with a longitudinal axis (ie Figure 5 The first outer annular groove 2131, the second outer annular groove 2132, the third outer annular groove 2133, and the fourth outer annular groove 2134 are arranged in sequence (in the vertical direction of the direction shown).

[0090] After adopting the above-mentioned setting method, the first wheel mounting groove 2111, the second wheel mounting groove 2112, the third wheel mounting groove 2113, and the fourth wheel mounting groove 2114 can not only realize the rotation installation of the first guide movable pulley 2121, the second guide movable pulley 2122, the third guide movable pulley 2123, and the fourth guide movable pulley 2124, but also make it possible for the rope structure mentioned later to pass through the outer drive wheel 21.

[0091] For the inner adaptive wheel 22, as Figure 6 As shown, in this embodiment, the outer peripheral wall of the inner adaptive wheel 22 is provided with a Figure 6 The first inner annular groove 221, the second inner annular groove 222, the third inner annular groove 223, and the fourth inner annular groove 224 are arranged in sequence (in the vertical direction of the direction shown).

[0092] In order to ensure that the inner adaptive wheel 22 can rotate smoothly, Figure 4As shown, in this embodiment, a first inner bearing 61 and a second inner bearing 62 are respectively provided on the outer sides of the inner adaptive wheel 22; the first inner bearing 61 is arranged between the motor connecting flange 51 and the inner adaptive wheel 22; the second inner bearing 62 is arranged between the encoder fixing seat 52 and the inner adaptive wheel 22.

[0093] In order to ensure that the outer drive wheel 21 can rotate smoothly, Figure 4 As shown, in this embodiment, an outer bearing 63 is provided on the outer sleeve of the encoder fixing seat 52 , and the outer bearing 63 is disposed between the encoder fixing seat 52 and the differential frame 23 .

[0094] Regarding the transmission mechanism 30, Figure 8 and Figure 9 As shown, the transmission mechanism 30 of this embodiment includes a transmission frame 35, and a linear guide rail 36, a first guide wheel group 31, a second guide wheel group 32, a third guide wheel group 33, and a fourth guide wheel group 34 provided on the transmission frame 35.

[0095] As for the transmission frame 35, the transmission frame 35 of this embodiment is roughly rectangular, and is mainly used to achieve connection with the nested rotating differential mechanism 20, as well as the installation of the linear guide rail 36, the first guide wheel group 31, the second guide wheel group 32, the third guide wheel group 33 and the fourth guide wheel group 34.

[0096] As for the linear guide rail 36, the linear guide rail 36 of this embodiment is extended along the length direction of the transmission frame 35, and the first clamping jaw 371 and the second clamping jaw 372 are slidably installed on the linear guide rail 36, so that the first clamping jaw 371 and the second clamping jaw 372 can move toward each other or move away from each other to meet the demand of using the clamping jaws to clamp objects.

[0097] The first clamping jaw 371 and the second clamping jaw 372 are connected to the nested rotary differential mechanism 20 by using a rope to realize a rope-driven transmission. Figures 4 to 6 ,as well as Figure 9 As shown, at this time, the first clamping jaw 371 and the second clamping jaw 372 are connected to the nested rotary differential mechanism 20 as follows:

[0098] 1. The surface of the first clamping jaw 371 facing away from the second clamping jaw 372 is connected to the first rope 381. The first rope 381 passes through the first guide wheel group 31, the first frame guide wheel 231, the first outer annular groove 2131, the first guide movable pulley 2121, and the first inner annular groove 221 in sequence, and is then connected and fixed to the inner adaptive wheel 22.

[0099] Among them, the specific configuration of the first guide wheel group 31 is as follows Figure 9As shown, at this time, the transmission frame 35 is provided with a first guide wheel group 31 adjacent to the connection between the first clamping jaw 371 and the first rope 381; the first guide wheel group 31 includes a first long-wall guide wheel 311 provided at the long side wall of the transmission frame 35, a first corner guide wheel 312 provided at the corner of the transmission frame 35, and a first short-wall guide wheel 313 provided at the short side wall of the transmission frame 35. The first rope 381 is connected to the first clamping jaw 371 after passing through the first long-wall guide wheel 311, the first corner guide wheel 312, and the first short-wall guide wheel 313 in sequence.

[0100] Moreover, the rotation axis of the first long-wall guide wheel 311 is perpendicular to the long side wall of the transmission frame 35, the rotation axis of the first corner guide wheel 312 is consistent with the rotation axis of the inner adaptive wheel 22, and the rotation axis of the first short-wall guide wheel 313 is consistent with the rotation axis of the inner adaptive wheel 22.

[0101] 2. The surface of the second clamping jaw 372 facing away from the first clamping jaw 371 is connected to the second rope 382. The second rope 382 passes through the second guide wheel group 32, the second frame guide wheel 232, the second outer annular groove 2132, the second guide movable pulley 2122, and the second inner annular groove 222 in sequence and is then connected and fixed to the inner adaptive wheel 22.

[0102] Among them, the specific arrangement of the second guide wheel group 32 is as follows Figure 9 As shown, at this time, the transmission frame 35 is provided with a second guide wheel group 32 adjacent to the connection between the second clamping jaw 372 and the second rope 382; the second guide wheel group 32 includes a second long-wall guide wheel 321 provided at the long side wall of the transmission frame 35, a second corner guide wheel 322 provided at the corner of the transmission frame 35, and a second short-wall guide wheel 323 provided at the short side wall of the transmission frame 35. The second rope 382 is connected to the second clamping jaw 372 after passing through the second long-wall guide wheel 321, the second corner guide wheel 322, and the second short-wall guide wheel 323 in sequence.

[0103] Moreover, the rotation axis of the second long-wall guide wheel 321 is perpendicular to the long side wall of the transmission frame 35, the rotation axis of the second corner guide wheel 322 is consistent with the rotation axis of the inner adaptive wheel 22, and the rotation axis of the second short-wall guide wheel 323 is consistent with the rotation axis of the inner adaptive wheel 22.

[0104] 3. A third rope 383 is connected to the surface of the second clamping jaw 372 facing the first clamping jaw 371. The third rope 383 passes through the first clamping jaw 371 and then passes around the third guide wheel group 33, the third frame guide wheel 233, the third outer annular groove 2133, the third guide movable pulley 2123, and the third inner annular groove 223 in sequence before being connected and fixed to the inner adaptive wheel 22.

[0105] Among them, the specific arrangement of the second guide wheel group 32 is as follows Figure 9As shown, at this time, the transmission frame 35 is provided with a third guide wheel group 33 at the adjacent position of the first clamping jaw 371 for the third rope 383 to pass through; the third guide wheel group 33 includes a third long wall guide wheel 331 provided at the long side wall of the transmission frame 35, a third corner guide wheel 332 provided at the corner of the transmission frame 35, and a third short wall guide wheel 333 provided at the short side wall of the transmission frame 35. The third rope 383 is connected to the second clamping jaw 372 after passing through the third long wall guide wheel 331, the third corner guide wheel 332, and the third short wall guide wheel 333 in sequence.

[0106] Moreover, the rotation axis of the third long-wall guide wheel 331 is perpendicular to the long side wall of the transmission frame 35, the rotation axis of the third corner guide wheel 332 is consistent with the rotation axis of the inner adaptive wheel 22, and the rotation axis of the third short-wall guide wheel 333 is consistent with the rotation axis of the inner adaptive wheel 22.

[0107] 4. A fourth rope 384 is connected to the surface of the first clamping jaw 371 facing the second clamping jaw 372. After passing through the second clamping jaw 372, the fourth rope 384 passes through the fourth guide wheel group 34, the fourth frame guide wheel 234, the fourth outer annular groove 2134, the fourth guide movable pulley 2124, and the fourth inner annular groove 224 in sequence, and is then connected and fixed to the inner adaptive wheel 22.

[0108] Among them, the specific setting method of the fourth guide wheel group 34 is as follows Figure 9 As shown, at this time, the transmission frame 35 is provided with a fourth guide wheel group 34 at the adjacent position of the first clamping jaw 371 for the fourth rope 384 to pass through; the fourth guide wheel group 34 includes a fourth long wall guide wheel 341 provided at the long side wall of the transmission frame 35, a fourth corner guide wheel 342 provided at the corner of the transmission frame 35, and a fourth short wall guide wheel 343 provided at the short side wall of the transmission frame 35. The fourth rope 384 is connected to the first clamping jaw 371 after passing around the fourth long wall guide wheel 341, the fourth corner guide wheel 342, and the fourth short wall guide wheel 343 in sequence.

[0109] Moreover, the rotation axis of the fourth long-wall guide wheel 341 is perpendicular to the long side wall of the transmission frame 35, the rotation axis of the fourth corner guide wheel 342 is consistent with the rotation axis of the inner adaptive wheel 22, and the rotation axis of the fourth short-wall guide wheel 343 is consistent with the rotation axis of the inner adaptive wheel 22.

[0110] Finally, this embodiment adopts the layout mode of various pulleys. Figure 4 and Figure 7In the design shown, on one side of the nested rotating differential mechanism 20, the differential frame 23 is provided with a first frame guide wheel 231 and a fourth frame guide wheel 234, the outer drive wheel 21 is provided with a second guide movable pulley 2122 and a third guide movable pulley 2123, and the inner adaptive wheel 22 is fixedly connected to the first rope 381 and the fourth rope 384; and on the other side opposite to the nested rotating differential mechanism 20, the differential frame 23 is provided with a second frame guide wheel 232 and a third frame guide wheel 233, the outer drive wheel 21 is provided with a first guide movable pulley 2121 and a fourth guide movable pulley 2124, and the inner adaptive wheel 22 is fixedly connected to the second rope 382 and the third rope 383.

[0111] In order to better explain the present invention, the following will provide corresponding principle descriptions, which are as follows:

[0112] The nested rotating differential mechanism 20 primarily comprises an outer drive wheel 21 (radius r1) and an inner adaptive wheel 22 (radius r2). The drive mechanism 10 rotates the outer drive wheel 21. One end of a fixed cable pair on the inner adaptive wheel 22 is guided through the outer drive wheel 21 and then through multiple guide pulleys before being transferred to the transmission mechanism 30, where it adaptively rotates based on the cable tension difference. The two cable pairs in this mechanism are cable pair 1 and cable pair 2. Each cable pair includes two cables. For example, in the aforementioned embodiment, cable pair 1 consists of a first cable 381 and a fourth cable 384, while cable pair 2 consists of a second cable 382 and a third cable 383. The differential principle is explained below in conjunction with the kinematics of the mechanism.

[0113] When the driving mechanism 10 drives the outer driving wheel 21 to rotate counterclockwise by θ1, the length changes of the rope pair 1 and the rope pair 2 are respectively (δl 11 ,δl 12 ),(δl 21 ,δl 22 ). Taking counterclockwise rotation as the positive direction, we have:

[0114]

[0115] From formula (1), we can see that δl 11 +δl 12 =0,δl 21 +δ 22 =0, that is, when no differential occurs, the mechanism can meet the requirement that the rope length on one side of the fingertip gripper increases while the rope length on the other side decreases by the same amount. 11 ,δl 21 The first clamping jaw 371 and the second clamping jaw 372 are driven to move toward each other.

[0116] On this basis, when the inner adaptive wheel 22 adaptively rotates counterclockwise by θ2, we have:

[0117]

[0118] From formula (2), we can know that the displacement r2θ2 generated by the counterclockwise rotation θ2 of the inner adaptive wheel 22 is equal to the counterclockwise rotation δl of the outer driving wheel 21. 11 The driving direction is opposite to that of the inner adaptive wheel 22, and the displacement r2θ2 generated by the counterclockwise rotation θ2 is the same as the displacement δl generated by the outer driving wheel 21 in the counterclockwise direction. 21 The driving direction is the same, that is, at this time, the four ropes on the inner adaptive wheel 22 are mutually tensioned so that the inner adaptive wheel 22 remains balanced and does not rotate. When the tension of the four ropes on the inner adaptive wheel 22 is unbalanced, non-uniform motion occurs. In addition, due to δl' 11 +δl' 12 =0,δl' 21 +δ' 22 =0, that is, when differential occurs, the mechanism can still meet the requirement that the rope length on one side of the fingertip gripper increases and the rope length on the other side decreases by the same amount.

[0119] From the above differential principle, we can know that:

[0120] (1) The fast drive stroke of the present invention is (r1+r2)θ, which is increased by r2 / r1 times compared to r1θ in the prior art. The slow drive stroke of the present invention is (r1-r2)θ. Compared to the prior art, the center offset of the clamping jaw can be 2r2θ, thereby ensuring that the fast drive stroke can quickly approach the target, and the slow drive stroke can achieve more precise contact by equally dividing the drive stroke into smaller parts.

[0121] (2) The maximum size of the present invention is determined only by the radius of the outer drive wheel 21. Compared with the prior art which depends on the radius of the drive wheel and the radius of the differential wheel, the size of the present invention can be greatly reduced, which greatly improves the space utilization.

[0122] (3) In the present invention, an encoder 40 is provided on the inner adaptive wheel to measure the differential displacement, so that the relative state of the target in the manipulator can be directly read, thereby achieving high-precision operation movement.

[0123] Finally, based on the description of the number of lines, the driving routes of the first rope 381, the second rope 382, the third rope 383, and the fourth rope 384, as well as the connection relationship between the various components, are obtained. The movement of the manipulator is analyzed below.

[0124] (1) Assuming that the loads on the first gripper 371 and the second gripper 372 of the manipulator are the same, the relative position offset between the manipulator center and the target center is set to 2r2θ. This ensures that the grippers at both ends contact the target simultaneously. The sum of the torques of the first rope 381, the second rope 382, the third rope 383, and the fourth rope 384 on the inner adaptive wheel 22 is zero. At this time, the first gripper 371 and the second gripper 372 move toward each other uniformly.

[0125] (2) Assuming that the loads on the first gripper 371 and the second gripper 372 of the manipulator are different (assuming that the first gripper 371 contacts the target), the relative position of the manipulator center and the target center is offset by 2r2θ. At this time, the side with a smaller offset corresponds to the slow drive stroke (for example, when tracking a dynamic target, the manipulator center will always lag behind or lead the dynamic target, so the slow drive stroke should correspond to the lag or lead direction). At this time, the combined torque of the first rope 381, the second rope 382, the third rope 383, and the fourth rope 384 on the inner adaptive wheel 22 will drive the inner adaptive wheel 22 to move. The change in the length of the rope wrapped around the inner adaptive wheel 22 will offset the change in the first rope 381 and the fourth rope 384, and the change in the length of the rope wrapped around the inner adaptive wheel 22 will double the change in the second rope 382 and the third rope 383, thereby achieving accelerated closure under reverse contact stiffness and realizing differential grasping.

[0126] (3) When the manipulator is fully closed, it waits for the drive motor 12 to reach the specified driving force, reads the information from the encoder 40, determines the relative position of the grasped object in the manipulator, and then drives the manipulator to move to the operation cooperation position.

[0127] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A nested rotary inverse stiffness rope-driven manipulator, characterized in that: It includes a driving mechanism, a nested rotary differential mechanism, a transmission mechanism, and an encoder; The driving mechanism is used to drive the outer driving wheel of the nested rotary differential mechanism to rotate; The nested rotary differential mechanism includes a differential frame, the outer drive wheel rotatably arranged in the differential frame, and an inner adaptive wheel rotatably arranged in a space surrounded by the outer drive wheel. The inner peripheral wall of the differential frame is provided with a first frame guide wheel, a second frame guide wheel, a third frame guide wheel, and a fourth frame guide wheel which are sequentially arranged and separated along the central axis thereof; The outer driving wheel has a peripheral wall provided with a first wheel mounting groove, a second wheel mounting groove, a third wheel mounting groove, and a fourth wheel mounting groove, which are sequentially arranged and separated along the central axis thereof and penetrate the inner and outer walls thereof, wherein the first wheel mounting groove, the second wheel mounting groove, the third wheel mounting groove, and the fourth wheel mounting groove are respectively rotatably mounted with a first guide movable pulley, a second guide movable pulley, a third guide movable pulley, and a fourth guide movable pulley; the outer peripheral wall of the outer driving wheel has a first outer annular groove, a second outer annular groove, a third outer annular groove, and a fourth outer annular groove, which are sequentially arranged and separated along the central axis thereof; The outer peripheral wall of the inner adaptive wheel is provided with a first inner annular groove, a second inner annular groove, a third inner annular groove, and a fourth inner annular groove which are sequentially arranged and separated along the central axis thereof; The transmission mechanism includes a transmission frame, and a linear guide rail, a first guide wheel group, a second guide wheel group, a third guide wheel group, and a fourth guide wheel group provided on the transmission frame; A first clamping jaw and a second clamping jaw are slidably mounted on the linear guide rail; A first rope is connected to a surface of the first clamping jaw facing away from the second clamping jaw, and the first rope is sequentially passed through the first guide wheel group, the first frame guide wheel, the first outer annular groove, the first guide movable pulley, and the first inner annular groove, and then connected and fixed to the inner adaptive wheel; A second rope is connected to a surface of the second clamping jaw facing away from the first clamping jaw, and the second rope is sequentially passed through a second guide wheel group, a second frame guide wheel, a second outer annular groove, a second guide movable pulley, and a second inner annular groove, and then connected and fixed to the inner adaptive wheel; A third rope is connected to a surface of the second clamping jaw facing the first clamping jaw, and the third rope passes through the first clamping jaw, passes through the third guide wheel group, the third frame guide wheel, the third outer annular groove, the third guide movable pulley, and the third inner annular groove, and is then connected and fixed to the inner adaptive wheel; A fourth rope is connected to a surface of the first clamping jaw facing the second clamping jaw, and the fourth rope passes through the second clamping jaw, passes through a fourth guide wheel assembly, a fourth frame guide wheel, a fourth outer annular groove, a fourth guide movable pulley, and a fourth inner annular groove, and is then fixedly connected to the inner adaptive wheel; The encoder is used to detect the output shaft rotation information of the inner adaptive wheel.

2. The nested rotary inverse stiffness rope-driven manipulator according to claim 1, characterized in that: The driving mechanism includes a driving bracket and a driving motor arranged in a space surrounded by the driving bracket; The driving bracket is connected and fixed to the differential bracket; The output shaft of the drive motor is fixedly connected to a motor connecting flange, and the motor connecting flange is fixedly connected to one end of the outer drive wheel. The other end of the outer drive wheel is fixedly connected to an encoding fixing seat, and the encoder is provided on the encoding fixing seat. The output shaft of the inner adaptive wheel extends into the detection area of the encoder.

3. The nested rotary inverse stiffness rope-driven manipulator according to claim 2, characterized in that: The two ends of the inner adaptive wheel are respectively covered with a first inner bearing and a second inner bearing; The first inner bearing is provided between the motor connection flange and the inner adaptive wheel; The second inner bearing is arranged between the encoding fixing seat and the inner adaptive wheel.

4. The nested rotary inverse stiffness rope-driven manipulator according to claim 2, characterized in that: The outer sleeve of the encoder fixing seat is provided with an outer bearing, and the outer bearing is arranged between the encoder fixing seat and the differential frame.

5. The nested rotary inverse stiffness rope-driven manipulator according to claim 1, characterized in that: A rotational center axis of the first frame guide wheel, the second frame guide wheel, the third frame guide wheel, and the fourth frame guide wheel is perpendicular to a central axis of the differential frame.

6. The nested rotary inverse stiffness rope-driven manipulator according to claim 1, characterized in that: Axial directions of rotation centers of the first guide movable pulley, the second guide movable pulley, the third guide movable pulley, and the fourth guide movable pulley are consistent with an axial direction of rotation center of the outer drive wheel.

7. The nested rotary inverse stiffness rope-driven manipulator according to claim 1, characterized in that: On one side of the nested rotary differential mechanism, the differential frame is provided with the first frame guide wheel and the fourth frame guide wheel, the outer drive wheel is provided with the second guide movable pulley and the third guide movable pulley, and the inner adaptive wheel is fixedly connected to the first rope and the fourth rope; On the other side opposite to the nested rotating differential mechanism, the differential frame is provided with the second frame guide wheel and the third frame guide wheel, the outer drive wheel is provided with the first guide movable pulley and the fourth guide movable pulley, and the inner adaptive wheel is fixedly connected to the second rope and the third rope.

8. The nested rotary inverse stiffness rope-driven manipulator according to claim 1, characterized in that: The transmission frame is provided with the first guide wheel assembly adjacent to the connection between the first clamping jaw and the first rope; The transmission frame is provided with the second guide wheel assembly adjacent to the connection between the second clamping jaw and the second rope; The transmission frame is provided with the third guide wheel assembly adjacent to the first clamping jaw for the third rope to pass through; The transmission frame is provided with the fourth guide wheel assembly adjacent to the first clamping jaw for the fourth rope to pass through.

9. The nested rotary inverse stiffness rope-driven manipulator according to claim 8, characterized in that: The first guide wheel assembly includes a first long-wall guide wheel provided on the long side wall of the transmission frame, a first corner guide wheel provided at the corner of the transmission frame, and a first short-wall guide wheel provided on the short side wall of the transmission frame. The first rope passes through the first long-wall guide wheel, the first corner guide wheel, and the first short-wall guide wheel in sequence and is connected to the first clamping claw. The second guide wheel assembly includes a second long-wall guide wheel provided on the long side wall of the transmission frame, a second corner guide wheel provided at the corner of the transmission frame, and a second short-wall guide wheel provided on the short side wall of the transmission frame. The second rope passes through the second long-wall guide wheel, the second corner guide wheel, and the second short-wall guide wheel in sequence and is connected to the second clamping claw. The third guide wheel assembly includes a third long-wall guide wheel provided on the long side wall of the transmission frame, a third corner guide wheel provided at the corner of the transmission frame, and a third short-wall guide wheel provided on the short side wall of the transmission frame. The third rope passes through the third long-wall guide wheel, the third corner guide wheel, and the third short-wall guide wheel in sequence and then is connected to the second clamping claw. The fourth guide wheel group includes a fourth long-wall guide wheel arranged at the long side wall of the transmission frame, a fourth corner guide wheel arranged at the corner of the transmission frame, and a fourth short-wall guide wheel arranged at the short side wall of the transmission frame. The fourth rope is connected to the first clamp after passing through the fourth long-wall guide wheel, the fourth corner guide wheel, and the fourth short-wall guide wheel in sequence.

10. The nested rotary inverse stiffness rope-driven manipulator according to claim 9, characterized in that: The rotation axes of the first long-wall guide wheel, the second long-wall guide wheel, the third long-wall guide wheel, and the fourth long-wall guide wheel are all perpendicular to the long side wall of the transmission frame; The rotation axes of the first corner guide wheel, the second corner guide wheel, the third corner guide wheel, and the fourth corner guide wheel are all consistent with the rotation axis of the inner adaptive wheel; The axial directions of the rotating shafts of the first short-wall guide wheel, the second short-wall guide wheel, the third short-wall guide wheel, and the fourth short-wall guide wheel are all consistent with the axial direction of the rotating shaft of the inner adaptive wheel.

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