Under-actuated dexterous arm-hand simulation platform and construction method thereof

Abstract

The invention discloses an under-actuated dexterous arm-hand simulation platform and a construction method thereof, and the method comprises the steps: 1, building a first XML file in an MJCF format, and setting a simulation environment parameter module and a simulation scene module; 2, a three-finger under-actuated dexterous hand or a five-finger under-actuated dexterous hand is installed on a mechanical arm in the assembly body model and converted into a URDF model, then the URDF model is converted into a second XML file through MuJoCo, and then a third XML file is obtained through merging; 3, a transmission driving module is arranged for the robot in the third XML file according to a real robot kinematics mechanism; 4, arranging a plurality of sensors for the robot in the XML file 3 so as to complete the setting of a multi-sensor module; and 5, the latest XML file 3 is in interactive butt joint with the Python program debugging module. According to the invention, through the design of the tendon and the driver, the driving simulation and the joint flexible coupling simulation of the under-actuated multi-fingered dexterous hand are effectively completed, so that the simulation result is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of robot simulation, and in particular to an underactuated dexterous arm-hand simulation platform and a construction method thereof. Background Art

[0002] With the rapid development of modern science and technology, robotics is increasingly being used in various fields. Dexterous and adaptive robotic systems, especially robotic arm-hand systems, have attracted much attention because they can adapt to multi-task scenarios. However, directly designing and verifying algorithms for such systems in a real physical environment brings great economic and time costs. Therefore, it has become an efficient way to simulate actual robotic task scenarios based on simulation platforms and conduct preliminary verification and optimization of algorithms.

[0003] As the end effector of the robotic arm, the dexterous robot hand can perform complex operations on objects of different shapes because of its human-like appearance, which has great advantages over traditional grippers. The dexterous hand is a highly integrated electromechanical system with a small internal space, so the under-actuated structure has become the current development trend. The so-called under-actuated structure refers to a structure in which the number of independent actuators is less than the number of degrees of freedom. While reducing costs and control difficulty, it ensures the flexibility and adaptability of the system. However, the introduction of under-actuation also brings great challenges to the simulation modeling of the dexterous hand.

[0004] In the current simulation modeling technology, there are still many difficulties in the accurate modeling of underactuated manipulators, such as joint coupling and decoupling problems, inter-finger adaptation problems, etc. Therefore, studying an underactuated dexterous arm-hand simulation platform based on the MuJoCo physical simulation engine and its implementation method is of great significance to solving the difficulties in the current simulation modeling of underactuated manipulators. Summary of the invention

[0005] The present invention provides a method for solving the technical problems mentioned in the background technology.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] The present invention provides a method for building an underactuated dexterous arm-hand simulation platform, comprising the following steps:

[0008] S1. Based on the MuJoCo simulation engine, create an XML file in MJCF format, set a simulation environment parameter module in the XML file, the simulation environment parameter module includes platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment; set a simulation scene module, the simulation scene module includes world information and robot workplace information in the simulation environment;

[0009] S2. In the assembly model, the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand is installed on the robotic arm to obtain an arm-hand robot model, and then the arm-hand robot model is converted into a URDF model according to the robot kinematic tree, and then the URDF model is converted into an XML file 2 in MJCF format through MuJoCo; then the XML file 1 is merged with the XML file 2 to obtain an XML file 3 in MJCF format;

[0010] S3. Set the transmission drive module for the arm-hand robot in XML file 3 in MJCF format according to the real robot kinematics mechanism;

[0011] S4. Arrange multiple sensors for the arm-hand robot in the XML file 3 in the MJCF format, thereby completing the setting of the multi-sensor module;

[0012] S5. Interact and connect the XML file 3 obtained in S4 with the Python program debugging module. At this point, the under-actuated dexterous arm-hand simulation platform is completed.

[0013] On the other hand, the present invention also provides an underactuated dexterous arm-hand simulation platform, which is constructed by the above-mentioned construction method; it includes a simulation environment parameter module, a simulation scene module, a robot structure module, a robot transmission drive module, a multi-sensor module and a Python program debugging module;

[0014] The simulation environment parameter module is used to store the platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment;

[0015] The simulation scene module is used to store the world information and robot work site information in the simulation environment;

[0016] The robot structure module includes a robotic arm and a three-dimensional model of a three-finger under-actuated dexterous hand or a five-finger under-actuated dexterous hand installed at the end of the robotic arm;

[0017] The robot transmission drive module is used to provide simulation drive for the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand;

[0018] The multi-sensor module is used to feedback and monitor the motion of the arm-hand robot model;

[0019] The Python program debugging module is a program interface used to implement the arm-hand robot model's grasping and manipulation tasks of objects in a multi-task simulation scenario.

[0020] Beneficial effects of the present invention:

[0021] 1. The present invention provides a method for building an underactuated dexterous arm-hand simulation platform. Through the design of virtual tendons, spatial tendons and position drivers, the driving of a three-finger underactuated dexterous hand and a five-finger underactuated dexterous hand, the coupling and decoupling of each joint, and the torsion spring between the index finger and the middle finger of the three-finger hand are effectively simulated, thereby achieving the adaptive ability within and between fingers, and at the same time making the simulation results of the built underactuated dexterous arm-hand simulation platform more accurate.

[0022] 2. On the other hand, the present invention also provides an under-actuated dexterous arm-hand simulation platform, in which the robot, operated tools and workbench parts in the simulation platform are modeled according to real size and physical parameters, effectively restoring the real working scene of the robot to facilitate the migration of the algorithm to reality.

[0023] 3. The underactuated dexterous arm-hand simulation platform provided by the present invention uses PyCharm as a program interface for interacting with it. MuJoCo, as an efficient robot physics simulation engine, provides a simple and easy-to-use API (application programming interface) for easy integration with other machine learning libraries to support the development of control algorithms.

[0024] 4. Each module in the underactuated dexterous arm-hand simulation platform provided by the present invention adopts a modular design. Users can modify the code to replace the robot arm, robot hand and operation object. At the same time, other sensors can be added to achieve richer state monitoring of the robot, which is highly scalable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural block diagram of the underactuated dexterous arm-hand simulation platform of the present invention;

[0026] Figure 2 A schematic diagram of a thumb coupling spring simulated by a spatial tendon in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of using a spatial tendon to simulate the torsion spring stiffness effect in an embodiment of the present invention;

[0028] Figure 4 It is an enlarged schematic diagram of the bending structure of the thumb flexion and extension module in the present invention;

[0029] Figure 5 It is an enlarged schematic diagram of the straightening structure of the thumb flexion and extension module in the present invention;

[0030] Figure 6 It is a schematic diagram of the bending structure of the index finger and middle finger flexion and extension module of the present invention;

[0031] Figure 7 It is a schematic diagram of the straightening structure of the index finger and middle finger flexion and extension module of the present invention;

[0032] Figure 8 It is a structural schematic diagram of the three-finger deflection module in the present invention;

[0033] Fig. 9 A schematic diagram of the connection between two coupling groups in the five-finger underactuated dexterous hand;

[0034] Fig.10 This is a schematic diagram of the structure of the drive group in the five-finger under-actuated dexterous hand.

[0035] Description of reference numerals:

[0036] 11. Near drive pulley 1; 12. Middle drive pulley; 13. Far drive pulley; 14. Near coupling pulley; 15. Middle coupling pulley; 16. Far coupling pulley; 17. Near drive pulley 2;

[0037] 20. Thumb flexion and extension module; 21. First lifting module; 211. Moving pulley 1; First lifting module 22. Bending drive rope 1; 23. Bending coupling rope 1; 24. Bending coupling rope 2; 25. Straightening drive rope 1; 26. Straightening coupling rope 1; 27. Straightening coupling rope 2; 28. Fixed pulley 1;

[0038] 30. Index finger and middle finger flexion and extension module; 31a. Second lifting module; 31b. Third lifting module; 32. Bending drive rope 2; 33. Bending drive rope 3; 34. Bending coupling rope 3; 35. Torsion spring; 36. Fixed pulley 2; 37. Straightening drive rope 2; 38. Straightening drive rope 3; 39. Straightening coupling rope 3;

[0039] 40. Three-finger deflection module;

[0040] 50. Driving group;

[0041] 60. Coupling group. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] It should also be noted that, in the embodiments of the present application, the same figure mark is used to represent the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0046] Reference Figure 1 The present application embodiment provides a method for building an underactuated dexterous arm-hand simulation platform, comprising the following steps:

[0047] S1. Based on the MuJoCo simulation engine, create an XML file in MJCF format, set a simulation environment parameter module in the XML file, the simulation environment parameter module includes platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment; set a simulation scene module, the simulation scene module includes world information and robot workplace information in the simulation environment;

[0048] S2. In the Solidworks assembly model, the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand is installed on the robotic arm to obtain an arm-hand robot model, and then the arm-hand robot model is converted into a URDF model according to the robot kinematic tree, and then the URDF model is converted into an XML file 2 in MJCF format through MuJoCo; then the XML file 1 is merged with the XML file 2 to obtain an XML file 3 in MJCF format;

[0049] S3. Set the transmission drive module for the arm-hand robot in XML file 3 in MJCF format according to the real robot kinematics mechanism;

[0050] S4. Arrange multiple sensors for the arm-hand robot in the XML file 3 in the MJCF format, thereby completing the setting of the multi-sensor module;

[0051] S5. Interact and connect the XML file 3 obtained in S4 with the Python program debugging module. At this point, the under-actuated dexterous arm-hand simulation platform is completed.

[0052] The Python program debugging module refers to the program interface that interacts with MuJoCo. It is implemented by installing Python libraries related to MuJoCo in the Python environment, such as mujoco-py. This module is used to control the robot's motion and collect information obtained in the simulation. It can integrate a variety of planning, control, and skill learning algorithms to achieve the robot's grasping and manipulation of objects in multi-task simulation scenarios.

[0053] In some embodiments, the platform configuration parameters are used to describe the basic characteristics of the under-actuated dexterous arm-hand simulation platform, and the platform configuration parameters include at least the selection of angle units, 3D model path settings, simulation time step settings, numerical integrator types, constraint solver types and maximum number of iterations, and one or more of the maximum number of joints and contact pairs allowed in each time step; some other platform configuration parameters may also be included; these parameters seriously affect the basic performance and stability of the simulation platform.

[0054] The overall physical parameters are used to describe the overall physical characteristics of the simulation environment. The overall physical parameters include at least one or more of gravity, friction, wind speed, stiffness, damping, and collision parameters; they may also include some other overall physical parameters; these parameters are essential for accurately simulating the behavior of robots or objects in the simulation environment. For some physical parameters, they can also be re-described in the robot structure model, in which case the physical laws follow the locally defined attribute values.

[0055] The visual configuration parameters are used to define visual effects and rendering effects. The visual configuration parameters include at least one or more of background configuration, lighting configuration, shadow configuration, mirror configuration, material, texture and color; other visual configuration parameters may also be included; the setting of these parameters can help create realistic simulation scenes and improve the visualization and realism of the simulation. Like physical parameters, some visual parameters can also be re-described in a specific robot model, and the visual effect meets the locally defined attribute values.

[0056] In some embodiments, the world information includes environmental factors such as the sky and the floor; the robot workplace information includes the specific operation site and related supporting facilities. In this embodiment, the workplace is a laboratory site, and the robot's work room is the size of a real room. The workbench is consistent with the actual table size, and the operated object is also modeled according to the real size and physical parameters to restore the robot's real working scene.

[0057] In some embodiments, the robotic arm adopts a commercial UR5 robotic arm. Since the robotic arm is an existing product on the market, its kinematic mechanism is not described in detail in this article. The following mainly analyzes the structure and motion mechanism of the two self-developed under-actuated dexterous hands.

[0058] In some embodiments, the three-finger underactuated dexterous hand comprises a thumb, an index finger, a middle finger, three independent drive modules, three near drive pulleys 11, three middle drive pulleys 12, three far drive pulleys 13, a near coupling pulley 14, three middle coupling pulleys 15, three far coupling pulleys 16, and two near drive pulleys 2 17;

[0059] The thumb, index finger and middle finger are installed on the palm, and the three fingers respectively include a distal knuckle, a middle knuckle, a proximal knuckle and a connecting seat; the proximal knuckle is rotatably connected to the connecting seat through a proximal joint, the middle knuckle is rotatably connected to the proximal knuckle through a middle joint, and the distal knuckle is rotatably connected to the middle knuckle through a distal joint;

[0060] The proximal joint of the thumb is evenly provided with a coaxially connected proximal driving pulley 11 and a proximal coupling pulley 14, and the proximal joints of the index finger and the middle finger are evenly provided with a proximal driving pulley 11;

[0061] The middle joints of the thumb, index finger and middle finger are all provided with a coaxially connected middle drive pulley 12 and a middle coupling pulley 15; the distal joints of the thumb, index finger and middle finger are all provided with a coaxially connected distal drive pulley 13 and a distal coupling pulley 16; two proximal drive pulleys 17 are respectively provided on the proximal joints of the index finger and the middle finger;

[0062] The three independent driving modules are a thumb flexion and extension module 20, an index finger and middle finger flexion and extension module 30, and a three-finger deflection module 40; the thumb flexion and extension module 20 is used to drive the thumb flexion and extension, the index finger and middle finger flexion and extension module 30 is used to drive the index finger and middle finger flexion and extension, and the three-finger deflection module 40 is used to drive the connection seats on the thumb, index finger, and middle finger to deflect, so as to realize the three-finger deflection;

[0063] The thumb flexion and extension module 20 includes a first lifting module 21, a bending driving rope 1 22, a bending coupling rope 1 23, a bending coupling rope 24, a straightening driving rope 1 25, a straightening coupling rope 1 26, a straightening coupling rope 27, and a fixed pulley 1 28 arranged below the first lifting module 21;

[0064] The first lifting module 21 is installed in the palm, and includes a fixed part 1, a sliding part 1 slidably connected to the fixed part 1, and a movable pulley 1 211 rotatably connected to the sliding part 1. One end of the curved driving rope 1 22 is fixed in the palm, and the other end is respectively passed around the movable pulley 1 211 and the fixed pulley 1 28, and is respectively wound around the near driving pulley 1 11, the middle driving pulley 12, and the far driving pulley 13 in a clockwise direction and then connected to the far finger joint; the curved coupling rope 1 23 is fixedly connected to the opposite sides of the near coupling pulley 14 and the middle coupling pulley 15 in an S shape; the curved coupling rope 2 24 is connected to the opposite sides of the middle coupling pulley 15 and the far coupling pulley 16 in an S shape; and the winding directions of the curved coupling rope 1 23 and the curved coupling rope 2 24 on the middle coupling pulley 15 are both counterclockwise;

[0065] One end of the straight driving rope 1 25 is fixed on the palm, and the other end is passed around the movable pulley 1 211, and is respectively passed around the near driving pulley 1 11, the middle driving pulley 12, and the far driving pulley 13 in a counterclockwise direction, and then connected to the far knuckle; the straight coupling rope 1 26 is connected to the opposite sides of the near coupling pulley 14 and the middle coupling pulley 15 in an S shape; the straight coupling rope 2 27 is connected to the opposite sides of the middle coupling pulley 15 and the far coupling pulley 16 in an S shape; and the winding directions of the straight coupling rope 1 26 and the straight coupling rope 2 27 on the middle coupling pulley 15 are both clockwise;

[0066] The thumb flexion and extension module 20 is independently controlled by the driving end on the first lifting module 21. The driving end of the first lifting module 21 is a motor. The driving end of the first lifting module 21 simultaneously drives the three finger joints (i.e., the distal joint, the middle joint, and the proximal joint) of the thumb to flex and extend by bending the driving rope 22 and straightening the driving rope 25. At the same time, there is a pair of thumb coupling ropes between the distal joint and the middle joint, and between the middle joint and the proximal joint on the thumb. When the thumb is not subjected to external force, the three finger joints have a coupling relationship and move proportionally; when the thumb is subjected to external force, the two pairs of thumb coupling ropes are deformed, the coupling relationship is broken, and the thumb contacts the object adaptively.

[0067] The index finger and middle finger flexion and extension module 30 includes a second lifting module 31a, a third lifting module 31b, a second bending driving rope 32, a third bending driving rope 33, two third bending coupling ropes 34, two torsion springs 35, two second fixed pulleys 36, a second straightening driving rope 37, a third straightening driving rope 38 and two third straightening coupling ropes 39; the second lifting module 31a and the third lifting module 31b each include a second fixed portion and a second sliding portion slidably connected to the second fixed portion, and the second sliding portion of the second lifting module 31a and the third lifting module 31b are rotatably connected to a second movable pulley and a third movable pulley respectively;

[0068] The middle part of the curved driving rope 2 32 is wound around the movable pulley 2 of the second lifting module 31a, one end of which is respectively wound around the proximal driving pulley 11, the middle driving pulley 12, and the distal driving pulley 13 on the index finger in a counterclockwise manner and fixed on the distal knuckle of the index finger; the other end is respectively wound around the proximal driving pulley 11, the middle driving pulley 12, and the distal driving pulley 13 of the middle finger in a clockwise manner and fixed on the distal knuckle of the middle finger; the middle part of the curved driving rope 3 33 is wound around the movable pulley 3 of the third lifting module 31b, one end of which is respectively wound around the proximal driving pulley 2 17 of the index finger in a counterclockwise manner, and the other end is respectively wound around the proximal driving pulley 17 of the middle finger in a clockwise manner. The two curved coupling ropes 34 are respectively connected in an S-shape between the middle coupling pulley 15 and the far coupling pulley 16 of the index finger and between the middle coupling pulley 15 and the far coupling pulley 16 of the middle finger; and the winding directions of the two curved coupling ropes 34 on the middle coupling pulley 15 of the index finger and the middle coupling pulley 15 of the middle finger are clockwise and counterclockwise respectively; one end of the two torsion springs 35 are respectively fixed on the sliding part 2 of the second lifting module 31a and the third lifting module 31b, and the other ends are respectively fixed on the movable pulley 2 of the second lifting module 31a and the movable pulley 3 of the third lifting module 31b;

[0069] The middle part of the straightened driving rope 2 37 is wound around the movable pulley 2 of the second lifting module 31a, and reversely wound around the fixed pulley 2 36 below the second lifting module 31a. One end of the straightened driving rope 2 37 is wound around the near driving pulley 11, the middle driving pulley 12, and the far driving pulley 13 in a clockwise direction and fixed to the far knuckle of the index finger; the other end is wound around the near driving pulley 11, the middle driving pulley 12, and the far driving pulley 13 of the middle finger in a counterclockwise direction and fixed to the far knuckle of the middle finger.

[0070] The middle part of the straightened driving rope 3 38 is wound around the movable pulley 3 of the third lifting module 31b, and reversely wound around the fixed pulley 2 36 below the third lifting module 31b; one end of the straightened driving rope 3 38 is wound around the proximal driving pulley 2 17 of the index finger in a clockwise direction and fixed on the proximal knuckle of the index finger; the other end is wound around the proximal driving pulley 2 17 of the middle finger in a counterclockwise direction and fixed on the proximal knuckle of the middle finger; the two straightened coupling ropes 3 39 are respectively wound in an S-shape between the middle coupling pulley 15 and the distal coupling pulley 16 of the index finger and between the middle coupling pulley 15 and the distal coupling pulley 16 of the middle finger, and the winding directions of the two straightened coupling ropes 3 39 on the middle coupling pulley 15 of the index finger and the middle coupling pulley 15 of the middle finger are counterclockwise and clockwise, respectively.

[0071] The index finger and middle finger flexion and extension module 30 is controlled by the movable ends on the second lifting module 31a and the third lifting module 31b. The movable ends on the second lifting module 31a and the third lifting module 31b are motors. The movable ends of the second lifting module 31a drive the movement of the bending driving rope 2 32 and the straightening driving rope 2 37, and the movable ends of the third lifting module 31b drive the movement of the bending driving rope 3 33 and the straightening driving rope 3 38 to achieve the flexion and extension of the three knuckles of the middle finger and the index finger. The movable end of the third lifting module 31b is used to drive the flexion and extension of the proximal joints of the index finger and the middle finger, while the movable end of the second lifting module 31a is mainly used to drive the flexion and extension of the middle joint and the distal joint of the index finger and the middle finger. There are two bending coupling ropes 3 34 between the middle joint and the distal joint of the middle finger, and there are two straightening coupling ropes 3 39 between the middle knuckle and the distal knuckle of the index finger, which ensures the coupling relationship and adaptability. In addition, the second lifting module 31a and the third lifting module 31b are both provided with a torsion spring 35, and the movable end of the second lifting module 31a is provided with a sliding part 2, and the movable end of the third lifting module 31b is provided with a sliding part 3. When the movement of one finger is restricted, the torsion spring 35 is deformed, and the other finger will continue to move.

[0072] Specifically, the appearance structure of the three-finger underactuated dexterous hand in this embodiment is similar to the three-finger robot dexterous hand with cooperative driving in CN 110171011 A (hereinafter referred to as reference document 1); the appearance structure of the three-finger underactuated dexterous hand is detailed in reference document 1. Figure 1 and Figure 2 The three-finger deflection module 40 is the same as the side swing mechanism in the reference document 1, and the specific reference is as follows: Figure 4 .

[0073] In some embodiments, the five-finger under-actuated dexterous hand comprises a thumb, an index finger, a middle finger, a ring finger, a little finger, three dual-motor drive modules and two single-motor drive modules; and the five fingers of the thumb, the index finger, the middle finger, the ring finger and the little finger respectively comprise a distal phalanx, a middle phalanx, a proximal phalanx and a connecting seat which are rotatably connected in sequence; wherein the proximal phalanx is rotatably connected to the connecting seat via a proximal joint, the middle phalanx is rotatably connected to the proximal phalanx via a middle joint, and the distal phalanx is rotatably connected to the middle phalanx via a distal joint;

[0074] Specifically, the appearance structure of the five-finger under-actuated dexterous hand is similar to a modular under-actuated manipulator in CN116551727A (hereinafter referred to as reference document 2), and the structure of the dual-motor drive module is the same as the drive structure of the thumb, index finger and middle finger in reference document 2;

[0075] The three dual-motor drive modules are used to drive the thumb, index finger and middle finger to flex, extend and swing sideways respectively; the dual-motor drive module includes a drive group 50, two coupling groups 60 and a differential coupling device; the differential coupling device is installed in the palm and is transmission-connected with the drive group 50, and the two coupling groups 60 are respectively installed between the distal joint and the middle joint, and between the middle joint and the proximal joint of the same finger; the drive group 50 is transmission-connected with the coupling group 60 on the distal joint side; the two motors on the dual-motor drive module are named motor three and motor four respectively;

[0076] The differential coupling device includes two motors, which are named Motor 1 and Motor 2 respectively. The details of Motor 1 and Motor 2 are as shown in the two motors in the reference document (the figure marked as 1503 in Reference Document 2). Motor 1 and Motor 2 cooperate to drive the flexion, extension and lateral swing of each of the three fingers (thumb, index finger and middle finger) through the differential coupling device. When Motor 1 and Motor 2 rotate in the same direction and at a constant speed, the fingers perform lateral swing movement; when Motor 1 and Motor 2 rotate in opposite directions and at a constant speed, the fingers perform flexion and extension movement. In addition, there is a coupling group 60 between the distal joints and the middle joints, and between the middle joints and the proximal joints of the three fingers. The two coupling groups 60 are specifically shown in Reference Document 2. Figure 3 , wherein the proximal knuckle coupling elastic gear (i.e., reference numeral 1305 in the figure), the proximal knuckle coupling inertial transmission gear (i.e., reference numeral 1306 in the figure), and the proximal knuckle coupling fixed gear (i.e., reference numeral 1307 in the figure) constitute the coupling group 60 between the middle knuckle and the proximal knuckle, and the middle knuckle coupling fixed gear (i.e., reference numeral 1205 in the figure), the middle knuckle coupling inertial transmission gear (i.e., reference numeral 1206 in the figure), and the middle knuckle coupling elastic gear (i.e., reference numeral 1208 in the figure) constitute the coupling group 60 between the distal knuckle and the middle knuckle. When the finger is not subjected to external force, the three knuckles have a coupling relationship and move in proportion; when the finger is subjected to external force, the spring (i.e., reference numeral 1403 in the figure of reference document 2) on the coupling group 60 is deformed, the coupling relationship is broken, and the finger adaptively contacts the object.

[0077] The two single-motor drive modules are used to drive the ring finger and the little finger to flex and extend respectively; the structure of the single-motor drive module is similar to that of the dual-motor drive module, except that the differential coupling device is replaced by a single motor, and the motor is connected to the drive group 50 on the single-motor drive module in a transmission manner. At the same time, four first springs are added, and the four first springs are connected to the left and right sides of the ring finger and the little finger in pairs, respectively. One end of the first spring on the left and right sides is connected to the finger, and the other end is connected to the palm, so as to realize the passive lateral swing of the ring finger and the little finger. The motor on the single-motor drive module is named motor five;

[0078] The drive group 50 in the dual-motor drive module is specifically a combination of the middle knuckle drive idler gear, fixed drive gear, drive gear and proximal knuckle drive idler gear in reference document 2; the specific structure of the differential coupling device is the same as the gear differential device in reference document 2.

[0079] In some embodiments, S2 specifically includes the following steps:

[0080] S21. First, establish three-dimensional models of a three-finger under-actuated dexterous hand, a five-finger under-actuated dexterous hand, and a robotic arm, and then assemble the three-dimensional model of the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand onto the three-dimensional model of the robotic arm; and add joint reference axes to each finger joint of the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand, the joint reference axes coincide with the rotation axes of each finger joint, and then establish a connecting rod reference coordinate system on the joint reference axes using the right-hand rule, the Z axis of the connecting rod reference coordinate system coincides with the joint reference axes, and the positive direction of the Z axis is consistent with the counterclockwise rotation direction of each finger joint; after installation, obtain a robot structure module;

[0081] S22, determine that the initial posture of the robot 3D model is correctly set, obtain the robot kinematics tree according to the kinematic relationship of each joint of the robot structure module, and then use the sw2urdf plug-in to export the robot structure module into a URDF model according to the robot kinematics tree; the URDF model includes the link name, the pose information with the parent link, the mass and inertia information, the joint information with the parent link, the appearance description and the collision information;

[0082] S23, then use MuJoCo to convert the URDF model into an XML file in MJCF format;

[0083] S24. Then, the XML file 1 and the XML file 2 are merged to obtain the XML file 3 in the MJCF format.

[0084] Specifically, URDF is a unified format for describing robots, providing a standardized way to describe robots in simulation and control environments. However, this format cannot be run directly in MuJoCo, nor is it the standard format for MuJoCo to describe robots. The engine uses its specific MJCF format to describe simulations.

[0085] To enable MuJoCo to run URDF, add the following code to the beginning of the file:

[0086] <mujoco>

[0087] <compiler

[0088] meshdir=”.. / meshes / ”

[0089] balanceinertia=”true”

[0090] discardvisual=”false” / >

[0091] < / mujoco>

[0092] Run the MuJoCo simulation engine and directly export the XML file in MJCF format. At this point, the robot structure module construction task is complete.

[0093] In some embodiments, S3 specifically includes the following steps:

[0094] S31, setting a corresponding position driver for each active joint of the robot arm in the XML file 3 in the MJCF format, and defining an appropriate drive range, the drive range matching the active angle range of each active joint of the robot arm, and obtaining a transmission drive submodule of the robot arm;

[0095] S32, then judging the dexterous hand installed on the robot arm, if it is a three-finger under-actuated dexterous hand, then entering S33, if it is a five-finger under-actuated dexterous hand, then entering S34;

[0096] S33, establishing a three-finger transmission drive submodule for the three-finger underactuated dexterous hand in the XML file 3 in the MJCF format according to the real robot kinematics mechanism; the mechanical arm transmission drive submodule and the three-finger transmission drive submodule constitute a robot transmission drive module, and then ending S3;

[0097] S34. Based on the real robot kinematics mechanism, a five-finger transmission drive submodule is established for the five-finger under-actuated dexterous hand in XML file 3 in MJCF format. The five-finger transmission drive submodule and the robotic arm transmission drive submodule constitute the robot transmission drive module.

[0098] In some embodiments, the S33 specifically includes the following steps:

[0099] S331, the transmission drive system of the thumb flexion and extension module 20 in the three-finger under-actuated dexterous hand is described by a formula, which is as follows:

[0100]

[0101] Where a1 is the drive position, T th,p12 is the deformation of the bending coupling rope 23 between the proximal joint and the middle joint in the thumb flexion and extension module 20, T th,p23 is the deformation amount of the bending coupling rope 24 between the middle joint and the distal joint in the thumb flexion and extension module 20; r th,s1 represents the radius of the proximal driving pulley 11 on the proximal joint in the thumb flexion and extension module 20; r th,s2 represents the radius of the middle driving pulley 12 on the middle joint in the thumb flexion and extension module 20; r th,s3 represents the radius of the distal drive pulley 13 on the distal joint in the thumb flexion and extension module 20; r th,p1 represents the radius of the proximal coupling pulley 14 on the proximal joint in the thumb flexion and extension module 20; r th,p2 represents the radius of the middle coupling pulley 15 on the middle joint in the thumb flexion and extension module 20; r th,p3represents the radius of the distal coupling pulley 16 on the distal joint in the thumb flexion and extension module 20; q th,1 q is the flexion and extension angle of the proximal joint of the thumb; th,2 q is the flexion and extension angle of the thumb middle joint; th,3 is the flexion and extension joint angle of the thumb distal joint;

[0102] S332, according to the formula in S331, using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format, the transmission drive system of the thumb flexion and extension module 20 is implemented in the underactuated dexterous arm-hand simulation platform;

[0103] The specific implementation method is as follows: using fixed type tendons as bending driving rope 1 22 and straightening driving rope 1 25 to jointly create a virtual tendon, namely virtual tendon 1, and connecting the position driver at the end of the tendon; using spatial type tendons to create two spatial tendons for two pairs of thumb coupling ropes, namely spatial tendon 1 and spatial tendon 2; one pair of thumb coupling ropes is bending coupling rope 1 23 and straightening coupling rope 1 26; the other pair of thumb coupling ropes are bending coupling rope 2 24 and straightening coupling rope 2 27;

[0104] Therefore, combining the above formula, the length of the virtual tendon is:

[0105]

[0106] Among them, L fixed represents the length of the virtual tendon 1; a1 is the actuator position; r th,s1 、r th,s2 、r th,s3 Respectively represent the radius of the driving pulleys on the proximal joint, middle joint and distal joint in the thumb flexion and extension module 20; q th,1 ,q th,2 ,q th,3 They represent the flexion and extension joint angles of the proximal, middle and distal joints of the thumb respectively;

[0107] At the same time, a position actuator is set at the end of the tendon, and the actuator position is the tendon length.

[0108] Different from virtual tendons, spatial tendons must be built on physical entities. Therefore, pulleys are set at the proximal, middle, and distal joints and the spatial tendons are wound around the pulleys to simulate springs to achieve the coupling function. The sizes of the pulleys are r and p1 、r p2 and r p3 . Reference Figure 2The spatial tendon is defined as the shortest path through the specified waypoints and around the specified obstacles, so a set of coupled ropes must be set up with two pulleys and three waypoints. To avoid the tendon path turning from one side of the pulley to the other during joint movement, the preferred side of the pulley must be defined, at which point the spatial tendon will automatically choose the obstacle wrapping method close to the specified station.

[0109] S333, the transmission drive system of the index finger and middle finger flexion and extension module 30 in the three-finger under-actuated dexterous hand is described by a formula, which is as follows:

[0110]

[0111] Wherein, a2 and a3 are the driver positions corresponding to the bending driving rope 2 32 and the bending driving rope 3 33 in the index finger and middle finger flexion and extension module 30, s2 and s3 are the rotation arc lengths of the movable pulley 2 on the second lifting module 31a and the movable pulley 3 on the third lifting module 31b, respectively. in,p 、T mi,p are the deformations of the two curved coupling ropes 34 on the index finger and the middle finger respectively; r in,s1 、r in,s2 、r in,s3 Respectively represent the radius of the near drive pulley 11, the middle drive pulley 12, and the far drive pulley 13 on the index finger, r mi,s1 、r mi,s2 、r mi,s3 Respectively represent the radius of the near drive pulley 11, the middle drive pulley 12, and the far drive pulley 13 on the middle finger; r' in,s1 Represents the radius of the proximal drive pulley 17 on the proximal joint of the index finger, r' mi,s1 r represents the radius of the proximal drive pulley 17 on the proximal joint of the middle finger; in,p2 、r in,p3 denote the radius of the middle coupling pulley 15 and the far coupling pulley 16 on the index finger, respectively, mi,p2 、r mi,p3 They represent the radius of the middle coupling pulley 15 and the far coupling pulley 16 on the middle finger respectively; q in,1 ,q in,2 ,q in,3 Respectively represent the flexion and extension joint angles of the proximal joint, middle joint and distal joint of the index finger, q mi,1 ,q mi,2 ,q mi,3 They represent the flexion and extension joint angles of the proximal joint, middle joint, and distal joint of the middle finger, respectively;

[0112] S334, according to the formula in S333, using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format, the transmission drive system of the index finger and middle finger flexion and extension module 30 is implemented in the underactuated dexterous arm-hand simulation platform;

[0113] The implementation method is as follows: using fixed type tendons to create two virtual tendons for two pairs of two-finger driving ropes, namely virtual tendon 2 and virtual tendon 3, and connecting position drivers at the ends of the two tendons; one pair of two-finger driving ropes is bending driving rope 2 32 and straightening driving rope 2 37; the other pair of two-finger driving ropes is bending driving rope 3 33 and straightening driving rope 3 38; using spatial type tendons to create two spatial tendons for two pairs of two-finger coupling ropes, namely spatial tendon 2 and spatial tendon 3; both pairs of two-finger coupling ropes are combinations of bending coupling rope 3 34 and straightening coupling rope 3 39;

[0114] Specifically, taking the torsion spring 35 on the third lifting module 31b as an example, one end of the torsion spring 35 is fixed on the movable pulley 3 on the third lifting module 31b, and the other end is fixed on the sliding part of the third lifting module 31b in the index finger and middle finger flexion and extension module 30. The torsion spring 35 is deformed as the movable pulley 3 rotates. Taking the bending drive rope 3 33 in the index finger and middle finger flexion and extension module 30 as an example, the movable pulley 3 has the following kinematic relationship:

[0115] 2r n θ=2s3=r′ in,s1 q in,1 -r′ mi,s1 q mi,1

[0116] Among them, r n is the radius of movable pulley 3 corresponding to the curved driving rope 33, θ is the rotation angle of movable pulley 3; s3 is the rotation arc length of movable pulley 3 corresponding to the curved driving rope 33; r′ in,s1 represents the radius of the proximal drive pulley 2 17 corresponding to the curved drive rope 3 33 on the proximal joint of the index finger, r′ mi,s1 represents the radius of the proximal driving pulley 2 17 corresponding to the curved driving rope 3 33 on the proximal joint of the middle finger; q in,1 represents the flexion and extension angle of the proximal joint of the index finger, q mi,1 It represents the flexion and extension angle of the proximal joint of the index finger. The above formula is shifted left and right, and we have:

[0117] 0 = r′ in,s1 q in,1 -r′ mi,s1 q mi,1 -2r n θ

[0118] Therefore, the simulation of the torsion spring 35 can be completed by combining the fixed and spatial type tendons. The length of the virtual tendon is set to be a linear combination of the proximal joint angles of the two fingers and the three rotation angles of the movable pulley, and its value is 0. At the same time, in order to simulate the stiffness effect of the torsion spring 35, a virtual pulley and a spatial tendon (i.e., spatial tendon 2) are introduced. Spatial tendon 2 is wound around the virtual pulley, one end of which is fixed to the virtual pulley, and the other end is fixed to the palm. Figure 3 The force constraint exerted by the torsion spring 35 on the real movable pulley 3 is k p , represents the torque generated by the real movable pulley for each arc of rotation. The radius of the virtual pulley is r v , then the force constraint generated on the circumference of the virtual pulley is:

[0119]

[0120] Among them, F p It represents the tension generated by the circumference when the virtual pulley rotates per arc. Therefore, the stiffness of spatial tendon 2 is:

[0121]

[0122] Among them, r ′ v It is the arc length corresponding to each arc degree of pulley rotation. So far, the torsion spring 35 has completed the simulation.

[0123] S335, the transmission drive system of the three-finger deflection module 40 in the three-finger under-actuated dexterous hand is described by a formula, which is as follows:

[0124]

[0125] Among them, q th,0 represents the lateral swing joint angle of the thumb, q in,0 represents the lateral swing joint angle of the index finger, q mi,0 represents the side swing joint angle of the middle finger; a4 represents the first driver position in the three-finger deflection module 40, and a5 represents the second driver position in the three-finger deflection module 40;

[0126] S336. According to the formula in S335, the transmission drive system of the three-finger deflection module 40 is implemented in the underactuated dexterous arm-hand simulation platform by using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format;

[0127] The specific implementation method is: use a fixed type tendon to create a virtual tendon for the three-finger deflection module 40, namely, virtual tendon four, and the length of virtual tendon four is a linear combination of the three side swing joints of the three fingers, and the length of virtual tendon four is always 0; set position drivers for the side swing joints of the thumb and index finger respectively, and at this point, the three-finger transmission drive submodule is created.

[0128] Specifically, the thumb side swing angle and the index finger side swing angle are driven by two motors, named motor 1 and motor 2 respectively, while the middle finger side swing angle is driven by motor 1 and motor 2 together. That is:

[0129] q mi,0 =2a4-a5=2q th,0 -q in,0

[0130] Move items:

[0131] 0=2q th,0 -q in,0 -q mi,0

[0132] Therefore, the coupling relationship between the three finger joints using a fixed type tendon can be used to achieve the restriction effect, that is, the length of the virtual tendon is a linear combination of these three joints, and the length is always 0.

[0133] When motor 1 and motor 2 are driven at the same speed at the same time, the three fingers rotate in the same direction; when motor 1 is stationary and motor 2 is driven, the index finger and middle finger rotate in opposite directions.

[0134] In some embodiments, the S34 specifically includes the following steps:

[0135] S341. The transmission drive system of the dual-motor drive module in the five-finger underactuated dexterous hand is described by a formula, as follows:

[0136]

[0137] Wherein, A1 and A2 are the positions of motor three and motor four in the differential coupling device, R1 represents the transmission ratio from the differential coupling device to the proximal joint, R2 represents the transmission ratio from the differential coupling device to the middle joint, R3 represents the transmission ratio from the differential coupling device to the distal joint, and R4 represents the transmission ratio from the differential coupling device to the side swing joint; θ1, θ2, θ3 and θ4 are the joint angles of the proximal joint, the middle joint, the distal joint and the side swing joint, respectively;

[0138] S342. According to the formula in S341, the transmission drive system of the dual-motor drive module is implemented in the underactuated dexterous arm-hand simulation platform by using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format;

[0139] The implementation method is as follows: using the fixed type tendon to create two virtual tendons for the driving group 50 of each finger, both named as virtual tendon five, and connecting the position driver to the end of the virtual tendon five; using the spatial type tendon to create two spatial tendons for the two coupling groups 60 of each finger, both named as spatial tendon four;

[0140] S344. The transmission drive system of the single motor drive module in the five-finger underactuated dexterous hand is described by a formula, as follows:

[0141]

[0142] Among them, A represents the position of motor 5, R ′ 1 represents the transmission ratio from motor 5 to the nearest joint, R ′ 2 represents the transmission ratio of motor 5 to the middle joint, R ′ 3 represents the transmission ratio from motor 5 to the distal joint; θ ′ 1. θ ′ 2 and θ ′ 3 are the joint angles of the proximal joint, the middle joint, and the distal joint;

[0143] S345. According to the formula in S344, the transmission drive system of the single motor drive module is implemented in the underactuated dexterous arm-hand simulation platform by using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format;

[0144] The implementation method is as follows: using a fixed type tendon to create a virtual tendon, namely, virtual tendon 6, for each finger's driving group 50, and connecting a position driver to the end of the virtual tendon 6; using a spatial type tendon to create two spatial tendons, namely, spatial tendon 5, for each finger's two coupling groups 60;

[0145] S346. Use the spatial tendon to simulate the first spring in the single motor drive module. The stiffness of the spatial tendon is the actual stiffness of the spring. At this point, the five-finger transmission drive submodule is created.

[0146] Reference Figure 1 On the other hand, the present invention further provides an underactuated dexterous arm-hand simulation platform, which is constructed by the above construction method, and the underactuated dexterous arm-hand simulation platform includes a simulation environment parameter module, a simulation scene module, a robot structure module, a robot transmission drive module, a multi-sensor module and a Python program debugging module;

[0147] The simulation environment parameter module is used to store the platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment;

[0148] The simulation scene module is used to store the world information and robot work site information in the simulation environment;

[0149] The robot structure module includes a robotic arm and a three-dimensional model of a three-finger under-actuated dexterous hand or a five-finger under-actuated dexterous hand installed at the end of the robotic arm;

[0150] The robot transmission drive module is used to provide simulation drive for the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand;

[0151] The multi-sensor module is used to feedback and monitor the motion of the arm-hand robot model;

[0152] The Python program debugging module is a program interface used to implement the arm-hand robot model's grasping and manipulation tasks of objects in a multi-task simulation scenario.

[0153] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention. In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for constructing an underactuated dexterous arm-hand simulation platform, characterized in that: The steps include: S1. Based on the MuJoCo simulation engine, create an XML file in MJCF format, set a simulation environment parameter module in the XML file, the simulation environment parameter module includes platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment; set a simulation scene module, the simulation scene module includes world information and robot workplace information in the simulation environment; S2. In the assembly model, the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand is installed on the robotic arm to obtain an arm-hand robot model, and then the arm-hand robot model is converted into a URDF model according to the robot kinematic tree, and then the URDF model is converted into an XML file 2 in MJCF format through MuJoCo; then the XML file 1 is merged with the XML file 2 to obtain an XML file 3 in MJCF format; S3. Set the transmission drive module for the arm-hand robot in XML file 3 in MJCF format according to the real robot kinematics mechanism; S4. Arrange multiple sensors for the arm-hand robot in the XML file 3 in the MJCF format, thereby completing the setting of the multi-sensor module; S5. Interact and connect the XML file 3 obtained in S4 with the Python program debugging module. At this point, the under-actuated dexterous arm-hand simulation platform is completed.

2. The construction method according to claim 1, characterized in that: The platform configuration parameters are used to describe the basic characteristics of the underactuated dexterous arm-hand simulation platform, and the platform configuration parameters at least include the selection of angle units, 3D model path settings, simulation time step settings, numerical integrator types, constraint solver types and maximum number of iterations, and one or more of the maximum number of joints and contact pairs allowed in each time step; The overall physical parameters are used to describe the overall physical characteristics of the simulation environment, and the overall physical parameters include at least one or more of gravity, friction, wind speed, stiffness, damping, and collision parameters; The visual configuration parameters are used to define visual effects and rendering effects, and the visual configuration parameters include at least one or more of background configuration, lighting configuration, shadow configuration, mirror configuration, material, texture and color.

3. The construction method according to claim 1, characterized in that: The world information includes the sky and the floor; the robot workplace information includes the specific operation site and related supporting facilities.

4. The construction method according to claim 1, characterized in that: The three-finger underactuated dexterous hand comprises a thumb, an index finger, a middle finger, three independent drive modules, three near drive pulleys (11), three middle drive pulleys (12), three far drive pulleys (13), a near coupling pulley (14), three middle coupling pulleys (15), three far coupling pulleys (16) and two near drive pulleys (17); The thumb, index finger and middle finger are installed on the palm, and the three fingers respectively include a distal knuckle, a middle knuckle, a proximal knuckle and a connecting seat; The proximal phalanx is rotatably connected to the connecting seat via the proximal joint, the middle phalanx is rotatably connected to the proximal phalanx via the middle joint, and the distal phalanx is rotatably connected to the middle phalanx via the distal joint; A proximal drive pulley (11) and a proximal coupling pulley (14) are evenly distributed on the proximal joint of the thumb, and a proximal drive pulley (11) is evenly distributed on the proximal joints of the index finger and the middle finger; The middle joints of the thumb, index finger and middle finger are uniformly provided with a coaxially connected middle drive pulley (12) and a middle coupling pulley (15); the distal joints of the thumb, index finger and middle finger are uniformly provided with a coaxially connected distal drive pulley (13) and a distal coupling pulley (16); and two proximal drive pulleys (17) are respectively arranged on the proximal joints of the index finger and the middle finger; The three independent driving modules are respectively a thumb flexion and extension module (20), an index finger and middle finger flexion and extension module (30) and a three-finger deflection module (40); the thumb flexion and extension module (20) is used to drive the thumb to flex and extend, the index finger and middle finger flexion and extension module (30) is used to drive the index finger and middle finger to flex and extend, and the three-finger deflection module (40) is used to drive the connection seats on the thumb, index finger and middle finger to deflect, so as to achieve three-finger deflection; The thumb flexion and extension module (20) comprises a first lifting module (21), a bending drive rope 1 (22), a bending coupling rope 1 (23), a bending coupling rope 2 (24), a straightening drive rope 1 (25), a straightening coupling rope 1 (26), a straightening coupling rope 2 (27), and a fixed pulley 1 (28) arranged below the first lifting module (21); The first lifting module (21) is installed in the palm and comprises a fixed part (1), a sliding part (1) slidably connected to the fixed part (1), and a movable pulley (211) rotatably connected to the sliding part (1); one end of a curved driving rope (22) is fixed in the palm, and the other end is respectively passed around the movable pulley (211) and the fixed pulley (28), and is respectively passed around the near driving pulley (11), the middle driving pulley (12), and the far driving pulley (13) in a clockwise direction and then connected to the far finger joint; the curved coupling rope (23) is fixedly connected to the opposite sides of the near coupling pulley (14) and the middle coupling pulley (15) in an S shape; the curved coupling rope (24) is connected to the opposite sides of the middle coupling pulley (15) and the far coupling pulley (16) in an S shape; and the winding directions of the curved coupling rope (23) and the curved coupling rope (24) on the middle coupling pulley (15) are both counterclockwise; One end of the straight driving rope (25) is fixed on the palm, and the other end is passed around the movable pulley (211), and is respectively passed around the near driving pulley (11), the middle driving pulley (12), and the far driving pulley (13) in a counterclockwise direction, and then connected to the far finger joint; the straight coupling rope (26) is connected to the opposite sides of the near coupling pulley (14) and the middle coupling pulley (15) in an S shape; the straight coupling rope (27) is connected to the opposite sides of the middle coupling pulley (15) and the far coupling pulley (16) in an S shape; and the winding directions of the straight coupling rope (26) and the straight coupling rope (27) on the middle coupling pulley (15) are both clockwise; The index finger and middle finger flexion and extension module (30) comprises a second lifting module (31a), a third lifting module (31b), a second bending driving rope (32), a third bending driving rope (33), two third bending coupling ropes (34), two torsion springs (35), two second fixed pulleys (36), a second straightening driving rope (37), a third straightening driving rope (38) and two third straightening coupling ropes (39); the second lifting module (31a) and the third lifting module (31b) both comprise a second fixed part and a second sliding part slidably connected to the second fixed part, and the second sliding parts of the second lifting module (31a) and the third lifting module (31b) are rotatably connected to the second movable pulley and the third movable pulley respectively; The middle part of the curved driving rope 2 (32) is wound around the movable pulley 2 of the second lifting module (31a), one end of which is respectively wound around the near driving pulley 1 (11), the middle driving pulley (12), and the far driving pulley (13) on the index finger in a counterclockwise manner and fixed on the far phalanx of the index finger; the other end of which is respectively wound around the near driving pulley 1 (11), the middle driving pulley (12), and the far driving pulley (13) on the middle finger in a clockwise manner and fixed on the far phalanx of the middle finger; the middle part of the curved driving rope 3 (33) is wound around the movable pulley 3 of the third lifting module (31b), one end of which is respectively wound around the near driving pulley 2 (17) of the index finger in a counterclockwise manner, and the other end of which is respectively wound around the near driving pulley 1 (17) of the middle finger in a clockwise manner. The two torsion springs (35) are respectively fixed at one end on the sliding part 2 of the second lifting module (31a) and the third lifting module (31b), and the other ends are respectively fixed at the movable pulley 2 of the second lifting module (31a) and the movable pulley 3 of the third lifting module (31b); The middle part of the straightened driving rope (37) is wound around the movable pulley (36) of the second lifting module (31a), and reversely wound around the fixed pulley (36) below the second lifting module (31a); one end of the straightened driving rope (37) is wound around the near driving pulley (11), the middle driving pulley (12), and the far driving pulley (13) in a clockwise direction and fixed to the far knuckle of the index finger; the other end is wound around the near driving pulley (11), the middle driving pulley (12), and the far driving pulley (13) of the middle finger in a counterclockwise direction and fixed to the far knuckle of the middle finger; The middle part of the straightened driving rope 3 (38) is wound around the movable pulley 3 of the third lifting module (31b), and reversely wound around the fixed pulley 2 (36) below the third lifting module (31b); one end of the straightened driving rope 3 (38) is wound around the near driving pulley 2 (17) of the index finger in a clockwise direction and fixed on the near knuckle of the index finger; the other end is wound around the near driving pulley 2 (17) of the middle finger in a counterclockwise direction and fixed on the near knuckle of the middle finger; two straightened coupling ropes 3 (39) are respectively wound in an S-shape between the middle coupling pulley (15) and the far coupling pulley (16) of the index finger and between the middle coupling pulley (15) and the far coupling pulley (16) of the middle finger, and the winding directions of the two straightened coupling ropes 3 (39) on the middle coupling pulley (15) of the index finger and the middle coupling pulley (15) of the middle finger are counterclockwise and clockwise respectively.

5. The construction method according to claim 4, characterized in that: The five-finger under-actuated dexterous hand comprises a thumb, an index finger, a middle finger, a ring finger, a little finger, three dual-motor drive modules and two single-motor drive modules; and the five fingers of the thumb, the index finger, the middle finger, the ring finger and the little finger respectively comprise a distal phalanx, a middle phalanx, a proximal phalanx and a connecting seat which are rotatably connected in sequence; wherein the proximal phalanx is rotatably connected to the connecting seat via a proximal joint, the middle phalanx is rotatably connected to the proximal phalanx via a middle joint, and the distal phalanx is rotatably connected to the middle phalanx via a distal joint; The three dual-motor drive modules are used to drive the thumb, index finger and middle finger to flex, extend and swing sideways respectively; the dual-motor drive module comprises a drive group (50), two coupling groups (60) and a differential coupling device; the differential coupling device is installed in the palm and is transmission-connected to the drive group (50); the two coupling groups (60) are respectively installed between the distal joint and the middle joint, and between the middle joint and the proximal joint of the same finger; the drive group (50) is transmission-connected to the coupling group (60) on one side of the distal joint; The two single-motor drive modules are used to drive the ring finger and the little finger to flex and extend respectively; the single-motor drive module has a similar structure to the dual-motor drive module, except that the differential coupling device is replaced by a single motor, and the motor is transmission-connected to the drive group (50) on the single-motor drive module; four first springs are also added, and the four first springs are connected in pairs to the left and right sides of the ring finger and the little finger respectively; one end of the first spring on the left and right sides is connected to the finger, and the other end is connected to the palm, so as to realize the passive lateral swing of the ring finger and the little finger.

6. The construction method according to claim 5, characterized in that: The S2 specifically includes the following steps: S21. First, establish three-dimensional models of a three-finger under-actuated dexterous hand, a five-finger under-actuated dexterous hand, and a robotic arm, and then assemble the three-dimensional model of the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand onto the three-dimensional model of the robotic arm; and add joint reference axes to each joint of the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand, the joint reference axes coincide with the rotation axes of each joint, and then establish a connecting rod reference coordinate system on the joint reference axes using the right-hand rule, the Z axis of the connecting rod reference coordinate system coincides with the joint reference axes, and the positive direction of the Z axis is consistent with the counterclockwise rotation direction of each joint; after installation, obtain a robot structure module; S22, determine that the initial posture of the robot structure module is correctly set, obtain the robot kinematics tree according to the kinematic relationship of each joint of the robot structure module, and then use the sw2urdf plug-in to export the robot structure module into a URDF model according to the robot kinematics tree; the URDF model includes the link name, the pose information with the parent link, the mass and inertia information, the joint information with the parent link, the appearance description and the collision information; S23, then use MuJoCo to convert the URDF model into an XML file in MJCF format; S24. Then, the XML file 1 and the XML file 2 are merged to obtain the XML file 3 in the MJCF format.

7. The construction method according to claim 5, characterized in that: The S3 specifically includes the following steps: S31, setting a corresponding position driver for each active joint of the robot arm in the XML file 3 in the MJCF format, and defining an appropriate drive range, the drive range matching the active angle range of each active joint of the robot arm, and obtaining a transmission drive submodule of the robot arm; S32, then judging the dexterous hand installed on the robot arm, if it is a three-finger under-actuated dexterous hand, then entering S33, if it is a five-finger under-actuated dexterous hand, then entering S34; S33, establishing a three-finger transmission drive submodule for the three-finger underactuated dexterous hand in the XML file 3 in the MJCF format according to the real robot kinematics mechanism; the mechanical arm transmission drive submodule and the three-finger transmission drive submodule constitute a robot transmission drive module, and then ending S3; S34. Based on the real robot kinematics mechanism, a five-finger transmission drive submodule is established for the five-finger under-actuated dexterous hand in XML file 3 in MJCF format. The five-finger transmission drive submodule and the robotic arm transmission drive submodule constitute the robot transmission drive module.

8. The construction method according to claim 7, characterized in that: The S33 specifically includes the following steps: S331, the transmission drive system of the thumb flexion and extension module (20) in the three-finger under-actuated dexterous hand is described by using a formula, which is as follows: Where a1 is the drive position, T th,p12 is the deformation amount of the bending coupling rope (23) between the proximal joint and the middle joint in the thumb flexion and extension module (20), T th,p23 is the deformation amount of the bending coupling rope 2 (24) between the middle joint and the distal joint in the thumb flexion and extension module (20); r th,s1 represents the radius of the proximal drive pulley 1 (11) on the proximal joint in the thumb flexion and extension module (20); r th,s2 represents the radius of the middle drive pulley (12) on the middle joint in the thumb flexion and extension module (20); r th,s3 represents the radius of the distal drive pulley (13) on the distal joint in the thumb flexion and extension module (20); r th,p1 represents the radius of the proximal coupling pulley (14) on the proximal joint in the thumb flexion and extension module (20); r th,p2 represents the radius of the middle coupling pulley (15) on the middle joint in the thumb flexion and extension module (20); r th,p3 represents the radius of the distal coupling pulley (16) on the distal joint in the thumb flexion and extension module (20); q th,1 q is the flexion and extension angle of the proximal joint of the thumb; th,2 q is the flexion and extension angle of the thumb middle joint; th,3 is the flexion and extension joint angle of the thumb distal joint; S332, according to the formula in S331, using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format, the transmission drive system of the thumb flexion and extension module (20) is implemented in the underactuated dexterous arm-hand simulation platform; The specific implementation method is as follows: fixed type tendons are used as bending drive rope 1 (22) and straightening drive rope 1 (25) to jointly create a virtual tendon, namely virtual tendon 1, and a position driver is connected to the end of the tendon; spatial type tendons are used to create two spatial tendons for two pairs of thumb coupling ropes, namely spatial tendon 1 and spatial tendon 2; one pair of thumb coupling ropes is bending coupling rope 1 (23) and straightening coupling rope 1 (26); the other pair of thumb coupling ropes are bending coupling rope 2 (24) and straightening coupling rope 2 (27); S333, the transmission drive system of the index finger and middle finger flexion and extension module (30) in the three-finger under-actuated dexterous hand is described by using a formula, which is as follows: Wherein, a2 and a3 are respectively the driver positions corresponding to the bending driving rope 2 (32) and the bending driving rope 3 (33) in the index finger and middle finger flexion and extension module (30), s2 and s3 are respectively the rotation arc lengths of the movable pulley 2 on the second lifting module (31a) and the movable pulley 3 on the third lifting module (31b), T in,p , T mi,p are the deformations of the two curved coupling ropes (34) on the index finger and the middle finger respectively; r in,s1 、r in,s2 、r in,s3 Respectively represent the radius of the near drive pulley 1 (11), the middle drive pulley (12), and the far drive pulley (13) on the index finger, r mi,s1 、r mi,s2 、r mi,s3 Respectively represent the radius of the near drive pulley 1 (11), the middle drive pulley (12), and the far drive pulley (13) on the middle finger; r′ in,s1 represents the radius of the proximal drive pulley 2 (17) on the proximal joint of the index finger, r′ mi,s1 represents the radius of the second proximal drive pulley (17) on the proximal joint of the middle finger; r in,p2 、r in,p3 denote the radius of the middle coupling pulley (15) and the distal coupling pulley (16) on the index finger, respectively, and r mi,p2 、r mi,p3 Respectively represent the radius of the middle coupling pulley (15) and the distal coupling pulley (16) on the middle finger; q in,1 ,q in,2 ,q in,3 Respectively represent the flexion and extension joint angles of the proximal joint, middle joint and distal joint of the index finger, q mi,1 ,q mi,2 ,q mi,3 They represent the flexion and extension joint angles of the proximal joint, middle joint, and distal joint of the middle finger, respectively; S334, according to the formula in S333, using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format, the transmission drive system of the index finger and middle finger flexion and extension module (30) is implemented in the underactuated dexterous arm-hand simulation platform; The implementation method is as follows: using fixed type tendons to create two virtual tendons for two pairs of two-finger driving ropes, namely virtual tendon 2 and virtual tendon 3, and connecting position drivers at the ends of the two tendons; one pair of two-finger driving ropes is bending driving rope 2 (32) and straightening driving rope 2 (37); the other pair of two-finger driving ropes is bending driving rope 3 (33) and straightening driving rope 3 (38); using spatial type tendons to create two spatial tendons for two pairs of two-finger coupling ropes, namely spatial tendon 3 and spatial tendon 4; both pairs of two-finger coupling ropes are a combination of bending coupling rope 3 (34) and straightening coupling rope 3 (39); S335, the transmission drive system of the three-finger deflection module (40) in the three-finger under-actuated dexterous hand is described by using a formula, which is specifically as follows: Among them, q th,0 represents the lateral swing joint angle of the thumb, q in,0 represents the lateral swing joint angle of the index finger, q mi,0 represents the side swing joint angle of the middle finger; a4 represents the first driver position in the three-finger deflection module (40), and a5 represents the second driver position in the three-finger deflection module (40); S336, according to the formula in S335, using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format, the transmission drive system of the three-finger deflection module (40) is implemented in the underactuated dexterous arm-hand simulation platform; The implementation method is specifically as follows: using a fixed type tendon to create a virtual tendon for the three-finger deflection module (40), namely, virtual tendon four, and the length of the virtual tendon four is a linear combination of the three side swing joints of the three fingers, and the length of the virtual tendon four is always 0; setting position drivers for the side swing joints of the thumb and index finger respectively; At this point, the three-finger transmission drive submodule is created.

9. The construction method according to claim 8, characterized in that: The S34 specifically includes the following steps: S341. The transmission drive system of the dual-motor drive module in the five-finger underactuated dexterous hand is described by a formula, as follows: Wherein, A1 and A2 are the positions of motor three and motor four in the differential coupling device, R1 represents the transmission ratio from the differential coupling device to the proximal joint, R2 represents the transmission ratio from the differential coupling device to the middle joint, R3 represents the transmission ratio from the differential coupling device to the distal joint, and R4 represents the transmission ratio from the differential coupling device to the side swing joint; θ1, θ2, θ3 and θ4 are the joint angles of the proximal joint, the middle joint, the distal joint and the side swing joint, respectively; S342. According to the formula in S341, the transmission drive system of the dual-motor drive module is implemented in the underactuated dexterous arm-hand simulation platform by using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format; The implementation method is as follows: using a fixed type tendon to create two virtual tendons for the driving group (50) of each finger, both named virtual tendon five, and connecting a position driver to the end of the virtual tendon five; using a spatial type tendon to create two spatial tendons for the two coupling groups (60) of each finger, both named spatial tendon four; S344. The transmission drive system of the single motor drive module in the five-finger underactuated dexterous hand is described by a formula, as follows: Among them, A represents the position of motor 5, R ′ 1 represents the transmission ratio from motor 5 to the nearest joint, R ′ 2 represents the transmission ratio of motor 5 to the middle joint, R′3 represents the transmission ratio of motor 5 to the distal joint; θ′1, θ′2 and θ′3 are the joint angles of the proximal joint, the middle joint and the distal joint respectively; S345. According to the formula in S344, the transmission drive system of the single motor drive module is implemented in the underactuated dexterous arm-hand simulation platform by using the tendon attribute and the actuator attribute in the XML file 3 in the MJCF format; The implementation method is as follows: using a fixed type tendon to create a virtual tendon, namely, virtual tendon 6, for each finger's driving group (50), and connecting a position driver to the end of the virtual tendon 6; using a spatial type tendon to create two spatial tendons, namely, spatial tendon 5, for each finger's two coupling groups (60); S346. Use the spatial tendon to simulate the first spring in the single motor drive module. The stiffness of the spatial tendon is the actual stiffness of the spring. At this point, the five-finger transmission drive submodule is created.

10. An underactuated dexterous arm-hand simulation platform constructed by the construction method according to any one of claims 1 to 9, characterized in that: It includes simulation environment parameter module, simulation scene module, robot structure module, robot transmission drive module, multi-sensor module and Python program debugging module; The simulation environment parameter module is used to store the platform configuration parameters, overall physical parameters and visual configuration parameters in the simulation environment; The simulation scene module is used to store the world information and robot work site information in the simulation environment; The robot structure module includes a robotic arm and a three-dimensional model of a three-finger under-actuated dexterous hand or a five-finger under-actuated dexterous hand installed at the end of the robotic arm; The robot transmission drive module is used to provide simulation drive for the three-finger under-actuated dexterous hand or the five-finger under-actuated dexterous hand; The multi-sensor module is used to feedback and monitor the motion of the arm-hand robot model; The Python program debugging module is a program interface used to implement the arm-hand robot model's grasping and manipulation tasks of objects in a multi-task simulation scenario.

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