Rigid-flexible coupled seven-degree-of-freedom mechanical arm and using method thereof

Abstract

The invention belongs to the technical field of mechanical arms, and particularly discloses a rigid-flexible coupled seven-degree-of-freedom mechanical arm and a using method thereof.The mechanical arm comprises a shoulder module, a large arm module, a small arm module, an execution module and a control module; one end of the shoulder module is connected with a working platform, the other end of the shoulder module is connected with one end of the large arm module, the other end of the large arm module is connected with the small arm module, and meanwhile, the structure of the shoulder module and the small arm module is a rigid structure and has five degrees of freedom; the other end of the small arm module is connected with the execution module, and a flexible section with two degrees of freedom is arranged in the middle of the small arm module; the execution module is used for stably grabbing materials and providing a multi-mode sensing capability; the control module is in communication connection with other modules; according to the mechanical arm, it is ensured that the tail end of the mechanical arm has excellent rigidity and positioning precision through the rigid section with the five degrees of freedom, the tail end has higher flexibility by adding the flexible section, the pose of grabbed materials is judged in real time through the execution module, and the operation precision is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of robotic arms, and more specifically, relates to a rigid-flexibly coupled seven-degree-of-freedom robotic arm and a method of using the same. Background Art

[0002] On-orbit assembly requires the use of rockets and other devices to carry the parts of the structural equipment upward in advance, and then assemble the parts or components into the corresponding structural equipment on-orbit manually or automatically. The development of related technologies is an important support for the on-orbit manufacturing and maintenance of space structural equipment and its components. At present, the on-orbit assembly of parts in the aerospace field mainly relies on astronauts to complete manually. Since most aerospace equipment has a compact structure and the assembly environment of some connection parts is poorly open, astronauts usually need to explore into a small space to complete the assembly task. The obstacles in the narrow space of aerospace equipment are numerous and densely distributed, and the operating space size is small (in some narrow space assembly tasks, the width of the operating position entrance is ≤150mm, the minimum height of the working space is only 120mm, and it is necessary to penetrate into the narrow space ≥500mm). Although the manual operation method can make full use of the dexterity of the astronauts' arms to complete various mission objectives, the obstacles in the narrow space are numerous and densely distributed (the distance of obstacles near the object to be operated is ≤60mm), which puts high requirements on the astronauts' obstacle avoidance operation ability, and requires high requirements on the astronauts' hand feel and assembly experience, making it difficult to ensure the quality and efficiency of parts assembly.

[0003] Therefore, using robots to achieve automatic assembly is an important way to improve on-orbit assembly efficiency and relieve astronauts' work pressure. In order to adapt to the working environment in a small space, existing technologies attempt to improve the flexibility and adaptability of robots by optimizing their configuration. For example, the volume of traditional rigid robotic arms (such as FANUC 6-axis short-arm robots and ECO62 robotic arms) is reduced through compact design (such as IP54 protection level and 355mm working radius); or, flexible robotic arms are made of lightweight materials, and by simulating the bending characteristics of human muscles or tree branches, they can bend freely according to environmental changes during operation to avoid interference from hard obstacles; in addition, modular design is used to disassemble the robotic arm into multiple functional modules, so that the configuration and size can be flexibly adjusted according to the needs of the task, environmental restrictions and the size of the space.

[0004] Although the existing technology has made certain progress in robot configuration optimization and end-user operation capabilities, there are still many defects in practical applications, which makes it unable to fully meet the needs of on-orbit assembly: (1) The rigid structure and limited degrees of freedom (usually 6 degrees of freedom) of the rigid robotic arm lead to insufficient flexibility of the end, making it difficult to adaptively adjust the posture in complex obstacle environments; (2) Although the flexible arm has strong adaptability in a small space, the bending nature of the flexible arm makes it difficult to accurately control the position and posture of each joint like a rigid robotic arm. This loss of precision becomes a problem that cannot be ignored in tasks that require extremely high precision; (3) The insufficient stiffness of the inter-module connection of the modular robotic arm leads to a decrease in the end positioning accuracy (the measured repeated positioning error is >±1.5mm), which cannot meet the needs of precision assembly. At the same time, the modular design leads to a decrease in the power density of the drive system, making it difficult to carry large loads. Summary of the invention

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a rigid-flexibly coupled seven-degree-of-freedom robotic arm and a method of using the same. The shoulder module, the upper arm module and the lower arm module simulate the movement of the human arm, and the five-degree-of-freedom rigid segments are used to ensure that the end of the robotic arm has excellent rigidity and positioning accuracy. At the same time, the addition of flexible segments makes the end more flexible and able to adapt to changing needs in a complex working environment. In addition, the execution module with multimodal perception capability can judge the position and posture of the grasped material in real time, thereby further optimizing the operating performance of the robotic arm in a small space and unstructured environment, and significantly improving the working accuracy.

[0006] In order to achieve the above-mentioned object, the present invention provides a rigid-flexible coupled seven-degree-of-freedom robot arm, comprising: a shoulder module, an upper arm module, a lower arm module, an execution module and a control module, wherein:

[0007] One end of the shoulder module is connected to the working platform and the other end is connected to one end of the upper arm module, and the other end of the upper arm module is connected to the lower arm module. At the same time, the structures are all rigid structures and have five degrees of freedom;

[0008] The other end of the forearm module is connected to the execution module and a flexible section with two degrees of freedom is provided in the middle thereof;

[0009] The execution module is used to stably grasp materials and provide multi-modal perception capabilities;

[0010] The control module maintains communication connection with other modules;

[0011] The shoulder module, the upper arm module and the lower arm module are used to simulate the movement of the human arm, and the rigid segment with five degrees of freedom is used to ensure that the end of the robot arm has excellent rigidity and positioning accuracy. The flexible segment is used to make the end have higher flexibility. At the same time, the execution module is used to judge the posture of the grasped material in real time to significantly improve the operation accuracy.

[0012] Further, the shoulder module comprises: a base assembly, a first drive assembly, a second drive assembly, a shoulder movable assembly and a first rotating shaft fixing member; one end of the base assembly is rigidly connected to the working platform; a steering gear is provided in the first drive assembly, which is rotatably connected to the base assembly, and the first axis of rotation is perpendicular to the working platform; a steering gear is provided in the second drive assembly, one end of which is rotatably connected to the first drive assembly through the first rotating shaft fixing member, and the second axis of rotation is perpendicular to the first axis; one end of the shoulder movable assembly is connected to the second drive assembly;

[0013] The rotation range between the first drive assembly and the base assembly is -170° to 170°;

[0014] The rotation range between the second driving assembly and the first driving assembly is -120° to 120°.

[0015] Further, the boom module includes: a third drive assembly, a fourth drive assembly, a boom connecting rod, a second rotating shaft fixing member and a boom movable assembly; the third drive assembly is provided with a steering gear, which is rotatably connected to the shoulder movable assembly, and the third axis of rotation is perpendicular to the second axis; the two ends of the boom connecting rod are respectively connected to the third drive assembly and the fourth drive assembly, and the two opposite surfaces thereof are respectively provided with a reserved assembly base for assembling an end effector or auxiliary equipment, and a heat dissipation hole for preventing internal components from overheating; the fourth drive assembly is provided with a steering gear, which is rotatably connected to the boom movable assembly through the second rotating shaft fixing member, and the fourth axis of rotation is perpendicular to the third axis;

[0016] The rotation range between the third driving assembly and the shoulder movable assembly is -170° to 170°;

[0017] The rotation range between the fourth driving assembly and the upper arm movable assembly is -120° to 120°.

[0018] Further, the small arm module also includes: a fifth drive component and a rigid bending component; the fifth drive component is provided with a steering gear, which is rotatably connected to the large arm movable component, and the fifth axis of rotation is perpendicular to the fourth axis; the two ends of the flexible section are respectively connected to the fifth drive component and the rigid bending component, which includes: a plurality of connecting discs, a plurality of steel wire ropes respectively connected to the connecting discs, and a plurality of maxon motors driving the steel wire ropes; one end of the rigid bending component is connected to the execution module;

[0019] The two degrees of freedom on the flexible segment are the sixth degree of freedom and the seventh degree of freedom, and the swing range is -60° to 60°;

[0020] The rotation range between the fifth driving assembly and the upper arm movable assembly is -170° to 170°.

[0021] Furthermore, the length of the flexible section is greater than 600 mm, and the diameter is less than or equal to 65 mm.

[0022] Furthermore, the execution module includes: a six-dimensional force sensor, a three-finger gripper, a camera and a tactile sensor; one end of the six-dimensional force sensor is connected to the rigid bending component; the three-finger gripper includes: a gripper base connected to one end of the six-dimensional force sensor, and three claws arranged on the opposite side of the gripper base; the camera is arranged at the outer edge of the gripper base, and its lens is aimed at the three claws and the material; the tactile sensor is arranged at the inner end of the claw.

[0023] Furthermore, the clamping jaw base is a double-ended elliptical plate as a whole, and its width is less than 120 mm.

[0024] Furthermore, the six-dimensional force sensor is an ATI Industrial Automation Mini40 six-dimensional force sensor;

[0025] The camera is an Intel RealSense D435i depth camera;

[0026] The tactile sensor is a GelSight tactile sensor.

[0027] Another aspect of the present invention provides a method for using a rigid-flexibly coupled seven-degree-of-freedom robotic arm, which is implemented by using the robotic arm as described above, and comprises the following steps:

[0028] S1: According to the operation requirements of the target material, the control module presets the target posture R target and the target position P target At the same time, the camera is used to identify the position of the target material and collect the target real-time posture R current and real-time location P current ;

[0029] S2: combining the perception information of the camera and the motion model of the robot arm, controlling the rigid segment and the flexible segment to align the end pose in each control cycle;

[0030] S3: Repeat step S1 and step S2 to complete the task through the control of the control module.

[0031] Further, step S2 includes:

[0032] S201: Establish the forward kinematics model of the rigid segment through the DH parameter table, and obtain the transformation matrix between adjacent links of the rigid segment and the total transformation matrix as follows:

[0033]

[0034] In the formula, is the transformation matrix of the adjacent link i-1 to i; a i-1 The distance between two adjacent connecting rods along X i-1 Direction, Z i-1 to Z i The distance between i-1 X is the distance between adjacent connecting rods. i-1 Direction of axis rotation, Z i-1 to Z i The angle between i The Z direction of the connecting rod and the adjacent connecting rod i Direction, X i-1 To X i The distance between i Z is the rotation between adjacent joints i Direction of rotation, X i-1 to Z i The angle of

[0035] S202: Assuming the total length of the flexible segment (32) is L, the flexible segment (32) is equivalent to an arc, the front end center of the flexible segment (32) is set as the coordinate starting point O, and a basic coordinate system OX is established at point O. 5 Y 5 Z 5 , and establish the auxiliary coordinate system OX at point O 6 Y 6 Z 6 To describe the bending direction of the flexible segment (32), the torsion angle of the flexible segment (32) is obtained. and bending angle θ;

[0036] S203: Add the projections of the flexible segment (32) on the coordinate axis to obtain the projection of the end in the coordinate system OX 6 Y 6 Z 6 The position in is P(P6x ,P 6y ,P 6z ),in:

[0037]

[0038] P 6y =0

[0039]

[0040] Where P 6x The end is in the coordinate system OX 6 Y 6 Z 6 The x-axis coordinate in P 6y The end is in the coordinate system OX 6 Y 6 Z 6 The y-axis coordinate in P 6z The end is in the coordinate system OX 6 Y 6 Z 6 The z-axis coordinate in;

[0041] S204: According to the coordinate system OX 5 Y 5 Z 5 and OX 6 Y 6 Z 6 The relationship between the end and the coordinate system OX 5 Y 5 Z 5 The position P(P 5x ,P 5y ,P 5z ), establish P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ), where:

[0042]

[0043] Where P 5x The end is in the coordinate system OX 5 Y 5 Z 5 The x-axis coordinate in P 5y The end is in the coordinate system OX 5 Y 5 Z 5 The y-axis coordinate in P 5z The end is in the coordinate system OX 5 Y5 Z 5 The z-axis coordinate in P 6x The end is in the coordinate system OX 6 Y 6 Z 6 The x-axis coordinate in P 6y The end is in the coordinate system OX 6 Y 6 Z 6 The y-axis coordinate in P 6z The end is in the coordinate system OX 6 Y 6 Z 6 The z-axis coordinate in; and θ are respectively the torsion angle and bending angle of the flexible segment (32);

[0044] S205: According to P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ) to obtain the attitude transformation matrix and homogeneous transformation matrix of the end relative to point O:

[0045]

[0046] Where R is the attitude transformation matrix; is the rotation matrix around the base coordinate z axis; R y (θ) rotation matrix around the local y-axis; is the compensation matrix for the reverse rotation around the z-axis; P is the end position coordinate P(P 5x ,P 5y ,P 5z );

[0047] So the homogeneous transformation matrix from the end of the robot to the base coordinate system is:

[0048]

[0049] S206: Combining the information sensed from the camera and the homogeneous transformation matrix The real-time posture R of the terminal extracted from current and the terminal real-time position P current , calculate its difference with the target posture R target and the target position P target The errors are:

[0050] e p =P target -P current

[0051]

[0052] In the formula, e p is the position error; e R is the attitude error; R current is the real-time posture of the terminal; P current is the real-time position of the terminal; R target is the target posture; P target is the target location;

[0053] S207: Ignoring the attitude error caused by the degree of freedom of the execution module rotating around the x-axis, the Lie algebraic representation and comprehensive error of the attitude error are obtained as follows:

[0054]

[0055] In the formula, is the projection component of the attitude error; e Ry is the y-axis projection component of the attitude error; e Rz is the z-axis projection component of the attitude error; e 5D is the terminal comprehensive error;

[0056] S208: For i=0, 1, ..., 4, define p i for Middle displacement part, base p 0 =(0,0,0); define z i for The third column of the rotation part indicates the Z-axis direction of the coordinate system, z 0 =[0,0,1] T ; For each rotation joint i (i = 1, 2, 3, 4, 5), the i-th column of the Jacobian matrix J consists of two parts, and the linear velocity J v,i =z i-1 ×(p 5 -p i-1 ), angular velocity J ω,i =z i-1 ; Join the two parts J 6×5 =[J 1 J 2 J 3 J 4 J 5 ], J v,i Keeping the three components unchanged, J ω,i Only two components related to the y and z axes are retained from the original three components to construct the rigid segment Jacobian matrix J;

[0057] S209: Get the rigid joint velocity command through the rigid segment Jacobian matrix J Send the obtained joint velocity command to the control module to make the end move in the correct direction, and calculate the new error in the next control cycle by updating the real-time pose T current , repeat the above process to complete the positioning.

[0058] Generally speaking, compared with the prior art, the above technical solution conceived by the present invention can achieve the following beneficial effects:

[0059] 1. The robotic arm of the present invention simulates the movement of the human arm through the shoulder module, the upper arm module and the forearm module, and uses the rigid segments with five degrees of freedom to ensure excellent rigidity and positioning accuracy at the end of the robotic arm. At the same time, the addition of the flexible segment makes the end more flexible, enabling it to adapt to changing requirements in complex working environments. In addition, the execution module with multi-modal perception ability can judge the pose of the grasped material in real time, further optimizing the operation performance of the robotic arm in narrow spaces and unstructured environments and significantly improving the operation accuracy.

[0060] 2. The robotic arm of the present invention, through the five-degree-of-freedom design of the rigid segment, realizes a fixed length and excellent bending and torsional strength in the front-end structure of the robotic arm, enabling the robotic arm to carry greater loads and torques, suitable for handling and supporting the forearm and end components, and effectively reducing deformation during operation to ensure higher stability and positioning accuracy; in addition, this rigid design effectively simplifies the number of moving parts, promotes the direct transmission of force, thereby reducing energy consumption, failure rate and maintenance difficulty, and greatly improving the operation efficiency. Especially when performing orbital assembly tasks, the robotic arm can provide more excellent accuracy, efficiency and stability, significantly enhancing the operation performance.

[0061] 3. The robotic arm of the present invention, through the cable drive mechanism, enables the flexible segment to perform yaw and pitch movements, endowing it with two degrees of freedom, making the flexible segment particularly suitable for operations in unstructured environments, and can exhibit less kinematic constraints and higher end operation flexibility even in space-constrained situations. Secondly, the design of the flexible segment reduces the possibility of damage caused by inevitable contact with environmental objects, improving the overall safety; in addition, by implementing two-degree-of-freedom control on the flexible segment, it is ensured that the robotic arm can imitate the seven-degree-of-freedom motion mode of humans. At the same time, it effectively reduces the complexity of precisely controlling the flexible segment, improves the operation accuracy and flexibility, thus maintaining the delicacy of the robotic arm operation while enhancing the practicality and safety.

[0062] 4. The robot arm of the present invention, by providing three claws, can maintain a relatively simple mechanical design while achieving high adaptability to a narrow working space, thereby reducing the complexity and manufacturing cost of the terminal. At the same time, by integrating visual, tactile, and force sensors on the three-finger gripper, it provides multi-modal perception capabilities in a narrow space operating environment where the line of sight is severely blocked and the perception ability of the visual system is reduced, thereby significantly improving the operability and flexibility of the terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a schematic diagram of the structure of a mechanical arm according to an embodiment of the present invention;

[0064] Figure 2 It is a structural schematic diagram of a shoulder module according to an embodiment of the present invention;

[0065] Figure 3 This is a schematic diagram of the structure of the upper arm module according to an embodiment of the present invention;

[0066] Figure 4 This is a schematic structural diagram of a forearm module according to an embodiment of the present invention;

[0067] Figure 5 It is a schematic diagram of the structure of the execution module of an embodiment of the present invention;

[0068] Figure 6 This is a schematic diagram of the structure of a control module according to an embodiment of the present invention;

[0069] Figure 7 A flowchart of the steps of the method for using the robotic arm according to an embodiment of the present invention;

[0070] Figure 8 is a coordinate diagram of a rigid segment according to an embodiment of the present invention;

[0071] Fig. 9 4 is a coordinate diagram of the flexible segment according to an embodiment of the present invention.

[0072] In all the drawings, the same figure marks represent the same technical features, specifically: 1-shoulder module, 11-base assembly, 12-first drive assembly, 13-second drive assembly, 14-shoulder movable assembly, 15-first rotating shaft fixing part, 2-upper arm module, 21-third drive assembly, 22-fourth drive assembly, 23-upper arm connecting rod, 231-reserved assembly base, 232-heat dissipation hole, 24-second rotating shaft fixing part, 25-upper arm movable assembly, 3-forearm module, 31-fifth drive assembly, 32-flexible section, 33-rigid bending assembly, 4-execution module, 41-six-dimensional force sensor, 42-three-finger gripper, 421-grip base, 422-claw finger, 43-camera, 44-tactile sensor, 5-control module, 51-processor, 52-communication bus, 53-user interface, 54-network interface, 55-memory. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0074] Example 1

[0075] like Figures 1 to 6 As shown, embodiment 1 of the present invention provides a rigid-flexibly coupled seven-degree-of-freedom robotic arm, comprising: a shoulder module 1, an upper arm module 2, a lower arm module 3, an execution module 4 and a control module 5; one end of the shoulder module 1 is connected to the working platform and the other end is connected to one end of the upper arm module 2, and the other end of the upper arm module 2 is connected to the lower arm module 3, and at the same time, the structure thereof is a rigid structure and has five degrees of freedom; the other end of the lower arm module 3 is connected to the execution module 4 and a flexible section 32 with two degrees of freedom is provided in the middle thereof; the execution module 4 is used for stably grasping materials and providing multimodal sensing capabilities; the control module 5 maintains communication connection with other modules. During use, the shoulder module 1, the upper arm module 2 and the lower arm module 3 are used to simulate the movement of the human arm, and the rigid segments with five degrees of freedom are used to ensure that the end of the robot arm has excellent rigidity and positioning accuracy. At the same time, the addition of flexible segments makes the end more flexible and can adapt to changing needs in complex working environments. In addition, the execution module 4 with multimodal perception capabilities can judge the posture of the grasped material in real time, further optimizing the operating performance of the robot arm in narrow spaces and unstructured environments, and significantly improving the operating accuracy.

[0076] Furthermore, if Figure 1 and Figure 2 As shown, the shoulder module 1 includes: a base component 11, a first drive component 12, a second drive component 13, a shoulder movable component 14 and a first rotating shaft fixing component 15; one end of the base component 11 is rigidly connected to the working platform; the first drive component 12 is provided with a steering gear, which is rotatably connected to the base component 11, and the first axis of rotation is perpendicular to the working platform; the second drive component 13 is provided with a steering gear, one end of which is rotatably connected to the first drive component through the first rotating shaft fixing component 15, and the second axis of rotation is perpendicular to the first axis; one end of the shoulder movable component 14 is connected to the second drive component 13.

[0077] Preferably, the rotation range between the first drive assembly 12 and the base assembly 11 is -170° to 170°. The rotation range between the second drive assembly 13 and the first drive assembly 12 is -120° to 120°.

[0078] In an optional embodiment, the first drive assembly 12 is connected to the base assembly 11 through a rotary joint, which is a rigid adapter and is assembled through a positioning pin and a fixing bolt. A high-precision bearing is provided inside the rotary joint to ensure that the first drive assembly 12 has a small friction force and a high repeatability when rotating around the base assembly 11, and at the same time ensure that the structure of the robot arm is stable during operation.

[0079] It can be understood that the rotation between the first drive component 12 and the base component 11 constitutes the first degree of freedom DF1 of the rigid segment, and the rotation between the second drive component 13 and the first drive component 12 constitutes the second degree of freedom DF2 of the rigid segment, thereby effectively simulating the movement of the human shoulder and ensuring the structural stability and positioning accuracy of the robotic arm.

[0080] Furthermore, if Figure 1 and Figure 3 As shown, the boom module 2 includes: a third drive component 21, a fourth drive component 22, a boom connecting rod 23, a second rotating shaft fixing member 24 and a boom movable component 25; the third drive component 21 is provided with a servo, which is rotatably connected to the shoulder movable component 14, and the third axis of rotation is perpendicular to the second axis; the two ends of the boom connecting rod 23 are respectively connected to the third drive component 21 and the fourth drive component 22, and the two opposite surfaces thereof are respectively provided with a reserved assembly base 231 for assembling the end effector or auxiliary equipment, and a heat dissipation hole 232 for preventing the internal components from overheating; the fourth drive component 22 is provided with a servo, which is rotatably connected to the boom movable component 25 through the second rotating shaft fixing member 24, and the fourth axis of rotation is perpendicular to the third axis.

[0081] Preferably, the rotation range between the third driving assembly 21 and the shoulder movable assembly 14 is -170° to 170°. The rotation range between the fourth driving assembly 22 and the upper arm movable assembly 25 is -120° to 120°.

[0082] It can be understood that the rotation between the third drive component 21 and the shoulder movable component 14 constitutes the third degree of freedom DF3 of the rigid segment, and the rotation between the fourth drive component 22 and the upper arm movable component 25 constitutes the fourth degree of freedom DF4 of the rigid segment, thereby effectively simulating the movement of the human upper arm and further ensuring the structural stability and positioning accuracy of the robotic arm.

[0083] Furthermore, if Figure 1 and Figure 4 As shown, the forearm module 3 includes: a fifth drive component 31, a flexible section 32 and a rigid bending component 33; the fifth drive component 31 is provided with a steering gear, which is rotatably connected to the large arm movable component 25, and the fifth axis of rotation is perpendicular to the fourth axis; the two ends of the flexible section 32 are respectively connected to the fifth drive component 31 and the rigid bending component 33, which includes: a plurality of connecting discs, a plurality of steel wire ropes respectively connected to the connecting discs, and a plurality of maxon motors driving the steel wire ropes; one end of the rigid bending component 33 is connected to the execution module. During use, the flexible segment 32 is enabled to perform yaw and pitch movements through a rope drive mechanism, giving it two degrees of freedom, making the flexible segment 32 particularly suitable for operations in unstructured environments, and can exhibit smaller kinematic constraints and higher terminal operation flexibility even when space is limited. Secondly, the design of the flexible segment reduces the possibility of damage during inevitable contact with environmental objects, thereby improving overall safety. In addition, by achieving dual-degree-of-freedom control on the flexible segment, it is ensured that the robotic arm can imitate the human seven-degree-of-freedom motion pattern. At the same time, it effectively reduces the complexity of precise control of the flexible segment, improves operational accuracy and flexibility, thereby maintaining the sophistication of the robotic arm operation and enhancing practicality and safety.

[0084] Preferably, the two degrees of freedom on the flexible section 32 are the sixth degree of freedom and the seventh degree of freedom, and the swing amplitude is -60° to 60°. The length of the flexible section 32 is greater than 600 mm, and the diameter is less than 65 mm, so as to meet the needs of working in a narrow space.

[0085] Preferably, the bending angle of the rigid bending component 33 is 30° to 90° to meet the working requirements of different materials in a narrow working space.

[0086] Preferably, the rotation range between the fifth driving assembly 31 and the upper arm movable assembly 25 is -170° to 170°.

[0087] Preferably, the servos are all Dynamixel servos to ensure the accuracy and consistency of rotation.

[0088] In an optional embodiment, the rotating structures at the second degree of freedom, the third degree of freedom, the fourth degree of freedom and the fifth degree of freedom are rotating joints, and multiple rotating joints are provided with adjustable limit devices and buffer mechanisms, and their connecting parts are fixed to corresponding components through hinge shafts and fixed seats to realize the rotational movement of the joints, while ensuring precise docking between the corresponding components during the movement.

[0089] It can be understood that the rotation between the fifth drive component 31 and the upper arm movable component 25 constitutes the fifth degree of freedom DF5 of the rigid section, thereby cooperating with the fourth degree of freedom DF4 to effectively simulate the movement of the human elbow, further ensuring the structural stability and positioning accuracy of the robotic arm. In addition, through the five degrees of freedom design of the rigid section, the robotic arm achieves a fixed length on the front end structure and has excellent bending and torsional strength, so that the robotic arm can carry a larger load and torque, suitable for carrying and supporting the small arm and the end assembly, and effectively reduces deformation during operation, ensuring higher stability and positioning accuracy; in addition, the rigid design effectively simplifies the number of moving parts, promotes direct transmission of force, thereby reducing energy loss, failure rate and maintenance difficulty, and greatly improving work efficiency. In particular, when performing track assembly tasks, the robotic arm can provide more excellent accuracy, efficiency and stability, and significantly enhance operational performance.

[0090] Furthermore, if Figure 1 and Figure 5 As shown, the execution module 4 includes: a six-dimensional force sensor 41, a three-finger gripper 42, a camera 43 and a tactile sensor 44; one end of the six-dimensional force sensor 41 is connected to the rigid bending component 33; the three-finger gripper 42 includes: a gripper base 421 connected to one end of the six-dimensional force sensor 41, and three claws 422 arranged on the opposite side of the gripper base 421; the camera 43 is arranged at the outer edge of the gripper base 421, and its lens is aimed at the three claws 422 and the material; the tactile sensor 44 is arranged at the inner end of the claw 422.

[0091] The six-dimensional force sensor 41 is an ATI Industrial Automation Mini40 six-dimensional force sensor, which directly measures the force and torque generated when the end of the robotic arm contacts the outside world, so as to further improve the mechanical perception ability of the end of the robotic arm.

[0092] The clamp base 421 is a double-ended elliptical plate with a width of less than 120 mm, thereby reducing the volume and weight while meeting the assembly conditions of other components to adapt to the working environment, so that it can better pass through and avoid obstacles in a small space.

[0093] The camera 43 is an Intel RealSense D435i depth camera, which is used to further improve the visual perception capability of the end of the robotic arm.

[0094] The tactile sensor 44 is a GelSight tactile sensor, which can provide high-resolution tactile images and perceive surface texture and shape to further improve the tactile perception ability of the end of the robotic arm.

[0095] It should be noted that by providing three claw fingers 422, a relatively simple mechanical design can be maintained while achieving high adaptability to a narrow working space, thereby reducing the complexity and manufacturing cost of the terminal. At the same time, by integrating visual, tactile, and force sensors on the three-finger gripper 42, multi-modal perception capabilities can be provided in a narrow space operating environment where the line of sight is severely blocked and the perception ability of the visual system is reduced, thereby significantly improving the operability and flexibility of the terminal.

[0096] Furthermore, if Figure 1 and Figure 6 As shown, the control module 5 maintains communication connection with other modules, and is used to receive the sensing signal of the execution module 4, and stably control the end to grasp the material to operate in a small space. The control module 5 includes: a processor 51, at least one communication bus 52, a user interface 53, a network interface 54 and a memory 55; wherein the communication bus 52 is used to realize the connection and communication between these components. Among them, the user interface 53 may include a display screen (Display), a keyboard (Keyboard), and optionally the user interface 53 may also include a standard wired interface and a wireless interface. The network interface 54 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 55 may be a high-speed RAM memory, or a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 55 may also be optionally at least one storage device located away from the processor 51. In addition, the memory 55 as a computer-readable storage medium may include an operating system, a network communication module, a user interface module and a device control application. The network interface 54 can provide a network communication function; the user interface 53 is mainly used to provide an input interface for the user; and the processor 51 can be used to call the device control application stored in the memory 55 to realize the assembly operation of various materials in a small space.

[0097] Preferably, the processor 51 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), one or more application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the type of device.

[0098] Example 2

[0099] like Figures 7 to 9 As shown, based on Example 1, Example 2 of the present invention provides a method for using a rigid-flexibly coupled seven-degree-of-freedom robotic arm, comprising the following steps:

[0100] S1: According to the operation requirements of the target material, the control module 5 presets the target posture R target and the target position P target At the same time, the target material position is identified by the camera 43, and the target real-time posture R is collected. current and real-time location P current ;

[0101] S2: combining the perception information of the camera 43 and the robot arm motion model, controlling the rigid segment and the flexible segment 32 to align the end pose in each control cycle;

[0102] S3: Repeat steps S1 and S2, and complete the operation task through the control module 5.

[0103] Furthermore, in step S2, the rigid segment is modeled by the Modified Denavit-Hartenberg (craig) parameter method, and the obtained DH parameter table is as follows:

[0104] Table 1 DH table of rigid segment of robot arm

[0105] Link <![CDATA[a i-1 ]]> <![CDATA[α i-1 ]]> <![CDATA[d i ]]> <![CDATA[θ i ]]> 1 0 0 L1 0 2 0 π / 2 0 0 3 0 -π / 2 L2 0 4 -a1 π / 2 0 0 5 a1 -π / 2 L3 0

[0106] In the table, Link is a connecting rod connecting two joints in the robot arm; a i-1The distance between two adjacent connecting rods along X i-1 Direction, Z i-1 to Z i The distance between i-1 X is the distance between adjacent connecting rods. i-1 Direction of axis rotation, Z i-1 to Z i The angle between i The Z direction of the connecting rod and the adjacent connecting rod i Direction, X i-1 To X i The distance between i Z is the rotation between adjacent joints i Direction of rotation, X i-1 To X i The angle of;.

[0107] Further, step S2 includes:

[0108] S201: Establish the forward kinematics model of the rigid segment through the DH parameter table, and obtain the transformation matrix between adjacent links of the rigid segment and the total transformation matrix as follows:

[0109]

[0110] In the formula, is the transformation matrix of the adjacent link i-1 to i; a i-1 The distance between two adjacent connecting rods along X i-1 Direction, Z i-1 to Z i The distance between i-1 X is the distance between adjacent connecting rods. i-1 Direction of axis rotation, Z i-1 to Z i The angle between i The Z direction of the connecting rod and the adjacent connecting rod i Direction, X i-1 To X i The distance between i Z is the rotation between adjacent joints i Direction of rotation, X i-1 To X i The angle of

[0111] S202: Assuming the total length of the flexible segment 32 is L, the flexible segment 32 is equivalent to an arc, the front end center of the flexible segment 32 is set as the coordinate starting point O, and a basic coordinate system OX is established at point O. 5 Y 5 Z 5 , and establish the auxiliary coordinate system OX at point O 6 Y 6 Z 6To describe the bending direction of the flexible segment 32, the torsion angle of the flexible segment 32 is obtained. and bending angle θ;

[0112] S203: Add the projections of the flexible segment 32 on the coordinate axis to obtain the projection of the end in the coordinate system OX 6 Y 6 Z 6 The position in is P(P 6x ,P 6y ,P 6z ),in:

[0113]

[0114] P 6y =0

[0115]

[0116] Where P 6x The end is in the coordinate system OX 6 Y 6 Z 6 The x-axis coordinate in P 6y The end is in the coordinate system OX 6 Y 6 Z 6 The y-axis coordinate in P 6z The end is in the coordinate system OX 6 Y 6 Z 6 The z-axis coordinate in;

[0117] S204: According to the coordinate system OX 5 Y 5 Z 5 and OX 6 Y 6 Z 6 The relationship between the end and the coordinate system OX 5 Y 5 Z 5 The position P(P 5x ,P 5y ,P 5z ), establish P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ), where:

[0118]

[0119] Where P 5x The end is in the coordinate system OX5 Y 5 Z 5 The x-axis coordinate in P 5y The end is in the coordinate system OX 5 Y 5 Z 5 The y-axis coordinate in P 5z The end is in the coordinate system OX 5 Y 5 Z 5 The z-axis coordinate in P 6x The end is in the coordinate system OX 6 Y 6 Z 6 The x-axis coordinate in P 6y The end is in the coordinate system OX 6 Y 6 Z 6 The y-axis coordinate in P 6z The end is in the coordinate system OX 6 Y 6 Z 6 The z-axis coordinate in; and θ are respectively the torsion angle and bending angle of the flexible segment (32);

[0120] S205: According to P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ) to obtain the attitude transformation matrix and homogeneous transformation matrix of the end relative to point O:

[0121]

[0122] Where R is the attitude transformation matrix; is the rotation matrix around the base coordinate z axis; R y (θ) rotation matrix around the local y-axis; is the compensation matrix for the reverse rotation around the z-axis; P is the end position coordinate P(P 5x ,P 5y ,P 5z );

[0123] So the homogeneous transformation matrix from the end of the robot to the base coordinate system is:

[0124]

[0125] S206: Combining the information sensed from the camera 43 and the homogeneous transformation matrix The real-time posture R of the terminal extracted from current and the terminal real-time position Pcurrent , calculate its difference with the target posture R target and the target position P target The errors are:

[0126] e p =P target -P current

[0127]

[0128] In the formula, e p is the position error; e R is the attitude error; R current is the real-time posture of the terminal; P current is the real-time position of the terminal; R target is the target posture; P target is the target location;

[0129] S207: Ignore the attitude error caused by the degree of freedom of the execution module 4 rotating around the x-axis, and obtain the Lie algebraic representation of the attitude error and the comprehensive error respectively:

[0130]

[0131] In the formula, is the projection component of the attitude error; e Ry is the y-axis projection component of the attitude error; e Rz is the z-axis projection component of the attitude error; e 5D is the terminal comprehensive error;

[0132] It should be noted that the degree of freedom of rotation of the execution module 4 around the x-axis has little effect on the execution of tasks such as grasping and assembly, and can be regarded as a non-critical control target, and the error caused by it can be ignored.

[0133] S208: For i=0, 1, ..., 4, define p i for Middle displacement part, base p 0 =(0,0,0); define z i for The third column of the rotation part indicates the Z-axis direction of the coordinate system, z 0 =[0,0,1] T ; For each rotation joint i (i=1,2,3,4,5), the i-th column of the Jacobian matrix J consists of two parts, and the linear velocity J v,i =z i-1 ×(p 5 -p i-1 ), angular velocity J ω,i =z i-1 ; Join the two parts J 6×5 = [J 1 J 2 J 3 J 4 J 5 , J v,i Keep the three components unchanged, J ω,i Only retain the two components related to the rotation about the y and z axes among the original three components to construct the Jacobian matrix J of the rigid segment;

[0134] S209: Obtain the rigid joint velocity command through the Jacobian matrix J of the rigid segment Send the obtained joint velocity command to the control module 5 to make the end move in the correct direction. In the next control cycle, update the real-time pose T current , calculate the new error, and repeat the above process to complete the positioning.

[0135] Furthermore, step S3 includes:

[0136] S301: Use the six-axis force sensor to monitor the force and torque between the end effector and the environment in real time. When the detected force or torque exceeds the preset threshold, it is determined that a collision has occurred; once a collision is detected, immediately stop the movement of the robotic arm and trigger an alarm signal. Through inverse kinematics calculation, adjust the joint angles of the robotic arm to make the end effector move away from the collision point;

[0137] S302: Real-time monitor the working status of the sensor through the self-check program and data consistency check. When the sensor data is detected to be abnormal, it is determined that the sensor may malfunction; when the sensor malfunctions, switch to the backup sensor or use redundant sensor data for compensation. At the same time, trigger an alarm signal to notify the maintenance personnel for repair;

[0138] S303: Real-time monitor the status of the communication link through the heartbeat signal and the data packet timeout mechanism. When a communication interruption is detected, trigger the corresponding processing flow; during the communication interruption, the robotic arm enters the safe mode and stops all movement operations. Try to re-establish the communication connection. If multiple attempts fail, record the fault information and wait for the maintenance personnel to handle it.

[0139] It should be noted that the processor 51 can be used to call the device control application program stored in the memory 55 to implement the above steps to complete the assembly operation of various materials in a narrow space.

[0140] Other technical features are the same as those in Embodiment 1 and can achieve the same technical effects, which will not be elaborated one by one here.

[0141] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0142] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their 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 at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0143] In the present invention, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Those skilled in the art will readily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A rigid-flexible coupled seven-degree-of-freedom robotic arm, characterized in that: include: A shoulder module (1), an upper arm module (2), a lower arm module (3), an execution module (4) and a control module (5), wherein: One end of the shoulder module (1) is connected to the working platform and the other end is connected to one end of the upper arm module (2), and the other end of the upper arm module (2) is connected to the lower arm module (3). At the same time, the structures are all rigid structures and have five degrees of freedom; The other end of the forearm module (3) is connected to the execution module (4) and a flexible section (32) with two degrees of freedom is provided in the middle thereof; The execution module (4) is used to stably grasp materials and provide multi-modal sensing capabilities; The control module (5) maintains communication connection with other modules; The shoulder module (1), the upper arm module (2) and the lower arm module (3) are used to simulate the movement of the human arm, and the rigid segment with five degrees of freedom is used to ensure that the end of the robot arm has excellent rigidity and positioning accuracy. The flexible segment is used to make the end have higher flexibility. At the same time, the execution module (4) is used to judge the position of the grasped material in real time to significantly improve the operation accuracy.

2. The robotic arm according to claim 1, characterized in that: The shoulder module (1) comprises: a base assembly (11), a first drive assembly (12), a second drive assembly (13), a shoulder movable assembly (14) and a first rotating shaft fixing member (15); one end of the base assembly (11) is rigidly connected to the working platform; the first drive assembly (12) is provided with a steering gear, which is rotationally connected to the base assembly (11), and the first axis of rotation is perpendicular to the working platform; the second drive assembly (13) is provided with a steering gear, one end of which is rotationally connected to the first drive assembly through the first rotating shaft fixing member (15), and the second axis of rotation is perpendicular to the first axis; one end of the shoulder movable assembly (14) is connected to the second drive assembly (13); The rotation range between the first driving component (12) and the base component (11) is from -170° to 170°; The rotation range between the second driving component (13) and the first driving component (12) is -120° to 120°.

3. The robotic arm according to claim 2, characterized in that: The arm module (2) comprises: a third drive assembly (21), a fourth drive assembly (22), an arm connecting rod (23), a second rotating shaft fixing member (24) and an arm movable assembly (25); a steering gear is provided in the third drive assembly (21), which is rotationally connected to the shoulder movable assembly (14), and the third axis of rotation is perpendicular to the second axis; two ends of the arm connecting rod (23) are respectively connected to the third drive assembly (21) and the fourth drive assembly (22), and two opposite surfaces thereof are respectively provided with a reserved assembly base (231) for assembling an end effector or auxiliary equipment, and a heat dissipation hole (232) for preventing internal components from overheating; a steering gear is provided in the fourth drive assembly (22), which is rotationally connected to the arm movable assembly (25) through the second rotating shaft fixing member (24), and the fourth axis of rotation is perpendicular to the third axis; The rotation range between the third driving component (21) and the shoulder movable component (14) is -170° to 170°; The rotation range between the fourth driving assembly (22) and the upper arm movable assembly (25) is -120° to 120°.

4. The robotic arm according to claim 3, characterized in that: The small arm module (3) further comprises: a fifth drive component (31) and a rigid bending component (33); the fifth drive component (31) is provided with a steering gear, which is rotatably connected to the large arm movable component (25), and the fifth axis of rotation is perpendicular to the fourth axis; the two ends of the flexible section (32) are respectively connected to the fifth drive component (31) and the rigid bending component (33), which comprises: a plurality of connecting discs, a plurality of steel wire ropes respectively connected to the connecting discs, and a plurality of Maxon motors driving the steel wire ropes; one end of the rigid bending component (33) is connected to the execution module; The two degrees of freedom on the flexible section (32) are the sixth degree of freedom and the seventh degree of freedom, and the swing amplitudes are both between -60° and 60°; The rotation range between the fifth driving assembly (31) and the upper arm movable assembly (25) is -170° to 170°.

5. The robotic arm according to claim 4, characterized in that: The flexible section (32) has a length of >600 mm and a diameter of ≤65 mm.

6. The robotic arm according to claim 4, characterized in that: The execution module (4) comprises: a six-dimensional force sensor (41), a three-finger gripper (42), a camera (43) and a tactile sensor (44); one end of the six-dimensional force sensor (41) is connected to the rigid bending component (33); the three-finger gripper (42) comprises: a gripper base (421) connected to one end of the six-dimensional force sensor (41), and three claws (422) arranged on the opposite side of the gripper base (421); the camera (43) is arranged on the outer edge of the gripper base (421), and its lens is aimed at the three claws (422) and the material; the tactile sensor (44) is arranged at the inner end of the claw (422).

7. The robotic arm according to claim 6, characterized in that: The clamping jaw base (421) is a double-ended elliptical plate as a whole, and its width is less than 120 mm.

8. The robotic arm according to claim 6, characterized in that: The six-dimensional force sensor (41) is an ATI Industrial Automation Mini40 six-dimensional force sensor; The camera (43) is an Intel RealSense D435i depth camera; The tactile sensor (44) is a GelSight tactile sensor.

9. A method for using a rigid-flexibly coupled seven-degree-of-freedom robotic arm, implemented by using the robotic arm as described in any one of claims 1 to 8, characterized in that: The steps include: S1: According to the operation requirements of the target material, the control module (5) presets the target posture R target and the target position P target At the same time, the target material position is identified by the camera (43) and the target real-time posture R is collected. current and real-time location P current ; S2: combining the perception information of the camera (43) and the robot arm motion model, controlling the rigid segment and the flexible segment (32) to align the end position in each control cycle; S3: Repeat steps S1 and S2, and complete the operation task through the control of the control module (5).

10. The robot arm according to claim 9, characterized in that: Step S2 includes: S201: Establish the forward kinematics model of the rigid segment through the DH parameter table, and obtain the transformation matrix between adjacent links of the rigid segment and the total transformation matrix as follows: In the formula, is the transformation matrix of the adjacent link i-1 to i; a i-1 The distance between two adjacent connecting rods along X i-1 Direction, Z i-1 to Z i The distance between i-1 X is the distance between adjacent connecting rods. i-1 Direction of axis rotation, Z i-1 to Z i The angle between i The Z direction of the connecting rod and the adjacent connecting rod i Direction, X i-1 To X i The distance between i Z is the rotation between adjacent joints i Direction of rotation, X i-1 To X i The angle of S202: Assuming the total length of the flexible segment (32) is L, the flexible segment (32) is equivalent to an arc, the front end center of the flexible segment (32) is set as the coordinate starting point O, a basic coordinate system O-X5Y5Z5 is established at point O, and an auxiliary coordinate system O-X6Y6Z6 is established at point O to describe the bending direction of the flexible segment (32), and obtain the torsion angle of the flexible segment (32) and bending angle θ; S203: Add the projections of the flexible segment (32) on the coordinate axis to obtain the position of the end in the coordinate system O-X6Y6Z6 as P(P 6x ,P 6y ,P 6z ),in: P 6y ＝0 Where P 6x is the x-axis coordinate of the end in the coordinate system O-X6Y6Z6; 6y is the y-axis coordinate of the end in the coordinate system O-X6Y6Z6; 6z is the z-axis coordinate of the end in the coordinate system O-X6Y6Z6; S204: Based on the relationship between the coordinate systems O-X5Y5Z5 and O-X6Y6Z6, and the position P (P 5x ,P 5y ,P 5z ), establish P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ), where: Where P 5x is the x-axis coordinate of the end in the coordinate system O-X5Y5Z5; 5y is the y-axis coordinate of the end in the coordinate system O-X5Y5Z5; 5z is the z-axis coordinate of the end in the coordinate system O-X5Y5Z5; 6x is the x-axis coordinate of the end in the coordinate system O-X6Y6Z6; 6y is the y-axis coordinate of the end in the coordinate system O-X6Y6Z6; 6z is the z-axis coordinate of the end in the coordinate system O-X6Y6Z6; and θ are respectively the torsion angle and bending angle of the flexible segment (32); S205: According to P(P 5x ,P 5y ,P 5z ) and P(P 6x ,P 6y ,P 6z ) to obtain the attitude transformation matrix and homogeneous transformation matrix of the end relative to point O: Where R is the attitude transformation matrix; is the rotation matrix around the base coordinate z axis; R y (θ) rotation matrix around the local y-axis; is the compensation matrix for the reverse rotation around the z-axis; P is the end position coordinate P(P 5x ,P 5y ,P 5z ); So the homogeneous transformation matrix from the end of the robot to the base coordinate system is: S206: Combining the camera 43 perception information and the homogeneous transformation matrix The real-time posture R of the terminal extracted from current and the terminal real-time position P current , calculate its difference with the target posture R target and the target position P target The errors are: e p =P target -P current In the formula, e p is the position error; e R is the attitude error; R current is the real-time posture of the terminal; P current is the real-time position of the terminal; R target is the target posture; P target is the target location; S207: Ignore the attitude error caused by the degree of freedom of rotation of the execution module (4) around the x-axis, and obtain the Lie algebraic representation of the attitude error and the comprehensive error respectively: In the formula, is the projection component of the attitude error; e Ry is the y-axis projection component of the attitude error; e Rz is the z-axis projection component of the attitude error; e 5D is the terminal comprehensive error; S208: For i = 0, 1, ..., 4, define pi as In the middle displacement part, the base p0 = (0,0,0); define z i for The third column of the rotation part represents the Z-axis direction of the coordinate system, z0 = [0,0,1] T ; For each rotation joint i (i=1,2,3,4,5), the i-th column of the Jacobian matrix J consists of two parts, and the linear velocity J v,i =z i-1 ×(p5-p i-1 ), angular velocity J ω,i =z i-1 ; Join the two parts J 6×5 =[J1 J2 J3 J4 J5], J v,i Keeping the three components unchanged, J ω,i Only two components related to the y and z axes are retained from the original three components to construct the rigid segment Jacobian matrix J; S209: Get the rigid joint velocity command through the rigid segment Jacobian matrix J The obtained joint speed command is sent to the control module (5) so that the end moves in the correct direction. In the next control cycle, the real-time posture T is updated. current , calculate the new error, repeat the above process to complete the positioning.

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