A space manipulator robot force-position collaborative optimization and control method

Abstract

The application relates to a space multi-arm robot force-position collaborative optimization and control method and relates to the field of space non-cooperative target capturing. In order to solve the technical problem that an accurate space non-cooperative target capturing mode has not been proposed in the prior art, the technical scheme provided by the application is as follows: a space multi-arm robot force-position collaborative control optimization and control method, which comprises the following steps: collecting a capturing configuration and obtaining a desired end position at each moment through path planning; correcting the desired end position of the motion planning through impedance control; obtaining control force and control torque according to the desired end position through PD position control; and generating super-redundant mechanical arm control signals according to the control force and the control torque. The method can be applied to the work of removing in-orbit threats and guaranteeing the safe and stable operation of a spacecraft.

Description

Technical Field

[0001] This involves the field of non-cooperative target acquisition in space. Background Technology

[0002] Currently, the number of non-cooperative space targets such as defunct satellites and space debris is increasing, posing a threat to spacecraft operating normally in orbit. Researching the capture of non-cooperative space targets is of great significance for eliminating threats in orbit and ensuring the safe and stable operation of spacecraft.

[0003] Most current capture robotic arms use no more than 7 degrees of freedom and rarely combine compliant control with motion planning. Therefore, no precise method for capturing non-cooperative targets in space has yet been proposed. Summary of the Invention

[0004] To address the technical problem of the lack of a precise method for capturing non-cooperative targets in space in existing technologies, the technical solution provided by this invention is as follows:

[0005] A space multi-arm robot, the mechanism comprising:

[0006] Satellite base and super-redundant robotic arm;

[0007] The super-redundant robotic arm is driven by a rope, with at least five cylindrical arm sections sleeved on the rope, and a universal joint is provided between every two arm sections.

[0008] The super-redundant robotic arm is equipped with an end gripper.

[0009] Furthermore, a preferred embodiment is provided in which three super-redundant robotic arms are connected to the satellite base via one end away from the gripper.

[0010] Furthermore, a preferred embodiment is provided in which the end gripper is a three-jaw gripper.

[0011] Furthermore, a preferred embodiment is provided in which the arm segment has ten segments.

[0012] Furthermore, a preferred embodiment is provided in which the number of degrees of freedom of the super-redundant robotic arm is 20.

[0013] Furthermore, a preferred embodiment is provided in which each arm segment is provided with 3 rope holes for securing 3 ropes.

[0014] Based on the same inventive concept, this invention also provides a method for force-position cooperative optimization and control of a space multi-arm robot. Based on the robot, the method includes:

[0015] The steps include acquiring the captured configuration and obtaining the desired end position at each time step through path planning;

[0016] The step of correcting the desired end position of motion planning through impedance control;

[0017] The steps of obtaining control force and control torque based on the desired end position through PD position control;

[0018] The step of generating super-redundant robotic arm control signals based on the control force and control torque.

[0019] Based on the same inventive concept, the present invention also provides a force-position coordination optimization device for a space multi-arm robot. Based on the robot, the device includes:

[0020] The module acquires and captures the configuration, and obtains the desired end position at each time step through path planning;

[0021] A module that corrects the desired end position of motion planning through impedance control;

[0022] A module that obtains control force and control torque based on the desired end position through PD position control;

[0023] A module that generates super-redundant robotic arm control signals based on the control force and control torque.

[0024] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program, wherein when the computer program is read by a computer, the computer executes the method described thereon.

[0025] Based on the same inventive concept, the present invention also provides a computer, including a processor and a storage medium, wherein when the processor reads a computer program stored in the storage medium, the computer executes the method described thereon.

[0026] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows:

[0027] This invention provides a spatial multi-arm robot force-position cooperative optimization and control method, which uses a spatial tethered super-redundant robotic arm with an end effector gripper to capture non-cooperative targets in orbit. Compared to most current capture robotic arms that use no more than 7 degrees of freedom, this super-redundant robotic arm has higher degrees of freedom and can perform capture operations more flexibly.

[0028] This invention provides a force-position cooperative optimization and control method for space multi-arm robots. Combining active stiffness and flexibility indices, it proposes a force-position cooperative optimization index to optimize impedance control stiffness. Through cooperative optimization, the motion flexibility of the ultra-redundant robotic arm's end effector can be maximized even after revisions to the desired impedance control position. Compared to existing robotic arms that do not integrate compliant control with motion planning, this approach, through the force-position cooperative optimization index, can better adjust the stiffness of impedance control and improve the robotic arm's flexibility.

[0029] This invention provides a force-position cooperative optimization and control method for spatial multi-arm robots. Based on force-position cooperative optimization, it achieves variable stiffness control of a tethered, ultra-redundant robotic arm, reducing collision forces during the capture process and improving safety. By using the system state and collision forces as inputs to the cooperative optimization solution module, the control stiffness is calculated to correct the impedance controller, thereby reducing collision forces during capture and improving the robotic arm's safety.

[0030] Compared with existing technologies, the spatial multi-arm robot force-position coordination optimization and control method provided by this invention has the following advantages: using a spatial super-redundant robotic arm with an end effector for capture, optimizing the force-position coordination optimization index of impedance control stiffness, and realizing variable stiffness control to reduce collision force and improve safety.

[0031] The space multi-arm robot force-position coordination optimization and control method provided by this invention can be applied to the work of eliminating on-orbit threats and ensuring the safe and stable operation of spacecraft. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a super-redundant robotic arm structure;

[0033] Figure 2 A schematic diagram of force-position synergy optimization indicators;

[0034] Figure 3 This is a schematic diagram of variable stiffness impedance control based on collaborative optimization. Detailed Implementation

[0035] To make the advantages and benefits of the technical solution provided by the present invention clearer, the technical solution provided by the present invention will now be described in further detail with reference to the accompanying drawings, specifically:

[0036] Implementation Method 1: This implementation method provides a space multi-arm robot, the mechanism of which includes:

[0037] Satellite base and super-redundant robotic arm;

[0038] The super-redundant robotic arm is driven by a rope, with at least five cylindrical arm sections sleeved on the rope, and a universal joint is provided between every two arm sections.

[0039] The super-redundant robotic arm is equipped with an end gripper.

[0040] Implementation Method 2: This implementation method further defines the space super-redundant robotic arm capture mechanism provided in Implementation Method 1. The super-redundant robotic arm has three arms, which are connected to the satellite base through the end away from the gripper.

[0041] Implementation Method 3: This implementation method is a further limitation of the spatial super-redundant robotic arm capture mechanism provided in Implementation Method 2, wherein the end gripper is a three-jaw gripper.

[0042] Implementation Method Four: This implementation method further defines the spatial super-redundant robotic arm capture mechanism provided in Implementation Method Three, wherein the arm has ten segments.

[0043] Implementation Method 5: This implementation method is a further limitation on the spatial super-redundant robotic arm capture mechanism provided in Implementation Method 4, wherein the super-redundant robotic arm has 20 degrees of freedom.

[0044] Implementation Method Six: This implementation method further defines the spatial super-redundant robotic arm capture mechanism provided in Implementation Method One. Each arm segment is provided with three rope holes for fixing three ropes.

[0045] Implementation Method Seven: This implementation method provides a force-position cooperative optimization method for a spatially redundant robotic arm capture mechanism, based on the robot provided in Implementation Method One. The method includes:

[0046] The steps include acquiring the captured configuration and obtaining the desired end position at each time step through path planning;

[0047] The step of correcting the desired end position of motion planning through impedance control;

[0048] The steps of obtaining control force and control torque based on the desired end position through PD position control;

[0049] The step of generating super-redundant robotic arm control signals based on the control force and control torque.

[0050] Implementation Method Eight: This implementation method provides a force-position cooperative optimization device for a spatially redundant robotic arm capture mechanism. Based on the robot provided in Implementation Method One, the device includes:

[0051] The module acquires and captures the configuration, and obtains the desired end position at each time step through path planning;

[0052] A module that corrects the desired end position of motion planning through impedance control;

[0053] A module that obtains control force and control torque based on the desired end position through PD position control;

[0054] A module that generates super-redundant robotic arm control signals based on the control force and control torque.

[0055] Implementation Method Nine: This implementation method provides a computer storage medium for storing a computer program. When the computer program is read by the computer, the computer executes the method provided in Implementation Method Seven.

[0056] Implementation Method 10: This implementation method provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method provided in Implementation Method 7.

[0057] Implementation Method Eleven: Combination Figure 1-3 This embodiment describes the technical solution provided above in further detail and completely through specific examples. Specifically:

[0058] To address the problem of capturing non-cooperative targets in space, this embodiment proposes a super-redundant robotic arm de-rotation mechanism and designs a three-arm capture mechanism. Motion planning is performed based on flexibility indices, impedance control is used to improve compliance, and force-position synergistic optimization is improved to variable impedance control, thereby changing the collision configuration and improving safety.

[0059] The technical solution adopted in this embodiment is:

[0060] The super-redundant robotic arm mechanism consists of a satellite base and three evenly distributed super-redundant robotic arms, each with 20 degrees of freedom. The super-redundant arms are driven by cables. At the end of each arm is a three-jaw capture mechanism; the three jaws are evenly distributed and can grip the edge of the satellite to achieve de-rotation capture.

[0061] The proposed force-position co-optimization index is a joint index of flexibility and stiffness error. To maximize the motion flexibility of the end effector of the hyper-redundant manipulator even after revising the desired position of impedance control, a force-position co-optimization method is introduced to adjust the stiffness of the impedance control. In the variable stiffness impedance control architecture of the hyper-redundant manipulator, the input of the co-optimization solution module is the system state and collision force, which calculates the control stiffness to correct the impedance controller. Variable stiffness impedance control can reduce the collision force during the capture process and improve safety.

[0062] The advantages of this implementation method compared to the prior art are:

[0063] 1. This embodiment uses a spatially redundant robotic arm with an end effector gripper, which can capture non-cooperative targets in orbit;

[0064] 2. This implementation method combines active stiffness index and flexibility index to propose a force-position synergistic optimization index to optimize impedance control stiffness.

[0065] 3. This implementation method is based on force-position coordination optimization, which can realize variable stiffness control of the super-redundant robotic arm, reduce the collision force during the capture process, and improve safety.

[0066] Specifically, Table 1 shows the details of the main components.

[0067] Table 1. Detailed List of Major Components

[0068] 1 satellite base 1 2 robotic arm segment 30 3 robotic arm universal joint 30 4 Drive rope 90 5 end grippers 3 7 Capture target 1

[0069] Figure 1 The hyper-redundant robotic arm mechanism consists of a satellite base and three evenly distributed hyper-redundant robotic arms. Each hyper-redundant arm comprises 10 segments, interconnected by gimbals with 2 degrees of freedom each, and the segments are also connected to the base. Each arm has 20 degrees of freedom. The hyper-redundant arms are cable-driven, with 30 evenly distributed cable holes on each segment. Cables pass through these holes and are fixed to the corresponding segments, with 3 cables fixed to each segment. At the end of each arm is a three-jaw capture mechanism with evenly distributed claws, capable of gripping the satellite's edge for de-rotation capture.

[0070] Figure 2 The force-position co-optimization index is a joint index of flexibility index and stiffness error index. In order to maximize the motion flexibility of the end effector of the super-redundant robot arm after the desired position of impedance control is revised, the force-position co-optimization method is introduced to adjust the stiffness of impedance control.

[0071] Figure 3 The architecture of the hyper-redundant robotic arm is a variable stiffness impedance control system. Motion planning calculates the capture configuration offline based on the optimization problem, and calculates the desired end-effector pose at each moment through path planning, which is then input to the outer loop control. The outer loop control is impedance control, used to correct the desired position of the motion plan, and calculates the desired joint angle at the current moment based on the collision force output by the system, which is then input to the inner loop control. The inner loop control is PD position control, which considers compensation for nonlinear terms in the robotic arm dynamics, and calculates the control force and control torque in real time based on the desired joint angle and the current state output by the system, which are then input to the system. In the co-optimization, the input to the co-optimization solution module is the system state and the collision force, and it calculates the control stiffness to correct the impedance controller. Variable stiffness impedance control can reduce the collision force during the capture process and improve safety.

[0072] The hyper-redundant robotic arm operates on the following principle: the robotic arm is driven by ropes, with 30 rope holes evenly distributed on each arm segment. The ropes pass through these rope holes and are fixed to the corresponding arm segments. Each arm segment is fixed with 3 ropes, which drive the movement of the corresponding arm segment.

[0073] Force-position synergistic optimization principle: The force-position synergistic optimization index is a joint index of flexibility index and stiffness error index.

[0074] The above description of several specific embodiments further details the technical solution provided by the present invention in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0075] In the description of this specification, only preferred embodiments of the present invention are described, and should not be construed as limiting the scope of the invention. Furthermore, the use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or N embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Additionally, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified. Any process or method described in the flowcharts or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logical functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain. The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, a “computer-readable medium” can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection having one or N wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic device, and portable optical disc read-only memory (CDROM).Furthermore, the computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory. It should be understood that various parts of the invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0076] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments. Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

Claims

1. A force-position cooperative control optimization method for space multi-arm robots, characterized in that, The method includes: The steps include acquiring the captured configuration and obtaining the desired end position at each time step through path planning; The step of correcting the desired end position of motion planning through impedance control; The steps of obtaining control force and control torque based on the desired end position through PD position control; The step of generating super-redundant robotic arm control signals based on the control force and control torque; Motion planning captures the configuration offline based on the optimization problem, and calculates the desired end pose at each moment through path planning, which is then input into the outer loop control. The outer loop control is impedance control, which is used to correct the desired position of the motion plan and calculate the desired joint angle at the current moment based on the collision force output by the system, and input it into the inner loop control. In collaborative optimization, the input to the collaborative optimization solution module is the system state and collision force, and the control stiffness is calculated to correct the impedance controller. The inner loop control is PD position control, and it takes into account the nonlinear term compensation of the robot arm dynamics. The control force and control torque are calculated in real time based on the desired joint angle and the current state of the system output, and then input into the system. Space multi-arm robots include: Satellite base and super-redundant robotic arm; The super-redundant robotic arm is driven by a rope, with at least five cylindrical arm sections sleeved on the rope, and a universal joint is provided between every two arm sections. The end effector of the super-redundant robotic arm is equipped with an end effector gripper; The super-redundant robotic arm has three parts, which are connected to the satellite base through the end away from the gripper. At the end of each arm is a three-claw capture mechanism. The three claws are evenly distributed and can grasp the edge of the satellite to achieve de-rotation capture.

2. The force-position cooperative control optimization method for a space multi-arm robot according to claim 1, characterized in that, The arm segment has ten parts.

3. The force-position cooperative control optimization method for a space multi-arm robot according to claim 2, characterized in that, The super-redundant robotic arm has 20 degrees of freedom.

4. The force-position cooperative control optimization method for a space multi-arm robot according to claim 1, characterized in that, Each arm segment has three rope holes for securing three ropes.

5. A force-position cooperative control optimization device for a space multi-arm robot, based on the method described in claim 1, characterized in that, The device includes: The module acquires and captures the configuration, and obtains the desired end position at each time step through path planning; A module that corrects the desired end position of motion planning through impedance control; A module that obtains control force and control torque based on the desired end position through PD position control; A module that generates super-redundant robotic arm control signals based on the control force and control torque.

6. A computer storage medium for storing computer programs, characterized in that, When the computer program is read by the computer, the computer executes the method of claim 1.

7. A computer, comprising a processor and a storage medium, characterized in that, When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 1.

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