CN-122018282-A - Layered control method and system for reconfigurable rigid-flexible coupling space on-orbit assembly robot

CN122018282ACN 122018282 ACN122018282 ACN 122018282ACN-122018282-A

Abstract

The invention relates to the technical field of space on-orbit robot control, in particular to a layering control method and a layering control system for a reconfigurable rigid-flexible coupling space on-orbit assembly robot, wherein the control system comprises a spacecraft formation control system and a rigid-flexible coupling robot control system, the working stroke of the robot can be changed by reconstructing and planning the formation of the spacecraft, and the rigid-flexible coupling robot control system fuses the visual sense, the force sense and the multi-perception information of the position on the basis of an upper task planner to realize layered control of the flexible cable driving robot and the mechanical arm. The control method is oriented to the assembly task of the large-size space component, and the robot layered controller fused with the multi-source information is designed by decoupling the kinematics and dynamics of the robot and combining the requirements of the operation scene, so that the overall operation efficiency and accuracy of the robot are improved, and the adaptability of the robot to different on-orbit tasks is enhanced.

Inventors

ZI BIN
LIU LIHAO
ZHENG YUQIAO
TANG WENJUN
ZHAO JIAHAO
FENG KAI
DUAN XUECHAO
DU JINGLI

Assignees

西安电子科技大学

Dates

Publication Date: 20260512
Application Date: 20260202

Claims (10)

1. The layering control method of the reconfigurable rigid-flexible coupling space on-orbit assembly robot is characterized by comprising the following steps of: S1, completing re-planning of spacecraft formation by a PSO-SCP method according to a target position and a job requirement, generating a reconstruction track, completing formation change of the spacecraft formation, and reaching a designated position; S2, determining the assembly sequence of truss units and the pre-assembly tail end pose of the rigid-flexible coupling robot when each truss unit is assembled according to the truss specification to be assembled; s3, determining the corresponding position of the movable platform and the configuration of the joints of the mechanical arm according to the pose of the preassembled tail end of the rigid-flexible coupling robot; S4, determining a robot kinematics and dynamics model according to current configuration data of the robot, driving a moving platform through a flexible cable, and controlling a mechanical arm to adjust the tail end pose to the pre-assembly pose of the robot by combining the position of the moving platform and the joint configuration of the mechanical arm through a cable-arm cooperative movement force/position hybrid PID controller; s5, controlling the movable platform to keep stable by adopting an anti-interference mechanical arm assembly force/position hybrid controller of the movable platform until the mechanical arm completes the assembly of a single truss unit; S6, repeating the steps S4 and S5 until the assembly of all truss units is completed.
2. The method for hierarchical control of a reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 1, wherein the step S1 comprises the steps of: Acquiring initial parameters of spacecraft formation, namely initial position Initial scale for spacecraft formation And initial angle of spacecraft formation ; Determining spacecraft formation target parameters, target position Target dimensions And a target angle ; Based on spacecraft formation initial parameters and spacecraft formation target parameters, solving spacecraft formation track planning under Clohessy-Wiltshire equation dynamics constraint, spacecraft collision avoidance constraint and flexible cable length constraint containing relaxation variables by adopting a hierarchical optimization algorithm combining particle swarm optimization and sequential convex optimization; And adjusting the spacecraft formation according to the solved spacecraft formation track planning.
3. The method for layering control of the reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 2, wherein the method for solving the spacecraft formation trajectory plan under Clohessy-Wiltshire equation dynamics constraint, spacecraft collision avoidance constraint and flexible cable length constraint containing relaxation variables by adopting an optimization algorithm combining particle swarm optimization and sequential convex optimization based on spacecraft formation initial parameters and spacecraft formation target parameters comprises the following steps: Constructing a spacecraft formation track planning objective function: Wherein, the Fuel consumption items are queued for the spacecraft, In order to discretize the time period, In discrete steps of the size of the step, Is the first The number of the space vehicles is one, For the total number of spacecraft in the spacecraft formation, As the weight of the location is given, Is the position error of the movable platform terminal, As the weight of the scale is given, The scale error is formed for the spacecraft, As the weight of the angle is given, Forming angle error items for the spacecraft; Is that Time of day (time) The state of motion of the individual spacecraft, For a system state matrix in Clohessy-Wiltshire equation, Control input matrix in Clohessy-Wiltshire equation; a rotation matrix for the formation of a spacecraft, A reference base vector for motion of the moving platform; For the length of the flexible cable, In order to relax the variables of the variables, For a minimum safe distance between the spacecraft, Is the maximum thrust of the spacecraft.
4. The method for layered control of a reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 3, wherein the step S2 comprises the steps of: determining the assembly of each truss unit according to the specification of the truss to be assembled; determining the pose of the tail end of the mechanical arm in the assembly process according to the assembly sequence of each truss unit : Wherein, the Is the coordinate value of the tail end of the mechanical arm in the X-axis direction in the global coordinate system, Is the coordinate value of the tail end of the mechanical arm in the Y-axis direction in the global coordinate system, Coordinate values of the tail end of the mechanical arm in the Z-axis direction of the global coordinate system; the global coordinate system O is positioned at the center of the pilot spacecraft; For the yaw angle of the end of the mechanical arm, Is the pitch angle of the tail end of the mechanical arm, Is the roll angle of the tail end of the mechanical arm.
5. The method for hierarchical control of a reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 4, wherein the step S3 comprises the steps of: S10, selecting the tail end pose of one mechanical arm in the assembly process as the current tail end target pose of the mechanical arm ; S11, setting the tail end position of the robot Is a convergence threshold of (2) Robot tip pose Is a convergence threshold of (2) Flexible cable tension feasibility function Threshold of (2) Robot motion platform position and robot arm joint configuration ; Wherein, the For the position of the movable platform in the global coordinate system, The joint angle of the mechanical arm; is the coordinate value of the movable platform in the X-axis direction in the global coordinate system, Coordinate values of the movable platform in the Y-axis direction in a global coordinate system; Is the first of the mechanical arms Components of the individual joint angles; s12, initializing the position of a robot moving platform and the joint configuration of a mechanical arm Let iteration times 1, Judging the iteration times Whether or not to meet If yes, continuing, if not, ending; s13, according to the current robot movable platform position and the mechanical arm joint configuration Updating the position of a global coordinate system of a mobile platform ; S14, according to the position of the global coordinate system of the current moving platform Calculating the current tail end pose of the mechanical arm ; S15, according to the pose of the tail end of the mechanical arm Calculating the pose of the tail end target of the current mechanical arm Position error of (2) And angle error ; S16, according to the position error And angle error Calculating the position of a moving platform of the robot and the increment of the joint configuration of the mechanical arm by adopting a damping least square method : Wherein, the For a hybrid jacobian of a robotic end effector, As a result of the damping factor, An error matrix consisting of position errors and angle errors; Is a dynamic platform jacobian matrix, In order to be a jacobian matrix of the mechanical arm, Is the jacobian of the position of the movable platform, The attitude jacobian is a moving platform attitude jacobian; s17, judging the iteration times If the set period is reached, tension optimization and feasibility assessment are carried out to obtain optimized flexible cable tension, if not, S18 is executed; S18, increasing according to the position of the robot movable platform and the joint configuration of the mechanical arm Or according to the optimized flexible cable tension, make K+1, updating the current robot movable platform position and the mechanical arm joint configuration; S19, obtaining the current robot pose according to the updated movable platform position and the robot arm joint configuration, and calculating the target pose at the tail end of the current robot arm Position error of (2) And angle error ; S20, judging the updated position error And attitude error Whether or not to simultaneously satisfy: Wherein, the As an error in the position of the end of the robot, The robot terminal attitude error; If yes, obtaining the current tail end target pose of the mechanical arm And if not, the current pose is considered to have no solution.
6. The layering control method of the reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 5, wherein the optimized flexible cable tension obtained by tension optimization and feasibility assessment comprises the following steps: Based on a robot inverse dynamics model, according to the current moving platform position and the mechanical arm joint configuration Calculating the current tension vector of the flexible cable ; Calculating feasible violation degree of flexible cable tension : If it meets Starting zero space optimization to obtain corrected flexible cable tension, otherwise, obtaining current tension vector Optimizing to obtain the optimized flexible cable tension: Wherein, the As a matrix of weights, the weight matrix, As a flexible cable tension feasibility function Is set to a threshold value of (2).
7. The method for hierarchical control of a reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 6, wherein the step S4 comprises the steps of: Performing track planning through an offline track planner to generate an end effector expected track comprising a time sequence; Sampling the expected track, and converting the tail end Cartesian space pose of each sampling point into a moving platform position and mechanical arm joint configuration of the robot through a robot inverse kinematics solver based on tension optimization to obtain an expected position sequence of the moving platform, an expected tension sequence of a flexible cable, an expected joint angle sequence of the mechanical arm and an expected joint moment sequence; The cable-driven parallel robot is adopted to feed back the PID controller to expect the difference value between the flexible cable tension and the actual flexible cable tension As PID control input, to obtain the difference between the desired length of the flexible cable and the actual length of the flexible cable As feed-forward input, generates a flex cable length control signal : Wherein, the 、 And Are all the parameters of the PID, and the parameters of the PID are the parameters of the PID, Is a feedforward gain parameter; the mechanical arm cascade PID controller is adopted, the outer ring position controller takes the expected joint angle as input, the expected joint angular velocity is generated through the position PID controller after the comparison with the actual joint angle, the inner ring speed controller takes the input, and the basic joint moment is output through the speed PID controller after the comparison with the actual joint angular velocity The final control output is: and the flexible cable system and the mechanical arm are driven to move through the cooperative control of the cable-driven parallel robot manpower feedback PID controller and the mechanical arm cascade PID controller, so that the robot end effector reaches the preassembly coordination pose.
8. The method for hierarchical control of a reconfigurable rigid-flexible coupling space on-orbit assembly robot according to claim 7, wherein the step S5 comprises the steps of: acquiring an assembly unit image through a camera at the tail end of the mechanical arm, and adopting a 6D pose estimation algorithm to realize shaft hole coarse alignment; Starting a dynamic platform damping compensation controller to take the dynamic platform position in coarse alignment as a desired position According to the actual position of the movable platform Generating compensated position instructions And speed command : Starting the fuzzy self-adaptive admittance controller of the mechanical arm, and measuring the interaction force according to the end force sensor Deviation from expected contact force, adjusting admittance parameters in real time through a fuzzy logic system to generate a mechanical arm reference track : Wherein, the As a factor of the adjustment of the stiffness, As a result of the inertia adjustment factor, Is a damping adjustment factor; To compensate position instruction And speed command And a robotic arm reference trajectory Inputting a robot inverse dynamics model, and calculating to obtain optimized flexible cable tension and mechanical arm joint moment; Tracking the optimized flexible cable tension by adopting a flexible cable tension PID controller, and tracking the joint moment of the mechanical arm by adopting a mechanical arm PID controller to realize the cooperative control of the anti-interference stability of the movable platform and the flexible assembly of the mechanical arm; And distinguishing a contact stage and an insertion stage according to the contact force signal characteristics in the assembly process, and adaptively adjusting admittance control parameters based on a fuzzy rule table to finish shaft hole fine alignment and insertion assembly.
9. The reconfigurable rigid-flexible coupling space on-orbit assembly robot layering control method of claim 8, wherein the mechanical arm fuzzy adaptive admittance controller model is: Wherein, the 、 And And the homoenergetic admittance parameter.
10. The layered control system of the reconfigurable rigid-flexible coupling space on-orbit assembly robot is characterized by being used for realizing the layered control method of the reconfigurable rigid-flexible coupling space on-orbit assembly robot, which is disclosed by any one of claims 1-9, and comprises the following steps: spacecraft formation control system: The task planning layer of the spacecraft formation system completes the re-planning of the spacecraft formation by a PSO-SCP method, and the re-planning of the working stroke of the robot is realized according to the assembly task demand according to the track obtained by re-planning; The sensing communication layer is used for realizing master-slave communication of the formation spacecraft and acquiring pose information of the current spacecraft; the single spacecraft driving layer realizes formation reconstruction according to a specified track among the single spacecraft to reach a specified operation position; the rigid-flexible coupling robot layered control system comprises: the robot sensing layer senses robot body information and environment information in real time; the rigid-flexible coupling robot task planning layer confirms preassembly pose of each truss unit of the robot and the current task target; the robot control layer is used for completing real-time calculation of robot kinematics and dynamics and controller data, controlling the movable platform and the mechanical arm to cooperatively move to grasp the truss unit to a preassembled coordination pose through the cable-arm cooperative moving force/position hybrid PID controller, and controlling the movable platform to keep stable through the movable platform anti-interference mechanical arm assembling force/position hybrid controller; And the robot driving layer inputs decoupling control quantity to the mechanical arm driving and the flexible cable parallel robot driving to perform layered control so as to complete assembly.

Description

Layered control method and system for reconfigurable rigid-flexible coupling space on-orbit assembly robot Technical Field The invention relates to the technical field of space on-orbit robot control operation, in particular to a layering control method and system of a reconfigurable rigid-flexible coupling space on-orbit assembly robot. Background Under the background of the progress of space engineering to higher targets such as deep space exploration, on-orbit service and the like, the continuous evolution of space technology and the remarkable improvement of space exploration task complexity bring forward more stringent requirements on the design and control performance of a space on-orbit robot. Aiming at the space oversized-scale assembly task, the space oversized-scale assembly task is subjected to double constraint of the loading capacity and the space size of the carrier rocket, related assembly work cannot be integrally launched after the ground is finished, the space on-orbit robot starts to be applied to finish the space assembly task, the assembly task has high precision index requirements on the operation precision of the robot and the influence of the space extreme environment, and further higher requirements on the stability and the robustness of a control system of the robot are provided. The method is relatively mature and is applied to the space on-orbit assembly task in a large scale, but has the problem of communication time ductility in the space extreme environment, meanwhile, the method relies on the astronaut to operate, the risk is high, the structure for assembling the far-beyond-arm scale is relatively difficult, the second method is used for assembling unitized robot clusters, the assembly task is completed by designing a modularized, light-weight robot, a plurality of robot clusters are cooperated, the robustness of the system is high, the assembly efficiency is high, the complexity of the system is high, the cooperative control is difficult, the light-weight design can influence the assembly precision, and the third method is used for a bionic climbing robot, the assembly task is completed by climbing on the surface of a complex structure, the movement precision and the force sensing control are high, the operation precision is high, the operation is self-redundancy, the structure cannot be further limited by the requirement of carrying on the space environment, and the like, and the method is still limited by the requirement of carrying of the space environment. The invention patent of China with the application number of CN202511465298.8 proposes an on-orbit assembly robot with a reconfigurable rigid-flexible coupling space, a spacecraft cluster is used as a movable base, the relative pose among the spacecrafts is dynamically adjusted according to task requirements, a flexible cable driver is arranged on each spacecraft, a movable platform is driven to move by a flexible cable system, a mechanical arm is loaded on the movable platform, an on-orbit assembly task is completed through cooperative control of the movable platform and the mechanical arm, the flexible cable system and the mechanical arm form a rigid-flexible coupling characteristic, the on-orbit assembly robot has the characteristic of reconfigurable working stroke, on-orbit operation of a variable-size and unstructured space target can be effectively performed, but the flexible cable system and the mechanical arm are required to cooperate with each other in a space microgravity environment, otherwise, the operation efficiency and the operation precision of the robot are seriously affected, and the stability of the operation process of the robot is required to be designed, and the operation efficiency and the operation precision are further improved. The invention patent of China with the application number of CN202110481248.4 provides a method and a system for designing a position observer of self-adaptive coordination control of a space manipulator, wherein the space manipulator is arranged on an aircraft, a task space observer is designed, a self-adaptive dynamics coordination control law and a parameter updating law are realized, the attitude adjustment of the aircraft and the tracking of an end effector on a desired track in a task space are realized, the problem of parameter uncertainty in space on-orbit tasks is solved, the method can be suitable for different on-orbit robot operation tasks, but the method is not suitable for robots in the scheme, the kinematics and the dynamics coupling relationship exist between a cable-driven parallel robot and the manipulator in the scheme, and the robot coupling relationship needs to be completely analyzed and decoupled to realize the layered control of the robot. The Chinese patent of the application number CN202410686786.0 provides a fuzzy reinforcement learning preset time vibration suppression method for a rigid-flexible coupling robot, which solves the technical pr