Robot Admittance Coordination for Accurate Compliant Motion
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Solution Overview
Problem
Existing robot compliance control methods, such as admittance control in Cartesian and joint spaces, often randomly select one method or implement them independently, leading to defects that affect accurate task positioning and increase the risk of damage from excessive contact forces due to positional errors during interactions with objects or people.
Innovation Solution
A robot control method that determines an end admittance compensation amount in Cartesian space and a joint admittance compensation amount in joint space, combining these to calculate a target joint commanding position, thereby effectively integrating Cartesian and joint space admittance controls to avoid excessive contact forces and ensure compliant and dynamic obstacle avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ordinary position control method with high rigidity is used, then positioning accuracy is improved, but excessive contact force is generated causing damage to operation object and robot
Solution Approach 1:
The patent implements dynamic switching between position control mode and compliance control mode based on real-time state detection. When contact force exceeds threshold or position deviation occurs, the system transitions from rigid position control to compliant control, allowing the robot to adapt its stiffness dynamically and avoid excessive contact forces while maintaining positioning accuracy when needed
Solution Approach 2:
The patent changes the control parameter from fixed position control to variable compliance control by adjusting the admittance matrix parameters. The system modifies control stiffness and damping parameters in real-time based on operational conditions, enabling the robot to transition between rigid and compliant states to prevent damage while maintaining positioning precision
2Object-affected harmful factors
If compliance control method is used, then collision damage is reduced, but positioning accuracy and task execution precision deteriorate
Solution Approach 1:
The patent employs dynamic mode switching between position control and compliance control based on real-time detection of contact forces and position deviations. The system activates compliance control only when necessary (during contact or deviation events) and returns to precise position control when safe, thereby maintaining both safety and positioning accuracy
Solution Approach 2:
The patent implements feedback mechanisms that continuously monitor contact forces, position deviations, and task execution status. Based on this feedback, the system intelligently switches between control modes and adjusts compliance parameters to maintain positioning accuracy while preventing collision damage, ensuring high-precision task execution
3Adaptability or versatility
If Cartesian space admittance control and joint space admittance control are implemented independently, then compliance control coverage is improved, but control coordination and task positioning precision deteriorate
Solution Approach 1:
The patent merges Cartesian space admittance control and joint space admittance control into a unified coordinated control framework. The system integrates both control spaces through transformation matrices and coordination algorithms, ensuring that compliance actions in either space contribute synergistically to accurate task positioning rather than working independently or conflicting with each other
Data Source
AI summary
A robot control method, a robot, and a computer-readable storage medium are provided. The method includes: obtaining a trajectory planning parameter of joint(s) of the robot, force data of an end of the robot, and force data of the joint(s); obtaining an end admittance compensation amount; determining a first joint parameter and a first slack variable corresponding to the end admittance compensation amount in a joint space of each of the joint(s) based on the end admittance compensation amount and the trajectory planning parameter; obtaining a joint admittance compensation amount; determining a second joint parameter based on the first joint parameter, the first slack variable, the joint admittance compensation amount, and the trajectory planning parameter; determining a target joint commanding position based on the second joint parameter; and controlling the robot to move according to the target joint commanding position.