Robot Arm Motion Planning for Continuous Joint Rotation
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Solution Overview
Problem
High-dimension robot arms, such as 7-DOF robots, face challenges in selecting optimal joint angle values to ensure continuous motion, leading to potential shaking and damage due to non-continuous joint angle variations during motion planning.
Innovation Solution
A motion planning method that calculates arm angle ranges, generates boundary curves, identifies abruptly changing ranges, and adjusts angles using a correction model to maintain continuity and smooth motion, ensuring stable robot arm movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a group of joint angle values with the smallest difference from the previous moment is selected for 6-DOF robots, then the motion continuity is maintained, but this approach fails for higher-dimension robots where each tail-end pose corresponds to numerous joint value groups
Solution Approach 1:
The patent pre-calculates and stores the optimal joint angle values in a lookup table before actual motion execution. By preparing the optimal joint angles in advance based on the motion trajectory, the system avoids real-time complex calculations and ensures continuous motion for high-DOF robots without selecting inappropriate joint angle groups.
Solution Approach 2:
The patent replaces the traditional mechanical approach of selecting joint angle groups with the smallest difference with an intelligent computation system. It uses a calculation unit that determines optimal joint angle values by comparing multiple inverse solution groups and selecting the one that ensures continuous motion, substituting simple difference comparison with a more sophisticated selection mechanism.
2Productivity
If non-continuous joint angle variations are used in high-dimension robot arms, then the motion planning is simpler, but shaking occurs during motion which severely affects motion effect and causes damages
Solution Approach 1:
The patent implements a feedback mechanism where the calculation unit continuously monitors the joint angle values from the lookup table and compares them with the current robot state. Based on this feedback, it selects the optimal joint angle group that ensures continuous variation and stable motion, preventing shaking while maintaining efficient motion planning.
Solution Approach 2:
The patent changes the selection criterion from simple proximity to previous angles to a comprehensive evaluation of multiple inverse solution groups. It selects joint angle values based on which group ensures continuous motion and stability, transforming the parameter selection from a simple geometric criterion to a performance-based criterion that prevents shaking.
Data Source
AI summary
A motion planning method for robot arms includes: calculating an arm angle range of each pose of a tail end of a robot arm in the motion trajectory; calculating a start arm angle value of a start pose of the tail end of the robot arm in the motion trajectory; calculating an arm angle proportion according to the start arm angle value and the arm angle range of the start pose; identifying an abruptly changing arm angle range in the arm angle range of each pose according to a upper boundary curve and a lower boundary curve; calculating an arm angle of a pose corresponding to the abruptly changing arm angle range; calculating arm angles corresponding to the other poses according to the arm angle proportion; and calculating an angle of a joint of the robot arm.