Robot Manipulator Stability Control Under External Force
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Solution Overview
Problem
Robot manipulators face challenges in maintaining dynamic stability when encountering unexpected external forces, such as bumps from people or objects, which can lead to instability and safety issues.
Innovation Solution
A control system that dynamically adjusts the arm and base of the robot manipulator to maintain stability by detecting applied forces and moving the base in the direction of the force if the stability criterion is not met, using a combination of compliance and motion control to neutralize the effect of external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the arm responds compliantly to an applied force, then safety and ease of operation are improved, but dynamic stability may be compromised
Solution Approach 1:
The control system dynamically switches between two operational modes: compliant mode (when stability criterion is met) and rigid mode (when stability criterion is not met). This dynamic adaptation allows the arm to be compliant for safety during normal operation, while automatically becoming rigid to maintain stability when external forces threaten to destabilize the robot
Solution Approach 2:
The system changes the stiffness parameter of the arm based on the stability criterion. When the criterion is satisfied, the arm operates with low stiffness for compliance; when the criterion is violated, the arm increases stiffness to resist external forces and maintain dynamic stability
2Stability of the object's composition
If the control system maintains rigid control of the arm, then dynamic stability is improved, but safety and ease of operation deteriorate
Solution Approach 1:
The control system dynamically adjusts the operational mode based on real-time stability assessment. Rather than maintaining constant rigidity, the system switches to compliant mode when stability is assured, providing safety benefits while maintaining stability through selective rigid control only when necessary
3Stability of the object's composition
If the base moves in response to applied forces to maintain stability, then dynamic stability is improved, but device complexity increases
Solution Approach 1:
The control system autonomously monitors the stability criterion and automatically triggers base motion when needed, without requiring external intervention or complex manual control. The system serves itself by detecting stability violations and initiating corrective base movements independently
Data Source
AI summary
A robot manipulator has a base; an arm connected to the base via at least a shoulder joint; and a control system with a dynamic stability determination module. The dynamic stability determination module of the control system determines whether a dynamic stability criterion is met. If the dynamic stability criterion is met, the arm is responds compliantly to an applied force; and if the dynamic stability criterion is not met, the control system causes motion of the base in the direction of the applied force.