Manipulator Control System for Contact Force Management
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Solution Overview
Problem
Existing control systems for manipulators cannot accurately control the contact force between a grasped object and a nearby object, leading to potential damage to either object during placement or lifting operations.
Innovation Solution
A control system for a manipulator that includes an environment recognition unit to identify nearby objects, an arm control unit to manage the arm's movement, and a hand control unit to predict the contact state and adjust the grasping force accordingly, ensuring appropriate contact force during object manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the manipulator tightly grasps the object during placement, then the object can be securely held, but excessive contact force is transmitted to the object causing damage
Solution Approach 1:
The grasping force is made dynamic rather than static. The hand control unit continuously adjusts the grasping force based on real-time detection of contact between the object and target surface, transitioning from strong grasping during movement to weakened grasping upon contact detection, thereby preventing damage while maintaining secure holding
Solution Approach 2:
A feedback mechanism is implemented where the hand control unit detects contact between the grasped object and the target surface, then uses this feedback information to adjust the grasping force by weakening it, creating a closed-loop control system that prevents excessive contact force
2Object-affected harmful factors
If the manipulator weakly grasps the object during placement, then contact force damage is reduced, but the object may not be successfully placed due to insufficient contact force
Solution Approach 1:
The grasping force is dynamically adjusted based on the placement phase. During approach and placement, stronger grasping force ensures successful placement, while upon detection of contact with target surface, the force is weakened to prevent damage, achieving both placement success and damage prevention
Solution Approach 2:
The system performs preliminary detection of contact state between the grasped object and target surface before final placement is completed, allowing proactive adjustment of grasping force to ensure both successful placement and prevent damage
3Object-affected harmful factors
If the manipulator switches between position control and impedance control upon impact detection, then impact damage is avoided, but the grasped object cannot be placed with appropriate contact force
Solution Approach 1:
The hand control unit acts as an intermediary between the arm control unit and the grasped object. It receives control commands, detects contact state, and adjusts grasping force independently to achieve precise contact force control, separating the control functions of arm movement and hand grasping
Solution Approach 2:
The control system is segmented into separate functional units: arm control unit for movement control and hand control unit for grasping force control. This segmentation allows independent optimization of each function, enabling precise contact force control while maintaining impact avoidance capabilities
Data Source
AI summary
A control system for a manipulator capable of controlling the movement of a manipulator in such a manner that, when bringing an object grasped by the manipulator into physical contact with a nearby object, the grasped object comes into contact with the nearby object with an appropriate contact force are provided. The control system for a manipulator includes an arm, and a hand attached to the arm and configured to grasp an object to be grasped. The control system includes an environment recognition unit configured to recognize a nearby object in an environment around the manipulator, an arm control unit configured to control a movement of the arm, and a hand control unit configured to predict a contact state between the grasped object and the nearby object, and adjust a grasping force of the hand according to the prediction of the contact state.