Robot Withdrawal Control Using External-Force Reduction
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Solution Overview
Problem
Current robot systems, particularly human-collaborative robots, face challenges in ensuring reliable withdrawal motions that minimize interference with obstacles during the release of objects, which affects their reliability and safety.
Innovation Solution
A robot system with a detector to monitor external forces and a controller that executes a backward withdrawal mode when a first condition is met, followed by an external-force reduction withdrawal mode if specific conditions are satisfied, ensuring the robot withdraws in a direction that reduces external force and minimizes contact with other obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robot executes a simple backward withdrawal along the original motion track, then the withdrawal speed is high and the process is simple, but the robot may interfere with obstacles when external forces are present
Solution Approach 1:
The patent implements dynamic withdrawal mode selection that adapts to real-time external force conditions. The controller dynamically switches between backward withdrawal mode and external-force reduction withdrawal mode based on detector feedback, making the withdrawal process flexible and reliable under varying external force conditions without requiring complex predefined paths for each scenario
Solution Approach 2:
The patent employs feedback control by using a detector to monitor external forces during withdrawal and adjusting the withdrawal mode accordingly. The controller receives external force information and determines whether to execute backward withdrawal or external-force reduction withdrawal, creating a closed-loop control system that ensures reliable withdrawal while managing complexity through intelligent decision-making
2Reliability
If the robot executes external-force reduction withdrawal to avoid obstacles, then the robot safety is improved, but the withdrawal time increases and the process becomes more complex
Solution Approach 1:
The patent uses dynamic mode selection to balance safety and time efficiency. When external forces are minimal, the system executes fast backward withdrawal; when external forces indicate potential obstacle interference, it switches to external-force reduction withdrawal. This dynamic adaptation ensures safety when needed while minimizing withdrawal time in safe conditions
Solution Approach 2:
The patent changes the withdrawal control parameters based on external force conditions. By adjusting the withdrawal mode parameter (backward vs. external-force reduction) according to detected external forces, the system optimizes the trade-off between withdrawal speed and obstacle avoidance, reducing unnecessary time loss while maintaining reliability
3Adaptability or versatility
If the robot uses a single withdrawal mode for all conditions, then the control system is simple, but the robot cannot reliably avoid obstacles under varying external forces
Solution Approach 1:
The patent implements a universal withdrawal control system that handles multiple withdrawal scenarios using a unified control architecture. The single controller executes both backward withdrawal and external-force reduction withdrawal modes through conditional logic, providing multi-functionality without requiring separate control systems for each mode, thus balancing adaptability with controlled complexity
Solution Approach 2:
The patent creates a dynamic control system that adapts its behavior based on real-time conditions. The controller dynamically selects between different withdrawal modes using external force detection, providing versatility in handling various obstacle scenarios while maintaining relatively simple control logic through conditional decision-making rather than multiple independent control systems
Data Source
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AI summary
A robot system includes a robot, a detector, and a robot controller. The robot includes a plurality of motion axes. The detector is configured to detect an external force acting on the robot. The robot controller is configured to control a motion of the robot, and includes a motion controller. When the external force detected by the detector satisfies a first condition, the motion controller is configured to execute a backward withdrawal mode of causing the robot to withdraw by following, in a backward direction, a motion track that the robot followed. When an execution situation of the backward withdrawal mode satisfies a second condition, the motion controller is configured to execute an external-force reduction withdrawal mode of causing the robot to withdraw in a direction in which the external force reduces.