Robot Hand Force Control for Stable Article Pickup
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Solution Overview
Problem
Existing article pickup systems by robots face issues with false detection, detection failure, and overload due to reliance on visual information for positioning and gripping, leading to unstable article pickup and potential damage.
Innovation Solution
An article pickup apparatus equipped with a visual sensor, force sensor, and control units that adjust the robot's hand to match the article's position and posture, using profile control to apply the correct force and prevent overload, ensuring stable gripping and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If visual information is used to detect article position and hand posture, then pickup operation can be automated, but false detection and detection errors occur leading to unstable gripping
Solution Approach 1:
The patent implements feedback control by continuously monitoring the external force acting on the hand during the pickup operation and adjusting the hand position and posture based on the detected force deviations. The system compares the actual external force with the target external force and dynamically corrects the hand's position and orientation to achieve accurate gripping despite initial visual detection errors.
2Object-affected harmful factors
If hand center is shifted from article center to avoid interference, then collision with surrounding articles is prevented, but abnormal operation is detected causing pickup operation to stop
Solution Approach 1:
The system uses force feedback to distinguish between intentional center shifting for collision avoidance and actual abnormal operations. By monitoring the external force patterns and comparing them with expected force profiles during normal operation with shifted centers, the system can differentiate between deliberate positioning adjustments and genuine abnormalities, allowing continuous operation when center shifting is intentional.
Solution Approach 2:
The patent employs dynamic force control during the pickup operation, allowing the hand to adapt its position and the force application in real-time. This dynamic approach enables the system to intentionally shift the hand center from the article center when necessary to avoid collisions, while continuously adjusting the gripping force to maintain stable pickup operation.
3Reliability
If hand is forcibly closed to ensure article holding, then article can be secured, but robot or hand is subjected to overload or article may be damaged
Solution Approach 1:
The patent implements feedback control by continuously monitoring the external force acting on the hand during the pickup operation and adjusting the hand position and posture based on the detected force deviations. The system compares the actual external force with the target external force and dynamically corrects the hand's position and orientation to achieve accurate gripping despite initial visual detection errors.
Solution Approach 2:
The system dynamically adjusts the gripping force parameter based on real-time feedback from force sensors. Instead of applying maximum force, the control unit modulates the closing force of the hand to match the actual article properties and environmental conditions, achieving secure holding while preventing overload and damage through continuous parameter optimization.
Data Source
AI summary
An article pickup apparatus according to the present invention is configured to control a robot or a hand in accordance with profile control when the hand holds an article so that an external force acting on the hand detected by a force sensor installed between an arm and the hand is closer to a target value of the external force set by a force target value setting unit.