Robot Arm Speed Control for Safer Human Proximity Operation
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Solution Overview
Problem
Existing robot systems face a trade-off between safety and operation efficiency, as they often lower operation speed when a moving subject is detected in the operation direction, potentially leading to incorrect collision determinations and reduced productivity.
Innovation Solution
A robot system with an arm operation control unit that adjusts speed based on the presence of a moving subject in the operation direction and position range, allowing normal speed when no subject is detected and reduced speed when a subject is present, while also incorporating a warning transmission unit to alert operators and restart operations when safe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robot operates at high speed without detecting moving subjects, then productivity is improved, but safety is compromised due to risk of collision
Solution Approach 1:
The monitoring space is divided into multiple regions (first region closer to robot, second region farther from robot) with different speed thresholds. This segmentation allows the robot to operate at higher speeds in safer zones while reducing speed only when subjects enter critical proximity, thus maintaining productivity while ensuring safety.
Solution Approach 2:
The robot's operation speed is dynamically adjusted based on the detected position of moving subjects. The control unit changes speed thresholds according to whether subjects are in the first or second region, enabling flexible speed adaptation that maintains high productivity when safe while ensuring collision prevention when necessary.
2Reliability
If the robot reduces operation speed when moving subjects are detected in the operation direction region, then collision prevention is improved, but productivity is reduced due to unnecessary speed reductions
Solution Approach 1:
Different speed reduction policies are applied to different spatial zones. The first region (closer to robot) triggers speed reduction at higher thresholds, while the second region (farther from robot) allows higher operation speeds. This local differentiation ensures collision prevention in critical zones while maintaining productivity in safer zones.
Solution Approach 2:
The system performs preliminary detection of moving subjects in the second region before they reach the critical first region. By detecting subjects early and adjusting speed based on their position, the system prevents collisions before they occur while avoiding unnecessary speed reductions when subjects are in less critical zones.
3Device complexity
If the robot uses a single speed threshold for all detection regions, then control simplicity is maintained, but measurement precision of collision risk is reduced
Solution Approach 1:
The system changes the speed threshold parameter based on the detected position of moving subjects. When subjects are in the first region, a lower speed threshold is applied; when in the second region, a higher speed threshold is applied. This parameter adaptation improves collision risk assessment precision while maintaining relatively simple control logic through predefined threshold values.
Data Source
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AI summary
There is provided a robot system that maintains productivity with high safety and with high operation efficiency. A robot system (1) includes an arm operation control unit (22) configured to control an operation of an arm (12) and a moving subject detection unit (21) configured to detect whether a moving subject is present in an operation direction region of the arm. When the moving subject detection unit has detected the moving subject, the arm operation control unit operates the arm at an operation speed that is different from an operation speed of the arm when no moving subject has been detected.