Industrial Robot Collision Avoidance via Predictive Distance Calculation
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Solution Overview
Problem
Existing methods for collision avoidance in multi-axial industrial robots are limited by large prediction errors and require significant safety margins due to reliance on past and present joint positions, velocities, and accelerations, leading to potential collisions despite programmed collision-free trajectories.
Innovation Solution
The method calculates the shortest distances between robot and object components at multiple future points, using planned paths to estimate the time until collision, allowing for a longer look-ahead time and improved collision detection, and defines protective zones to anticipate imminent collisions, reducing the need for large safety margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If collision avoidance methods use protective zones and calculate shortest distances at multiple future points, then collision detection precision is improved, but device complexity increases
Solution Approach 1:
The system calculates shortest distances at multiple future points in time before actual collision occurs, enabling early detection and preventive action. This preliminary calculation approach improves detection precision by anticipating potential collisions rather than reacting to them after they occur.
Solution Approach 2:
Protective zones are introduced as intermediary virtual boundaries around robot components. These zones serve as mediators between the physical robot and potential collision risks, allowing the system to detect and prevent collisions before actual contact occurs, thereby improving detection precision without requiring direct physical sensors on all components.
2Reliability
If large safety margins are used to prevent collisions, then reliability is improved, but productivity deteriorates due to unnecessary stops
Solution Approach 1:
The system dynamically adjusts safety margins based on real-time calculated shortest distances and predicted trajectories. Instead of using fixed large safety margins that cause unnecessary stops, the system adapts the safety buffer dynamically, maintaining high reliability when risks are present while minimizing interruptions when the environment is safe, thus improving productivity.
Solution Approach 2:
The system changes the parameter of safety margin from a static large value to a dynamic value that adjusts based on calculated future positions and detected risks. This parameter transformation allows the system to maintain reliability only when necessary, reducing unnecessary stops and improving overall production efficiency.
3Productivity
If robot moves at high speed during production phase, then productivity is improved, but the risk of severe damage from collisions increases
Solution Approach 1:
By calculating shortest distances at multiple future points, the system performs preliminary collision risk assessment before high-speed movement continues. This allows the robot to maintain high speed during normal operation while having the capability to detect and prevent collisions in advance, thus maintaining productivity while reducing damage risk.
Solution Approach 2:
The system continuously monitors and calculates future positions and shortest distances, providing real-time feedback on collision risks. This feedback mechanism allows high-speed operation to continue safely by immediately detecting potential collisions and triggering preventive stops only when necessary, thereby maintaining productivity while minimizing damage risk.
Data Source
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AI summary
The invention relates to a device for avoiding collisions between components of a multi-axial industrial robot (1,2) and at least one other object (1,2,3), wherein the device comprises a computation unit (13) adapted to estimate the time left until a collision occurs between the robot and the object, to compute a stopping time for the robot, and to compare the estimated time left until collision and the stopping time for the robot, and to generate an order to stop the robot or the object in case the estimated time left until collision is close to the stopping time for the robot.