Robot Motion Control Using Dynamic Risk Zones in Assembly
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Solution Overview
Problem
Existing safety technologies for collaborative robot and worker operations in assembly lines are inefficient as they stop the robot unnecessarily when obstacles or people are far away, leading to decreased operation rates due to not considering moving velocities and directions.
Innovation Solution
A robot controlling device that calculates position and velocity vectors for both the robot and worker, generates risk determination areas, and determines collision avoidance trajectories based on these calculations to optimize collision avoidance and maintain operation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety is determined based only on distance between robot and obstacle/person without considering velocity and direction, then worker safety is improved, but robot operation rate decreases due to unnecessary stops
Solution Approach 1:
The patent changes the safety determination parameters from static distance-only measurement to dynamic multi-parameter measurement including position, velocity, and direction vectors. This allows the system to distinguish between situations where the robot is approaching the worker versus moving away, enabling more accurate risk assessment and reducing unnecessary stops while maintaining safety
Solution Approach 2:
The patent introduces dynamic elements to the safety determination system by continuously monitoring and calculating velocity vectors and movement directions of both the robot and the worker. This dynamic approach allows the safety system to adapt to changing motion states in real-time, preventing false safety violations when both parties are moving away from each other or when the robot's motion trajectory does not pose a collision risk
2Reliability
If a safety fence is installed widely to prevent worker from being caught between robot and fence, then worker safety is improved, but installation area increases and factory space utilization decreases
Solution Approach 1:
The patent replaces the mechanical safety fence system with an electronic/software-based safety determination system that calculates collision risk based on position, velocity, and direction vectors. This substitution eliminates the need for physical safety fences, allowing the robot and worker to operate in the same space without physical barriers while maintaining worker safety through intelligent motion analysis
Data Source
AI summary
A robot controlling device inputs an operation state of a worker from a sensor. The robot controlling device calculates a position vector and a velocity vector of each of the robot and the worker from the operation state of the robot and the operation state of the worker, generates a risk determination area (an area where the robot is stopped, an area where the robot is evacuated, and an area where the robot is decelerated) around each of the robot and the worker, determines a risk based on overlapping between the generated risk determination area of the robot and the generated risk determination area of the worker, generates a collision avoidance trajectory in which collision between the robot and the worker is avoided from a result of the determination, and controls the robot based on the generated collision avoidance trajectory.