Robot Motion Path Interference Checking With Combined Approximated Bodies
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Solution Overview
Problem
Current methods for determining interference between a robot arm and its surroundings are time-consuming, especially when dealing with multiple grip-target objects on a belt conveyor, as they require checking for shared regions between convex hulls and obstacles, leading to prolonged computation times that affect production efficiency.
Innovation Solution
An interference determination method that approximates the robot and obstacle shapes as polyhedrons, allowing for the generation of combined approximated bodies to quickly assess potential interference by setting intermediate positions on the motion path and determining interference using these approximated bodies, thereby reducing the need for exhaustive posture checks and improving computation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all convex hulls are checked for shared regions with obstacles, then interference determination accuracy is improved, but computation time increases
Solution Approach 1:
The robot arm is divided into multiple links, and the motion path is divided into multiple discrete time instances. Convex hulls are calculated for each link at each time instance, creating segmented representations that can be processed independently and efficiently.
Solution Approach 2:
Instead of checking all convex hulls against all obstacles, the patent performs partial checks by first identifying time instances where the robot is closest to obstacles, and only performing detailed interference determination for those specific cases. This reduces the overall computation while maintaining accuracy.
2Reliability
If multiple discrete time instances are used to calculate convex hulls, then interference detection coverage is improved, but computation complexity increases
Solution Approach 1:
Before performing detailed interference determination, the patent pre-calculates the motion path and identifies key time instances where the robot is closest to obstacles. This preliminary action reduces the number of convex hull calculations needed while ensuring comprehensive coverage of potential interference zones.
Solution Approach 2:
The patent applies different levels of analysis to different parts of the motion path. Regions closer to obstacles receive more detailed examination with additional time instances, while regions farther away use coarser sampling, optimizing the balance between detection coverage and computational complexity.
3Reliability
If robot path generation considers surrounding obstacles, then path safety is improved, but path computation speed decreases
Solution Approach 1:
The patent performs interference determination selectively rather than for the entire path. It focuses computational resources on critical sections where the robot is closest to obstacles, achieving adequate safety verification without the full computational burden of checking every point along the path.
Solution Approach 2:
The path computation is segmented into phases: initial path generation, identification of critical time instances near obstacles, and targeted interference determination. This segmentation allows the system to maintain good computation speed while ensuring safety at critical points.
Data Source
AI summary
Provided is an interference determination method with which whether or not a robot interferes with a surrounding object on a motion path can be computed. At least one intermediate position is set on a motion path of movement from the first position to the second position, a plurality of robot approximated bodies that are each constituted by combining at least two robot approximated bodies at a plurality of postures corresponding to each position are generated, a second combined approximated body constituted by combining at least two first combined approximated bodies is generated with respect to at least one focused part, and the second combined approximated body interferes with a surrounding object approximated body is determined.