Robot Path Interference Checking With Segmented Collision Models
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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 extensive computation to check for shared regions between convex hulls and obstacles, affecting production efficiency.
Innovation Solution
The method involves approximating the robot and obstacle shapes as polyhedrons, using a first cuboid for initial interference checks and a second cuboid for detailed analysis only when necessary, reducing unnecessary computation and improving determination speed and accuracy by focusing on specific regions and postures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detailed interference determination is performed for all robot positions and orientations, then measurement precision is improved, but computation time increases
Solution Approach 1:
The robot's motion range is segmented into multiple regions based on distance from the origin. The space is divided into a first motion range (farther from origin) and a second motion range (closer to origin). This segmentation allows different determination methods to be applied to different regions, reducing overall computation time while maintaining accuracy where needed.
Solution Approach 2:
Different determination approaches are applied to different spatial regions. In the first motion range, a simplified determination method is used that considers only positional information. In the second motion range, a more detailed determination method is used that also considers orientation information. This local differentiation optimizes the balance between accuracy and computation time.
2Loss of time
If simplified interference check is used for all regions, then computation time is reduced, but measurement precision deteriorates
Solution Approach 1:
The motion space is segmented into regions where simplified determination is sufficient and regions where detailed determination is necessary. By calculating distance from the origin and comparing against a threshold, the system automatically selects the appropriate determination level for each region, ensuring accuracy is not compromised where it matters most.
Solution Approach 2:
The determination method dynamically changes parameters based on spatial position. When the robot is in the first motion range (larger distance from origin), only positional parameters are used for determination. When in the second motion range (smaller distance), both positional and orientational parameters are used, changing the determination criteria based on location.
3Reliability
If comprehensive path verification is performed for multiple grip-target objects, then reliability is improved, but productivity decreases
Solution Approach 1:
The verification process is segmented based on robot position. For positions in the first motion range, a quick verification using only positional data is performed. For positions in the second motion range, a more thorough verification including orientation data is performed. This allows comprehensive safety checking while maintaining high processing speed for most positions.
Solution Approach 2:
The system performs partial verification (position-only) for regions where it is sufficient, and excessive verification (position and orientation) only for regions where it is necessary. This avoids the excessive computation that would result from performing full verification everywhere, while still ensuring reliability in critical zones.
Data Source
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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 high speed. 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.