Robot Point-Set Interference Checking for Real-Time Motion Planning
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Solution Overview
Problem
Existing robot interference checking techniques are either computationally intensive, inaccurate due to approximations, or require significant time and effort to set up, making them impractical for real-time motion planning in complex robot workspace environments.
Innovation Solution
A robot interference checking motion planning technique using point sets, where CAD models of robot arms and obstacles are converted to 3D points, updated at each time step, and then converted to 1D indices to perform interference checks and swept volume computations efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If geometry primitives are used to approximate robot arms and obstacles, then the interference checking calculation complexity is reduced and computation speed is improved, but accuracy deteriorates due to approximation errors and false positive interference conditions
Solution Approach 1:
The patent creates simplified copies of the robot arms and obstacles as point sets, where each object is represented by a collection of points rather than detailed geometry. This copying approach maintains the essential spatial information needed for interference detection while dramatically reducing computational complexity, allowing fast interference checking without the accuracy loss inherent in geometry primitive approximations.
2Measurement precision
If CAD models are used for interference checking calculations, then accuracy is improved by avoiding geometry primitive approximations, but computation time increases significantly making it impractical for real-time motion planning
Solution Approach 1:
The patent extracts only the essential spatial information from the full CAD models by representing objects as point sets. Instead of using complete CAD model geometries which require intensive distance calculations between all surface points, the method extracts key positional data into simplified point representations, maintaining accuracy while reducing computation time to enable real-time motion planning.
3Ease of manufacture
If geometry primitives are defined around each robot arm and obstacle, then the setup process becomes manageable for interference checking, but significant time and effort are required to define the primitives
Solution Approach 1:
The patent implements a self-service approach where the point set representations are automatically generated from the CAD models without requiring manual definition of geometry primitives. The system automatically processes the CAD data to create point sets, eliminating the tedious and time-consuming manual setup process while maintaining ease of use through automated workflows.
4Reliability
If conservative geometry primitive shapes are used to ensure safety, then collision avoidance is improved, but false positive interference conditions increase leading to unnecessary motion restrictions
Solution Approach 1:
The patent applies local quality by using point sets that precisely represent the actual geometry and spatial distribution of robot arms and obstacles. Instead of using conservative geometry primitives that uniformly overestimate object boundaries, the point set method locally captures the true shape and position of each object, enabling accurate interference detection that distinguishes between real and false positive interference conditions, thereby maintaining safety while improving motion planning efficiency.
Data Source
AI summary
A robot interference checking motion planning technique using point sets. The technique uses CAD models of robot arms and obstacles and converts the CAD models to 3D point sets. The 3D point set coordinates are updated at each time step based on robot and obstacle motion. The 3D points are then converted to 3D grid space indices indicating space occupied by any point on any part. The 3D grid space indices are converted to 1D indices and the 1D indices are stored as sets per object and per time step. Interference checking is performed by computing an intersection of the 1D index sets for a given time step. Swept volumes are created by computing a union of the 1D index sets across multiple time steps. The 1D indices are converted back to 3D coordinates to define the 3D shapes of the swept volumes and the 3D locations of any interferences.