3D Point-Set Interference Checking for Real-Time Motion Planning
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Solution Overview
Problem
Existing interference checking techniques for industrial robots and machine tools are computationally intensive, inaccurate, or require significant setup time, making them impractical for real-time motion planning due to the use of geometry primitives or CAD models.
Innovation Solution
An object interference checking technique using point sets, where CAD models are converted to 3D points, then to 1D indices, and stored as sets per object and per motion step, allowing for fast interference checking by computing intersections and swept volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CAD models are used for interference checking, then measurement precision is improved, but productivity deteriorates due to computational intensity
Solution Approach 1:
The patent segments the continuous CAD model into a discrete set of points sampled from the object's surface and volume. This segmentation transforms the infinite precision problem into a manageable finite set of points that can be processed quickly while maintaining sufficient accuracy for interference detection.
Solution Approach 2:
The patent creates a simplified copy of the CAD model by generating point sets that represent the essential geometry. These point set copies retain the critical spatial information needed for interference checking while being computationally much lighter than full CAD models, enabling real-time processing.
2Productivity
If geometry primitives are used for interference checking, then productivity is improved through faster computation, but measurement precision deteriorates due to approximation errors
Solution Approach 1:
Instead of using simplified geometry primitives that approximate objects, the patent creates accurate point set copies directly from CAD models. These copies preserve the true geometry of complex objects like vehicle bodies while remaining computationally efficient for real-time interference checking.
3Measurement precision
If CAD models are used for interference checking, then measurement precision is improved, but device complexity increases due to computational requirements
Solution Approach 1:
The patent simplifies the computational system by segmenting CAD models into point sets and using efficient set operations (union, intersection, difference) rather than complex continuous geometry calculations. This segmentation reduces algorithmic complexity while maintaining accuracy.
Solution Approach 2:
The patent replaces complex mechanical geometry calculations with simpler set theory operations. By transforming geometric interference problems into set operations on point clouds, the system achieves the same function with lower computational complexity.
4Device complexity
If geometry primitives are used for interference checking, then device complexity is reduced through simpler models, but measurement precision deteriorates
Solution Approach 1:
The patent creates accurate point set copies directly from precise CAD models, avoiding the need for simplifying geometry primitives. This copying approach maintains high measurement precision while keeping the computational representation manageable through discrete point sets rather than continuous surfaces.
Data Source
AI summary
An object interference checking technique using point sets which uses CAD models of objects and obstacles and converts the CAD models to 3D points. The 3D point locations are updated based on object motion. The 3D points are then converted to 3D grid space indices defining space occupied by any point on any object or obstacle. The 3D grid space indices are then converted to 1D indices and the 1D indices are stored as a set per object and per position. Swept volumes for an object are created by computing a union of the 1D index sets across multiple motion steps. Interference checking between objects is performed by computing an intersection of the 1D index sets for a given motion step or position. The 1D indices are converted back to 3D coordinates to define the 3D shapes of the swept volumes and interferences.