Height-Map Tool Path Checking for Real-Time Collision Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing interference checking techniques for multi-axis machine tools are computationally intensive and time-consuming, leading to inefficiencies in real-time motion planning, particularly when dealing with complex workpiece geometries and obstacles.
Innovation Solution
The use of height maps to convert CAD models of workpieces and obstacles into a grid-based format, allowing for rapid interference checking by comparing tool path coordinates to grid cell heights, and incorporating tool height maps to account for tool body interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CAD models are used for interference checking, then accuracy is improved, but computational time increases significantly
Solution Approach 1:
The workspace is divided into a grid of cells, and each cell is assigned a height value representing the maximum Z-coordinate of obstacles in that cell. This segmentation transforms the continuous CAD model into a discrete height map, enabling faster comparison operations while maintaining sufficient accuracy for collision detection.
Solution Approach 2:
Instead of directly using complex CAD models for real-time interference checking, the patent creates a simplified height map copy of the obstacle geometry. This height map serves as a lightweight representation that can be rapidly queried during motion planning without the computational overhead of full CAD model processing.
2Productivity
If geometry primitives are used for interference checking, then computational speed is improved, but accuracy deteriorates due to approximation errors
Solution Approach 1:
The patent creates an exact height map representation of the obstacle geometry rather than using approximating geometry primitives. This height map copy preserves the true shape and dimensions of obstacles while enabling fast computational operations, eliminating the accuracy losses inherent in primitive-based approximations.
3Reliability
If complete CAD model interference checking is performed, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential height information from complete CAD models to create simplified height maps. This extraction process removes unnecessary geometric detail while retaining the critical Z-coordinate data needed for collision detection, thereby reducing system complexity without compromising detection reliability.
4Productivity
If real-time motion planning is implemented, then productivity is improved, but computational requirements increase
Solution Approach 1:
By segmenting the workspace into a grid and representing obstacles as height maps, the patent reduces the computational complexity of interference checking from O(n*m) for complete CAD models to O(1) for height map queries. This enables real-time motion planning with minimal computational power requirements.
Data Source
AI summary
An object interference checking technique using height maps, for machine tooling and other applications. A CAD model of a workpiece or other obstacle is converted to a height map defining obstacle height above a plane of a reference frame for each cell of a grid. A machine tool center point path is then transformed to the same reference frame. Interference checking is performed by comparing a height coordinate of each transformed tool path check point to the height map value for a corresponding grid cell. Any interference that is detected is addressed by defining new path points with increased height coordinate to replace the interference-critical path points. An entire tool can be interference checked by creating a bottom-up height map of the tool and comparing each pixel of the tool height map against the corresponding grid cell of the obstacle height map.