Machine Collision Monitoring Using Spline-Based Geometry Envelopes
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Solution Overview
Problem
Existing methods for collision detection in machines with multiple axes require a compromise between accuracy and computational effort, often resulting in inefficient collision monitoring due to the use of triangular networks or elementary geometric figures.
Innovation Solution
The use of two-dimensional splines defined by nodes, checkpoints, and weights for modeling machine surfaces, allowing for precise collision detection with reduced computational resources by determining envelopes that enclose machine elements, which are used to assess potential collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If triangular networks or elementary geometric figures are used for modeling machine elements, then the modeling can be performed with simpler computational methods, but the accuracy of collision detection deteriorates and false alarms increase
Solution Approach 1:
The patent changes the mathematical representation parameters from simple geometric figures (spheres, cuboids) or triangular networks to NURB surfaces defined by control points, weights, and basis functions. This parameter transformation enables exact representation of complex machine element geometries while maintaining computational efficiency through the mathematical properties of NURB surfaces, thereby resolving the contradiction between modeling ease and collision detection accuracy.
2Measurement precision
If higher accuracy modeling is implemented using triangular networks or detailed geometric figures, then collision detection precision improves, but computational effort and processing time increase disproportionately
Solution Approach 1:
The patent uses NURB surface representations that are already available from CAD models as exact copies of the machine element geometries. This eliminates the need for time-consuming triangular mesh generation or approximation by elementary geometric figures, achieving both high collision detection accuracy and fast processing by directly utilizing the existing precise digital models without additional computational overhead.
Solution Approach 2:
By transforming the geometric representation to NURB surfaces with their inherent mathematical continuity and exactness, the patent achieves high collision detection accuracy without requiring dense triangular meshes. The parametric nature of NURB surfaces allows efficient mathematical evaluation of surface positions and normals, maintaining high monitoring speed while improving collision detection precision.
3Reliability
If detailed geometric modeling is performed to reduce false alarms, then collision detection reliability improves, but storage requirements and computational resources increase
Solution Approach 1:
The patent transforms the geometric data representation to NURB surface parameters (control points, weights, knot vectors, basis functions) which provide exact mathematical definitions of machine element surfaces. This parametric representation achieves high collision detection reliability and false alarm reduction while requiring minimal storage space, as the entire complex surface geometry is defined by a compact set of mathematical parameters rather than numerous discrete triangular facets or detailed mesh data.
Data Source
AI summary
Elements of a machine are moved relative to one another along several axes. A monitoring device receives groups of position values of the axes which specify the relative position of the elements to one another. The surfaces and/or volumes of the elements taking up working space are determined therefrom. The monitoring device checks whether a collision risk between the elements exists. The monitoring device models at least parts of the surfaces of the elements with two-dimensional splines defined by nodes and checkpoints. The monitoring device further determines from the checkpoints of the splines for sections envelopes which envelop respective element in the respective section, and uses the respective envelope as a surface that is taken up by the respective element in the respective section. Boundary lines of faces of the envelopes are straight connecting lines of the checkpoints.