Proposal for Automated Generation of Collision Spheres for Robotic Arms #80
Description
Here's a proposal for automatically generating collision spheres for robotic arms:
The approach would involve reading both URDF files (to extract link structure and hierarchy) and corresponding STL model files (to obtain detailed geometric information of each link). For each link, the vertices of the triangular faces in the STL model would be extracted to form a point cloud, representing the 3D shape of that link.
To approximate the link's geometry, a cylinder-fitting algorithm (such as one leveraging PCA for axis alignment) could be applied to the point cloud. This would help determine the primary axis and extent of the link. However, it’s important to note that the accuracy of this step may be influenced by the mesh resolution of the STL model—coarser meshes might lead to less precise centroid calculations, potentially affecting the fit.
Building on this cylinder approximation, a custom program could then automatically generate a set of collision spheres tailored to envelope the link. These spheres would be optimized to balance coverage (ensuring all critical areas of the link are protected) and computational efficiency (minimizing the number of spheres for faster collision checks).
The generated sphere parameters (e.g., center coordinates, radii) could then be exported as a configuration file (e.g., YAML) for direct integration with path planning software, eliminating the need for manual sphere definition.