In this article, a novel wideband circularly polarized (CP) square-slot antenna with perturbation elements is proposed. The antenna comprises of an inverted L-shaped feeding line, pairs of corner cuts, a rectangular slot, and a semielliptical patch. The numerous CP resonant modes were excited simultaneously using these slots and patches as perturbation elements. To verify this concept, an antenna prototype was built and tested. The measured results indicate the À10-dB impedance bandwidth (IBW) is 69. 3.7 GHz) and 3-dB axial ratio bandwidth (ARBW) is 59% (2.58-4.74, 3.66 GHz). Furthermore, the measured peak gain is 4.3 dBi, and the gain variation within the certain bandwidth is less than 1 dB. Therefore, the presented antenna features wide CPBW and stable gain characteristics.
Aiming at the problem that the traditional industrial robot may interfere with the workpiece when running in the offline simulation environment, a hybrid bounding box algorithm based on octree is proposed. First, AABB is used for rough interference checks, which quickly eliminates the pairs of impossible objects to intersect, then OBB hierarchical bounding box is used for precise interference checks. A new OBB construction method is proposed, which recalculates the semi-axis length and centre of the constructed traditional OBB to make it surround the object as much as possible and reduce the space gap. A traversal method based on distance priority is proposed, which traversed the closest node every time by maintaining a priority queue. And in the update strategy, “update on demand” is adopted, which discards updating the entire tree before each intersection and only updates the current node during the intersection traversal to achieve the purpose of partial update. Experiments show that the proposed hybrid bounding box algorithm can detect interference faster and perform better real-time performance and accuracy.
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