Path planning for robotized mobile supports

• A fixturing system for supporting large flexible workpieces.
• A method of planning head, manipulator and mobile base motions.
• Initial experimental results of the operation of the system and the planner.

The paper presents a method of placement and relocation of the movable components of a self-reconfigurable robotic fixture system. The system consists of a set of mobile platforms carrying parallel type manipulators equipped with deformable heads. The heads support large flexible workpieces during machining. The machined workpieces have complex spatial geometry. Drilling requires the static placement of supporting robots at each drilling position, while milling necessitates their continuous relocation during machining. The paper reference case is a milling operation on thin sheets supported by two mobile robots. The two heads consecutively relocate and affix themselves to the supported thin metal sheet, so that one of them supports the workpiece while the other relocates itself in such a way as to precede the working tool. This task requires the adequate positioning of the heads in order to follow the workpiece geometry simultaneously providing stable support. Mobile base motion plan and sequences of manipulator postures assure the required real-time positioning of the heads. As the tool proceeds along the required path with the velocity dictated by the machining procedures the relocation of supports is critical. The presented method was successfully applied and tested in an industrial environment.