Design of the locomotion and docking system of the SwarmItFIX mobile fixture agent

The European project SwarmItFIX has developed a new highly adaptable self-reconfiguring fixturing system which uses a swarm of mobile agents moving freely on a bench and repositioning in real time to better support the machined part. The project investigates the application of robotic multi-agent fixtures for the support of automotive and airplane body panels during their manufacturing and assembly. Each fixturing robot comprises an adjustable end effector, a parallel manipulator, and a mobile-base-docking-bench module. This paper describes the base-bench subsystem which ensures rapid and precise locomotion, as well as secure docking, of the agent during the machining process. The design addresses with particular care the need for a reliable bench-robot coupling and interface as well as the requirement for robustness of the robot's displacements despite the predicaments of the machining environment, such as flying chips, accumulated swarf, spilled fluids, and vibrations. After a brief review of the state of the art, an overview of the whole project is given. Various candidate robot-base designs and locomotion methods are considered and compared. The final design, selected on the basis of the industrial requirements, is described in detail. A prototype of the SwarmItFIX system has been realized within the project and tested on the premises of an Italian aircraft manufacturer.