Force-Based Interaction for Distributed Precision Assembly

This thesis documents the efforts to incorporate force sensing into the minifactory environment. The minifactory is a high-precision assembly system that makes use of low DOF robots to cooperatively perform higher DOF tasks. Minifactory targets the assembly of small mechatronic devices, many of which require high tolerance vertical insertion tasks. Force sensing provides a means for instantiating cooperative behaviors between robotic agents to perform such insertion tasks. Force sensing is a natural medium in which position and force information is acquired, allowing the compliancy needed to perform the task to be built into the behaviors of the robots performing the task. Integrating force sensing into the minifactory required that a custom force sensor be developed as well as control and communication systems to coordinate the action of two minifactory agents. Test results are presented from experiments in which two high-precision 2-DOF robotic agents cooperatively perform contact and “peg-in-hole” tasks. These results document the first experimental confirmation of high-bandwidth (> 100Hz) coordination between agents within the minifactory system. Thesis supervisor: Dr. Ralph Hollis Principal Research Scientist, Robotics Institute