A computational framework for the verification and synthesis of force-guided robotic assembly strategies

Abstract

Robotic assemblies are inherently hybrid systems. This paper pursues a class of multi-tiered peg-in-hole assemblies that we call peginmaze assemblies. These assemblies require a force-responsive, low-level controller governing physical contacts plus a decision-making, strategiclevel supervisor monitoring the overall progress. To capture this dichotomy we formulate hybrid automata, where each state represents a different force-controlled behavior and transitions between states encode the high-level strategy of the assembly. Each of these behaviors is set in 6-dimensional space, and each dimension is parameterized by spring and damper values (an impedance controller). Our over-arching goal is to produce a computational framework for the verification and synthesis of such force-guided robotic assembly strategies. We investigate the use of two general hybrid systems software tools (HyTech and CEtool) for the verification of these strategies. We describe a computational environment developed at Case to help automate their synthesis. The implementation of these strategies on actual robotic assemblies is also described.