Adaptive Accommodation Control for Complex Assembly: Theory and Experiment

In this paper, an adaptive accommodation control for complex assembly is presented. The complex assembly (CA) is defined as a task whose wsembled parts have complex geome~ including concavity. The concept of the adaptive accommodation, which is inspired by the insertion operation of a blindfold human, is to adaptively change the accommodation property depending on the sensed contact wrench and the current target twist. Both the bounded wrench condition and the target approachability condition can be satisfied simultaneously by applying the adaptive accommodation control law. By using the convex optimization technique, an optimum target approaching twist with adaptive accommodation property can be determined at each instantaneous contact ~tate as a global minimum solution. Incorporated with an admissible perturbation method, a new adaptive accommodation control law, which is independent of part geomet~, is developed without motion planning nor contact analysis procedure. A VME-bus based real-time control system is built to experiment various CA tasks. Tinsertion task as a planar CA and double-peg assembly task as a spatial assembly were successfully executed by implementing the adaptive accommodation control law.