On the Dynamics and Control of Flexible Multibody Systems with Closed Loops

Abstract

The motion control problem for cooperating flexible robot arms manipulating a large rigid payload is considered. An output that depends on the payload position and contributions from the joint motion of each arm is constructed whose rate yields the passivity property with respect to a special input. The input is a combination of the torques from each arm and contains a free load-sharing parameter. The passivity property is shown to depend on the payload mass properties, and in cases where the payload is large, a passivity-based controller combining feedforward and feedback as elements is devised, which yields tracking. An experimental facility consisting of two planar 3-DoF arms is used to implement the strategies. Good tracking is observed and compared with simulation predictions for closed-loop flexible multibody systems.