Coordination strategy for a system of manipulators coupled via a flexible object

This paper presents a control strategy for N robot arms cooperating through a flexible object. The dynamic equations of the system under consideration are described, with position and force parameters being considered in an extended 6N-dimensional space. The control strategy is based on the decomposition of the position and the force parameters. The strategy includes feedforward and feedback levels, which take into account the object compliance. The force and the moments applied to the object by manipulators as well as the end-point accelerations are considered to be the control inputs for the Cartesian-level control system. The feedback level includes the nonlinear decoupling control law to ensure the tracking of the object trajectories in the position and the force spaces. To damp out the object oscillations, an additional control input, which is added to the prespecified internal forces, is introduced. The applicability of the control strategy is tested under a case study.