A cooperative robotic system for handling a geometrically unknown object for non-rigid contact without force sensors

This paper presents a new approach to control a cooperative telerobotic system consisting three slave robots for grasping and handling of an object with unknown geometry and center of mass. A phantom Omni desktop robot is used as a master robot. The contact points between slave robots and the grasped object are non-rigid. It means that rotation in contact points is permitted. Slave robots and the grasped object form a closed kinematic chain with non-actuated joints. This paper proposes a new approach to control the system copping with the non-actuated joints. The dynamic equations of cooperative system are transformed from the joint space into the object space. The slaves dynamic passively decomposed into a locked and a shaped system. The locked system and the shaped system are controlled by two PD controllers. Simulation results show that the position of the slave system that is modeled in Matlab, converges to the position of the real Phantom Omni given by an operator.