Robust cooperative control systems for multiple manipulators in the presence of external force

This paper describes robust cooperative motion control systems based on workspace and joint space disturbance observers for multiple manipulators. In the modeling phase, the workspace disturbance observer based system uses a standard diagonal mass matrix while the joint space disturbance observer based system utilizes a diagonal nominal inertia matrix which results in the acceletation based motion control which means that both approaches provide a simple, flexible and robust cooperative motion control schemes. The effectiveness of the proposed systems is verified by several experimental results using two units SCARA manipulators grasping an object and moving the object according to the desired trajectory in free motion condition as well as in the existence of external interaction force.