Multisensor fusion for operational space control of single and dual arm robots

Operational space impedance control proved to be an efficient way to achieve robot trajectory generation and obstacle avoidance. The implementation of the impedance controller requires exact linearization in operational space which is achieved by a computed torque approach. One of the limits of computed torque schemes is due to the presence of unknown dynamics, such as dry friction. In order to account for unknown and unmodelled dynamics terms, a perturbation observer has been added to the impedance controller to improve its performance. In the paper a perturbation observer has been used in one case to obtain the complete linearization torque and in another case to obtain only the compensating torque for unmodelled dynamic terms. Operational space control was verified experimentally using outputs from joint resolvers and linear accelerometers for a data fusion scheme. The solutions proposed were tested experimentally for single and dual-arm robots.