Control of bilateral teleoperators with time delays using only position measurements

A major drawback in the control of bilateral teleoperators is time delays. The nature of the communication channel that interconnects the local and the remote manipulators imposes these delays, which can be time‐varying. Several commercially available robots do not incorporate velocity sensors, and velocities are usually estimated using dirty derivatives. In this paper, we are interested in the control of bilateral teleoperators with variable time delays and without requiring velocity measurements. The proposal makes use of a second‐order dynamical controller that backpropagates damping to the local and the remote manipulators. If sufficient damping is injected in the controller and under the common passivity assumption of the human operator and the environment, it is proved that position errors and velocities are bounded. Invoking Barbalat's lemma, when the human and the environment do not inject forces in the system, it is shown that position error and velocities globally asymptotically converge to zero. A simulation comparison with other two control techniques shows the performance of the novel proposal. Experimental results evidence the robustness of the proposed scheme to interconnecting time delays.