Experimental Comparison Study of Control Architectures for Bilateral Teleoperators

A detailed experimental comparison study of several published algorithms for motion and force control of bilateral teleoperators, with emphasis on Internet-based teleoperation, is presented. The study investigates the effects of data losses, communication delays, and environmental constraints on a teleoperation system for different control techniques, which are based on wave variables, Smith predictors, and recent algorithms on synchronization. The controllers are compared on stability, transparency, and complexity using two identical nonlinear robots coupled via a stochastic network model that allowed transmission round-trip delays and data-loss rates to range from 8 to 1088 ms and 0% to 50%, respectively. A total of 18 subjects, which were distributed among 26 experiments with the aims of regulating the effects of the operators learning process and dynamic properties, participated in this study. Overall, the comparison study reports a deteriorating effect in the performance (i.e., larger position errors and lower fidelity of contact information) from delays and data losses. Yet, the effect of data losses is less critical when compared with time delays. In addition, the preference for a particular control framework is shown to strongly depend on the operational conditions of the system, such as the characteristics of the coupling channel, the specifics of the remote task, and the computational capabilities of the manipulators.