Bilateral telemanipulation: Improving the complementarity of the frequency- and time-domain passivity approaches

Passivity of bilateral telemanipulation systems ensures stability of the interaction with such systems. In the frequency domain, passivity of a linear time invariant approximation of the system can be designed for a considered set of operating conditions. Non-linear control structures have been proposed that enforce passivity of the system in the time domain. In this paper, extensions are proposed that increase the complimentarity of the frequency- and time domain approaches. The combination of both approaches allows a guaranteed measure of transparency to be designed in the frequency domain for a desired set of operating conditions. For operating conditions outside the desired set, stable interaction is guaranteed by the non-linear passivity enforcing control structure. Simulation results of the combined approach are presented that show that the stability properties of the bilateral controller designed in the frequency domain are improved and the transparency properties are improved with respect to those of the standard passivity-enforcing algorithm in the time domain.