Robust Sampled-Data Bilateral Teleoperation: Single-Rate and Multirate Stabilization

This paper investigates robust sampled-data control design strategies for nonlinear bilateral teleoperators exposed to communication constraints, using discrete-time approximate models of the master and slave robots and assuming both single-rate and multirate sampling. The single-rate design guarantees input-to-state stability of the (unknown) exact discrete-time model in a semiglobal practical sense, in spite of norm-bounded channel uncertainties. Then imposing different sampling rates on positions/velocities or torque inputs in each side of the system, a multirate scheme is proposed and shown to maintain similar stability properties under a well-known Nyquist frequency assumption on control torques. Simulation results verify the advantages of our direct sampled-data design. The example also shows that the multirate controller successfully stabilizes the teleoperation system even when the single-rate bilateral setup is ineffective in the presence of different sampling rates.