A passive bilateral control scheme for a teleoperator with time-varying communication delay

In this paper, a passive bilateral control scheme is proposed for a teleoperator with time-varying communication delay. Recently proposed two-port time-domain passivity approach (TDPA), which composed of Passivity Observer (PO) and Passivity Controller (PC), is extended. A set of sufficient conditions is derived, which satisfies the passivity of the two-port delayed network system, by separating the input and output energy at each port. This condition satisfies the passivity of the network system independent of the amount of delay, its variation and lost packet. Two PCs are designed at each port based on its causality to guarantee the passivity condition. In order to filter out the sudden force change of the PC, a passive virtual dynamic system, composed of virtual mass and spring, is inserted between the master and the PC. Even under a large time-delay with variation and communication blackout, the proposed approach can guarantee passive bilateral teleoperation.