Stability is the most important requirement for bilateral teleoperation, and time-varying delays inherent in the communication channel have a strong destabilizing effect. Time invariant passivity based approaches have been proposed to stabilize teleoperation with constant communication delays. However they dissipate energy considering the worst case scenario and result in a significant position drift between master and slave robots.

Passivity based approaches to bilateral teleoperation control ensure robust stability against disruptive effects of communication delays and achieve velocity tracking, but severely compromise on position tracking and force reflection capability of the telerobotic system. Recently, the Time Domain Passivity Approach (TDPA) has been gaining interest in field of bilateral teleoperation due to its simplicity, ease of implementation, robustness to communication delays, and adaptive control design which promises less conservatism.