Position Synchronization in Bilateral Teleoperation Under Time-Varying Communication Delays

Passivity-based approaches to bilateral teleoperation sacrifice performance to achieve robust stability against time-varying delays. Typically, force and velocity signals are exchanged in passivity-based bilateral teleoperation resulting in good velocity tracking, but may accrue a position drift. Recently, a power-based time domain passivity approach (TDPA) was proposed to passivate the communication channel in bilateral teleoperation with time-varying delays, which has the potential to be less conservative than other time-invariant passivity-based approaches. Several approaches have been proposed to address the problem of position drift in time-invariant passivity-based approaches to bilateral teleoperation, but the problem of position drift with power-based TDPA remains unsolved. We propose a feedback passivity-control-based scheme to achieve position synchronization in bilateral teleoperation with power-based TDPA. Our proposed method encodes position information with velocity to construct a composite signal, which is transmitted across the communication channel to attain position tracking. The proposed method utilizes time delay power network formulation, enabling extension to position-measured force bilateral teleoperation scheme. Simulations and experiments conducted on a custom one degree of freedom teleoperation setup demonstrate robust position tracking performance with our approach under time-varying communication delays and remote environment conditions.