Improving transparency in Time-Domain Passivity Approach based Bilateral Teleoperation


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. We developed a novel transparency compensation architecture using TDPA, employing virtual dependent energy sources which leverage the passivity margins allowed by the communication channel to inject energy and recover transparency without compromising system passivity. The proposed method is generalizable to all bilateral teleoperation architectures, and is robust against different communication delay and remote environment conditions. Experiments are conducted on a dual-Phantom teleoperation setup to validate the efficacy of the approach, and demonstrate position tracking and increased force reflection with up to 1000 ms round-trip delays in both free space motion and hard wall contact scenarios.