Passivity-based control for haptic teleoperation of a legged manipulator in presence of time-delays

TL;DR

This paper presents a passivity-based control architecture for haptic teleoperation of legged robots, ensuring stability despite communication delays and frequency mismatches, demonstrated on a quadrupedal robot.

Contribution

It introduces a novel hybrid control scheme combining energy modulation and passivity constraints for stable teleoperation of multi-limbed robots with delays.

Findings

Stable teleoperation achieved despite network delays.

Effective hybrid control scheme demonstrated on quadrupedal robot.

Energy-based control methods ensure system passivity.

Abstract

When dealing with the haptic teleoperation of multi-limbed mobile manipulators, the problem of mitigating the destabilizing effects arising from the communication link between the haptic device and the remote robot has not been properly addressed. In this work, we propose a passive control architecture to haptically teleoperate a legged mobile manipulator, while remaining stable in the presence of time delays and frequency mismatches in the master and slave controllers. At the master side, a discrete-time energy modulation of the control input is proposed. At the slave side, passivity constraints are included in an optimization-based whole-body controller to satisfy the energy limitations. A hybrid teleoperation scheme allows the human operator to remotely operate the robot's end-effector while in stance mode, and its base velocity in locomotion mode. The resulting control architecture is demonstrated on a quadrupedal robot with an artificial delay added to the network.