Hybrid sensorless bilateral teleoperation of two-wheel mobile manipulator with underactuated joint

Bilateral teleoperation is expected to be a key technology for the next generation of robots. Indeed, in many fields of operation, a master-slave system is needed to remotely perform tasks in unknown environments. However, most ground-based haptic devices show some limitations when exploring large workspaces with a high mobility slave robot. In order to address this issue, a hybrid control strategy, which integrates both position control and rate control of the slave manipulator, is proposed. The originality of the proposed approach lies in the combination of switching teleoperation strategy with sensorless force feedback realized by torque observers. Additionally, pitch angle torque observer (PATO) has been implemented to enable force estimation in the passive joint of the slave robot. Experimental results are provided to show the efficiency of the proposed control algorithm.