Remote haptic sensing using sliding-mode assist disturbance observer as force detector

Bilateral controlled master-slave robot system is an important intermediary to realise remote haptic sensing. This study proposes a sliding-mode assist disturbance observer (SMADO) to detect force information in wider bandwidth without force sensors by making use of the fast switching of sliding-mode control values. Moreover, a bilateral control law is proposed based on the SMADO. The proposal tolerates the presence of disturbances and uncertainties in the robots. The influence of these factors is degraded by using the net forces to design the bilateral control rather than employing a robust compensation. This design shows such a feasibility that high performance haptic sensing can be achieved using the SMADO as a wide bandwidth force detector without any robust compensators. The validity of the proposal is confirmed by experiments in practice. The proposal realises the position tracking and action-reaction law between the two robots, which makes the operator vividly feel the remote object.