Bilateral Teleoperation Control for Improving Transparency in Stiff Environment with Time Delay

This paper proposes a new bilateral control scheme to ensure the both transparency and robust stability under unknown constant time delay in stiff environments. Presented method guaranties system performance and robust stability while the transition between soft and stiff environments occur. Presented framework is a combination of adaptive sliding mode controller and adaptive impedance controller, in which an online estimation of environment impedance is performed to be used as desired impedance in master side. Numerical simulations under different conditions such as constant and timevarying delays and obstructed environments are provided to verify the theoretical results. Transition between soft and stiff environments is also considered. Finally, the proposed method is compared with a recent work in this field.