Transparent master-slave teleoperation without force nor velocity measurements

A master-slave teleoperation system is considered. It is well-known that force feedback can enhance the teleoperation system performance as well as its transparency. Nevertheless, force sensors are not always available for a variety of reasons, e.g., space constraints, costs, weight. To overcome the lack of a force sensor, a state observer algorithm is proposed to estimate simultaneously the joint velocity and the external forces for both the master and the slave manipulators. These estimated signals are then employed in the design of a controller scheme. For the non-delayed case, the analysis of the controller in closed loop with the dynamics of the system guarantees ultimate boundedness of all the estimation and tracking errors as well as transparency. Experimental results are presented to validate the effectiveness of the proposed approach for both the non-delayed and delayed scenarios.