The Effect of Interaction Force Estimation on Performance in Bilateral Teleoperation

Measuring interaction forces in bilateral teleoperation systems may be difficult, due to size and cost restrictions on the force sensors. Obtaining the interaction forces by estimation can be a viable alternative. The primary contribution of this paper is the study of the effect of interaction force estimation on performance in bilateral teleoperation. A distinction is made between the obvious effect as a result of inaccurate estimation, and the less obvious effect as a result of the inherent theoretical properties of a system that has two points of interaction with its surroundings (a teleoperator) as opposed to one point of interaction (single robot). Specifically, the existence of a singularity property is pointed out, at which interaction force estimation is impossible, and close to which it may be infeasible. The secondary contribution of the paper is the Force Sensor Free (FSF) transformation for linear teleoperation systems, which is an automated procedure that turns a teleoperation controller with force sensing into an equivalent controller with force estimation. An experiment is reported whose objective is to validate the operation of the FSF transformation on a real teleoperator.