Force feedback control design for nonideal teleoperators

Achieving force feedback for a nonideal teleoperator is challenging, due to complications such as friction, force sensor noise, non-backdriveability and structural resonances. Furthermore, non-collocation of the force sensors and the point of interaction results in shunt dynamics that degrade the interaction force estimation. In this paper, a method is presented to model, identify and compensate for the influence of shunt dynamics. Furthermore, a recently developed two-layer approach that enforces passivity in the time domain is implemented and evaluated in a practical setup that is dedicated for application in surgery. Experiments demonstrate that using a combination of these techniques with an impedance reflecting controller, stable bilateral interaction with both soft and hard environments is achieved, for a nonideal system. A teleoperated robot for minimally invasive surgery is used as a representative example of a nonideal surgical system.