Time delay compensation by fuzzy control in the case of master-slave telesurgery

Telesurgery means the remote application of interventional medical techniques; a concept that is currently widely practiced around the world for short distance through master-slave robot systems. The concept has the potential to service long distance telesurgery as well. However, this requires the effective handling of communication latency. The current paper suggests a fuzzy control solution for telesurgical applications aiming at the alleviation of the disturbing effects of large latencies with the concept of remote surgical robotics. The fuzzy control solution is supported by a cascade control system structure with two proportional-integral-derivative (PID) controllers in the inner and outer control loops and designed by Kessler´s Extended Symmetrical Optimum empirical criteria. The PID controller in the outer loop is next replaced by Takagi-Sugeno-Kong PID-fuzzy controllers which combine several separately designed PID controllers. The combination of separately designed PID controllers and the modal equivalence principle are expressed as a design and tuning method of the Tagaki-Sugeno-Kong PID-fuzzy controllers.