Transparency and stability analysis of a surgical teleoperator system

This paper discusses transparency and stability issues for a three channel teleoperator system to be used in sensitive skullbase operations. Based on a design model of the combined master human system with parameter uncertainties and teleoperator optimal transparency conditions, the interaction (communication) channel controllers are derived. One of the interaction channel controllers is then altered to make the teleoperator closed loop meet requirements imposed by the robustness property passivity. Transparency of the teleoperator system is analysed by analysing the gain plots of all the four transfer functions in the H-matrix. The three channel teleoperator is found to have a bandwidth of around 90 rad/sec in the force reflection channel, a small influence on the reflected force from the master velocity for low frequencies, a bandwidth of 150 rad/sec in the forward channel and a slave which is relatively unaffected by external forces. The theoretical results from the stability analysis are verified by experimental results.