The workability of sliding perturbation observer as haptic signal at the surgical robot instrument

In spite of the nonlinear characteristic of cable pulley mechanism, surgical robot has adopted it for safety. The sliding mode control with sliding perturbation observer has been applied to surgical robot instrument because of the robustness of the control algorithm. In the previous study, it was found that the output of perturbation observer followed disturbance such as loaded on the tip very similarly. Thus, this paper confirms that the perturbation observer in SMCPSO controller is sufficient estimator which finds out the mount of loaded force on the robot end-effect. To prove the proposition, the dynamic of surgical robot instrument will be analyzed, and used to make simulation test which shows that the observer could overcome the nonlinearity in the system. The simulation results show that the sliding perturbation observer can substitute for tactile force sensor to build haptic system. It means that the perturbation observer contributes to build sensorless surgical robot haptic system.