Tracking Control For Cardiac Surgery Slave Robots

The surgery assisted robotic tool helps the surgeon to cancel the relative motion between the beating heart and robotic tool, keeping the heart beating during the surgery, which will lessen post surgery complications for patients. In this dissertation, some control algorithms be designed to control surgical robot tracking beating heart motion fast and accurate for the highly irregular and non-stationary nature of heart motion, cancelling the relative motion between heart and robotic tool.A characteristic analysis of 3D heart motion data through spectral tool is used to demonstrate the quasi-periodicity of coupling between respiration and heartbeat in heart motion, then a time-varying double Fourier series based recursive least square with forgetting factor algorithm is proposed to establish the heart beat motion model. The nonlinear model would accurately describe the heart motion and the recursive least square algorithm would satisfy the real time needs.Analyzing the workspace, kinematics and dynamics for the slave force feedback surgical robot PHANTo M. Due to the cardiac beating in a small space, the PHANTo M’s linear model will be obtained through approximate linearization method.There are four kind of control algorithms are proposed and simulated on Matlab for time-varying cardiac signal. In order to ensure the control system tracking real-time, we need optimal programming algorithm and shorten the run time of Matlab program.Creating a virtual environment to simulate the actual heart based on Quick Haptics toolkit of sensable technologies, then implementing tracking control experiment on PHANTo M for the PD plus, computed torque, saturated and optimal control algorithm.The comparative simulation and experiment results indicate that the optimal tracking control algorithm outperforms the other three algorithms for the small range cardiac signal.