Research On Force Detection And Force Feedback Control Of Minimally Invasive Robot Based On Force Observer

Minimally invasive surgical robot has the advantages of high flexibility,accurate positioning,smooth movement and hand-eye coordination,and many other advantages;however,the existing minimally invasive robot system is lack of force sensing and force feedback for the particularity of the minimally invasive surgery Aiming at the above mentioned problems,an external force observer was constructed to observe the interaction force between the slave and the environment on the analysis of existing force detection technology.Master-slave robust sliding mode controllers and a master-slave force feedback structure were designed to realize the force detection and force feedback control without a force/torque sensor,which lay the research foundation of master-slave motion and force feedback control without a force/torque sensor.The main research content of this thesis is as follows:Firstly,the kinematics of master-slave minimally invasive robot was analyzed based on the screw theory,and the dynamics model of the master-slave robot were established by combining the Lagrange dynamics modeling method.The correctness of the slave robot dynamics model was verified by the simulation of ADAMS and MATLAB.The master-slave minimally invasive robot dynamic model were simplified by analyzing the contribution of each term in the dynamics equation of the master-slave robot to the total torque.Secondly,to observe the interaction force between robot and environment,a nonlinear external force observer for the slave robot was put forward on analyzing the nonlinear disturbance observer,and the stability of the observer was also proved.The Stribeck model was adopted as the joint friction model of the slave robot.The friction parameters were identified by the genetic algorithms.To achieve accurate external force observation,the friction compensation was carried out in the external force observer of the slave robot.Thirdly,master-slave robust sliding mode controllers for minimally invasive surgical robot were designed,and a master-slave force feedback system was constructed.The effectiveness,accuracy and master-slave position tracking of the force feedback control system with or without friction compensation were verified by Simulink simulation.Finally,an experimental platform of master-slave minimally invasive robot was constructed.The experiments of the external observer and master-slave force feedback control were carried out.The results showed that the control system has better force feedback perfonnance,and could realize the external force observation and force feedback control without the force/torque sensor.