Magnetorheological fluid based force feedback performance for main manipulator of invasive surgical robot

In view of the lack of effective feedback function for the minimally invasive surgical robot at present, the design of force feedback device and verification of force feedback effect of the master manipulator are carried out, so that the operator of the master manipulator can obtain force feedback and improve the quality of surgery. A force feedback method based on the variable shear stress characteristics of magnetorheological fluid is proposed. The telecentric mechanism of the main manipulator end and the force feedback device are designed. And the relationship model of the output torque of the force feedback device, magnetic field intensity and angular velocity is established. The output characteristics of the device is analyzed by the experiment, and the linear relationship model between input current and output force of the force feedback device is obtained. The working performance of the force feedback device is tested by simulating the force conditions of surgical instruments in different cases of prostatectomy. The experimental results show that the delay of the force feedback device is 0.1-0.2 s, and the output performance of the force feedback device is related to the type and value of the applied force signal. When the input force signals are step signal, pulse signal and small range fluctuation signal, the average error of force feedback decreases with the increase of applied force. Analyzed from the experimental results, the overall force feedback effect of the force feedback device is well, which proves its feasibility and effectiveness in assisting doctors to carry out minimally invasive surgery.