Research On The Key Technology Of Micro Devices Finger Force Measuring System Based On Rope Tension

The force sense plays an important role in minimally invasive surgery, which could provide tissue stiffness and tumor location information for doctors, prevent excessive force causing damage to normal tissues, and help doctors make the appropriate force during some fine operations. However, the existing minimally invasive surgical robots could overcome many problems and provide a great help to the doctor in minimally invasive surgery. At the same time, the doctor has lost the interaction force information generated when the contact between the patient and the organization. The thesis mainly discusses the force detection of the micro mechanical finger; aims at exploring the micro mechanical finger force-measuring system based on the tension of the rope, thus providing force information for the surgical robot's force feedback system.Firstly, through the further research on the composition of micro devices finger force measuring system, the overall system scheme was established. The micro mechanical fingers,fingertip force loading platform, guide wire wheel mounting platform, sensors and motor mounting platform were designed respectively, and the mechanical body of force measuring system was established. The forward and inverse kinematics model of micro mechanical fingers was established based on D-H method. Then the simulation model was built with the Simulink toolbox of Matlab and verified the correctness of the forward and inverse kinematics model of the fingers.Secondly, the control system was designed based on the structure of "PC+ motion control card" upper and lower computer. We selected proper hardware and set up the control system of machine body. Based on the LabVIEW development environment, the software program of the control system was written to realize the data acquisition of the force measuring system and the function of the finger movement control.Thirdly, the prototype of the finger force-measuring system of micro instrument was developed. Based on the system, the zero drift experiment, return error experiment, and finger touch force detection experiment were completed. We obtained the touching force of micro mechanical finger in different positions and poses, the elongation of the motor and the tension of the wire rope who drives the fingers.,and the experimental data was normalized.Finally, based on the experimental data, we designed the neural network model of the force measuring system. Based on the improved BP and RBF algorithm, the neural network models were established respectively. Through analyzing and comparing ,we selected a more reasonable model to load into the working space of LabVIEW, and realized the on-line detection of the force measuring system.