Development And Application Research Of A 6-DOF Virtual Laparoscopic Surgery Hand Controller

Virtual surgery is a new surgical training technique.With virtual surgery technology available,doctors can repeat surgical simulation training in a safe and realistic environment,getting familiar with the operation process and improving the operation ability quickly.Force feedback technology plays an important role in virtual surgery system during the humanmachine interaction.The application of force feedback hand controller enables doctors to fully feel the shape and structure of virtual human tissue,leading to higher sense of immersion and more authentic interaction.The operability and force sensing performance of the force feedback hand controller are closely related to the experience of virtual operation operators.Under the requirement of the simulation training in laparoscopic surgery,the paper conducts the research on force feedback hand controller.Firstly,the mechanical design of hand controller,and modeling and simulation of kinematics and gravity compensation algorithm are completed.Besides,dimension parameter optimization is achieved based on the operability and force output performance of the hand controller;then the prototype of the hand controller is produced and the original system integrated with hardware and software is built.Finally a series of prototype testing and interactive performance evaluation on the hand controller are applied.The main contents of this paper are as follows:(1)In view of the actual process of laparoscopic surgery,the design indicators and design principles of the hand controller are proposed to complete the overall mechanism design of the hand controller.The kinematics and gravity compensation algorithm of the hand controller are modeled,and the relationship between the required gravity compensation torque and the structural dimension parameters is studied.Furthermore,Adams is applied to establish the virtual prototype to simulate the kinematics and gravity compensation algorithm.The simulation results of Adams and the theoretical calculation results of MATLAB are compared to verify the accuracy of kinematics and gravity compensation algorithm.(2)The performance evaluation and dimension parameter optimization method of the hand controller are studied.The operability of the hand controller is analyzed based on the global dexterity index,and the calculation method of the maximum continuous output force of the hand controller considering gravity compensation is proposed.Multi-objective particle swarm optimization algorithm is used to optimize the dimension parameters of the hand controller,which improves the output performance of the hand controller while maintaining good operability.Based on the optimized dimension parameters,the physical model of the hand controller is built.(3)The original system of the hand controller is built,including the hardware system composed of the mechanical structure,controller,and power supply,etc,the debugging software of the upper computer for the device debugging and data communication of the hand controller,and the application example of cholecystectomy based on Unity3 D.The original system achieves pose acquisition,shear and contact force feedback,and other functions.(4)Prototype testing and interactive performance evaluation are conducted on the hand controller.Firstly,the output force measurement system integrating industrial robot and force sensor is built to realize the real-time acquisition of the terminal position and output force of the hand controller.The data acquisition and analysis results proved that the hand controller boasts a good effect of gravity compensation,and both the output force error and the maximum continuous output force in the actual force output performance meet the application requirements.In addition,an application example called ”Running Ring” is developed based on Unity3 D,and a comparison experiment is conducted between the hand controller and a training box equipped with a real surgical scissor.The good interactive performance of the hand controller is verified from the subjective evaluation of the testers and objective data analysis.