Simulation Research On Bilateral Teleoperation System For Remote Ultrasound

Since the bilateral teleoperation system was proposed,due to its ability to overcome the obstacles of space distance,it has been applied in many fields,such as medical treatment,industry,space exploration,deep-sea operations,etc.However,due to the time delay in the bilateral teleoperation system,the system is unstable and affects its tracking performance.Therefore,over the years,researchers have never stopped researching bilateral teleoperatinon systems,and many methods have been developed to improve the stability and transparency of the system.In this paper,based on the medical application of bilateral teleoperation system,the improvement of the transparency of bilateral teleoperation system is studied,and the effectiveness of the proposed method is considered when the slave environment is a human organ with half-period motion.The contributions of thesis are as follows:(1)Summarize the basic theory of bilateral teleoperation system,including existing system modeling methods,analysis methods of stability and transparency,control structure of bilateral teleoperation system(two-channel structure,three-channel structure and four-channel structure)and Classical delay compensation algorithms(wave variable and their related algorithms and time-domain passive algorithms).On this basis,the wave variable algorithm and three-channel control structure are selected for improvement.(2)A wave variable compensation structure based on a three-channel control structure is studied.Two compensation terms are introduced on the basis of the traditional wave variable method to compensate the bias term in the traditional wave variable algorithm and improve the tracking performance of the system.In addition,in order to maintain the passivity of the system,two energy resevior are introduced into the system.Finally,it is verified through simulation experiments that the wave variable compensation structure with energy resevior can compensate for the constant time delay existing in the communication channel of the system.At the same time,it ensures the stability of the system and improves the transparency of the system.(3)Considering the influence of periodic or quasi-periodic motion disturbance on the tracking performance of the bilateral teleoperation system caused by the physiological movement of viscera such as respiration and heartbeat on the patient's body surface in the process of remote ultrasonic diagnosis,the heart movement which is difficult to compensate in quasi-periodic motion disturbance was selected to compensate.At the same time,it also proves the feasibility of the compensation method under the interference of other human surface motion.The cardiac motion modeling was carried out,a motion compensation system was built,and a dual Kalman filter was used to compensate the noise and time delay in the measured cardiac data.Finally,it is verified by simulation experiments that when the environment is a beating heart,the wave variable compensation structure with energy resevior can also achieve the optimal tracking performance and ensure stability by the motion compensation of dual Kalman filtering.