| Compared with traditional minimally invasive surgery,robotic minimally invasive surgery has demonstrated the advantages of relatively clearer field of vision,more precise operations,and relatively higher comfort for doctors.However,there are still some challenges in the development of robotic minimally invasive surgery: Commonly used minimally invasive surgical robots are mainly divided into two parts: the master hand and the slave hand.The slave hand includes a mirror arm and a mechanical arm.Among them,the holding arm needs to enter the human body,so it is faced with the problems of small operating space,high flexibility and precision requirements,etc.,and the use of steel wire cable for surgical instrument transmission can meet these requirements well.However,in the process of wire cable transmission,mechanical gap,friction between cable wheels and deformation of wire cable have all caused the phenomenon of lagging operation of surgical instruments,which has caused great interference to the clinical application of cable-driven surgical instruments.In order to solve the phenomenon of hysteresis in the transmission of surgical instruments,this paper has carried out research on the dynamic modeling of cable-driven surgical instruments and the identification and compensation control of hysteresis.In this paper,the existing cable-driven surgical instrument transmission model is used for modeling,and it is analyzed that the existence of friction between the cable wheels is an important cause of the hysteresis of surgical instruments.Therefore,this paper further analyzes the friction force model,obtains the factors affecting the friction force between the cable wheels,such as the wrap angle between the cable wheels,the rigidity of the wire cable,and the friction coefficient,and gives optimization guidance suggestions,and analyzes it according to the transmission process of the cable-driven surgical instrument.The current can be used as the basis for judging the hysteresis stage of surgical instruments.According to the analysis of the transmission process,the current can be used as a basis for judging whether the surgical instrument is in the hysteresis stage.And according to the characteristics of current in different hysteresis and non-hysteresis stages,the transmission process of surgical instruments is divided into three stages.Using the collected one-dimensional current data as a training set,a one-dimensional UNet learning network is established to learn the motor current characteristics,and the verification set is used to detect the accuracy of the hysteresis identification model.In order to more accurately compensate the amount of compensation into the motor,improve the accuracy of surgical instrument operation,and reduce the degree of jitterduring surgical instrument operation,this paper uses the idea of ??Probabilistic Movement Primitives(Pro MPs)to learn the hysteresis characteristics during the hysteresis of surgical instruments,and calculate the compensation displacement curve that should be performed under the premise of satisfying the expected displacement of surgical instruments,and compensate the compensation hysteresis curve to the motor.Finally,in order to verify the accuracy of the hysteresis identification algorithm,this paper first builds a motor simulation transfer model that meets the requirements according to the transfer model of the position loop and the speed loop in the motor transfer process,and compares it with the speed and displacement collected by the experiment to verify The accuracy of the simulation model.Then input the desired displacement that meets the actual demand to the simulation model to obtain the output displacement of the motor,then establish the hysteresis model according to the hysteresis characteristics of the surgical instrument,and substitute the output displacement of the motor as the hysteresis model input into the model to obtain the cable Drive the actual displacement curve of the surgical instrument.Finally,the compensation algorithm is used to learn the hysteresis characteristics of the actual surgical instrument and convert it into the corresponding compensation amount to the motor.The output displacement of the surgical instrument is obtained to verify the accuracy and effectiveness of the model and the hysteresis compensation control algorithm. |
