Research On The Reliability Of Transmission System In Minimally Invasive Surgical Robot Based On Fault Correlation

Because of the advantages of robot surgery,including minimal wound,fast postoperative recovery,high operation accuracy,and surgeons are not easy to fatigue,minimally invasive surgery robot is widely used in clinical surgery.However,once there is a fault in the operation process of the surgical robot,it will directly endanger the life safety of patients.Therefore,it is necessary to study the reliability of the surgical robot system.In this paper,aiming at the faults of the minimally invasive surgery robot mechanical system,the reliability of the system are analyzed,,the reliability simulation and test of the key parts are carried out,and the service life of the key parts is estimated.Details are as follows.First,the faults of surgical robot system are counted,the system level is divided,the corresponding relationship of function and structure is found,the fault reason,failure mode,global effect,severity and detection mode are analyzed and counted,and failure modes and effects analysis table is established.According to the relationship between the system faults,the fault tree of the master manipulator and the slave manipulator is constructed.Second,according to the working condition of arm wire rope,the reliability test device of mobile arm wire rope is designed,the accelerated life test of wire rope is carried out,and the three pulley mechanical sensor is used to measure the tension change of wire rope in real time.Based on the experimental results,the meantime to failure of the wire rope is calculated.It is found that the wire rope is easy to wear at the contact position with the pulley.The wear process of the wire rope is observed with a microscope,and the failure reason of the wire rope is analyzed.According to the experimental data,the maximum likelihood method is used to estimate the life distribution model of the steel wire rope,and the goodness of fit test is carried out for the model.The life distribution model of the steel wire rope is determined to be a threeparameter Weibull distribution.The reliability curve and cumulative fault distribution curve of steel wire rope are drawn.Using Py Qt,a life prediction software for key parts of surgical robot is developed.The input service time can calculate the failure probability and help engineers estimate the service life of key parts.Finally,according to the configuration of the arm,the kinematic model of the arm is established,the cause of joint gap and the gap model are analyzed,the reliability index of motion accuracy is given,and the influence of joint rotation on reliability is analyzed by Monte Carlo simulation.