Reliability Analysis Of Injection System Of Chemotherapy Pharmacy Robotand Control System Design

In the field of chemotherapy medicine preparation, there are two serious problems that need to be considered: safety of the operators and the precise preparation of medicine. Because of the disadvantages of low precision and lack of protective measures for operators, the traditional and artificial method for preparation is being replaced by PIVAS(Pharmacy Intravenous Admixture Services) gradually. With the unified management and centralized distribution for the intravenous drugs, PIVAS can effectively reduce the medication risk factors. However, the injury from chemotherapy drugs to the operator still exists in it. As a kind of medical products for automatic preparation of chemotherapy drugs, chemotherapy pharmacy robot can improve the precision and efficiency of dispensing, and liberate the medical staff from the heavy and dangerous work to improve the quality of treatment for patients, which provides a new way for the preparation of chemotherapy drugs. The chemotherapy pharmacy robot has already been applied in the clinical field in Europe and America, but studies in our country are few. In this paper, the reliability of injection system and the control system of chemotherapy pharmacy robot have been studied and the main contents are as follows:For the drug injection system is one of the key processes of the preparation, its reliability was analyzed. Considering the uncertain of failure mechanism, the uncertain of failure probability of components and the uncertainty of failure state of components when assessing the reliability of the complex electromechanical system, reliability assessment method based on T-S fuzzy fault tree and Bayesian network was used to assess the drug injection system to obtain the system failure probability, the probability importances of components and the posterior probabilities. According to the results, the weak links of the system were obtained.According to the requirement of reliability, the weak links were further analyzed and the design requirements were given. Based on the design requirements, the overall scheme of the control system was developed. The realization of the dispensing function depends on the coordinated action of each function module. According to the different actions corresponding to different function modules, specific performance indicators were proposed, and the overall scheme of the control system was developed by applying the idea of layered design. Furthermore, the dispensing process was planned to guide the design of software.According to the overall scheme of the control system, the hardware system and software system were designed in detail. Hardware design includes controller architecture design, component selection and motor drive circuit design, while software system can be divided into three layers: application layer, user driven layer and board support package. The weak links of the system(a core rod driver and a core rod gripper) should be considered especially in the detailed design of hardware and software. The motor driver or driver chip selected should be reliable and in order to realize linear reciprocating motion of the syringe core rod driver and clamp and release of syringe core rod gripper, the frequency control algorithm for step motor and motion control algorithm for DC motor were studied.Finally, according to the control system design, the experiment platform was built, and an experiment of precision of drug delivery process and an experiment of drug preparation were curried out to verify the performance of the control system.