| Severe urinary incontinence caused by urethral sphincter dysfunction is not only bringing serious trouble to patients in social life but also leading to urinary tract infections and other complications, which affects the quality of patient’s seriously. The disease is likely to occur in different age and gender, and hardly cured by drugs or surgery, so it is fairly important to take measures to control the urethra open and closed autonomously. In order to solve this kind of severe urinary incontinence, a urethral valve driven by ultrasonic-vaporized steam is designed in this paper, the mathematic model of urethral valve is built, the reliability simulation algorithm of urethral valve is proposed, and the performance and reliability of urethral valve are studied. Then, the urethral valve applied to the urination assist system driven by ultrasonic-vaporized steam is studied by experiment. The specific contents are as follows:Based on the theories of ultrasonics, thermodynamics and magnetism, the mathematic models of driving force and magnetic force are built. The simulated experimental system is designed and built, and the effectiveness of the mathematic models of driving force and magnetic force is verified by experiment.The effect of ultrasonic control parameter and structural parameter of urethral valve on driving performance is analyzed by simulation in the Matlab based on the mathematic model of driving force, and the effect of ultrasonic control parameter on driving performance is studied by experiment. The opening/closing condition is established based on the working principle of urethral valve, and the opening/closing performance is verified by experiment.The reliability of urethral valve is analyzed using the fault tree analysis. Based on the combination of fault tree analysis and Monte Carlo method, the reliability simulation algorithm of urethral valve is proposed. The reliability index of urethral valve is calculated by simulation, and the validity of reliability simulation algorithm is verified by theoretical arithmetic.Based on the composition principle of urination assist system driven by ultrasonic-vaporized steam, the application program of urethral valve is designed. The effect of urethral valve on the urine flow function of urination assist system is studied by experiment.The research results show that: the principle of urethral valve is feasible, the opening/closing performance of urethral valve is good, the mathematical model and the reliability simulation algorithm of urethral valve are simple and effective; the driving performance of urethral valve is improved by increasing ultrasonic control parameter; the corrosion and aging of driving bags are the weak links of urethral valve, and the reliability reaches 0.85 when the average life of urethral valve is 50000 times. The findings can provide the basis for optimizing the structure of urethral valve and improving the reliability of urethral valve, and provide a new solution for the urine flow of urination assist system. |
