The Design Of A Synthesis Testing System For Computer Adjustable Pressure Casting

On the basis of brief introduction about the technical procedure and requirements of adjustable pressure casting, this paper puts forwards a scheme on TY-2 adjustable pressure casting control system. In the system, the process of adjustable casting is controlled by using automatic control mode. The paper introduces the control process of the adjustable pressure casting system in detail. With regard to the distributed computer control system, the paper develops the software of the measuring computer which is programmed with a graphical programming language known as LabVIEW. The software consists of data acquisition program, curve input program, asynchronous serial communication program, pressure sensor calibrating program etc. All the functions of the software run well. The software also considers the fault operations to guarantee the safety and reliability of the system. In addition, hardware structure is designed according to the expected system functions. The paper also introduces the approaches on how to select, connect and test the data boards.After acquiring the rough model of the system by analyzing the work principle, the system gives the accurate mathematical models of the upper and lower systems by identification method—least squares estimation. Based on the existing PID controller, to deal with the disturbance of the input pressures and the coupling problem, a linear quadratic controller is designed. Since the changing rate of the pressures could not be measured, a state observer is designed and the compensator is constructed. Simulation results show that the outputs track the expecting input well. The system matches the requirements.In the last chapter, the problem of the fault detection and diagnosis for sensorfailures is studied. The fault tolerant control methods are also investigated.