A Certain Type Of Variable Thrust Rocket Engine Control System Design

The design and realization of a variable thrust liquid rocket engine control system is present in this paper.Firstly, according to the traits of the variable thrust engine, the hardware of the control system is designed. Microprogrammed Control Unit and PSD831F2 are adopted to simplify the design of hardware, reduce the volume and improve the reliability of the system; the drive circuit of rapid switching between high voltage and low voltage is designed to shorten the deadzone of electromagnetic valve. Correspondingly, the precision of system is improved and the response time is shortened greatly.Secondly, The real time operation system uC/OS-II was transplanted to single-chip 80C196KC, then software structure becomes clear, stratified , easy for development and maintenance.Thirdly, the mathematical model of the system is founded with the practical data of water-experiment and fuel-experiment. To modeling the linear part of the system, the method of system identification and mechanism analysis are applied; To modeling the nonlinear part, nonlinear PWM process is linearized by equivalent-area method, so linear models of whole system in every condition are built. Dynamic and static characteristics are discussed in discrete domain with the predigested model.Finally, using rtwin of matlab ,semi-physical simulation system is built. To get better control objective, Self-tuning control method is proposed and validated by semi-physical test.The control system has been tested in water-experiment and fuel-experiment which proved the reliability of hardware and software. Theresult of simulation shows that the system model can present I/O characteristics of the real system accurately. The control law, which we designed , is satisfied with expected objective.