Research And Realization Of An Network Based Measurement And Control System For Liquid Rocket Engine Test

In the traditional measurement and control system for the liquid rocket engine test,there are some problems as following, the extreme requirement of reliability for themainframe and the embedded card, the list orders lapse causing the test failure, thelong spread cable leading to the signal reduction, the disturbance from EMI and theother electric source, the difficult share between the system status and the test data, theextensive fee of system for the initial installment and maintain. The establishment ofthe modern network of measurement and control system is the development directionfor the resolution of the above problems in the system, and provides the technicalfoundation for the long distance expert diagnosis in the future liquid rocket engine test.The research concluding the constitution and realization of the networkmeasurement and control system is the topic of this paper. The detail analysis from thetraditional measurement and control system to the modern network structure, thediscussion of the clock synchronous method based on the network measurement andcontrol system by adopting the system accurate clock synchronous negotiation of IEEE1588 network real time system and the synchronous performance of the each devicemodular in the system are presented in the paper.According to the modular composition and the characteristics of the sensor andcontroller used in the liquid rocket engine test, the analysis is performed to input andoutput channel of the measurement and control, designed the pre-amplifier and filerwith the multi adjustable constant voltage source and current source and the powerinterface of the switch passage amount upon the different controlled requirement. Withrespect to the development direction of the imbedded controller and the performancerequirement of the micro-control board, the ARM microprocessor and the developmenttemplate are applied in the system. The explanation about the new type of intelligenceexecutor and transducer also is in the paper.Based on the real time operational system of the target machine, theμC/OS-Ⅱistransplanted to the new system, and programmed the driving procedure ofμC/OS-Ⅱto the Ethernet according the characteristics of network controller. The program ofacquisition and control is built in the embedded operational system in the measurementand control module. The development of closed loop regulated PID procedure for thetank pressure is based on the algorithm of fuzzy controller and the variable tankpressure in the rocket engine test. On analysis of the mode of the host machine and themechanism of the server, the configure program of host machine to measure andcontrol target machine passage is designed. According to the way of the data exchangeof target machine, the procedure of communication and display for host machine dataalso designed.