Design And Implementation Of Negative Pressure Control System Based On IPC

Oxygen monitor is one of the key equipment in the airborne oxygen system. Its stability and reliability is very important. And it has great influence on the physiological safety of the pilot. So it needs to be tested strictly before using it. And the primary method of testing oxygen monitor is manual testing with low efficiency and low accuracy and low real-time and so on. This method is more and more difficult to meet the requirements of oxygen monitor batch production test. With the rapid development of automatic control technology, automated production and testing of aviation equipment has made great progress. Testing of oxygen monitors is moving toward automation. In this dissertation,taking a type of oxygen monitor as an object, a kind of negative pressure control system is designed with the IPC used as the control core, which can provide the simulated high altitude environment for the automatic test of oxygen monitor.Firstly, the main technology and related theories in the field of automatic control are analyzed On this basis, combined with the design requirements of the pressure control system,the design scheme of the overall system is put forward. The system is made up of hardware and software. The hardware part mainly includes the pneumatic control system.The software is mainly composed of man-machine interface and the design and implementation of control program.Secondly,the software and hardware are designed in detail,according to the design requirements of system. In the hardware design of the system, a negative pressure chamber which can accurately and quickly simulate the negative pressure environment of the aircraft is designed based on IPC used as the control core and high speed on-off valve worked on PWM. The vacuum pump and high-speed on-off valve are used as negative pressure chamber pressure regulation tools. At the same time high precision pressure sensor and pressure flow sensor are used to coordinating fine adjustment pressure. And the high speed on-off valve based on L298N module drive circuit, power supply circuit,data acquisition circuit are designed. Accurate control of air pressure is the key point of system design. And the control algorithm is realized by software programming. Then,based on C# programming language, the system control software is developed in Windows system. The software includes front-end user interface, back-end data acquisition and processing and analysis,system control and data storage database. In addition to providing control engineering display of the control process, the software also provides the user's operating function, and has good scalability.Finally,a large number of comparative test results show that the negative pressure control system can quickly and accurately simulate the high-altitude negative pressure environment. And it's efficient, reliable, automatic and satisfies to the requirement of testing oxygen monitor. At present, the negative pressure control system has been applied to oxygen monitor automatic test platform.