0 Preface
The aero engine is the core component of the aircraft and the source of power for the aircraft. The quality of aero engine maintenance directly affects the use of the aircraft, and even affects the flight safety of the aircraft. In order to ensure flight safety during the life of the aero engine, it is necessary to regularly test the aircraft engine according to regulations and check the performance of the engine. There is a pointer instrument in the cockpit of the aircraft that displays the test parameters, but the observation is inconvenient, the accuracy is not high, the human error is large, and the crew members reflect that when the engine is tested, a large number of parameters need to be recorded, especially when the engine is faulty. Analysis of the test drive data makes the test run time longer, and data recording, analysis and processing are very inconvenient. These shortcomings are very incompatible with the requirements of modern high-tech warfare, and cannot meet the maintenance requirements of the field. The test system parameter test system is based on PC104 bus technology, which can detect, display, store and print the main technical parameters of the engine test process in real time, so that the crew can accurately analyze, judge and eliminate engine failures, and improve engine reliability. At the same time, it can greatly shorten the maintenance time, save manpower and material resources, and make the engine maintenance more scientific and targeted.
1 Design foothold
1.1 Guaranteed reliability
System development always pays attention to its reliability and safety. For outsourcing equipment, it is proposed to the supplier that the supplied product must meet the reliability requirements of the GJB standard. The supplier provides complete product qualification certificates, use and maintenance instructions and other documentation materials, and signs a contract to ensure the reliability of the outsourcing equipment . The hardware and software design is carried out in strict accordance with the design specifications and reliability outline. The electromagnetic isolation sensor is used. The signal input and output of the sensor are isolated from the power supply. No circuit is added to the instrument on the aircraft. The original instrument can work normally. . When the system is connected to the aircraft, even if the tester does not work or does not work normally, the original instruments on the aircraft can work normally.
1.2 Ensure operability
In the development of the system, people-oriented design ideas are adopted, and the use requirements of the crew are fully taken into consideration. It has a high degree of intelligence, a good man-machine interface, simple operation, convenient use, and good operability.
1.3 Guarantee interchangeability
In the system design, the interchangeability of components is fully considered, and standard and versatile components are selected as much as possible. For military products, aviation products are used as much as possible to ensure that the equipment has good interchangeability and is convenient for maintenance by maintenance personnel.
1.4 Guaranteed accuracy
Guaranteeing accuracy is a design idea that has always been adhered to during the development of the system. The following methods are mainly adopted in the development: first, the use of high-precision sensors, so that the accuracy of the collected signals can meet the test requirements: second, the use of software filtering methods to filter out interference data To ensure the accuracy of the collected data; the third is to ensure the accuracy of the hardware design. The data collection does not affect the normal work of the sensors and instruments on the machine, and the collected data is true and accurate.
2 Features and functions
The aero-engine test parameter testing system is a device developed on the basis of reference to foreign ground testing equipment. It adopts PC104 bus industrial computer and EL screen display, so that the detection system has the characteristics of small size, light weight, easy to move, simple operation, high degree of automation, good reliability, rich display information, good human-machine interface, etc., and can fully detect the cockpit The displayed engine performance parameters are more accurate than the cockpit indicator.
System functions include: 1) Real-time detection and display of engine high and low pressure rotor speed, engine vibration speed, oil pressure, oil temperature, main and auxiliary oil passage fuel pressure and exhaust temperature: 2) real-time drawing of test curve; 3) Save the test parameter data; 4) After the test is completed, you can view the data of each parameter and the test curve during the test; 5) The tester communicates with the computer data, and the data of each parameter is transferred to the computer during the test, the crew can use the computer View the data of each parameter for analysis and troubleshooting.
3 Structural composition and working principle
The design idea of ​​the test parameter testing system is to use the aircraft's original sensors to achieve it without affecting the normal operation of the aircraft instruments and ensuring the safe and reliable operation of the engine. The work of the detection system does not affect the normal operation of the maintenance personnel. When in use, test the engine according to the ground detection engine program. This system includes various sensors, controllers, data acquisition cards, detection circuits, keyboards, power supplies, and display screens. The detection principle is shown in Figure 1.
During the test run, the high and low pressure rotor speed analog signals, vibration speed analog signals, oil pressure analog signals, oil temperature analog signals, and exhaust temperature analog signals output from the engine are derived from the aircraft's connection plug, and each parameter is passed through the detection circuit The isolated analog signal is converted into a DC voltage signal. The fuel pressure transmitters of the main and auxiliary oil passages are connected to the measuring joints on the main and auxiliary oil transfer rings of the fuel. The pressure transmitter senses the change of the oil pressure and outputs a DC voltage signal proportional to the fuel pressure of the main and auxiliary oil passages. These DC voltage signals are converted into digital quantities by the data acquisition card and sent to the controller, and the values ​​of each parameter are calculated by the program in the controller. The controller stores the detected data to the data memory through program control, and displays the test data and test curves of various parameters on the EL display.
The controller is the core part. The main function is to read the data corresponding to each parameter from the data acquisition card according to the user program. The actual value of each parameter is calculated and stored in the data memory; the EL flat panel display is used to display the man-machine Interactive interface, test data of various parameters, test curve, etc. It uses the embedded industrial computer of PC104 bus produced by Shengbo Technology Co., Ltd., with the model of SysCentreModule / SDXpn. The main technical data are: 1) embedded 486 processor, operating frequency 50MHz; 2) 16M bytes of RAM; 3) 1M video memory; 4) standard DMA, interrupt timing controller; 5) industry standard BIOS with expansion; 6) VGA supports monochrome LCD, EL display, and analog CkT; 7) supports DOC electronic disk; 8) power requirements: + 5V ± 5%, 0.8A; 10) working environment temperature: -40 ~ +80 .
The data acquisition card completes the collection of various parameters of analog signals. It uses the PC104 bus multifunctional data acquisition card PM511P produced by Beijing Zhongtai Research and Computing Technology Co., Ltd. It has 16 A / D conversion channels and 4 D / A channels. , 24 programmable switch input and output, 3 counting channels, and can work under the environmental conditions of -40 ~ +80 ℃. In addition, the acquisition card also completes the collection of keyboard signals.
The power supply is used to convert the 27V direct current of the airport into the + 5V, ± 12V, + 24V direct current required by the internal circuit of the system. Two DC-DC converters are used to convert the 27V direct current to PC104 and other electrical components + 12V, -12V, + 24V and + 5V DC power supply. It has high conversion accuracy and can work stably in the environment of -40 ～ 55 ℃.
The EL display screen is used to display the prompt characters during human-computer interaction, the data of each parameter detected, and the test curve, etc. The model used is EL640.480-AGI-ET. Its main technical parameters are: 1) Resolution: 640 & TImes; 480; 2) Size: 8.1 inches; 3) Power supply: 12V; 4) Working temperature: -40 ～ + 85 ℃.
The DOC electronic disk is used to save the parameter data detected during the test run, and is also used to store the operating system file of the controller and the control program file of the instrument. The capacity of DOC electronic disk is 128M. The keyboard uses a simple switch-type keyboard, and the keyboard signal is sent to the industrial computer of the PC104 bus through the data acquisition card.
The keyboard on the panel is used for human-computer interaction to input commands and data to the controller. It has 6 keys. A simple switch-type keyboard is selected. The keyboard signal is entered into the controller through the data acquisition card. The interface is simple, convenient and applicable.
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