Dynamic testing system of the hottest servo mechan

2022-08-11
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The dynamic test system of servo mechanism

[editor's note] the programmable missile servo mechanism simulator is designed based on the principle of various types of missile servo mechanism. Its purpose is to facilitate the training and operation of soldiers, and also to verify the work of servo mechanism and the correctness of servo mechanism test software. In actual use, it can also provide reference for servo mechanism design, and improve the design water level. Combined with virtual testing and fault diagnosis expert system, the simulator can be tested and the fault location can be diagnosed, and the fault can be located to the smallest replaceable unit

with the demand of military reform for weapon system, the equipment structure of modern weapon system is more and more complex, the function is more and more perfect, the degree of automation is higher and higher, and the performance of weapon system has been greatly improved [4]. However, it also brings many problems to the testing and fault maintenance of weapon systems, such as longer testing time, increased use and maintenance costs, making it more difficult for grass-roots soldiers to operate and maintain

the programmable missile servo mechanism simulator is designed based on the principle of various types of missile servo mechanism. The purpose is to facilitate the training and operation of soldiers, and also to verify the work of the servo mechanism and the correctness of the servo mechanism test software. In practical use, it can also provide reference for servo mechanism design and improve the design level. Combined with virtual testing and fault diagnosis expert system, the simulator can be tested and the fault location can be diagnosed, and the fault can be located to the smallest replaceable unit

I. system composition

the whole system consists of two parts. The hardware consists of missile servo mechanism simulator, signal conditioning module, VXI Test System and measurement and control computer, and the software includes simulator parameter setting software, test diagnosis software and data print out software. First, use the simulator setting software to set the parameters of the servo mechanism simulator, then test the simulator through VXI instrument, output the test results synchronously, and display the fault location and cause on another display at the same time. The system is shown in Figure 1

first, it is necessary to debug the parameters of the servo mechanism simulator. By setting different parameters, the simulator can simulate many types of servo mechanisms. For a specific model, you can first input the standard parameters, and then adjust the simulator hardware by comparing the output and input parameters to ensure that the simulator truly reflects the objects that need to be simulated

the control computer sets the simulator to a certain state through the simulator parameter setting software. The simulator setting software provides two ways to communicate with the simulator: Digital IO interface and LPT interface. When setting a certain type of servo mechanism, the software also provides the standard parameters of the model and customizable fault parameter settings. After setting the parameters, the software electromechanical power-off will input the set parameters to the simulator according to the current temperature and the specified interface. At this time, the simulator is in the state of preparation for testing

the test and diagnosis software is based on the vite (virtual instrument test environment) platform developed by the aerospace measurement and control center. The vite platform provides the functions of TPS graphical programming of test process, test instrument configuration and test task configuration. On this basis, according to the characteristics of the servo mechanism test, different data are determined and different tension test mechanisms are selected to output the test data display interface, which can judge the fault location and cause according to the test data at the same time, greatly increasing the intuition of the fault diagnosis results

second, test the design adopts the Plexiglas material project

the test content includes static parameters and dynamic parameters. The system adopts the full digital test method to complete the test of servo mechanism zero position, oil level height and inflation pressure, pressure building time, motor voltage and current, speed characteristics, speed loop, position loop and frequency characteristics

(I) static parameter test:

mainly includes the polarity check of servo mechanism, non working zero position, non working air pressure and non working oil level test. Because the static parameters are unidirectional slowly changing signals, the first-order digital filtering method is used for processing. By using a/d module to collect fixed points of signals, the sampling speed is set to 100k/s. The processing formula is:

where n is the number of points sampled

(II) dynamic parameter test

1 Pressure build-up time test

pressure build-up time is actually a test of the air pressure when the servo mechanism changes from non working state to working state. When sampling for a certain time, the pressure build-up time is calculated according to the sampling frequency and the number of sampling points

after the motor starts working, the air pressure begins to increase. After a certain time, the air pressure is basically stable, and then it can be considered that the pressure building is completed. In the calculation, the first step is to use the first-order digital filtering method to calculate the starting pressure and the stable pressure from the 1024 points in the front and rear parts of all sampling points, and then start from the sampling point to find the point greater than 1% of the stable pressure until the point greater than 90% of the stable pressure, and calculate the sampling point between the two points. The pressure building time is divided by the sampling frequency

2. Position loopback test

position loopback is the position characteristic, which is the relationship between the output angle of the servo mechanism and the input current, and reflects the ability of the servo mechanism system to track changes. Ideally, it is a straight line. Due to the hysteresis of the electromagnetic device, the slow change of the oil pressure in the servo valve and the friction of each part

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