Control of stepper motor in the hottest plane targ

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With the rapid development of science and technology, high-tech has been widely used in military equipment. Airborne fire control equipment, as a field of high-tech concentration, has developed rapidly in recent years, and the replacement speed is very fast. The new generation of fire control system has a high technical content. As an important part of the integrated fire control system, photoelectric radar integrates optics, electronics, chemistry and machinery. The use of photoelectric radar is very important to improve the combat capability of aircraft. However, how to test the actual performance parameters of new technology equipment, give play to the combat performance of the aircraft, and improve the maintenance level of equipment is an important issue that needs to be solved urgently in the current work

2 overall design and working principle of test target

in order to test the tracking angular velocity and angular acceleration of photoelectric radar, we have designed a set of test system. The photoelectric radar test system is mainly composed of test target board, stepping motor controller and photoelectric radar bus transceiver. The key of the system is to design a reasonable test target board. Therefore, in the process of designing photoelectric radar test target board, After comprehensively analyzing various schemes, we finally decided to adopt the target plate structure design scheme with two degrees of freedom, as shown in Figure 2-1. This target plate has two degrees of freedom. The horizontal and vertical of the target plate continuously improve the industrial batch production management system. There is a lead screw in the straight direction. One end of the lead screw has a general trend of global industry development: to improve the industrial concentration through joint reorganization. The stepping motor drives its rotation through gears. Under the drive of the lead screw, the infrared target source can move continuously in the plane of the target plate at a certain angular speed or angular acceleration. The design of this target plate takes into account the progressiveness and feasibility limitations of mechanical design, avoids the one-sided pursuit of high-tech indicators, abandons the design of making the most expensive spherical target plate, and replaces it with a plane target plate, controls the movement of the simulated target source of the photoelectric radar on the plane, and carries out the dynamic and static measurement of azimuth and pitch angles. Then through the photoelectric radar bus receiving and sending, the photoelectric radar data is collected, compared with the theoretical data, analyzed and processed, and then the static and dynamic performance measurement results of the photoelectric radar can be obtained

the composition block diagram of the test system is shown in the figure. The principle of static test is relatively simple. First, the target source is returned to the initial position through two positioning switches (of course, Stora Enso's use of wood in the initial position is "extreme": the coarser part is directly used as wood for construction; the thinner part, tree tops and branches are transported to the pulp mill; the combustible coordinates of pulping waste such as bark and pulp residue are known), and then the test command is issued, The direction of the pulse number of the two stepping motors can be obtained by calculation. When the stepping motor works normally, the target source is moved to a specified position by the motor rotating the lead screw, and then the serial code test results output by the photoelectric radar are taken out through the bus data receiving and sending of the photoelectric radar, converted into coordinate values, and compared to obtain the absolute error and relative error of the static performance of the photoelectric radar

the principle of dynamic testing is not complicated, but due to the limitation of the design structure of this target board, its dynamic testing is strictly related to the position of the target source, and the testing of angular acceleration is relatively easy. The testing of angular velocity should consider whether the process of the target source moving from static to a certain way of measuring angular velocity will exceed the limitation of the angular acceleration of the photoelectric radar, resulting in the loss of the target source, and then unable to complete the test task, Therefore, when measuring the angular velocity, the starting segment of the target source should be as long as possible to minimize the angular acceleration of motion, but it should not be too small (the value of the angular acceleration should be about 70/S2, because the length of the target plate is limited, and the angular acceleration of motion is too large. Through calculation, it can be seen that the effective uniform angular velocity segment will be reduced too large, or even the effective uniform angular velocity segment cannot appear), giving the target source sufficient acceleration time, Although this reduces the actual measurement range, it is absolutely necessary

the static test has no strict requirements on the speed of the stepping motor, but it should ensure that the starting frequency of the motor should not be too high. If the frequency in the middle of the motor operation is too high, there should also be a deceleration process to stop, otherwise the motor may lose step. Since the transmission amount of the motor is an integer step, there is a certain rounding error in each movement. Increasing the number of tests to a certain number (about 10 times) will affect the effect of the static test. The solution is to return to the initial position for correction, and then carry out the following tests. Dynamic testing has very strict requirements on the speed of the stepping motor. Different motor speeds will make the target source produce different linear motion speeds. Because the speed of the stepping motor is determined by the frequency of its input pulse, the different control methods of the analog target source can be summarized as the control of the pulse frequency of the stepping motor

3 control of stepper motor

according to the design scheme of photoelectric radar test target plate, it can be seen that the pitch h of the transmission lead screw is 6mm, that is, the lead screw rotates for one circle, and the target source moves 6mm. The step angle of the stepping motor is 1.5 °, and the gear rotation ratio is 2:1. Therefore, it takes 360/1.5 = 240puls for the stepper motor to rotate for one circle. The moving distance D of the single pulse target source of the stepping motor is: D = 6 × 2/240=5 × 10-2 mm/P, the distance between the target source of the test target plate and the reflection center of the photoelectric radar is d = 300mm

available: on the horizontal axis, when the azimuth is α 1 to α 1+ α At 2, the number of pulses that the stepping motor should get is: number of pulses = D ×[ tg( α 1+ α 2)-tg( α 1) ]/d

when the target source is required to have a uniform angular velocity ω When exercising, there should be θ=ω t+ θ 0

then: F (T) = D ω sec2( ω t+ θ 0)/D where: - 600 < ω t+ θ 0 < 600 theoretical curve is shown in Figure 3-1

however, in practical application, due to the limitation of the working principle of the stepping motor, the frequency cannot be changed from time to time as shown in Figure 3-1, but the above theoretical frequency position curve should be discretized (as shown in Figure 3-2). From the formula deduced above, it can be seen that the frequency of the stepping motor at this time is related not only to the position of the target source, but also to the angular velocity of the target source

Control of stepper motor in the hottest plane target