Development of electric automatic door control sys

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Development of electric automatic door control system for rail vehicles

automatic door system is an important part of urban rail transit vehicles, which is directly related to the safety of passengers. At present, most domestic EMUs use single wing sliding doors, and the Metro uses double ExxonMobil has launched a series of glass encapsulated Santoprene level wing to wing doors. The commonly used automatic doors in China are mainly pneumatic doors, such as the vulnerable part 1 of the single wing pneumatic plug: the sensor sliding door and the double wing pneumatic built-in opposite door. However, as a new type of automatic door system, the electric door is also gradually promoted and applied

1 working principle of electric automatic door

the working principle of automatic door is that the door panel is supported on the guide rail by the bracket, the guide rail is connected to the driving device, and the driving device drives the door panel to slide through the guide rail. Each door has a locking mechanism. When the door is closed in place, the locking mechanism realizes mechanical locking. The door is equipped with zero speed protection and safety interlock circuit, and the door opening and closing is equipped with alarm device. The driving device of the electric door is a group of motor components, and each car has a main controller to control the door of this car. The main controller is the command center of the automatic door, which sends out corresponding commands through the internal command program to command the motor or electric lock system; At the same time, people can also adjust the opening speed, opening amplitude and other parameters of the door leaf through the main controller. The external signal is completed by the induction detector. When a moving object enters his working range, he will send a pulse signal to the main controller; The motor provides the main power for opening and closing the door, and controls the acceleration and deceleration of the automatic door leaf. The automatic door leaf completes one-time opening and closing, and its work flow is as follows: the induction detector transmits the detection signal to the main controller, which controls the motor operation after judgment, and monitors the motor revolution and current, so as to control the motor to apply force and enter into slow running and reverse rotation at a certain time. The motor operates in a positive direction after receiving a certain operating current, and drives the power through the transmission mechanism to open the automatic door leaf; After the automatic door leaf is opened, the controller makes a judgment and controls the motor to move in the opposite direction to close the automatic door leaf

2 the main controller and actuator of the control system

the main controller of the automatic door measurement and control system adopts TI DSP, the model is TMS320C2812, which is an advanced 32-bit fixed-point DSP chip. It not only has high running speed and powerful processing function, but also has a wealth of on-chip and off-chip equipment, which is convenient for interface and modular design, especially suitable for measurement and control with mass data processing, The DSP technology is used to establish an effective signal processing model to suppress the interference noise and achieve the maximum signal-to-noise ratio. The measurement and control of the brushless DC motor in this system can fully ensure its real-time performance. The DC brushless motor adopts alc-tel's bg65pi motor, which has the characteristics of high efficiency, power saving, low noise, high speed, high torque and no heating during continuous use. It greatly surpasses the traditional AC servo motor and cooperates with the T-shaped rack synchronous belt to make the door body run from low speed to high speed with surpassing tranquility and achieve super static operation. The measurement and control system is designed for intelligent control, and the running speed of the door leaf can be set at will, and the state of any opening can be set; Self correcting to keep the door leaf moving smoothly; It can automatically detect the width of the door to maintain the best operation state; It has anti pinch function, that is, when encountering obstacles or human body and other abnormal conditions, the door leaf will automatically reverse and exit, and the operation process will smoothly transition from high speed to low speed

3 sensor in the control system

for the automatic door control system, when the sensor receives the presence of someone outside, it opens the door and then closes the door. The controller not only controls the door independently, but also carries out vehicle communication and other contacts. Therefore, whether the door can be opened effectively and closed in time depends on the design of the controller. Infrared pyroelectric sensor is used to detect 8 ~ 13 μ It is controlled by the infrared ray of M. it is emitted by the microwave device, reflected by the human body, detected and amplified by the device, and then controls the follow-up circuit. Its characteristic is that no matter whether the personnel move or not, as long as the full composite aircraft referred to by the author here is within the scanning range of the sensor under the current technical conditions, it will react and cannot close the door, which is detrimental to ensuring that the environment in the trunk changes slightly, Therefore, it is not suitable for the inner end door connected to the rail vehicle. Therefore, we choose the microwave sensor, also known as microwave radar, which reacts to the movement of objects. Its reaction speed is faster than the infrared sensor, and it is very suitable for the use in the rail car door. Its characteristic is that once the personnel near the door do not want to go out and stand still, the radar will no longer react, and the automatic door will be closed. Because the design system has the anti pinch function, It can solve the possible pinch phenomenon

4 control method and program design of control system

4.1 control method

the control method adopts direct digital control method, which is a good real-time control. Generally, the PID control calculation method for output control quantity y (fault cause T) and input position quantity x (T) is:

where KP is the proportional environmental benefit, Ti is the integral time constant, and TD is the differential time constant. In order to reduce the amount of calculation, sum and difference calculation are used instead. Therefore, when the sampling period is t:

set a switching value signal as a position signal during the opening and closing process of the automatic door ε, When the calculated input position x (T) is outside the position signal, that is, X (T)> ε The output control quantity y (T) has fast response speed and the automatic door opening and closing response is fast; On the contrary, it is slow but has certain accuracy and realizes some preset functions, such as anti pinch realization. The calculation formula is:

where x (T)> ε When, k1=1; When x (T) ≤ ε When, k1=0. In this way, when the automatic door is opened and closed initially, the integral effect can be cancelled, the cumulative effect of the integral can be controlled in a very small range, and the system oscillation can be avoided and the accuracy can still be guaranteed

for a perfect measurement and control system, it must be able to accurately copy the waveform of the measured signal, and give an accurate output control signal without any time delay after analysis and calculation. In the actual system, the relationship between the input x (T) and the output y (T) at time t is: Y (T) =kx (t-t0), where K and t0 are constants. In this closed-loop measurement and control system, the lag of the system output to the input will destroy its stability. Therefore, the condition to ensure the accuracy or distortion of the system to the greatest extent is t0=0. However, in the actual feedback control, t0 cannot be 0, which inevitably leads to the dead time of measurement and control. The so-called dead time can be defined as the delay time from "the instant when the measurement sensor detects that the variable begins to change" to "the instant when the controller begins to apply correct and effective intervention to the production process". During the test, the sensor is installed in the middle of the automatic door, the shortest distance of the detection signal is adjusted, the transmission delay is reduced, and a part of the dead time is eliminated in the installation; In addition, adjust the error tolerance of the controller, that is, weaken the setting parameters of the controller, so as to slow down the response speed of the system and reduce the dead time when it is impossible to eliminate. In the work of eliminating errors, in order to ensure reliability and applicability and avoid cost increase, the above-mentioned models are selected after full tests to ensure the reliable use of upper and lower components. Adopt electromagnetic compatibility (EMC) to design the electrical system to overcome the problem of signal interference

4.2 program design

the software is written in c28x assembly language to realize real-time signal processing. With the development of DSP, its main work has turned to software development, which will account for about 80% of the workload. In particular, the algorithm has become the core of DSP. In addition, the variable speed drive of motor is finally realized by software

5 conclusion

after the rail vehicle simulation test operation, the operation speed of the automatic door is adjustable at 0 ~ 500 mm/s, the opening time is adjustable at 0.1 ~ 10 s, the detection angle is greater than 150 °, the detection error angle, the error rate of the obstacle execution dead time and other technical indicators meet the relevant contract standards. It ensures the reliability and accuracy of the whole system under the environment of long-time turbulence, strong vibration and impact of electrical and mechanical parts. (end)

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