Mine Vehicle Reversing Early Warning System That Include Ultrasonic And Image

In the process of coal mining, safety is always the most important problem. Mine interior space is relatively narrow, inadequate lighting, and mine generally have a lot of electrical equipment and machinery and equipment, frequent personnel exchanges, which bring the operation and mining transport equipment driver great challenges, slightly has carelessly will give close to the staff and other devices bring great threat. The underground coal mine is a kind of special environment of inflammable and explosive. The existing warning system can not meet the intrinsic safety characteristics and cannot be used in the mine.In order to solve this problem, this paper develops and implements a mine vehicle reversing warning system which combines ultrasonic and image to meet the demand of the vehicle in the mine. The reversing warning system includes three parts: intrinsic safety type ultrasonic ranging alarm system; intrinsic safety reversing video systems; output intrinsic safety type DC regulated power supply. The intrinsically safe type ultrasonic ranging system have four transducers collaborative work, which can real-time detect the obstacle distance of each direction and display the distance on the LCD12864 screen, and can send out a warning signal of different frequency according to the obstacle distance. Intrinsically safe type reversing video systems can make up for the deficiency of the ultrasonic ranging system, more intuitive display out of the real-time image after the car. The power supply of the whole system is the designed output intrinsic safety type DC regulated power supply, the power supply has a dual overvoltage, over current protection function, which can realize fault protection of the system. This topic mainly carries on the following aspects:First the basic theory of intrinsically safe circuits and intrinsically safe power supply were studied, then the output intrinsic safety type DC regulated power supply with dual over-voltage and over-current protection function of was designed and implemented. The monolithic switching regulator IC LM2576-ADJ was choosed as the voltage stabilizing chip alternative traditional DC linear regulator type regulated power supply switch. Through matching device selection and peripheral circuit, it can achieve stable output voltage 12 V. Based on LM339 comparator, the dual overvoltage and overcurrent protection circuit was designed to ensure the power supply output intrinsic safety characteristics. Besides, the automatic recovery circuit was designed. When the circuit failure causes the output voltage or current exceeds a threshold, cut off the power supply, after the lifting of the fault and automatic recovery of power supply.Based on ultrasonic ranging chip GM3101 and MCU MSP430F149, the intrinsically safe ultrasonic distance measurement system was designed. First the principle and characteristics of ultrasonic ranging was analyzed, then the internal structure and working mechanism of ultrasonic transducer are studied, and the internal structure was transformed to equivalent circuit and impedance matching was done. Then, a new scheme of intrinsically safe ultrasonic ranging system was put forward, and the various parts of the hardware circuit was designed and software program was edited. Key presents a new ultrasonic transducer drive circuit based on high-speed optocoupler, the driving circuit can be good isolation effect on the input and output signals, and the driving circuit does not have energy storage element such as inductive, through calculation and analysis, we can find that the circuit meet intrinsically safe circuit requirements.The intrinsically safe reverse image system based on a single chip video driver chip MST703 was designed. Basic theory of reverse image system, which including the pixel structure and driving principle of TFT-LCD screen, is studied. Then we designed the hardware of reverse image system, including video signal input circuit, MST703 power supply circuit, SPI communication interface, etc. Then the software design is carried out. Finally, the system is realized and debugged.Finally, each part of the designed reversing warning system of mine vehicle was device realization and test analysis. Test results show that the designed output intrinsic safety type DC regulated power supply has a rated output voltage of 12 V, overvoltage protection action value for 12.7 V, over-current protection action value of 453 mA, and has a good characteristics of short circuit protection. The designed intrinsically safe ultrasonic ranging alarm system has a good linearity and repeatability. The designed reverse image system achieves a resolution of TFT-LCD 800*480 low delay, high stability display.Development of the mine vehicle reversing warning system combine ultrasonic and image realized mine vehicle warning, and it can real-time observation of the rear of the vehicle image and can accurately know the distance to the obstacle, and the scheme has solved the non intrinsically safe problem of traditional reverse warning system, which is of great significance in the protection of the coal mine vehicles and personnel safety.