Research And Design On Mine Vehicle Reversing Early Warning System

China is a big country of coal production and consumption.The safe production of coal is closely related to the healthy development of national economy.While the extensive use of mining transport vehicles such as trackless rubber-tyred vehicles improves the production and transportation efficiency,due to the constraints of many conditions such as narrow underground space,dim light and complicated equipment,drivers are facing great risk of reversing in the process of reversing,which brings hidden dangers to production.Therefore,it is necessary to design an early warning system for mine backing in order to improve driving safety.Ultrasonic ranging system is an important part of reversing warning system.However,the traditional ultrasonic ranging device introduces transformer in the driving circuit to meet the driving requirements of the ultrasonic transducer.Because of the existence of the non-linear characteristics of inductance,its energy is much higher than the minimum ignition energy of explosive gases,which is very easy to ignite explosive gases,resulting in safety accidents.So we have developed the corresponding technology research,designed the ultrasonic driving circuit without transformer and calculated the intrinsic safe parameters.On this basis,we have designed a mine reversing warning system composed of three subsystems: transformerless ultrasonic ranging system,FPGA reverse image system and ranging data and video fusion system.The system is powered by intrinsically safe power supply.On the basis of completing the design of power supply circuit of each part,the hardware circuit of transformerless ultrasonic ranging system with elmos chip as the core is completed through the design of peripheral circuit and communication circuit.According to its ranging sequence and instruction set,the function of edge capture of STC microprocessor is used to realize distance measurement and data transmission.At the same time,the analog switch chip with low resistance is used.On the basis of the design of the peripheral circuit of the FPGA,Verilog programming is carried out by using Quartus II software to realize the communication configuration of the video decoder ADV7180,the conversion of PAL video format and color space,and the driving of TFTLCD to complete the decoding and display of the video signal.After researched the LIN bus and OSD chip MAX7456,the peripheral electricity is achieved.The research of time sequence and control instructions of circuit and communication clarifies the flow of video signal fusion,uses LIN communication to receive distance data of ultrasonic ranging system,and collects video signal to realize data fusion output and display of composite video signal.On the basis of verifying the hardware and software functions of each subsystem,the debugging of the whole system is completed.The experiment shows that the system can realize four-way distance measurement,ranging from 250 mm to 2700 mm with error less than 30 mm;the measurement fluctuation is less than 10 mm;the data can be transmitted reliably and accurately through LIN bus,and the system can realize 800*480 resolution TFTLCD display of fusion signal including distance information.The development of this mine backing early warning system provides a feasible scheme for the early warning of underground vehicles in coal mines.Drivers can accurately understand the real-time distance of obstacles while observing the image of backing area in real time.It is of great significance to reduce the occurrence of backing accidents in coal mines to ensure the safety of life and property of underground workers.