The Research About Detecting System Based On The ARM Microprocessor For Mining Anchor Bolt' Length

Mining anchor bolt is a wide-range material for underground coal mine production. It is a force which is installed in geotechnical layers.It's one end is connected to the engineering building, and the other end is anchored in geotechnical layers,when it is necessary, pre-gravity can be imposed to it for bearing structural load effectively, preventing structural deformation, as well as maintaining the stability of the buildings. Mining anchor bolt 's quality affect the safety of coal mine production to a large extent. The study on this issue is produced for the detecting problems about the quality of mining anchor bolt. Our research objective is to design a mining anchor bolt length detecting system based on the ARM microprocessor.This issue in according to the basic principles that ultrasonic in the process of dissemination will be reflected at heterointerface, designs a mining anchor bolt length detecting system based on the ARM microprocessor.Firstly, this paper through a series of theoretical analysis of ultrasonic characteristics, the application method of ultrasonic, ultrasonic sensors'principle,sound field,near field,far field and the relationship between length of near field and ultrasonic piezoelectric wafer'diameter, identifies the feasibility of applying that high-frequency narrow pulsed ultrasonic to length determination to mining anchor bolt.Secondly, this paper designs a ultrasonic transmiting circuit according to the principle that the ultrasonic is produced by an instant high-voltage pulse inciting ultrasonic sensors's piezoelectric wafer, and according to the requirement of narrow pulsed ultrasonic sensors, using of optoelectronic components such as isolators 6N137, MOSFET driver IC IR2110, power switch IRF740 and other electronic components. According to the characteristics of ultrasonic echo signals, a ultrasonic receiver circuit which is composed of the limiter circuit, multi-stage amplification and filter circuit, zero-crossing detection circuit,etc, is designed.This paper also selects the ARM7 LPC2210 as microprocessor and completes the design of relevant basic circuit. achieve the design of system software which takes ultrasonic incitation program and interruption of counting program as its core.Thirdly, this paper build up a experimental platform consists of power source, oscilloscope, 5M?10 ultrasonic sensors(frequencies are 5MHZ, 10 mm in diameter), ultrasonic transmiting circuit, ultrasonic receiver circuit, microprocessor ARM7 LPC2210 and related modules. Inaddition, it obtains detecting data through experiment.Finally, this paper analyzes the experimental detecting data by the least square method, obtaining the fitting function between the length of mining anchor bolt and counting value of detecting system, and deducing the calculation algorithm of the length of mining bolt when the system is detected.