Research And Development On The Portable Intelligent Instrument Of Cable Tension Testing Based On ARM System

This project takes the research team two years to independently develop a set of portable intelligent instrument on testing the bridge's cable tension. In the course of development the team has successfully amended the testing equipment as well as the methods, and has improved the theory of tension testing. I am proud to be one of the two developers. In December 2005, this instrument was announced as the provincial technological achievement in Jiangsu province.So far as the equipment is concerned, a 32-bit RISC(Reduced Instruction Set Computer) intelligent chip called ARM(Advanced RISC Machine) is chosen as its MPU(Micro Process Unit). ARM can both manage the whole system automatically and do digital signal process effectively. At present, in the domestic relevant fields there are some junior industry portable intelligent products as well as some lab ones, with SCM(Single Chip Micyoco) or DSP(Digital Signal Process) as their MPU. However, the product basing on ARM has not developed yet. By experiments, it has been proved that this instrument is more reliable and more practical so that it's worthy of recommendation in the relevant field. What's more, the team has designed and realized three modules for this instrument, which respectively are matching module for sensor(accelerometer), processing module for electric signal and modulating module for power supply. The integrator of these three modules provides a solid hardware foundation for precise testing. The LCD(Liquid Crystal Display) with great pixels and 16-keyboard matrix make the man-machine conversation much easier. All parts of this instrument are installed in a special metal box(250×190×50), so it can meet the demands of field testing.In order to get precise frequency, 4096-dot FFT(Fast Fourier Transform) and low frequency sampling(50Hz) are adopted. Therefore, this instrument can tell 10-2Hz at most. The integrator of preamplifier and 10-bit ADC(Analog-Digital Conversion) is able to recognize the faint signal produced by the sensor. The technologies of zoom display and switching display play an important role in showing the various signals of different frequencies and different amplitudes. Thanks to these two technologies, the LCD of this instrument can display better curves than the screen of PC(Personal Computer) does. Finally, adapting from the existing method, a more effective method has been designed to make this intelligent system tell the main frequencies of the signal and eliminate the low-frequency noise automatically.With regard to the theory, the vibration-based cable tension evaluation is not suitable for all cables, especially the ones of great stiffness. So the theory of margin between even instinctive frequencies has been applied to calculate the tension of such cables, which can remove the interference of the stiffness and achieve a more reliable result.