New Compactness Measuring Instrument Based On DSP Technology

Nearly ten years, our country is in a rapid development of highway construction,the state highway construction quality requirements becoming more and moresophisticated, and the main factors affecting the level of road quality is good or badthat subgrades compactness, so studying the technology of highway compactnessdetection has a vital significance. The typical traditional detection method, namelysand filling method and water bag method; their technical characteristics that can onlybe drawn after the subgrade compaction experiment completed, the choice of samplingpoint is random, so that part of the road may cause a leakage of inspection and thetraditional test takes a longer time. Aimed at the shortcomings of traditional detectiontechnology and the current project requirements a higher compaction quality, the statusof the short duration of the project, so it is necessary to develop a real-time andaccurate detection of subgrade compactness measuring instrument.For the working characteristics of vibratory roller, combined roadbed constructionprocess, selecting the drum vibratory roller excitation signal as the signal source todetect the density, acquired the compactness by analysising the signal of frequencydomain. Implementation process is divided into three part:(1) by the accelerationsensor excitation signal to obtain vibratory roller, because the excitation signal is aweak signals and clutter, you need to amplify the signal; signal amplified is acquiredby A/D converter of DSP,processing FFT transform and summing the amplitudes.(2)the resulting data processed by DSP will be sent to the microcontroller and single-chipmicrocomputer with color screen display and key function of human-computerinteraction, through a peripheral circuit convert vibration signal into pulse signal, themethod of using single-chip microcomputer pulse counting realize vibration frequencymeasurement, the single-chip microcomputer implement the compactness of data inthe U disk by driving CH376chip.(3)In view of the drive to store data, developed the corresponding data analysis software. Through this software analysis, we can visuallysee that the density of data every roller in the rolling process, and the overalldistribution of the density.Experiment shows that the development of compactness measuring instrumentcan realize real-time, continuous compaction test, to meet the needs of engineeringconstruction, compared with the traditional method of measurement, the error is small,and speed is fast.