Research Of Height Trace System Based On DSP In Laser Cutting Machine

Height trace system is a very important technology in CO₂laser cutting machines.Referring to the technical solutions of many scholars this thesis come up with an innovativesolution, a height trace system based on DSP. This solution uses improved Clapp Oscillatoras the the capacitance sensor’ frequency modulation detector, makes use of high-speed DSPCPU to count the FM signal’ frequency in order to demodulate the distance signal.Then DSPCPU cmputes the accurate ditace value through the method of least square curve fitting.Aprecise and steady servo driver voltage is produced according to the distance value.Moreover,with the help of CPU counter we filter the plasma interruption. By now, we realize ahigh-solution steady-response height trace system.The Clapp Oscillator is improved by chosing reliable transistor and capacitance. In thisway the stability and quality factor of the oscillator has been improved immensely.We use the bootstrapping emitter follower as the Pre-Amp to augment the inputresistance and isolate the Post-Amp from the pre-stage circuit. The modulated signal isamplified and converted into FM digital signal as the input of DSP processing system.DSP oprates the equalprecision frequency measuring algorithms and least square curvefitting algorithms to count the frequency of the FM signal and cmpute the high-precisiondistance value by fitted curve. The distance will be sent to D/A converter to obtain the DCvoltage which is input into servo driver to adjust the distance between nozzle and workpiece.Moreover, the DSP timmer uses timelag to filter the interference of plasma and slopping.