Research And Design Of High-Speed Laser Displacement Device Based On Dsp

With the development of modern control technology, information processing technology, semiconductor technology, the demands of displacement measurement is raising up day by day, and the non-contact measurement based on laser displacement sensor technology due to its accuracy, timeliness, and without damage has been used widely in the fields of research and manufacture.As a laser sensor, position sensitive detector PSD (Position Sensitive Detector) has a small size, high photoelectric sensitivity, high response speed, high resolution, and simple application circuit, the PSD-based displacement measurement technology has broader application in non-contact measurement.A DSP-based high-speed laser displacement device scheme is proposed in this paper. The basic idea of the scheme is as follows:PSD combined with laser triangulation is used by the displacement information collection terminal which implements A/D conversion on the photocurrent generated by the PSD through the current input analog-to-digital converter DDC112; The DSP is taken as the central process unit of the system, and the DSP control the conversion of DDC112and transmission of the result of conversion, and the conversion result is formatted to calculates the laser’s displacement information on the photosensitive surface of PSD using the correlation formula. Then displacement information is displayed by the LCD and sent to PC through serial communication for further analysis and processing.In this paper, the current research status of PSD based laser displacement sensor research status is surveyed firstly, and the laser triangulation method and the working principle of PSD is analyzed, and the characteristic of PSD, influence factors and points for attention in use are pointed out. Secondly, the overall design scheme of the system is proposed and the feasibility of the scheme is analyzed. To address light current signal processing problems produced by PSD, the software and hardware design method of data acquisition system using the current input ADC DDC112and TI’s TMS320F2812DSP chip is described. On the basis of system design, the photoelectric current signal acquisition module in the system, A/D conversion module, data processing and transmitting module of the hardware and software design are given in detail. Finally, this paper introduces the whole testing process of the system in a laboratory environment, and some design reference is provided for others to improve this program in future.The high-speed laser displacement device based on DSP converts the photocurrent signals generated by the PSD directly by using current input ADC DDC112. Compared with the existing method that converts light current signal into a voltage signal, it reduces the signal interferences and system delay of the signal acquisition caused by hardware circuit significantly. It can achieve the purpose of the high speed measurement to provide precise control signal and a clock signal and process acquisition data rapidly and accurately by the powerful digital signal processing ability of the DSP. The measuring error of the system in this paper is0.1mm and system response time is less than1us, so the design system has certain advantage of measurements in real time occasion.