Study Of Grating Signal Processing System Based On DSP

Grating measure technology is based on detection of moiréfringe signal by a grating-coupled. After moiréfringe signals undergo a series of processing, such as subdividing, sensing and so on, displacement of grating move can be achieved. High precise measure can be realized by combining sensors of grating displacement and the technology of electronics. With the development of grating process technology, the quality of moiréfringe signals has been greatly improved. Meanwhile, the development of photo-electronic sensors makes signals of the photo-electronic conversion able to reflect moiréfringe signals more truly. Therefore, the processing capability of moiréfringe signals, which is the core of the grating detection system, decides such index as measure precision, measure speed and capability of anti-jamming of the whole grating detection system.This paper introduces present detection of moiréfringe signals and ways of processing, and analyzes characteristics of various ways and their shortcomings. The processing platform of"DSP+MCU"with the digital signal processor as its core is adopted. DSP mainly collects and processes signals, while MCU mainly controls data communication and the whole system. It can overcome such shortcomings of traditional counting methods and to improve intelligence of the system,Not only an effective way is chosen to measuring the displacement of the single grating couple, but also a scheme to measure the displacement of the double grating couple is designed, and corresponding software programs is designed to make the hardware processing platform not only suited for the displacement measurement of single channel signals and double channel signals, but also befitting for measuring displacement differences between the two-road grating signals. This platform has characteristics of good flexibility and universality.To perfect the system in hardware and software, the following work have finished: According to functional characters of DSP and MCU, circuits suited for data collection and data communication of moiréfringe signals have been designed to display their advantages of DSP and MCU. Discussions of characteristics of moiréfringe signals output by grating and its influence to data procession has been made, and appropriate FIR digital filter has been designed and realized it in programs. Dynamic data characteristics of grating in complex movement have been analyzed and designs of subdivision and sensing programs has been optimized. Accidental situations possible in processing signals have been fully considered and its ability of getting rid of errors has been enhanced. What's more, serial port communication and LCD display for the system has been provided.Finally, the system of grating signal procession has been debugged wholly, the results of debugging has been analyzed, and then improving measures has been put forward to gain better processing effects.