Research On Signal Processing System Of Laser Interferometer And Control System Of Nano-Measuring Machine

As the growth of the economic capacity and independent innovation in our country, nanotechnology has been widely applied to hi-tech industries such as nanomaterial, integrated circuits, super finishing and MEMS. Therefore, nanometrology is needed for the standard and traceability in nanometer scale. The nanometrology machine for large-scale geometric structure, also called nano-measuring machine (NMM), will offer the traceability for large-scale nanometer value transfer system to guarantee the unity of nanometer value in our country.This paper designed the laser interferometer signal processing system as measuring system, and nanometer measuring control system as control system, for the NMM. The main work of this paper is as follows.1. The composition of NMM has been studied and the measuring control system with PC plus double DSP processor has been designed. I-DSP processor for laser interferometer signal and the Z-DSP for the control of probe in NMM have been designed. With DSP as the core of data processing and control, the stacked bus for data transmission, and CPLD as the core of logical control, the universalization of double DSP processor was realized.2. The principles of laser interferometer, optical multi-pass and phase subdivision, were introduced. According to the error source and error correcting technology of the laser interferometer, the design of error correction and phase subdivision based on harmonic separation algorithm were realized. The way for hardware look-up table based on shifted divided algorithm by CPLD was designed for the error correction and phase subdivision of the laser interferometer signal.3. The interferometer signal processing circuit, including photoelectrioc conversion, signal regulation, signal acquisition based on CPLD, error correction ans phase subdivision based on CPLD was designed and verified.4. The control system for the NMM was gained. This system adopted the method of high address space for printed circuit board(PCB),middle address space for chip and low address space for device interior to distribute address space for every interface of the double DSP. This system used CPLD as the logical control core and enabled the DSP to communicate with high-speed IO board, CPLD,PIO, RS232 and GIO, which ensured high-speed, reliable and stable transmission of both data and orders.5. The reliability and precision of hotoelectrioc conversion PCB, signal regulation PCB and signal acquisition PCB for laser interferometer were verified by experiment results. It was proved that shifted-filter method based on CPLD can well reduce the effect of noise. Finally, according to test data, the stability and reliability of communication between DSP and high-speed IO board in PC, and communication between DSP and CPLD were testified.