Design And Experimental Study Of Ultra-precision Displacement Measurement For Grating Interferometer Positioning System Based On Stripe Phase Shift

As the foundation of precision manufacturing and precision equipment, precise positioning technology has been restricting the development of our country’s precision manufacturing and precision equipment industry. Yet precise positioning itself is restricted by nanoscale displacement measurement. The two most important research directions of modern nanoscale precision displacement measurement technique are laser interferometer length measuring systems and precision grating length measurement system. Compared with laser interferometer, precision grating length measuring system is not lost on resolution, accuracy and measuring stroke. Yet precision grating length measuring system owns a lot advantages such as better environmental adaptability, anti-interference ability, simpler optical structure and mechanical structure, easier to install, smaller footprint, lower cost, and wider adaptability. Study on precision grating length measurement system abroad is quite mature now and has already achieved mass production, while China still has some gaps compared to the international advanced level because of a late start. Therefore, research on nanoscale displacement measuring system based on diffraction grating is of great significance.This paper studies the nanoscale displacement measurement system based on stripe phase shift method. This system use grating interferometer to achieve optical quadruple, and then, use a stripe phase shift mechanism to further subdivided optical signal, providing a sub-nanometer resolution to the measurement system.This paper proposes a stripe phase shift scanning method basing on grating interferometer principle and phase scanning principle. According to this method, design and set up an ultra-precise measuring system with sub-nanometer resolution.The control method for precision position system is studied, successfully integrating the measuring system into precise positioning system, improving its’ positioning accuracy. Fulfilled the design of an PC control software to conduct precision position process according to the positioning process.Built an experiment platform based on stripe phase shift method to conduct performance test of each unit of the displacement measuring system, by integrating optical system, stripe phase shift system, precision positioning system and position signal generation and acquisition system. Positioning accuracy of precision positioning platform is measured. Experimental results are analyzed, system performance parameters are evaluated. The results show that the proposed displacement measuring system based on grating interferometer stripe phase shift scanning does achieved sub-nanometer resolution.