交变光场时空耦合型位移测量系统的研制

Developement of alternating light field space-time coupling type displacement measuring system

针对现有光栅精密刻划加工难度大制约测量精度的问题,设计了一种以交变光场为测量媒介的时空耦合线性位移测量系统。该测量系统利用四路正交的交变光场与四组正交的正弦透光面调制耦合形成电行波信号实现高精度位移测量。在对测量系统测量原理分析的基础上,建立了该系统的理论模型和误差模型,通过仿真详细分析了该系统在时间相位不正交、空间相位不正交以及结构安装不平行时的误差规律。开展实验验证了一次、二次和四次谐波的产生原因,根据误差来源改进了测量装置的结构,优化了相应的参数。实验结果表明:在180mm测量范围内,用栅距0.6mm的测量系统实现了±0.4μm的测量精度。该测量系统规避了现有光栅精密刻划的问题,结构简单、安装方便,为光学位移测量提供了新思路。

Regarding the restriction of precision ruling process difficulty on the measurement precision, a linear space-time coupling displacement measuring system was designed, taking an alternating light field as the measuring medium. The measuring system coupled four orthogonal alternating light fields and four orthogonal sinusoidal light transmitting surface into electrical traveling wave signal, thus a- chieving high precision displacement measurements. Through analysis of the measu the system. The theory model and error model of this measurement system were esta measuring error characteristic was analyzed in detail by model simulation when time rin bli g principle of shed, and the ase and soace phase were not orthogonal and mechanical installation was inaccurate respectively. Experiments were conducted for verification of the origins of the first harmonic, the second harmonic and the fourth har- monic. According to which, the measuring equipment was improved and its parameters were opti- mized. The experiment result shows that the measuring errors of the optimized measuring system are controlled within μ0.4 μm in the measuring range of 180 mm with grating pitch of 0.6 mm. The sys tem avoids precision ruling process of current grating, and has simple structure and easy installation, which provide an excellent approach for optical displacement measurements.