光强正交调制型位移传感器的数学模型与误差分析

Mathematical model and error analysis of light intensity orthogonal modulation type displacement sensor

针对传统光学位移测量方法对环境要求高和制造精度难以提高等问题,提出了一种以交变光场为测量媒介的新型线性位移检测方法。基于提出的方法,设计了一种光强正交调制型位移传感器。该方法采用基于光强正交变化的两路电驻波合成电行波信号,通过对行波信号时间先后的测量实现空间位移的测量。为了深入理解传感器的传感机理,推导了传感器的测量模型,分析了与传感机理相关的关键因素对测量误差的影响。根据测量原理和测量模型的理论分析,研制出传感器原理样机,通过实验测试了各种关键因素对测量误差的影响,并进一步优化设计了传感器结构与参数。实验显示,优化后的传感器在108mm测量范围内的测量精度达到±0.5μm,是一种新的无需精细刻划的位移检测方案。

Traditional measurement methods for optical displacement have higher demands for the environment and it is difficult to improve the manufacturing precision of measuring devices.Therefore,a novel linear displacement measurement method was proposed by using the alternating light field as measuring medium.On the basis of the method,a light Intensity orthogonal modulation type displacement sensor was designed.The method combined two electrical standing waves with orthogonal changes into the electrical traveling wave signals,then,it measured the time sequence of traveling waves to achieve the spatial displacement measurement.In order to explore the sensing mechanism of the sensor,the actual measurement model of the sensor was derived,and the influenceof key factors associated with the sensing mechanism on the measurement error was analyzed in detail.According to the analysis of the measuring principle and model theory,a sensor prototype was developed and various critical factors effecting on measurement error levels were tested.Then,sensor structures and parameters were optimized.The experimental results show that measuring errors of the optimized sensor are controlled within ± 0.5 μm in the measuring range of 108 mm,which demonstrates that proposed method is a new displacement detection solution without demands for precise photolithographic processing.