The Displacement Measurement Method Research Of Adaptive Dynamic Phase Comparison Based On Optical Field Time-grating

The precision level of displacement measurement is one of the important indexes indicating the development of modern industry development,displacement sensor is the key component of displacement measurement,and the precision of displacement measurement directly determined by the accuracy of displacement sensor.At present,a class of displacement sensor with precision ruling grating line is widely used in the field of precision displacement measurement,but there exists a common problem that the measurement accuracy and speed have restricted each other.The development and fabrication level of high-precision sensor abroad is far beyond that of our country,most of the high-precision sensors used in our country are imported,but it is still in short supply.Only seeking new ways can surpass or approach the foreign advanced level.Time-grating is a kind of displacement sensor which is independently developed by our country,and its measurement accuracy does not dependent on the precision ruling of the grating line,which can greatly reduce the difficulty and cost of manufacture.Essentially time-grating is a static displacement sensor with uniform time sampling,which causes the measurement resolution changed with the velocity in dynamic measurement.In time-grating products,the optical field type time-grating have strong to electromagnetic interference,and fast dynamic frequency response.To solve the above problems,based on the optical field type time-grating,this paper designs an adaptive dynamic phase comparison method for measuring displacement.Under the condition of unchanging the excitation frequency,an adaptive control model for measurement speed and phase comparison times in time-grating unit time is established,so the measurement resolution keep steady at different speeds,but also keep its original precision.The main innovation points of the dissertation are listed as below:(1)After the theories researching of the optical field type time-grating measuring principle,the crux of the measurement resolution changed with the velocity is analyzed and the adaptive dynamic phase comparison method is put forward.(2)Based on the optical field type time-grating measuring theoretical research,the adaptive control algorithms has been analysed.the adaptive dynamic phase comparison measuring principle is derived,the design and implementation of the system is described.(3)The experimental platform is set up to verify the feasibility and effectiveness of the adaptive dynamic phase comparison method,and analysis of the actual data arrives at conclusions.By studied the adaptive dynamic phase comparison method’s experimental data,the result shows that in the measurement range of 180 mm and the speed range of 0 ~ 60mm/s,the position feedback precision can reach ±0.5μm at the same time keep the measurement resolution constant.It has presented the effective solutions to the time-grating’s measurement resolutions changing with different speeds.