Design And Analysis Of Low-temperature, Large-stroke, High-precision Linear Scanning Mechanism

In order to achieve high space-time efficiency measurement of multiple atmospheric components at the same time,atmospheric spectrum detection technology is one of the important methods.However,due to the small molecular weight of most gases in the atmosphere,the infrared characteristic absorption spectrum formed is very narrow.If the spectral resolution of the detector is not high enough,it will not be able to accurately distinguish and identify.The interferometer scanning mechanism is an important mechanism for optical path scanning modulation in spectral detection,and its maximum optical path difference,accuracy and rate stability directly affect the detection imaging quality.It is understood that the existing designs are based on swing-arm and linear scanning,and the swing-arm type has a short optical path.When the optical path is large,the optical path difference varies nonlinearly with the rotation angle,resulting in an increase in deviation from the optical path error;The linear type can achieve a large mechanical stroke,but the accuracy is poor and the stability is low.At present,the interferometer scanning mechanisms cannot meet the requirements of running at 180 K ultra-low temperature conditions.For this reason,a linear scanning mechanism with large optical path and high precision is proposed in this paper to realize high-resolution scanning of the spectrometer.In this paper,a linear scanning angle mirror mechanism is designed for the application and target requirements of the scanning mechanism.The direct drive linear motor and the high precision THK LM double slide guide are used to ensure the rigidity and motion accuracy of the whole system.Different sensors are designed for the normal temperature,low temperature test and test environment and the on-orbit operating environment.The design self-locking link is locked before and after the scanning mechanism is launched;After the design of the overall mechanical structure is completed,the analysis error factors exist on the parallelism and straightness error of the guide rail.The Monte Carlo method is used to combine and distribute the errors,and it is reasonable to verify according to the existing processing level.On the other hand,an improved “repetitive control” algorithm is designed to be inserted into the original model,effectively suppressing the friction torque generated by the large-stroke linear guide.Finally,through the modeling,analysis and simulation of the linear scanning mechanism and control system,combined with the test results for analysis,It ensures that the scanning mechanism device has high rigidity,stability better than 5%,high precision of X?Y?Z three-direction runout <0.01 mm,large mechanical motion stroke±85mm,large optical path difference±34cm,and Simple assembly,no transmission,suitable for excellent performance in 180 K ultra-low temperature outer space environment.The paper breaks through the temperature limitation,effectively avoids the influence of temperature on the optical path,and on the other hand breaks through the instability of the large-stroke linear scanning mechanism and the poor reciprocating precision,and improves the spectral resolution,and the spatial spectrum imaging technology is moving toward higher spectrum.Related research has been done on the direction of resolving power.