Research on Technology of Airborne Optoelectronic Tracking Platform Based on Dual Liquid Crystal Polarization Grating
With the continuous progress of optoelectronic tracking technology,optoelectronic tracking systems,as core components in engineering fields such as laser communication,laser guidance,and space observation,are increasingly widely used in optoelectronic platforms.However,in some special cases,the application of traditional optoelectronic tracking equipment is greatly limited due to factors such as narrow installation space,limited platform load,and higher requirements for tracking accuracy and response speed.The dual grating optoelectronic tracking device is a new type of beam deflection device that rotates two coaxial gratings for beam deflection.This device has the advantages of small rotational inertia,small volume,and high tracking accuracy,and has broad application prospects in fields such as laser communication,laser guidance,and LiDAR.In order to overcome the shortcomings of traditional airborne optoelectronic tracking devices such as large volume and weight,and achieve lightweight of the new airborne optoelectronic tracking platform.A miniaturization and high-precision design has been proposed for an optoelectronic tracking method based on a dual grating beam deflection mechanism applied to airborne platforms.This article establishes a dual grating optoelectronic tracking and aiming platform control system based on Linear Quadratic Regulator(LQR)optimal control,selects two independent rotating liquid crystal polarization gratings placed in parallel along the same axis as the beam deflection actuator,and establishes a beam deflection reverse formula based on line of sight decoupling for target tracking.The three meter collimator is used to simulate the long-distance target,the double grating photoelectric tracking and aiming system is placed on the six degrees of freedom swing table,and the azimuth axis and elevation axis disturbances are applied.The 1 053 nm laser is emitted into the double grating photoelectric tracking and aiming system through the ten meter collimator,and the tracking accuracy is tested.The dual grating optoelectronic tracking and aiming system has successfully completed tracking experiments based on platform disturbances of different frequencies and amplitudes.Through experimental data analysis,it is found that the tracking accuracy of the airborne optoelectronic tracking and aiming system based on the dual grating meets the system design indicators,with a tracking residual RMS(Root mean square)statistical value less than 350 μrad.Compared with the PID tracking algorithm,the peak to peak values of real-time miss distance data for azimuth and elevation have decreased by more than 25%.After adding LQR and Axis of Sight Decoupling Algorithm,the RMS statistical values of the biaxial miss distance under 2°@0.5 Hz and 5°@0.2 Hz disturbances are 328 μrad and 289 μrad,respectively,ensuring the reliability of subsequent experiments based on the dual grating optoelectronic tracking system A dual grating optoelectronic tracking and aiming system based on LQR optimal control and line of sight decoupling has been designed,which has advantages such as high tracking accuracy,small moment of inertia,small weight,and small volume.The effective aperture of the liquid crystal polarization grating in the system is 50 mm,and the RMSstatistics of the off axis reflection system wave aberration are less than λ/12.Select the incident light band as λ=1 053 mm,after coating the optical antenna with a thickness of 1 053 mm,the reflectivity of the 1 053 nm laser beam is greater than 99.95%.The maximum beam diffraction deflection angle of the dual grating system is±15°.After experimental testing,it was found that the dual grating optoelectronic tracking and aiming system has achieved tracking of simulated long-distance targets,and the system's azimuth and elevation tracking accuracy has been greatly improved,achieving the design target of a biaxial miss distance RMS less than 350 urad.The correctness and effectiveness of the combination of LQR control theory and line of sight decoupling algorithm have been verified,providing experimental reference and theoretical support for the development of new optoelectronic tracking technology based on dual gratings.
Double Liquid Crystal Polarization GratingsOptoelectronic tracking and aiming platformTracking performanceInverse solution formulaLinear Quadratic Regulator controlAxis of sight decoupling
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