Research On Precise Pointing Control Of Aerostat Spectral Telescope

When detecting a deep space target based on a telescope equipped with aerostats,compared with ground telescopes,it has the advantages of little image quality affected by the atmosphere,and has the advantages of low launch maintenance costs compared to space telescopes.When the telescope system is mounted on the aerostat platform floating in the stratosphere about 30 kilometers,due to the problems of stratospheric atmospheric disturbance and platform stability,the aerostat spectral telescope spindle servo control system is often required to suppress the disturbance and ensure the aerostat.It is used to ensure the control precision of the aerostat spectral telescope system.The two factors that affect the control accuracy of the spectroscopic telescope are the control accuracy of the telescope spindle servo control system and the measurement accuracy of the attitude measurement system.This article analyzes and studies around the above two factors and discusses the high-precision control and stabilization method based on the telescope based on the aerostat.First,the internal and external disturbances of the spectral telescope system are analyzed.This section analyzes and studies the factors that affect the control accuracy of the main axis servo control system of the spectral telescope,and builds mathematical models,such as aerostat platform motion characteristics,friction,sensor measurement accuracy,wind disturbance and model interference.Secondly,based on the traditional control strategy,the analysis of the main axis servo system of the spectrum telescope is completed.In order to reduce the influence of complex disturbances on the control accuracy of the spectroscopic telescope system,and improve the control accuracy and stability of the spectroscopic telescope system,an adaptive sliding mode strategy is proposed for the speed loop to achieve a sinusoidal tracking accuracy of 0.6061?.Compared with the traditional PI,the control strategy is improved by 25%,and the effectiveness of the controller is verified.The different types of disturbances in the azimuth axis and the pitch axis are analyzed respectively.The results show that the adaptive sliding mode control strategy of the speed loop has better disturbance suppression ability,and the pointing tracking accuracy RMS is better than 20?.The control accuracy meets the telescope system's requirement for coarse-level pointing control accuracy of better than 20?.Finally,the accuracy of the attitude determination of the spectral telescope system will be reduced when the star sensor has no measured value.In view of this situation,a smooth filtering algorithm is proposed.This algorithm which reduces the error by about 35% can perform smooth filtering on the gyro output data.The proposed smoothing algorithm is combined with the generalized Kalman filter algorithm to form an Improved Kalman Filter algorithm.The experimental results show that the Improved Kalman Filter algorithm can be used to determine the attitude of the telescope system,and the accuracy of the attitude determination of the telescope system is better than 1.5?.This algorithm effectively improves the attitude determination accuracy of the attitude measurement system of the spectral telescope.