Design On Strapdown Stabilized Pod Control System

The working condition of POD is very complicated, many factors, such as change of carrier vehicle's posture , high-frequency vibration and wind resistance torque can cause instability of the axis of the LOS, thus it makes bad influence on the blur-free imaging of the POD. In order to overcome these influences, it needed to design a stabilization loop in the POD control system to isolate the vehicle disturbance, so as to stabilize the photoelectric detector in the direction of the fixed inertial space. The conventional proposal uses the gyros platform, but for the smaller systems, owing to subjecting strict constraints, the conventional gyros platform is not applicable .Based on this situation, the paper studies the strapdown proposal that is suitable to solve the problem.First of all, the development history and the present situation of the strapdown stabilized platform both at home and abroad are summarized. Some technological difficulties about the platform structure and the control strategy are analyzed which provides the basis for the study subsequent of the research field of gyro stabilized platform. Secondly, on the basis of the configuration features of two-degree-of-freedom strapdown stabilized platform, the paper builds its dynamics model. Besides, the coupling relations between platform formulations and carriers influences on the seeker's LOS. Simulation indicates that strapdown plan is suitable to solve the problem.In the research of the strapdown stabilized POD control system, firstly the paper introduces the principle of the strapdown stabilized platform, and then builds strapdown stabilization loop model. It proposes two kinds of stabilizational algorithms-angle algorithm and angle-rate algorithms. Two kinds of Strapdown algorithms are compared in ideal situation and when there exists measure noise respectively. At the same time, the influence on the stability of the optical axis owing to the existence of the measure noise is tested, so it is necessary to adopt gyro filtering.In the end, Coulomb adaptive control system is applied to the strapdown stabilized POD control system for the uncertainty of the friction torque and variability of interference. Simulation result indicates that the system performance is greatly improved after that the adaptive compensation based on Coulomb friction model is introduced. Meanwhile, three filtering ways including wavelet filtering, moving filtering, kalman filtering are adopted because of the existence of measure noise. the filtering results are compared by simulation., and compare the three filtering ways by simulating.