Study On Error Analysis And Compensation Of Semi-strapdown Photo-electricity Stabilized Platform

Because of its advantages of small volume, light weight and low cost,Semi-Strapdown Photo-Electricity Stabilized Platform (SSPESP) has become animportant part of seeker technology research, its stability and tracking precisionshould be gradually improved. The thesis mainly has a central research on thestability and tracking precision of SSPESP. Based on the analysis of the kinematics,dynamics and stability mechanism for SSPESP, this paper discussed its error sourcesand made a deep research on the effect rule of error, error modeling, parametercalibration and error compensation etc.Firstly, according to the theory of Lie group and Lie algebras and with thestructure of SSPESP considered, a local product of exponentials (Local POE)representation of framework pose was established for SSPESP. The couplingrelationships of the velocity and acceleration between the missile and theframeworks were analyzed. Following that, the stability equation of optical axis inthe inertial space was established. Two different semi-strapdown stabilizationmethods were compared and each’s advantages and disadvantages were pointed out.Based on the kinematic analysis, the pitch and yaw dynamics models were derivedaccording to momentum moment theorem of rigid body rotating around movingpoint, including the inertial coupling torque model and the mass imbalance torque model. According to stabilized platform of semi-strapdown seeker, the angularvelocity and acceleration, inertial coupling torque and mass imbalance torque wereanalyzed by numerical simulation, which provided a fundamental for future controlsystem design.On the basis of analysis of various error sources of SSPESP, the optical axispointing error model was defined and set up according to the kinematics errormodeling theory of multi-body system. Then, Matlab was used to simulate and analyze the influence of the errors on optical axis pointing, which lay a foundation forprecision allocation and error compensation.In order to correct the optical axis pointing error of SSPESP, the basicparameter model and Local POE model were established and calibrated through theleast squares method and self-designed genetic algorithm respectively. Thecalibration experimental results indicate that the compensation accuracy andstabilization of Local POE models are superior to the basic parameter model, theoptical axis pointing precision increases from119.9″to21.3″.Finally, after compensating for the inertial coupling torque and the optical axispointing error, the stability and tracking precision of semi-strapdown seeker weretested on the semi-physical simulation platform. The results show that, the stabilityprecision rises79.7%when the system speed is0.5°/s and the missile disturbancefrequency is1Hz and amplitude is2degree; the tracking precision of yaw and pitchdirection rises20.7%and18.9%when the tracking speed is3°/s; the isolation ofyaw and pitch framework is5.63%and5.08%when missile disturbance frequencyis2Hz and amplitude is1degree.