Adaptive Robust Control Of Inertial Stability Platform

Airborne optoelectronic stabilized platform is widely applied in reconnaissance,orientation,striking,effect evaluation and other areas.The optical sight axis stabilized precision of the airborne optoelectronic stabilized platform as one of the important ref-erence factors,will directly decide the imaging resolution and information accuracy of the optoelectronic stabilized platform.Therefore,the stable control of optical sight axis in airborne optoelectronic stabilized platform for high stable accuracy is of great significancesv particularly.However,in practical working environment,various po-tential factors,such as vibration from the carrier plane,attitude variation of the plane,the airflow disturbances,the assembled wire cable,friction between gimbals will al-1 introduce the disturbance torque into the stable control of the platform.In addition,during the long time service of platform,the changing load size,the operation envi-ronment with different temperature and components wearing from frequent use,which will lead to changes in the inertial stabilized platform system parameters,can all affect those parameters-based controller design.Based on that the inertial stabilized platform is the primary structure of the airborne optoelectronic platform,improving disturbance rejection ability of inertial stabilization platform and developing stable control law of adaptive capacity is particularly critical in the technology of airborne photoelectric sta-bilized platform.In this dissertation,we mainly deal with the disturbance rejection and adaptive ability of the controller in inertial stabilized platform and propose the disturbance com-pensation adaptive robust control strategy.Firstly,we modify the adaptive robust con-trol law under system input and output constraint of lower-triangular systems.A 2-order kinematic system of the lower-triangular system is studied as an example for the disturbance observer-adaptive robust control method.And then we apply disturbance observer and smooth friction model to study the tracking and stable problems of inertial stabilized platform as the specificized object of 2-order system.Finally,the problem of coupling and delay in practical application is discussed.The main content of the dissertation is as follows:1)We first consider the input saturation and output constraints in the actual control system,and study the adaptive robust control method under those constraints.We use the auxiliary state variable system for adaptive robust control law design with neces-sary stability analysis.The improved controller can perform effective input saturation compensation when system input saturation occurs.In addition,we study the adap-tive robust control problem with output constraints,and use Barrier Lyapunov function method to design adaptive robust control law with output constraint.Then,we design the adaptive robust control law under both constraints.2)The position control and speed control of DC motor,which is the main actuator of 2-order motion system,are studied.In view of the parameter uncertainties and the external disturbance in motor systems,we proposed an extended disturbance compen-sation-adaptive robust control law with parameter adaptive ability,disturbance estima-tion and suppression capability.Through the stability analysis,we prove that the control method can make the system uniformly ultimately bounded.In addition,we re-design the disturbance observer by using the approximation of the saturation function,and put forward the application of the proposed composite method in systems with input satu-ration constraint.The relative numerical simulation verifies the controller performance in parameter estimation,disturbance estimation,the output asymptotic tracking.3)The stability control of the single pitch stabilized gimbal is studied.A smooth friction approximation model based robust integral control law is proposed to compen-sate the system friction.Thereby,we enhanced the control performance of the robust integral control method by introducing extended disturbance observer in the inertial stability platform.Simulations and experiments show the effectiveness of the proposed composite law.4)The stability control problem of two-axis inertial stability platform is studied.The system dynamics equations of pitch-yaw-gimbal are analyzed.Through the es-timation and compensation of the disturbance,we realize the decoupling control and adaptive robust stability control of the two-axis inertial stability platform.In addition,a dual-disturbance observation compensation tracking control method is proposed to solve the problem of delay and perturbation when the image tracking system is applied as the information source for inertial stability platform.The stability tracking control is realized when the sensor-delay is large and the input external disturbance exists.