Research On Method About Guidance And Control Based On Extended State Observer

With development of science and technology, high-tech weapons are usedwidely in modern warfare. High-tech weapons, espically the precision-guidedvehicles, are necessary to win a modern warfare. Usually, operational environmentof the vehicles is complex. It is impossible for the vehicle to avoid effects derivedfrom disturbances and uncertainties. Guidance and control methods inhibiting oreliminating these effects should be developed. In this paper, guidance and controlmethods based on extended state observer(ESO) are proposed for terminalguidance of precision-guided vehicles.Firstly, force and moment impacting on the vehicle are analysised.Mathematic models orienting guidance and control are established. Vehicle-targetengagement geometry model is developed for guidance law design. Navigationmodel and auxiliary computing model are presented. These models are basises forthe following work.Secondly, a new method for ESO design is proposed. In this method,finite-time convergence extended state observer(FCESO) is researched based onnon-singular terminal sliding mode. And convergence character of the FCESO isproved. Uncertainties of the system are observed by FCESO, and compensated inreal-time. Combined with angular constraint optimal guidance design method, aFCESO-based guidance law is proposed. Simulation results show that the guidancelaw is able to enforce good dynamic characteristics and robustness for the vehiclewith disturbances and mobile target.Thirdly, attitude control model is simplified based on certain assumptions.State-space equations are derived with attitude angular velocity, roll angle andoverload as the system states. Based on an ESO and nonlinear error feedbackstructure, a real-time compensation method is applied in designing the attitudecontrol law. Angular velocity feedback inner loop and overload feedback outerloop are introduced in pitch and yaw control laws design. A double-loop attitudecontrol law is used for roll control. Simulation results show that the attitudecontrol law is effective and has good performance for commands tracking.Finally, the guidance and control laws proposed in this paper aredemonstrated via numerical simulation. Simulation scenarios include a nominalcase, cases with disturbances of wind, cases with mobile targets and casesconsidering both wind disturbances and mobile targets. Simulation results showthat the proposed guidance and control laws satisfy distant miss requirement,observe angular constraint, and have well dynamic quality and properties fordisturbance and uncertainty suppression. Because of considering actual uncertainties and disturbances, the ESO-basedguidance and control methods proposed in this paper are valuable for practicalapplications.