Missile Autopilot Design Based On The Constraint Of Servo

The main topic of this thesis is to design the control system for STT missile based on the constraints of actuator.It divides the constraints of actuator into two parts,the open loop frequency constraint and the fin deflection rate limit,then represents them as formula to join the controller design process.With this method,the controller will automatically satisfy the open loop frequency constraint and the fin deflection rate limit.According to the characteristics of the STT control system,the design of controller is divided into lateral channel and rolling channel.The design of lateral channel uses optimal control theory,selecting the square integral criteria of the error as the performance index,and getting the analytical expression of the performance index,then using the open loop frequency constraint and the fin deflection rate limit as constraints to solve the controller parameters.The rolling channel is based on PD control structure and the controller is designed by classical control theory and optimal control theory respectively.In order to improve the performance of the autopilot,this thesis optimizes the design of lateral channel,adds the actuator model to the system structure diagram,uses state space model and internal model principle to build control structure which reveals the source of the pseudo angle of attack three-loop autopilot structure.It takes the distance between non-dominant pole and imaginary axis as the open loop frequency constraint,and uses the relationship between zero point and the position of the dominant pole to restrain the undershoot.Finally this thesis uses partial state feedback control to place the system pole with the constraints of actuator dynamics and zero point position.Finally,this thesis uses appropriate missile model and guidance law that match the control structure to simulate the performance of the autopilot,and analyzes some aspect of autopilot that can be improved.