Research On Control Strategy Of Flexible Nozzle Load Simulation System

Flexible nozzle control system is the most important part of rocket control system;The motion performance and control accuracy of rocket largely depend on the control effect of thrust vector servo mechanism.In the development and production process of thrust vector servo mechanism,it is necessary to use the ground hardware in the loop experimental equipment to test and verify,that is,using the load simulator system to simulate the actual load and test its control performance.Based on the cooperative project of a certain Institute of Aerospace Academy,the design of flexible nozzle load simulation system is completed,and the control algorithm of force loading system and position servo system is deeply studied.The effectiveness of the control strategy is verified by simulation and experimental research.Firstly,the mechanical structure and working principle of the flexible nozzle load simulation system are introduced.On the basis of this system,the characteristics of the force loading system and position servo system are analyzed,and the mathematical models of the two systems are established respectively from the basic equations of the servo valve and the hydraulic cylinder by using the theory of fluid mechanics,which lays the foundation for the design of the subsequent controller.Secondly,according to the control requirements and system characteristics of the force loading system,through the analysis of PID control algorithm,the influence of membership function on the control accuracy of the system is analyzed on the basis of fuzzy control theory;On the basis of the above theoretical research,the fuzzy PID controller for the force loading system is designed;Finally,through comparing simulation results with the ordinary PID,the effectiveness of the fuzzy PID control algorithm is verified.Then,for the position servo system,considering the external force interference in the process of motion and the requirement of dynamic tracking accuracy,based on the research of variable universe theory and structure invariance principle,the influence of the parameter design of the common exponential and proportional scaling factors on the system performance is discussed,Finally,the compound control strategy suitable for position servo system is designed;The simulation is carried out in the case of no disturbance and with disturbance respectively.Effectiveness of the Feedforward variable universe fuzzy PID control algorithm is verified by comparing and analyzing the experimental results of various control strategies.Finally,the composition and structure of the experimental system and the selection of components are introduced;On this basis,force loading experiment and position servo control experiment are carried out.Experiments show that the fuzzy PID controller has faster response speed and higher control precision in the force loading control system;In the position servo system,the variable universe fuzzy PID controller with feedforward compensation has stronger anti-interference ability and better position tracking accuracy.