Cold Launcher Structural Dynamics Test Platform Leveling System Design And Simulation Study

The simulation experiment platform of cold launch structure dynamics consisting of the impacting hydraulic-cylinder system and the support platform system was the research object in this paper. This simulation experiment platform was used to simulate the effects of the impact load on the stress and displacement of launch vehicle launching the missile. The automatic leveling system for support platform was an important component of the simulation experiment platform. The reliability and the precision of the experimental results were determined by the leveling accuracy. According to requirements of the experiment, an automatic hydraulic leveling system was designed, and the automatic leveling strategies was introduced, as well as the control algorithm for the hydraulic servo system was given in this paper. This paper solved the problems of the parameters uncertainty and disturbances in hydraulic system, and ensured the process of leveling was quick and stable.(a) On account of the characteristic that the impact load on the support platform was large, this paper designed the mechanical structure of the support platform. Because the hydraulic cylinder was chose as the actuating mechanism for the automatic leveling system of the support platform, this paper designed the hydraulic control system and calculated the technical parameters of the hydraulic cylinder, the hydraulic servo valves and the hydraulic pump. Simultaneously, electrical control system for the automatic leveling system was designed.(b) This paper established the four points support platform model, and analyzed the conversion relationship between the hydraulic leg forces and the support platform which was not in a horizontal position, then obtained the mathematical matrix between the hydraulic leg length and the inclination angle of the supporting platform. According to the leveling strategy based on the angle error and the position error, the movement distance of each hydraulic cylinder supporting leg was given, and the detailed leveling process strategy based on angle error was described, and the advantages and disadvantages of the various leveling strategies were compared in this paper.(c) The mathematical model of the asymmetrical hydraulic cylinder servo control system controlled by the symmetrical valve was established in this paper. Aiming at the nonlinear, uncertainty parameters of the hydraulic system, a adaptive fuzzy PID cascade control algorithm was adopted for the movement of a single hydraulic cylinder supporting leg. A master-slave synchronization motion control mode was adopted in double cylinder synchronous motor in view of the chose leveling strategies. The main hydraulic cylinder adopted the self-adaptive fuzzy PID cascade control algorithm, and the slave hydraulic cylinder used the nonlinear differential and integral adaptive sliding mode control algorithm. Finally this paper created the hydraulic servo control system model in AMESim and the control algorithm model in Matlab separately.According to the automatic leveling strategy and the control algorithm for the hydraulic servo system, this paper simulated the leveling movements of the support platform. The results of co simulation indicated that the leveling strategies and the control algorithm satisfied the leveling accuracy requirement of the simulation experiment platform.