Design Of Leveling Control Method For Heavy-duty Launch Platform

The topic of this paper comes from the National Natural Science Foundation of China.Based on the problem of low leveling accuracy of overload launching platforms,the paper has researched the high-precision leveling control strategies.The main content is shown as the following aspects:1.Refined modeling based on the leveling mechanism of an overload launching platform.Considering the geometry of the launch vehicle,tires,suspension,launching parts,leveling legs and so on,the virtual model of the leveling mechanism was established based on the real overload launching platform.2.Mathematical modeling based on the leveling system of an overload launching platform.Considering the simplicity,accuracy and time-varying diaturbance characteristics of the hydraulic leg model,a nonlinear model of the electro-hydraulic position servo system of each hydraulic leg was established.At the same time,taking the four-leg-support overload launching platform as the research object,based on certain assumptions,the mathematical model of the launching platform in non-horizontal state was established.3.Research on nonlinear control strategies of the hydraulic leg.Based on the nonlinear model of the electro-hydraulic position servo system of each hydraulic leg,the finite-time disturbance observer based asymptotic robust integral tracking control strategy and the adaptive disturbance-observer based asymptotic tracking control strategy were proposed for time-varying disturbance in the system.And performance analysis was carried out by Lyapunov stability theory.The proposed control strategies were simulated and verified by Simulink software.At the same time,based on the existing experimental conditions,the corresponding experimental research was carried out to verify the feasibility of the proposed control strategies.4.Research on the four-leg-support leveling control strategy.Taking the four-leg-support overload launching platform as the research object,based on the mathematical analysis of the launching platform model in the non-horizontal state,the "chasing the highest point" leveling strategy was adopted.The position error between the remaining support points and the highest support point was calculated,and converted into a torque signal after solved by the hydraulic leg control strategy,which is treated as the drive signal,so as to realize the design of the launch platform leveling control strategy.5.ADAMS/Simulink co-simulation.Taking ADAMS/Simulink as the simulation environment and the four-leg-support overload launching platform as the research object,the co-simulation of the launching platform was carried out to verify the effectiveness of the leveling control strategy.