Research On Structure Optimization And Control Strategy Of Load Simulation System

With the development of aerospace,weapon equipment and civil equipment in China,more and more high-performance servo mechanisms have been developed.In order to ensure their reliability,a large number of tests are essential.In order to transfer the destructive and complex field experiment into predictive research under laboratory conditions,so load simulation system has been developed.Load simulation system is a hardware in the loop simulation test system.Load simulation system can simulate various loads,inertia and other parameters of the tested servo mechanism in the working process,and its performance directly affects the reliability of the tests.Based on the scientific research project of China Aerospace Science and Technology Corporation,this dissertation develops the load simulation system,carries out structural optimization and modal analysis of its key parts,studies the load control algorithm of the load simulation system,and analyzes and verifies the algorithm through simulations and experiments.Firstly,according to the technical specifications,the overall design and planning of the load simulation system is carried out,the load simulation system is divided into several subsystems: mechanical subsystem,hydralic subsystem and control subsystem.The design and calculations are carried out respectively,and the load simulation system is analyzed and the mathematical model is established.Secondly,according to the working condition under large actual loading force of the system,the structure analysis is carried out,the strength of the two key parts of the base frame and T-shaped rocker arm are checked by using Finite Element analysis,and then the variable density topology optimization is carried out using ANSYS Workbench.Thirdly,the resonance of the load simulation system is discussed,and the natural frequency of the installation stiffness plate is calculated by using the method of theoretical calculation.The modal analysis of the main shaft and the whole system is carried out by using the method of finite element analysis.Through comparative study,it is concluded that the system will not produce resonance during operation.Then the loading control strategy of load simulation system is studied,the PID control algorithm and the PID compound control algorithm with feedforward compensation based on structure invariance are discussed,and the nonsingular terminal sliding mode variable structure(NTSMC)control algorithm based on "double power +exponential" reaching law is discussed and designed.Through simulation analysis,it is concluded that the control performance of NTSMC algorithm is better strategy of the three.Finally,through the control experiment on the load simulation system test-bed,the feedforward compensation PID compound controller and the NTSMC controller are compared,the suppression ability of surplus force under undisturbed loading and disturbed multi-load spectrum loading is analyzed,and the improvement scheme is proposed according to the simulation and experiment result.