Design Of Vertical Control And Attitude Stabilization System For Air Bearing Platform

In order to explore the space environment,countries have successively developed a variety of spacecraft to carry out exploration missions.However,the ground development environment is far from the actual working environment of the spacecraft.For example,the lack of microgravity,vacuum and radiation on the ground,and the development of spacecraft will consume a lot of manpower and material resources,so the full physical simulation platform came into being.The all-physical simulation platform can simulate the environment of the spacecraft in space and the scene of performing tasks,greatly reducing the cost of spacecraft experiments.In order to improve the overall performance of the six-degree-of-freedom air-floating simulation platform and shorten the preparation time of the experiment,the vertical motion and attitude stability control of the air-floating platform will be analyzed.Firstly,the vertical air bearing of the six-degree-of-freedom air-floating platform is introduced,and its working principle and mechanical structure are analyzed.In order to improve the accuracy of the model,it is abstracted into a variable mass air cavity,and the BP neural network is used to identify the model parameters of the pressure regulating mechanism;at the same time,taking into account the air film resistance existing in the air bearing,the Z-direction motion model is established and simplified;the feasibility of the model is simulated.Secondly,the control framework of the vertical double-valve segmentation control is built,and the selection of the segmentation switch is analyzed,and three different control strategies are designed.In view of the slow response and overshoot of PID and Smith,the fuzzy control strategy is adopted in the Z-direction floating position and the coarse adjustment position,and the Smith estimation is adopted in the position fine adjustment stage.In order to simplify the whole design process,the genetic algorithm that improves the main factor is used to optimize the control rules of the coarse adjustment stage and and the simulation is verified.Then,considering the vertical lifting and air bearing ball unlocking process,the instability of the attitude platform will be caused,which is not conducive to the simulation of the subsequent rendezvous and docking task.Firstly,the kinematics and dynamics model of the attitude platform will be analyzed,and the mathematical model of the attitude error quaternion is established.Considering the characteristics of the model,a new non-singular fast terminal sliding surface(NFTSM)is designed,and then the control law is derived.Finally,the simulation experiment is verified.Finally,the hardware involved in the air-floating simulation platform is selected.Combine software and hardware architecture,design software interface,and carry out actual experimental verification.