| The role of the sling hanging low gravity simulation system is to test the space probe before its launching. It’s necessary that space probe should be tested on the ground because effective test can ensure that the device is stabilized in harsh working conditions after launching. Laboratory traditional low gravity simulator is made of spring, pendulum, motor and other components, the system is complex, costly and inconvenient for maintenance. In this paper, aiming at these problem, a new low gravity simulation system based on magnetic powder clutch is designed, and the mathematical model of the system is established. Due to the existence of parameter uncertainty and disturbance in the actual system, a controller with robustness is designed.Firstly, in the first chapter, the significance of low gravity simulator to the development of the aerospace industry is analyzed, then various implementations of the low gravity simulator and research status in domestic and foreign are introduced. In the second chapter, the advantages and disadvantages of three possible sling hanging low gravity simulation system implementation plan are compared and finally using magnetic powder clutch to produce low-gravity simulator is proposed. Then the working principle, performance, advantages and disadvantages of magnetic powder clutch are studied, and it confirmed that the program is feasible. After that the selection principles and transfer functions of the magnetic powder clutch are given. Finally the structure of the system is designed.Secondly, in the third chapter the control models of magnetic powder clutch and motor are given, then the dynamics model of the complete system is established. Then the role of magnetic powder clutch in the system is analyzed and it confirmed that the magnetic powder clutch can reduce the impact of ground acceleration interference on the system to some extent. Finally, the model of the system is simplified according to the characteristics of the system.Finally, due to the magnetic powder clutch system’s characteristics and work environment, a robust H ∞ controller is designed. In the fourth chapter, the causes and treatment of the system uncertainty are analyzed, then generalized system model and performance weighting function are designed. After that, a controller which can meet the requirements is designed by Matlab. Finally, system simulation is made to demonstrate the system can meet the accuracy requirements and well suppress the influence of disturbances and uncertainties of the system. |
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