Global Sliding Mode Variable Structure Control Of 3-DOF Helicopter And Maglev System

Recently, people pay more and more attention to helicopters because of their many advantages such as directly taking off, landing and multi-directional rotating. Helicopters have taken a great role in aviation and people's life, and it is obvious that more and more helicopters will be needed in our nation due to our vast territory. But with flying tasks more complex, the defaults of helicopters have gradually began to come up, like being slow, low in performance, sensitive to disturbance and so on. In order to improve the survival ability of helicopters and meet the needs of Hi-Complex tasks in the future, the control system of the helicopter is not only supposed to possess such characteristics as speediness, stability, dependability, agility, etc., but also adopt the control methods which have robust performance.With development of space cause, space maglev technique which simulates microgravity environment has become corresponding methods of studying high technology. Due to its no touch on plants, maglev system eliminates constrains of frictional resistance and speed upper bound. But maglev system is nonlinear and unstable in essence, so nonlinear robust feedback control strategy is needed.The traditional linear control method has these abilities including adjusting controller's gain, dispelling the deviations of the control system, and increasing the system's stability, however, it is based on the suppositions that perturbation is small, and the parameters don't change. It also neglects the influence of the non-linearity and the coupled factors in system modeling. So in this condition, the whole designed system must exist many shortcomings as not exact modeling, sensitive to disturbance and parameters changing. To overcome the defects of the traditional method, in addition to considerate nonlinear factors in modeling, we also need to take a robust control strategy. The global sliding mode variable structure control inherits a series of advantages of traditional sliding mode variable structure control, and has the whole robustness on uncertainty of parameters and disturbance outside. Thus the research on applying it to 3-DOF helicopter and maglev system control is made. First, the 3-DOF helicopter system of Quanser company is introduced in detail. The dynamic performance of 3-DOF helicopter is analyzed and its mathematical model is build in 3 DOF, and then the final control plant comes up with 7-dim. All these make a foreshadowing for designing controller.Subsequently, the feedback control is planned which combining global sliding mode variable structure control and a reaching law。Matlab and Wincon simulation software are utilized to control the 3-DOF helicopter in real time. Simulations demonstrate that global sliding mode variable controller has good static and dynamic performance and is robust to parameters uncertainty as well as disturbance outside.Finally, aiming at 1 -DOF maglev system, together with reaching law, which is used to control reaching rate and reduce chatting, global sliding mode controller is designed. Through experiment it can be concluded that this method has fast dynamic response and well robustness to disturbance outside.