Robust Controller Reduction And Research Of Its Application In Helicopter

In view of many practice systems are high-order dynamics models. The order of its controller is also usually as high as the generalized system by H_∞control theory. But the low-order controllers not only have many conveniences, but also have low manufacturing cost. From the DGKF method based on 2-ARE and the method based on LMI were proposed, we pay close attention to discuss and analyze the problem of designing the low-order controllers. The discussion of this problem is also hot and difficult in the area of H_∞control during these years. But because that it is a convex optimization problem, these are many unsolved problems need be investigated. Such as how to balance the performance of the system and the order of controllers; the sectional astringency of some optimized methods and the reduction of the robust controller of some large systems.In this paper we study the theory of robust control. Specially discuss and analyze the research and application of H_∞robust controller reduction method in helicopter, and solve the extant problems. The main contributions of this dissertation are as follows:1,The extant H_∞robust controller reduction methods are summarized and analyzed, and the reduced control methods are assorted with two kinds. One is based on model reduction; the other is based on some optimum way. And all the methods are used in a four-tray control system problem, the control result was analyzed and compared.2,About the method based on some optimum way, a computationally efficient controller reduction method based on Krylov subspace is introduced. A reduced-order controller obtained via Krylov subspace is guaranteed to match the desired full-order closed loop system response. And this method does not require solving any Lyapunov equations and using computational tools, becomes a small computation task. A frequency and breadth robust control of engine-generator example reveal that the effectiveness of the proposed method. It also can be applied to helicopter controller and anther the high-order controller system.3,The method based on model reduction is applied to controller. A concise and effective controller reduction method is obtained by a model descending way synthesized the balanced method and the singular value decomposition. And improve on the balanced method, settle the range of the application of the balanced method. Then is used to a 25 orders controller of 17 orders line mode of UH-60A helicopter, comparing with other methods, it is shown that the method proposed in this paper can obtain a better order-reduction effect and practicality range. 4,In application of helicopter, the two methods proposed in this paper can triumphantly transform the high-order controller to low, and also suffice the requests of the system. But synthesized method is better than Krylov method.