A systematic method of smooth switching LPV controllers design for a morphing aircraft

Weilai Jiang, Chaoyang Dong, Qing Wang
2015 Chinese Journal of Aeronautics  
This paper is concerned with a systematic method of smooth switching linear parametervarying (LPV) controllers design for a morphing aircraft with a variable wing sweep angle. The morphing aircraft is modeled as an LPV system, whose scheduling parameter is the variation rate of the wing sweep angle. By dividing the scheduling parameter set into subsets with overlaps, output feedback controllers which consider smooth switching are designed and the controllers in overlapped subsets are
more » ... d from two adjacent subsets. A switching law without constraint on the average dwell time is obtained which makes the conclusion less conservative. Furthermore, a systematic algorithm is developed to improve the efficiency of the controllers design process. The parameter set is divided into the fewest subsets on the premise that the closed-loop system has a desired performance. Simulation results demonstrate the effectiveness of this approach. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). problem amounts to solving a feasibility problem which involves nonlinear matrix inequalities. What's more, to design smooth switching LPV controllers, the scheduling parameter set must be divided into several subsets. Nevertheless, the parameter set division process of Refs. 14-16 has a certain degree of blindness. In other words, the division process depends more on the experience of a designer, or even by trial and error. To address this issue, a parameter set automatic partition method has been proposed, and the systematic technique has been applied to robust control for hard disk drives 27,28 , switching gain-scheduling control for plants with measurable time-varying parameters 29 , and switching LPV control for a mass-spring-damper system. 30 Although the related achievements are very encouraging, there are still some extensions that can be done based on the mentioned literature. Note that the control laws in Refs. 23, 24 are limited to the state feedback case. In Ref. 25 , output feedback controllers have been designed; however, it is a complicated process to find a feasible solution by solving an iterative descent algorithm. The parameter set automatic division methods proposed in Refs. 27-29 may lead to the situation that there is no overlapped region between adjacent subsets. Furthermore, to our knowledge, the problem of smooth switching control for morphing aircraft via a parameter set automatic partition method hasn't been fully investigated yet, which constitutes the main focus of this paper. This paper presents a systematic method of smooth switching LPV control for a morphing aircraft with a variable wing sweep angle. Firstly, choosing the change rate of the wing sweep angle as the scheduling parameter, the LPV model of the morphing aircraft is deduced. Then, the scheduling parameter set is partitioned into several subsets with overlaps and the output feedback smooth switching controllers are constructed. A switching law without constraint on the average dwell time is obtained which makes the conclusion less conservative. Moreover, a systematic design algorithm is given to avoid the blindness of the parameter set partition. By solving a series of linear matrix inequality (LMI) optimization problems, the parameter set is divided into as few subsets as possible and the smooth switching LPV controllers which satisfy a desired performance can be obtained efficiently. Finally, simulation results verify the stability, robustness, and smoothness of the morphing aircraft flight system under the proposed controllers.
doi:10.1016/j.cja.2015.10.005 fatcat:lqgspq6xq5gzvdie2dr7wzbosa