Control Of Switched LPV Systems With Applications To The Hypersonic Vehicles

The switched linear parameter-varying (LPV) system is a class of systemscombining the characteristics of both the switched systems and LPV systems, and it hasreceived widespread applications in the industrial process, especially in the area ofaeronautics and astronautics. Essentially, the switched LPV systems are a kind ofextension of the conventional LPV systems and they are capable of coping with thosesystems with large-scale time-varying parameters. Therefore, they have beenextensively applied in the guidance and control of various aircrafts. In this paper, thestability and H_∞analysis are carried out for switched LPV systems under typicalswitching signals such as average dwell time switching (ADT) and mode-dependentaverage dwell time switching (MDADT). Furthermore, the influence on theperformance of the networked control systems (NCSs) caused by the uncertain packetdropouts is analyzed, as well as the H_∞control problem for switched LPV systems.Finally, the switched LPV modeling approach is successfully employed in the referencetracking control of hypersonic vehicles.Firstly, for the general discrete-time switched LPV systems, in the paper, thestability analysis and H_∞control is investigated by including the asynchronousswitching into consideration. The asynchronous switching takes place due to the timeneeded in the detection of switching signal. As a result, the switching of controllersgenerally lags behind that of system modes. It is assumed in this paper thatasynchronous switching is mode-dependent, and in which meanwhile, the closed-loopsystem is unstable. By constructing the Lyapunov-like function, this paper presents thestability criteria and H_∞controller design method for the underlying systems. Thesimulation results demonstrate the validity and effectiveness of the aforementionedapproach.Secondly, in this paper, the emphases are placed on the impacts resulting from theuncertain packet dropouts on the performance of the NCSs. The uncertain packetdropouts derive from the difficulty in acquiring the accurate expectation of thetraditionally Bernoulli-distributed packet losses. The complexity of the NCSsenvironment gives rise to the necessity to investigate the uncertain packet dropout. Thestability analysis and H_∞control problem are primarily conducted for the general lineartime-invariant (LTI) NCSs. Furthermore, this paper considers the analysis and synthesisof switched LPV systems with uncertain packet dropouts. The detailed methodologyand conditions for the stability and H_∞control are illustrated and the numericalexamples in the following are used to test the results. Thirdly, this paper considers a class of stochastic switched LPV systems withuncertain packet dropout rate. This class of stochastic switched LPV system can bemodeled as T-S fuzzy Markov jump systems. Here, the probability transition matrix(TPM) orchestrating the jump of the Markov process is assumed to be partiallyunknown. Furthermore, the fuzzy-basis-dependent and mode-dependent Lyapunovfunctions are employed to derive the H_∞analysis and controller design criteria for theunderlying systems, and simulations for the single-link robot system are conducted toprove the validity of the obtained results.Finally, the specific application on the modeling of hypersonic vehicles with aid ofswitched LPV systems is shown in the last chapter. The hypersonic vehicles areinherently characterized by high nonlinearity and large parameter ranging scope, thus itis of importance to list the specific procedures of the modeling process. Afterwards, thereference tracking problem is addressed for the established switched LPV model underaverage dwell time and mode-dependent average dwell time switching logic,respectively. At last, the nonlinear simulations are performed to show the referenceresults with comparison between the above two switching logics as well, whichvalidates the effectiveness of the designed controllers.