Control Allocation And Adaptive Reconfigurable Control Design For A Jumbo Jet Transport Aircraft

This study is supported by the Chinese Civil Aircraft DevelopmentPlan. The main work includes three aspects, that is, building up a dynamicsmodel of a jumbo jet transport aircraft, proposing a control allocationalgorithm and designing a control reconfiguration strategy. The detailedcontents are described as followed,1. A database of the dimensionless aerodynamic force coefficients andmoment coefficients of B747-100/200is set up and fitted into figures andfunctions with flight parameters. Furthermore, the nonlinear dynamicmodel of the B747-100/200is presented and linearized into decoupledlongitudinal and lateral model using small-disturbance theory.2. A model reference direct adaptive control reconfiguration method isproposed for the control reconfiguration of a jumbo jet transport aircraftwith structure failures. The advantages of the method is as followed: a) theobject and reference model are small-disturbance linear model, and can beeasily simulated by the software of MATLAB; b) the effects of structurefailures are considered into control inputs to avoid the troublesome ofbuilding the failure model; c) the proposed method applies the outputtracking error but not the state tracking error to adjust the controllerparameters, which is more appropriate with practical engineering whenstates are partly measured; d) the proposed approach applies the states butnot outputs of the reference model as the feed-forward information toavoid information loss. The performances of the algorithm are evaluatedby using linear state-space models of B747-100/200in the flight situationsof cruise and approach modes, longitudinal and lateral modes, normal and failed modes. The results show that the algorithm can overcome thedisadvantages of off-line control theory and indirect adaptive controlmethods, adjust the control parameters on-board, and have better capabilityof control reconfiguration for actuator failures.3. The effects and characteristics of the B747-100/200actuators areanalyzed for the control allocation problem. A linear model with elevencontrol inputs of B747-100/200is presented, and decoupled intolongitudinal and lateral models. The cascaded generalized inverse method(CGI) and fixed-point method are used to realize the control allocation ofthe B747-100/200in longitudinal mode. For example, the pitch angle ratecommand is employed as the desired virtual control and four elevators andthe stabilizer are applied to implement the desired control allocation at theflight situation of7000m height and241m/s air speed. The result showsthat the CGI method has better processing speed but bad accuracy, whilethe processing speed of fixed-point method depends on their iterations, thehigher iteration numbers the higher accuracy. The fixed-point method isrecommended by the author when the speed of the flight control computeris fast enough.