Research On Flight Control Law Designing And Evaluating For Concept Aircraft Design

The effects that Flight Control System (FCS) have on conceptual aircraft distribution are becoming more and more considerable, in order to design aircrafts with expected performances and flying qualities, FCS should be considered at the conceptual design phase. The work present here is the designing and evaluating techniques of Flight Control Law (FCL) from the point of view of conceptual aircraft design. The purpose of the research is to supply references to the domain conceptual design departments which lack the ability of designing and evaluating FCL.The main works of this paper are as follows:First, according to the requirements of flying qualities and agilities of modern fighter, the design requirements of FCL are given in this paper. By analyzing the structures, designing methods and gain scheduling methods of FCL, the designing techniques of FCL which can indicate the main functions of modern fighters' FCS are established. As an example, the FCL for a typical 3rd generation fighter is designed by optimal Linear Quadratic with output feedback;the gains of the FCL are scheduled by BP neural networks.Secondly, by analyzing the effects of each part of FCS on the dynamics of the aircraft, a simplified model, which can indicate the characteristics and functions of FCS. is established. In order to implement visual modeling and high efficiency FCS simulation, an object-oriented FCS simulation method is introduced.Thirdly, the FCL evaluating methods are established from the sides of flying qualities and agilities. The flying qualities are evaluated by equivalent system matching and pilot operation on ground-based simulator;the maneuvers and flying situations are chosen by the requirements of flying qualities. And the agilities are evaluated by flying test on ground-based simulator;the matrices which are tested are the ones which have direct relationship with FCS.Lastly, this paper evaluates the FCL which is designed in the example. The result of the evaluation indicates that the flying qualities and agilities of the aircraft with new FCL are better than the original aircraft;the result also indicates that such design method is effective.