Aircraft Capacity Ice Flight Control System Design Theory And Methods

Aircraft icing is one of the most important reasons for aircraft accident. The accidents caused by flight icing have proved that if only depend on anti-icing/de-icing system could not eliminate all potential flight safety hazard caused by icing because the anti-icing/de-icing system could not work absolutely excellent every time. So how to resolve the security issue about aircraft ice tolerant flight becomes a new and crucial research subject. Centering around the technique of aircraft icing tolerant flight control, this paper researches aircraft icing dynamic model and theory of parameter identification, states feedback of reconfigurable control and envelope protection for inflight aircraft icing. On these bases, it sets up a synthetic ice protection system, which contains ice tolerant conception and the simulation result. Seeing from the simulation result, this system can provide effective envelope protection and make sure the operational stability of the icing inflight aircraft. The study of aircraft ice tolerant flight control includes fluid mechanics, flight dynamics, parameter identification, flight control, artificial intelligence and so on. It belongs to multidisciplinary cross-subjects research field.1) Analyses the aircraft icing dynamic model which includes the icing severity parameter, then presents a detection method for qualitative tests of aircraft icing based on neural network.2) Lucubrates aircraft icing parameter identification of quantitative analysis. This dissertation studies three methods of parameter identification and their applications on aircraft icing parameter identification. The three methods are "time-invariant", "time-varying" and "time-invariant"/"time-varying" synthetic H∞parameter identification. This dissertation presents "time-invariant" and "time-varying" synthetic H∞parameter identification and its rules. Moreover the simulation results prove that synthetic H∞parameter identification can reduce delay time for detection and improve the method's utility.3) Discusses methods of aircraft icing reconfigurable control. This paper expounds the rationale of robust control and linear matrix inequality. By comparing the controller effect of H∞control, H2 control and H2/H∞control, it concludes H2 control can get best reconfigurable control result. Furthermore, by analyzing the simulation results which are getting from using three control methods based on the basic theory, the three control methods' applicable scopes and feature sbecome much more distinct.4) Establish the synthetic ice protection system which has ice tolerant conception. This system comprises the aircraft icing flight control system (FC) and aircraft icing envelope protection system (EP). The aircraft icing flight control system, here just refer to the synthetical system of aircraft icing parameter identification and reconfigurable control. The aircraft icing envelope protection system limits the input signal by identifying the key state of aircraft. Although the two systems have different functions, the FC and EP can be joined together to make up a whole system to protect flight's safety.Therefore, the study idea of this dissertation is to find the best method of parameter identification and reconfigurable control by comparing different methods, and then establish a synthetic ice protection system. From the simulation result, the aircraft icing tolerant flight can be showed feasibility.