Aircraft Engine Control Based On Nonlinear Models

As an aircraft engine is a complicated thermo-mechanical system with strong nonlinear dynamiccharacteristic, it can only be represented by a nonlinear process model. This necessitates the study ofthe nonlinear control techniques for its control system design.Firstly, the paper introduces a variety of aircraft engine control methods such as linear control,nonlinear control, intelligent control and adaptive control.Secondly, a method for designing nonlinear control of an aircraft engine is proposed using aLyapunov approach on its nonlinear model. Choosing a Lyapunov function stabilizes the controlsystem according to Lyapunov stability theorem. Then a nonlinear controller can be obtained for theaero-engine. What’s more, the method is used to redesign a set of PID control parameters of the otheraircraft engine. Simulation results show that the proposed design can improve control systemperformance.Thirdly, a Generalized Gronwall-Bellman lemma approach is used to design nonlinear controllerof the aero-engine and study the convergence rate of system state variable based on the formernonlinear model. Next, a strategy that combining Lyapunov approach with GeneralizedGronwall-Bellman lemma approach is proposed to study control system of aircraft engines. Firstly, anonlinear controller can be obtained for an aero-engine using Lyapunov stability theorem. Then theGeneralized Gronwall-Bellman lemma approach is used to analyze the convergence rate of systemstate variable and validate the controller performance.Finally, a method for designing switching control of a one-spool aircraft engine is proposed. Themethod can decrease switching frequencies among the models. Firstly, a Lyapunov approach is usedto stabilize the nonlinear control system by choosing a suitable set of control parameters, leading tononlinear model-based acceleration control. Then switching-based acceleration control is obtained forthe two operating points. Simulation results show that the nonlinear model-based acceleration controlmethod achieves the acceleration control and uses only one nonlinear model, avoiding the modelswitching problem that is encountered in the switching-based method. The correctness of theproposed design approach is thus validated.