Abstract: The decoupling controller design method based on the output shaping is presented in this paper.For a double variable control system of certain turbine-fan engine,two first order systems are selected to make two independent control paths.The responses of this two paths have no coupling.The step outputs of the two independent paths are assumed to be chosen to be the target outputs of the close-loop control system.Using the design process of LQR controller as an example,the weighting matrixes Q and R of the LQR controller can be obtained through genetic algorithm (GA) optimization.Then the step output of the LQR close-loop control system designed by the optimal Q and R can be consistent with the target output.Through the optimization algorithm,the control system with the LQR controller gets very well dynamic and steady state decoupling performance.

Key words: aero-engine, decoupling, output shaping, LQR controller, genetic algorithm