固定时间预设性能下涡扇发动机模糊自适应控制

Fuzzy adaptive control for turbofan engines with fixed-time prescribed performance

为解决涡扇发动机大包线内多变量鲁棒控制问题,提出了一种基于干扰观测器的非线性涡扇发动机系统固定时间预设性能模糊自适应控制方法.首先,利用平衡流形建模方法构建了涡扇发动机的仿射非线性数学模型.借助反馈线性化技术,推导了受扰涡扇发动机系统的输出跟踪误差系统.然后利用模糊逻辑系统逼近系统不确定项,并设计非线性干扰观测器估计未知干扰和逼近误差组成的复合干扰.为保证控制系统的瞬态性能和稳态精度,引入固定时间预设性能函数,并通过误差转换函数将系统转化成无约束误差系统,进而设计涡扇发动机复合非线性鲁棒抗扰控制器.仿真结果表明,该控制方法能够使得涡扇发动机系统的转速和压比有效地跟踪参考指令并且跟踪误差始终限制在预设性能边界内.

To deal with the multivariable robust control problem of turbofan engines with a large envelope,a fixed-time prescribed performance fuzzy adaptive control scheme is proposed for the nonlinear turbofan system based on a disturbance observer.Firstly,the equilibrium manifold modeling method was adopted to construct the affine nonlinear turbofan engine model.Through the feedback linearization method,the output tracking error system of the disturbed turbofan engine system was obtained.Then the fuzzy logic system was used to approximate the uncertainty term.A nonlinear disturbance observer was designed to estimate the unknown disturbance and the approximate error.In order to ensure the transient performance and steady-state accuracy of the control system,the fixed-time prescribed performance function was adopted and the system was transformed into an unconstrained error system by the error conversion function.Based on these,a composite nonlinear robust anti-disturbance controller was further developed.Finally,the simulation results indicated that the proposed method can ensure the rotor speed and pressure ratio to effectively track the reference command,and the tracking errors are always limited to the prescribed performance bound.