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航空发动机随着环境条件和工作状态的变化,其特性参数将发生很大的变化,且由于燃烧延迟等因素的存在,航空发动机可以被看作是带有一定程度的纯延迟的时变系统。而针对带有纯延迟特性的控制算法———Smith控制器,通常用于定常纯延迟系统的控制。当被控系统参数未知且时变时,Smith控制算法就不能完全补偿时变参数对系统特性所造成的影响,从而很难获得令人满意的控制效果。利用最速下降法和自动调整遗忘因子的最小二乘参数估计修正算法,分别在线辨识某涡轴发动机的延迟时间和动态模型参数,并将辨识获得的参数用于Smith控制器的自适应实时调整,进行控制算法的设计,实现涡轴发动机的实时闭环控制。仿真结果表明,该算法能够快速准确地辨识出系统参数,具有良好的跟踪性能。把该算法应用于纯延迟系统的闭环控制时,大大改善了Smith控制器的抗干扰能力,明显改善了涡轴发动机控制系统的稳定性和鲁棒性。
With the change of environmental conditions and working conditions, the characteristics of aeroengine will change greatly. And due to the existence of combustion delay and other factors, the aero-engine can be regarded as a time-varying system with a certain degree of pure delay. But for the control algorithm with pure delay characteristic --- Smith controller, it is usually used for the control of steady pure delay system. When the controlled system parameters are unknown and time-varying, the Smith control algorithm can not fully compensate for the influence of the time-varying parameters on the system characteristics, so that it is difficult to obtain a satisfactory control effect. Using the steepest descent method and the least squares parameter estimation and correction algorithm that automatically adjusts the forgetting factor, the delay time and dynamic model parameters of a turboshaft engine are identified online respectively, and the parameters obtained by the identification are used for adaptive real-time adjustment of the Smith controller. Control algorithm design, real-time closed-loop control turbine shaft. Simulation results show that the proposed algorithm can identify system parameters quickly and accurately and has good tracking performance. Applying this algorithm to closed-loop control of a purely delay system greatly improves the anti-interference ability of the Smith controller and obviously improves the stability and robustness of the turboshaft engine control system.