【作者】 刘晓锋；

【导师】 于达仁； 赵军；

【作者基本信息】 哈尔滨工业大学 ， 动力机械及工程， 2008， 博士

【摘要】 在飞行包线内,随着航空推进系统的环境和工作状态(如巡航、最大、加速以及减速等状态)的变化,航空发动机的气动热力过程将发生很大的变化,不同工作状态下控制性能也呈现不同的要求。本文针对航空发动机控制所面临的快速响应与安全性之间的矛盾,研究了航空发动机调节/保护的控制策略。首先,通过分析航空发动机的控制任务、运行过程中的安全边界,根据航空发动机运行时工况的复杂性,以及控制中的快速响应与安全性之间的矛盾,提出了具有状态约束、输出量约束、或状态与输出之间的组合函数约束的航空发动机调节/保护多目标的控制问题。阐述了这个多目标的控制问题本质上可归属于一个多模型的控制问题。在系统结构上设置多个控制回路,并按照某种切换规则进行切换的控制模式。将安全性和快速响应的指标要求分解,在航空发动机正常运行时,投入正常的控制回路,保证发动机的性能要求;在系统运行逼近安全边界时,则切换到保护控制回路,保证发动机的安全要求。从而通过在相对简单的控制器之间的切换,解决航空发动机的快速响应和安全性之间的矛盾。其次,分析了航空发动机多回路切换的规则。针对目前存在于航空发动机中的Min/Max规则进行了分析。分析了Min/Max规则对发动机动态响应能力与安全性上带来的优势,详细阐述了Min/Max切换规则机理,指出了Min/Max切换规则的不足之处。在完成对Min/Max切换规则的分析之后,论文给出一种改进型的规则,此种规则消除了前者的不足。并从理论上分析了这种切换规则本质上属于状态依赖的切换规则,通过实时判断被控制对象运行过程中所处的状态进而选择控制发动机的回路。最后给出了基于Lyapunov函数的多回路稳定性条件。然后,针对某型涡扇发动机的控制问题,给出基于平衡流形展开模型结构的表征涡扇发动机安全边界的特征参数,分析其控制系统要求与各控制回路的动态特性。仿真结果表明利用多回路切换控制方法在不影响系统安全性的前提条件下,可提高涡扇发动机的动态响应能力。最后,将多回路切换控制应用于冲压发动机控制系统设计当中。研究了冲压发动机控制系统的设计要求与设计限制因素,给出了各个子控制回路的特性,确定了各子控制回路的被控参数以及控制模型,分析了冲压发动机实际运行过程中存在的摄动因素,通过对典型工况的仿真表明利用多回路切换控制的设计方法在保证安全的前提条件下,可使发动机获得更好的性能。同时可降低闭环系统的增益,有效抑制外干扰的影响作用。从这个角度上看,如果单回路设计的控制器不能使一个系统具有良好的H∞性能指标γ,可在给定的控制器之间使用切换技术实现这一目的。更多还原

【Abstract】 With the changes of the aero engine proplusion systems enviroment and the working conditions (such as speed, accelerating, decelearating, etc), the aero engine aerodynamic and thermodynamic process will change greatly, the control problems have some particularites, so the basic problems of the aero engine control should be researched.This paper makes scientific research and in-depth discussion on aero engine control as follows:First of all, the paper analyzed the control tasks, safe boundaries during working, the aero engine working conditions, and the contradiction between the shortage of the control parameter numbers and the of the controlled parameter numbers, the paper presented a multi-objective regulating and protecting control problem in aero engine, which had states constraints, outputs constratints and the functions constraints combinated the states with ouputs. And the paper expounded the multi-objective control problem is a multi-model control problem, and proposed the multi-loop control system in structure, and according to one switching strategy to control. The concept is that we can decompose the safety problem and rapid response in aero engine control. The normal control loop control the aero engine to ensure the aero engine performances. And when the aero engine works near the security boundaries, the control system switched to the protection control loop to ensure the safety problem. And through the relatively simple method to switch between the controllers, the aero engine can get balance between the rapid response and safety.Secondly, the paper analyzed the multi-loop switch strategy in aero engine. The Min/Max strategy was researched detailly. The paper analyzed the andvantage between the dynamic response performance and the safety in Min/Max switching strategy. And the paper detailed the Min/Max switching strategy’s mechanism, pointed out that the Min/Max switch strategy’s shortcomings. Upon completion analysis of the Min/Max switch strategy, the paper presented a modified strategy to remove the former deficiencies. The strategye is judged by real-time control targets in the course of running the state which in turn choose the engine control loop. Based on the Lyapunov function, the paper gave stability conditions of the multi-loop switching.Thirdly, this paper dealt the turbofan engine with multi-loop switching control method. The paper used the equilibrium manifold expansion model to give safe parameters’models in turbofan engine, and analyzed the dynamic characteristics. The simulations show that using the method not only can improve the dynamic performance of the engine control system, but also can guarantee the stability in some occasions.Finally, this paper used the switching control design method to ramjet control system. The paper researched the demands and the constraints in designing the control system, and gave the dynamic characterisitics of sub-systems. Controlled paremeters and the models were given, and the uncertainties were investigated. Then through some simulations, the paper showed that using the method the safety can be guaranteed, and the performance can be got. With the method, the conservatism is reduced, the dynamic performance is improved and the multi-loop controllers are regulated well.更多还原