一类级联系统的单控制器设计

本文研究了由３个子系统构成的级联系统的单控制的设计方法,并给出了用单控制器保证级联系统终极一致有界的条件。     

一类非线性系统的神经网络自适应控制

针对一类单输入单输出不确定非仿射型非线性系统,基于多层神经网络提出了一种直接自适应控制方法。该设计方法首先应用多层神经网络自适应模拟逼近逆解中的未知部分,然后应用逆设计和自适应反演设计出虚拟控制量,最后应用反馈线性化设计方法和神经网络设计了直接自适应控制律。并利用Lyapunov稳定性定理推导了神经网络的参数调节律,保证了闭环系统的所有信号均最终一致有界。     

航空发动机神经网络反步控制方法

针对航空发动机非线性和不确定性的特点,提出了一种基于神经网络的反步控制方法.采用径向基神经网络估计未知系统方程,并用一种平滑切换法有效避免了控制器奇异问题.反步法的设计基于Lya-punov稳定性原理,保证了闭环系统一致渐近有界.最后针对某型涡扇发动机非线性模型设计了高压转速控制器,仿真结果验证了该方法的有效性.      

不对称推力完全自动补偿技术

研究了一种适用于多发飞机的不对称推力完全自动补偿策略,并针对发动机失效后的不对称推力飞行特性进行研究。首先,推导了横航向达到平衡状态的条件,提出了一种基于发动机转子转速信号的自动补偿控制方法,在保证补偿效果的同时,解决了自动补偿系统可靠性低的问题,该自动补偿控制方法将高压转子转速信号与低压转子转速信号进行逻辑运算,结合高压转子转速差控制副翼和方向舵偏转,再与主飞行控制系统共同作用使飞机达到平衡状态。然后,基于横航向主飞行控制系统具有滚转角保持功能的特点,优化自动补偿控制系统。最后,全包线内建立飞机达到平衡状态的线性化数学模型,设计了不对称推力完全自动补偿控制律。通过MATLAB/Simulink建模并进行仿真验证,仿真结果表明完全自动补偿控制方法对不对称推力飞行具有良好的补偿效果。     

Non-affine parameter dependent LPV model and LMI based adaptive control for turbofan engines

The precise control of turbofan engines thrust is an important guarantee for an aircraft to obtain good flight performance and a challenge due to complex nonlinear dynamics of engines and time-varying parameters. The main difficulties lie in the following two aspects. Firstly, it is hard to obtain an accurate kinetic model for the turbofan engine. Secondly, some model parameters often change in different flight conditions and states and even fluctuate sharply in some cases. These variable parameters bring huge challenge for the turbofan engine control. To solve the turbofan engine control problem, this paper presents a non-affine parameter-dependent Linear Parameter Varying(LPV) model-based adaptive control approach. In this approach, polynomial-based LPV modeling method is firstly employed to obtain the basis matrices, and then the Radial Basis Function Neural Networks(RBFNN) is introduced for the online estimation of the non-affine model parameters to improve the simulation performance. LPV model-based Linear Matrix Inequality(LMI) control method is applied to derive the control law. A robust control term is introduced to fix the estimation error of the nonlinear time-varying model parameters for better control performance. Finally, the Lyapunov stability analysis is performed to ensure the asymptotical convergence of the closed loop system. The simulation results show that the states of the engine can change smoothly and the thrust of the engine can accurately follow the desired trajectory, indicating that the proposed control approach is effective. The contribution of this work lies in the combination of linear system control and nonlinear system control methods to design an effective controller for the turbofan engine and to provide a new way for turbofan engine control research.     

CFM56-3发动机可变几何控制系统对发动机性能的影响

CFM56-3发动机目前广泛应用于民航干线飞机,其可变几何控制系统由可调放气活门(Variable BleedValve)和可调静子叶片(Variable Stator Vane)子系统组成,工作情况直接决定着发动机能否稳定可靠地工作.系统介绍和全面分析了CFM56-3发动机可变几何控制系统的构成与控制原理和对发动机性能的影响,为排除该系统故障提供了依据.     

Design for aircraft engine multi-objective controllers with switching characteristics

The aircraft engine multi-loop control system is described and the switching control theory is introduced to solve the regulating and protecting control problems in this paper. The aircraft engine multi-loop control system is firstly described and the control problems are formulated. Secondly, the theory of the smooth switching control is devoted and a new extended scheme for the smooth switching of a switched control system is introduced. Then, for the key technologies of aero-engines switching control, a design algorithm is presented which can determine which candidate controller should be put in feedback with the plant to achieve a desired performance and the procedure to design the aircraft engine multi-loop control system is detailed. The switching performance objectives and the switching scheme are given and a family of PID controllers and compensators is designed. The simulation shows that using the switching control design method can not only improve the dynamic performance of the aircraft engine control system and reduce the switching times, but also guarantee the stability in some peculiar occasions.     

Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes

An adaptive sliding mode control(ASMC) law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot.Each joint of the system is a free ball joint capable of rotating with three degrees of freedom(DOF).A cluster of control moment gyroscopes(CMGs) is mounted on each link and the base to actuate the system.The modified Rodrigues parameters(MRPs) are employed to describe the angular displacements,and the equations of motion are derived using Kane's equations.The controller for each link or the base is designed separately in decentralized scheme.The unknown disturbances,inertia parameter uncertainties and nonlinear uncertainties are classified as a ‘‘lumped" matched uncertainty with unknown upper bound,and a continuous sliding mode control(SMC) law is proposed,in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty.A general amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input.Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov's method.Simulation results based on a three-link system verify the effectiveness of the proposed controller.     

Control and stabilization of nonlinear uncertain elastic roboticarm

An approach is presented to the control of an uncertain nonlinear flexible robot arm (PUMA-type) with three rotational joints. The third link is assumed to be elastic. A torquer control law, which is a function of the trajectory error, is derived for controlling the joint angles. The knowledge of the system dynamics is not required for the derivation of the controller. This controller includes a reference model to generate command joint angle trajectories, and a dynamic system in the feedback path which requires only joint angle and rate for feedback. The torquer controller asymptotically decouples the elastic dynamics into two subsystems, representing the transverse vibration of the elastic link in two orthogonal planes. For the damping of the elastic vibration, a force control law using modal velocity feedback is synthesized. Simulation results are presented to show that the combination of the torque and force control law accomplishes reference joint angle trajectory tracking and elastic mode stabilization despite the uncertainty in the system     

自适应变循环发动机性能优势评价方法

为了综合评价自适应变循环发动机相比常规涡扇发动机的性能优势,提出了从发动机耗油率降低和质量增加2个维度以及从发动机耗油率、飞机燃油消耗量和燃油效率之间关系的角度来评价自适应变循环发动机性能的2种方法。结果表明:发动机耗油率降低和质量增加之间存在某个平衡点,只有质量增加幅度小于耗油率降低幅度时,才能体现自适应变循环发动机的性能优势,并且飞机航程越长,越能体现自适应变循环发动机耗油率降低带来的优势;发动机耗油率、飞机燃油消耗量和燃油效率之间呈指数关系变化,当假设飞机巡航航程为3500 km、飞机升阻比为10.5时,自适应变循环发动机巡航耗油率相比常规涡扇发动机的降低1%,可使飞机燃油消耗量减少约1.9%,飞机燃油效率提高约2.4%。     

基于自适应滑模观测器的航空发动机故障诊断

为解决现有航空发动机基于模型的在线故障诊断方法存在对模型精度要求高等的问题,利用滑模方法设计一种自适应滑模观测器对航空发动机进行在线故障重构、诊断与隔离。对传感器故障和执行机构故障分别设计了重构算法,针对两者重构故障的特点提出了判断逻辑,讨论了设计参数对于观测效果与抖振的影响。 Matlab/Simulink仿真结果显示,重构的故障与实际故障基本吻合,对故障的诊断、隔离、定位具有良好效果,并对环境不确定性具有优良的鲁棒性。     

DECENTRALIZED ROBUST CONTROL FOR UNCERTAIN FLEXIBLE SPACE STATION

ＤＥＣＥＮＴＲＡＬＩＺＥＤＲＯＢＵＳＴＣＯＮＴＲＯＬＦＯＲＵＮＣＥＲＴＡＩＮＦＬＥＸＩＢＬＥＳＰＡＣＥＳＴＡＴＩＯＮＷａｎｇＱｉｎｇ；ＣｈｅｎＸｉｎｈａｉ（ＣｏｌｌｅｇｅｏｆＡｓｔｒｏｎａｕｔｉｃｓ，ＮｏｒｔｈｔｖｅｓｔｅｒｎＰｃｌｙｔｅｃｈｎｉｃａ...     

一种直升机自旋训练过程涡轴发动机控制规律设计与仿真

针对直升机自旋训练过程中涡轴发动机快速响应要求,提出了一种以燃油流量和导叶角为控制量的鲁棒控制规律抑制自由涡轮转速瞬态下垂.首先,通过改进UH-60直升机/T700发动机综合模型,使之能够模拟自旋进入及自旋恢复过程动态变化.其次,提出并设计一种基于燃油流量和导叶调节的涡轴发动机鲁棒控制规律,并通过典型的自旋训练过程仿真,验证了该控制规律相比仅以燃油流量为变量的控制规律,自由涡轮转速瞬态下垂量降低至3%以下,且燃油流量变化更加平缓,改善了执行机构的工作条件.     

基于相似理论的航空发动机风扇转速换算方法的改进

基于相似理论提出一种通过变指数因子计算航空发动机风扇换算转速的改进方法.收集不同公司的某型航空发动机的巡航数据建立数据样本.采用支持向量回归机方法建立指数因子与大气温度的数学模型并利用遗传算法对模型参数进行寻优,进而得到由风扇指示转速和大气温度计算风扇换算转速的变指数因子模型.使用该模型对样本数据进行计算,并把结果与定指数因子方法求解的风扇换算转速进行对比,对改进算法与定指数法换算结果进行了误差分析.结果表明:改进后的变指数因子模型计算的航空发动机风扇换算转速具有更高的精度,同时具有良好的推广泛化性能,该方法是航空发动机风扇换算转速的一种有效算法,在航空发动机性能预测也具有实际的指导意义.      

有约束的航空发动机加速最优控制

本文研究了采用非线性最优化程序解航空发动机加速最优控制问题的方法。非线性最优化程序采用的约束变尺度法,发动机采用非线性模型。论文论述了目前发动机加速优化问题研究的一般情况;应用非线性最优化程序,采用非线性发动机模型解最优加速控制问题的基本方法;优化方法的选择问题;发动机模型的建立过程;应用约束变尺度法解最优加速控制问題的几个技术问题:对一些典型的计算结果进行了分析;最后提出了需进一步研究的几个问题。     

基于LMI的不确定线性系统观测器设计

研究了不确定线性系统的观测器设计问题。利用凸优化理论将基于线性矩阵不等８式（ ＬＭＩ）的观测器设计转换为鲁棒控制器设计,给出了标准的ＬＭＩ形式。采用该方法的设计过程只需求解三个线性矩阵不等式就可得到鲁棒控制器。在航空发动机控制应用中表明,基于ＬＭＩ的观测器对于具有干扰的系统仍然能保持系统稳定,数值仿真表明控制效果优于文献「１」的结果。     

发动机非包容性转子失效布置与防护设计

民用飞机发动机服役经验表明:发动机非包容性转子失效仍会发生。为将这种非包容性转子失效可能带来的危害降至最低,基于一种发动机翼吊式安装的民用飞机,结合咨询通告AC20-128A的要求以及民用飞机设计的工程经验,开展了飞机内部系统布置和结构防护设计研究。首先介绍了减小发动机非包容性转子失效危害的设计流程和分析模型,其次从民航局审查关注的角度,重点阐述了不可控制的着火、推力损失、飞机操纵的损失、对乘客和机组人员的保护和结构完整性等五个方面的设计思路和方法。研究结果表明:飞机设计时,通过采取将关键部件和系统移出碎片影响区、冗余设计、提供可接受的防护等预防措施来减小发动机非包容性转子失效对飞机的危害,对发动机非包容性转子失效的设计和适航验证具有指导意义。     

基于适航要求的飞机和发动机多余度信号表决设计

为保证机双发或4发在相同油门杆/操纵杆角度下的推力/功率一致,发动机控制系统可使用来自飞机的环境温度、压力信号。适航要求当飞机信号发生错误时发动机推力变化不超过3%,因此发动机控制系统需要具备飞机信号容错能力。为满足以上要求,以发动机传感器信号为基准,根据适航条件计算飞机各信号的加权系数,综合发动机传感器基准信号、飞机信号加权系数及其优先级顺序,设计出飞发系统之间多余度信号加权平均综合表决算法。结果表明：利用该算法,在同时满足飞机多台发动机推力一致性需求和适航要求的前提下,可选择出精度、可信度较高的信号,在信号选择状态发生变化时,能够保证发动机推力平稳过渡。     

基于模式重要度的航空电源系统可靠性估计

针对航空电源系统可靠性分析的需要,研究现有典型系统的结构特点,提出基于模式重要度的系统可靠性估计方法。该方法首先根据航空电源各子系统的组成,采用蒙特卡罗方法对各子系统可靠性进行分析。根据子系统中各部件的模式重要度,建立子系统可靠性估计模型,进而获取并联系统和总系统的可靠性估计模型。该方法结合了蒙特卡罗方法的优势和系统本身的结构特点,既解决了复杂航空电源系统可靠性分析的难题,又克服了单纯采用蒙特卡罗方法对其进行分析时,仿真效率较低的问题。最后,采用所提出的方法对两种类型的电源系统进行仿真分析,并与单纯蒙特卡罗方法仿真分析结果进行比较,验证了该方法的可行性和有效性。     

航空发动机试车数据分析软件简介

介绍了使用高级程序设计语言Visual Basic开发的航空发动机试车数据分析软件的构成、功能和特点。实际应用与试验对比证明,该软件不仅结果准确,而且省时、简便、实用性强。