飞机直接力模态控制律设计

 本文应用特征结构配置理论提出了一种飞机直接力模态控制系统设计方法,即适当选取闭环特征向量使得飞机相应状态动态解耦,从而实现飞机直接力模态控制要求。本文为某型飞机设计了直接力两种模态——机身俯仰和垂直平移的控制器。     

Fault tolerant control system design with explicit consideration of performance degradation

A new approach is proposed for active fault tolerant control systems (FTCS), which allows one to explicitly incorporate allowable system performance degradation in the event of partial actuator fault in the design process. The method is based on model-following and command input management techniques. The degradation in dynamic performance is accounted for through a degraded reference model. A novel method for,selecting such a model is also presented. The degradation in steady-state performance is dealt with using a command input adjustment technique. When a fault is detected by the fault detection and diagnosis (FDD) scheme, the reconfigurable controller is designed automatically using an eigenstructure assignment algorithm in an explicit model-following framework so that the dynamics of the closed-loop system follow that of the degraded reference model. In the mean time, the command input is also adjusted automatically to prevent the actuators from saturation. The proposed method has been evaluated using the lateral dynamics of an F-8 aircraft against actuator faults subject to constraints on the magnitude of actuator inputs. Very encouraging results have been obtained.     

Unified Voltage and Pitch Angle Controller for Wind-Driven Induction Generator System

A unified voltage and pitch angle controller (UVPC) for a wind-driven induction generator system is presented to reach effective voltage control and to stabilize generator speed and system frequency. The proposed UVPC comprises a linear optimal controller (LOC), a supplementary voltage regulator (SVR), and a supplementary pitch angle controller (SPC). An ac voltage regulator and a dc voltage regulator are designed in the SVR to generate the desired voltage magnitude and phase angle for the voltage-sourced inverter (VSI). On the other hand, the SPC is designed based on fuzzy logic inference rules in order to generate the desired pitch angle command for the variable blade pitch such that the mechanical power can be controlled in a very efficient manner. When the system is operated in the islanding condition, an approach based on the concept of relative rotating speed has been developed for the measurement of system frequency deviation. Simulation and experimental results reveal that both bus voltage and mechanical power can be effectively controlled by the proposed UVPC for the wind energy conversion system (WECS) either connected with or disconnected from the power grid when there is sufficient wind energy.     

Analysis and tuning of a ‘Total Energy Control System’ control law using eigenstructure assignment

The Total Energy Control System (TECS) is a complete airplane longitudinal dynamics flight control concept for autopilot operational control modes and Fly-By-Wire command augmentation for civil airplanes. Unlike conventional strategies, it facilitates fully integrated control of the airplane elevator and engines. This system, which is based on simple proportional and integral control of the energy states of the airplane, is much easier to design and understand than most conventional airplane controllers.This paper describes why the high visibility of the two input, two output command augmentation structure of TECS is an improvement over current flight control system architectures. Deriving a control law for TECS is currently a heuristic process. However, there is potential for tuning to be done more systematically, and this is examined by using eigenstructure analysis and assignment. To illustrate the concepts, a linear model of the longitudinal dynamics of the Aerospace Technologies Demonstrator (ATD) airplane is used. A heuristically designed TECS controller for this model is first described. The controlled airplane is then analysed using eigenstructure analysis and the results are utilised to produce an improved TECS controller for the ATD model using eigenstructure assignment.     

BTT导弹的抖动抑制多模型切换控制

 基于线性系统特征结构配置和模型跟踪方法,以及优化工具,提出了可以有效抑制抖动的多模型切换控制策略,并用该策略设计了 BTT导弹俯仰 /偏航通道的自动驾驶仪。在导弹的整个飞行轨道上选取了若干点,分别建立起描述 BTT导弹俯仰 /偏航运动的线性时不变数学模型。对各个线性时不变模型,分别用特征结构配置方法设计反馈控制器对系统进行镇定。为了使导弹过载跟踪制导指令,又基于模型跟踪方法设计了前馈控制器。当导弹跨越不同特征点区域时,控制器要进行切换。为了减小切换时的抖动,针对切换后的特征结构配置反馈控制器,利用优化工具合理选取其自由度。仿真结果表明,所提出的方法令导弹的输出过载准确跟踪制导指令,而且切换抖动得到有效抑制。     

一种飞机大仰角飞行的模糊控制方法

提出了一种飞机大仰角飞行的动态逆模糊集成控制方法。首先使用动态逆方法求得系统的逆，使系统反馈线性化，然后，用具有在线规则自调整的模糊控制方法来确保系统的最终特性。该方法应用在高性能收音机俯仰机动指令系统的设计中，仿真结果表明，所设计的控制器满足操纵品质的要求，并且，在大仰角飞行时具有较好的鲁棒性。     

考虑多边界状态约束的飞翼布局无人机姿态控制

以大展弦比飞翼布局无人机为研究对象,针对强扰动环境下多边界状态约束时的飞行姿态控制问题,提出一种指令-控制律联合限制的全状态约束控制方法。该控制方法分别独立设计了指令边界限制器、过渡指令产生器和指令跟踪控制器3个部分。首先,基于无人机动力学特性设计的指令边界限制器,利用无人机的各个状态边界来限制姿态控制器的指令,实现了将非受控状态的约束问题转化为受控状态的约束问题;其次,基于"安排过渡过程"的思想并考虑约束限制环节,设计了过渡指令产生器,为无人机在线生成从当前姿态到期望跟踪姿态的过渡指令;最后,基于障碍Lyapunov函数和扩张状态观测器,设计了指令跟踪控制器,使无人机能够克服干扰且快速稳定地跟踪过渡指令。通过采用Lyapunov稳定性理论分析,该控制方法能够保证姿态跟踪误差收敛有界,且始终处于给定区间内部。仿真结果表明,该控制方法能够保证无人机飞行状态在不超出约束边界的同时,实现对姿态指令的准确跟踪。     

Digital Flight Control Research Using Microprocessor Technology

The Flight Research Laboratory at Princeton University is engaged in an experimental program to investigate a variety of approaches to digital control by actual flight test. Experimentation is being conducted with Princeton's 6-DOF variableresponse research aircraft (VRA), which is equipped for direct side-force control, direct-lift control, feedback of all motion variables, and multiple-pilot command modes. VRA avionics have been augmented by a microprocessor digital flight control system (Micro-DFCS), which uses off-the-shelf computer components capable of operating in parallel or in series with the existing variable-response system. The digital control laws operate in conjunction either with the "bare airframe" dynamics of the VRA or with the dynamics of a simulated aircraft, provided by the existing variable-response system. The initial flight control computer program CAS-1 provides three longitudinal control options: direct (unaugmented) command, pitch rate command, and normal acceleration command. The latter two options are "Type 0" systems designed by linear-quadratic control theory. Future Micro-DFCS software will provide a variety of increasingly complex control options, including "Type 1," logic, gain scheduling, coupled 3-axis control, and "CCV" command modes.     

飞机引导控制指令研究

飞机引导控制指令的选择直接影响到飞行控制性能,对引导控制指令的种类和优劣进行研究具有重要意义。首先,以纵向为例,分析认为可选择的引导控制指令有俯仰角指令、法向过载指令和垂直速率指令;然后,在几个合理假设的基础上,采用理论分析方法对上述三种引导控制指令进行比较,所得结论如下:在抑制风对迎角、高度的干扰,以及抑制参数摄动对高度的干扰等方面,能力由高到低分别为过载指令、垂直速率指令和俯仰角指令。最后,通过仿真对上述结论进行了辅助验证。     

特征结构配置在设计直接升力控制律中的应用

采用直接力控制可弥补常规飞机在轨迹操纵方面的不足,并产生某些新的运动模式。文中首先对飞机直接升力控制的3种基本运动模式进行了讨论。归纳出直接升力控制律的设计就是输出解耦控制系统的设计问题。在简述了用特征结构配置和模型跟踪技术求算反馈和前馈增益阵的主要步骤之后,以CitationⅡ型飞机为算例,设计了其直接升力控制律。计算结果是令人满意的,说明特征结构配置是一种设计飞行控制系统的有效方法。     

飞机机动指令生成器设计及蛇形机动仿真

分析了飞行仿真中飞机三自由度质点仿真模型机动指令生成器设计原理，并以蛇形机动飞行为例．建立了蛇形机动指令生成器数学模型。最后通过蛇形机动飞行仿真算例，验证了指令生成模型的合理性。结果表明，机动指令生成器能够完成仿真任务，从而将在飞机飞行仿真中得到广泛应用。     

具有迎角／过载限制器的俯仰增稳系统控制律的研究

本文以JJ-6飞机为例,研究了采用具有迎角/过载限制器的俯仰增稳系统对该机在大迎角下稳定性和操纵性的影响.并根据该机在大迎角下的偏离/失速运动机理,探讨系统中限制器边界值确定的原则。研究结果表明,该系统具有抗偏离/失速的能力,进而可以防止尾旋发生。但在大迎角下过大的横侧操纵,飞机仍能进入尾旋运动。     

飞机航路飞行的自动飞行仿真

给出了航路飞行自动飞行仿真的总体框架,介绍了采用分段线性函数描述控制指令的机动指令生成器算法,对机动指令跟踪器的控制律结构进行了设计,并对其参数进行了整定与调整。采用飞机六自由度模型对航路飞行过程进行了自动飞行仿真。仿真结果表明,飞机能够较好地完成航路飞行仿真任务。     

Online identification and control of linearized aircraft dynamics

An approach for online identification and control that requires weaker excitation than the existing approaches based on least-squares schemes and closed-loop systems is examined. It uses multiple-objective optimization theory to resolve the conflict between identification and controller performance as they compete for the only available resource, the inputs to the aircraft. The approach is applied to a longitudinal model of a representative linearized high-performance aircraft model. Simulation results compare the final controller with a conventional gain-scheduled pitch command augmentation system. It is demonstrated that by allowing some control input to be given to the identification process, the controller's overall performance is improved     

直升机控制增稳系统的一种综合设计方法

提出了特征结构配置/奇异值灵敏度分析/回路传递复现（LTR）综合设计方法,为某直升机在悬停飞行状态下,设计了控制增稳系统,并对飞机系统状态参数改变及由某个速度下过渡到飞机悬停状态的过渡过程进行了数字仿真。     

F/A-18E/F全自动着舰飞行特性分析

以F/A-18E/F舰载机为对象,针对航迹精确控制和安全性要求,分析了舰载机全自动着舰飞行特性。首先,基于自动着舰控制系统,建立了全自动着舰飞行控制系统的动力学模型;然后,对下滑轨迹纠偏与控制能力、控制器指令响应特性、变换下滑道机动特性进行了仿真分析。仿真结果表明,在全自动着舰安全边界范围内,舰载机能在较短时间内将航迹控制在理想下滑线附近;控制器具有良好的高度变化率、俯仰角、俯仰角速度等状态指令响应特性及控制面指令响应特性;F/A-18E/F变换下滑道机动则需要配合油门完成,说明仅通过平尾控制实现该机动并非安全着舰的必要条件。     

特征结构配置法及其在飞行控制系统设计中的应用

 本文研究了状态反馈系统的特征结构配置（Eigenstructure Assignment）问题。文中提出了配置具有多重特征值及复共轭特征值的特征结构的算法。并以某飞行控制系统的设计为例说明了算法的应用;最后还给出了设计方案的数字～模拟计算机仿真实验结果。     

武装直升机控制增稳系统的设计

用现代控制理论的方法对武装直升机进行控制增稳系统的设计。所给的状态方程为29阶,用内部平衡系统的性质来获得一个降阶模型,用特征结构配置的方法来设计一个控制器,模态解耦是通过特征向量的选型获得的。设计的结果表明,系统得到了良好的解耦效果及闭环特性,从而提高现代攻击直升机的操纵品质。     

无人机着陆控制的特征结构配置方法实现

针对无人机纵向着陆系统的控制需求,采用特征结构配置方法的设计方案。阐述了全状态反馈理论基础上的特征结构配置的原理以及根据设计指标确定特征结构配置的方法,并对某型无人机纵向飞控系统动态响应进行分析,给出仿真实例。仿真结果表明,应用特征结构配置方法设计出的控制器,能够使飞机准确地跟踪期望轨迹,满足系统动态性能要求。在工程中具有一定的实用价值     

俯仰姿态保持模式下飞机结冰边界保护方法

在研究飞机结冰机翼和平尾失速机理的基础上,以飞机迎角作为关键参数,飞机俯仰指令作为指令参数,提出一种基于飞机自驾仪的结冰后边界保护方法.通过引入铰链力矩检测模块,提前告警飞机失速,为边界保护提供了裕度.建立飞机纵向动力学方程,针对俯仰姿态保持（PAH）模式下机翼失速进行了仿真计算.结果表明:结冰条件下,通过铰链力矩的检测,飞机能在失速迎角为2°之前,进入边界保护模式,增加飞行安全的裕度.通过控制指令的限制,自动驾驶模式下飞机迎角能保持在失速迎角之内.