基于AFSMC算法的飞机飞行姿态自适应滑模控制系统

传统飞机飞行姿态滑膜控制系统,存在飞机飞行姿态自适应系数稳定性差的问题,在控制过程中会受到多重因素影响,导致飞行姿态可控误差系数增大,需要辅助控制系统修正才能完成飞行姿态的控制操作;针对上述问题,提出基于AFSMC算法的飞机飞行姿态自适应滑模控制系统;系统硬件基于PID自适应滑模控制器,对飞机飞行姿态控制器进行结构设计;软件部分通过引入自适应滑模控制策略,对PID控制器姿态控制变量进行适配;引入AFSMC算法计算姿态控制器当前时间点下的运动控制方程,得到飞行姿态自适应滑模控制的最优量,完成基于AFSMC算法的飞机飞行姿态自适应滑模控制系统设计;实验结果表明,所设计系统能够在不同飞行工况下,对飞机飞行姿态作出准确控制,系统的整体控制精度范围为90%~97.4%,飞机飞行控制稳定性较好,有效提升了系统对飞机飞行姿态的控制准确度。     

Fighter aircraft lateral directional axes full envelope control law design

A decoupled wide envelope lateral/directional axes control design is presented for a supermanoeuvrable version of an F-18 aircraft. A control structure is developed that separates gain scheduling issues from aircraft performance issues. Flight condition dependent state and control effectiveness variations are accounted for by an inner loop controller designed using eigenstructure assignment. Structured singular value synthesis is used to design an implicit model following outer loop controller that addresses flying qualities performance specifications. A control selector is designed that generates lateral/directional aerodynamic and thrust vectoring commands from generalized control inputs of roll and yaw acceleration. Flying qualities and robustness analyses show that the control system performs well despite neglected dynamics and system uncertainties. Nonlinear simulations are presented showing excellent decoupling of roll and yaw responses.     

垂直起降飞机的全局轨迹跟踪控制

研究垂直起降飞机在任意输入耦合作用下的轨迹跟踪控制问题．垂直起降飞机是具有3个自由度、2个控制输入的欠驱动系统．首先通过控制输入和坐标变换,使飞机的动力学方程变换成严格反馈形式;然后基于后推法的思想推导出保证系统渐近收敛于参考轨迹的时变反馈控制规律．该方法将系统分解为低阶子系统来处理,利用中间虚拟控制变量和部分Lyapunov函数筒化了控制器的设计．仿真结果表明所设计的控制器是有效的．     

飞机除冰车加热系统的P-Fuzzy-PID控制

根据新型飞机除冰车加热系统的实验数据及其工作原理,建立了加热系统数学模型,并针对该系统的大迟延和模型不确定性,将基于模糊规则切换的P-Fuzzy-PID多模控制引入到加热系统的温度控制中。理论分析和仿真结果表明,应用这种方法所设计出的飞机除冰车加热系统,在稳定时间和稳态精度方面均优于单一的PID控制和模糊控制。该研究具有一定的实用价值,为P-Fuzzy-PID控制在飞机除冰车加热系统中的应用打下理论基础。     

Nonlinear Fly‐By‐Throttle H∞ Control Using Neural Networks

A neural network approach to gain scheduling H∞ controllers for propulsion controlled aircraft (PCA) systems is introduced. The PCA system is applied to backup control of aircraft experiencing control surface failure. The H∞ technology is applied to the problem of matching the crippled aircraft and the nominal model. Various H∞ controllers at various flight conditions are used to train radial basis function networks (RBFN), which can then be used as the nonlinear controller. Simulation on an L‐1011 under fly‐by‐throttle control demonstrates that the RBFN controller can stabilize the crippled airplane to obtain the desired model and possesses robustness against the engine delay.     

Passification-based robust flight control design

A passification-based robust autopilot for attitude control of flexible aircraft under parametric uncertainty is designed. A high gain controller with forced sliding motions is used to secure good performance over a wide range of the aircraft model parameters. The shunting method is applied to ensure closed-loop system stability under lack of aircraft state information. The series reference model is used to assign the desired closed-loop system performance. An example illustrating a typical design procedure for aircraft attitude control in the horizontal plane for different flight conditions is given. The simulation results demonstrate the efficiency and high robustness of the suggested control system.     

Adaptive actuator failure compensation for nonlinear MIMO systems with an aircraft control application

A direct adaptive approach is developed for control of a class of multi-input multi-output (MIMO) nonlinear systems in the presence of uncertain failures of redundant actuators. An adaptive failure compensation controller is designed which is capable of accommodating uncertainties in actuator failure time instants, values and patterns. A realistic situation is studied with fixed grouping of actuators and proportional actuation within actuator groups. The adaptive control system is analyzed, to show its desired stability and asymptotic tracking properties in the presence of actuator failure uncertainties. As an application, such an adaptive controller is used for actuator failure compensation of a twin otter aircraft longitudinal model, with design conditions verified and control structure and adaptive laws developed for a nonlinear aircraft dynamic model. The effectiveness of adaptive failure compensation is demonstrated by simulation results.     

Direct adaptive neural flight control system for an unstable unmanned aircraft

A direct adaptive controller design using neural network is proposed for an unstable unmanned research aircraft similar in configuration to combat aircraft. The control law to track the pitch rate command is developed based on system theory. Neural network with linear filters and back propagation through time learning algorithm is used to approximate the control law. The bounded signal requirement to develop the neural controller is circumvented using an off-line finite time training scheme, which provides the necessary stability and tracking performances. On-line learning scheme is implemented to compensate for uncertainties due to variation in aerodynamic coefficients, control surface failures and also variations in center of gravity position. The performance of the proposed control scheme is validated at different flight conditions. The disturbance rejection capability of the neural controller is analyzed in the presence of the realistic gust and sensor noises. Hardware-in-loop simulation is also carried out to study the behavior of control surface deflections in real-time.     

控制面故障下的飞机运动建模与重构控制能力分析及设计

对控制面故障影响飞机运动的机理进行了推导,系统地阐述了控制面故障下的飞机运动建模方法。在建模的基础上,对故障系统的可重构性进行研究。分别从线性系统运动和物理运动两个方面,给出了可重构能力的评定方案。推导了误差反向传播的前向神经网络用于控制系统设计时满足Lyapunov稳定性的学习算法,提出了一种新型的采用反向传播神经网络补偿常规控制器的重构飞行控制设计方案。采用非线性飞机运动模型对控制器进行了仿真,验证了重构飞行控制器的性能。     

弹性飞机的QFT控制器设计

以某弹性飞机纵向模型为例,考虑模型的不确定性及外部扰动,应用定量反馈理论设计了其俯仰姿态保持系统.仿真结果表明,利用该理论方法设计的控制器能很好地抑制弹性飞机的结构弹性变形,具有良好的鲁棒性,并取得了满意的控制效果,证明了该方法在弹性飞机控制律设计中的有效性和实用性.     

基于GSAGA的模糊PID控制在自动油门系统中的应用研究

针对现代民用飞机非线性和时变的特点,设计了一种用于民机自动油门控制系统的模糊PID控制器;模糊控制器以速度跟踪误差及其微分信号作为输入调节PID控制器的比例、积分及微分参数,进而控制油门开度以调节发动机推力,最终实现对速度的控制;文中进一步采用广义自适应遗传算法(GSAGA)对模糊PID控制器的输出因子进行优化,在着陆模态下采用所设计的优化控制策略与传统模糊PID控制进行了对比仿真,仿真结果显示,在民机自动油门控制系统中基于GSAGA的模糊PID控制器的控制效果优于传统模糊控制方法,仿真结果符合飞行品质指标,控制效果良好。     

倾转旋翼机平均驻留时间切换鲁棒H∞跟踪控制

针对倾转旋翼飞行器模态转换阶段的飞行控制问题,本文给出了倾转旋翼机纵向运动飞行控制系统模型和一种基于参考模型的鲁棒跟踪控制方法.为了保证闭环系统在切换过程中稳定并同时满足指定的鲁棒H∞性能指标,利用状态观测器对系统不可观测状态进行估计,结合模型依赖平均驻留时间方法提出了一种倾转旋翼机切换鲁棒H∞跟踪控制方法,通过求解线性矩阵不等式得到控制器增益,并分析了系统的鲁棒稳定性.仿真结果表明,所提出的方法能够使飞行器系统准确跟踪指令,且对于控制器切换具有鲁棒性.     

Hierarchical control of aircraft propulsion systems: Discrete event supervisor approach

This paper presents an application of the recently developed theory of language-measure-based discrete event supervisory (DES) control to aircraft propulsion systems. A two-layer hierarchical architecture is proposed to coordinate the operations of a twin-engine propulsion system. The two engines are individually controlled to achieve enhanced performance and reliability, as necessary for fulfilling the mission objectives. Each engine, together with its continuously varying control system, is operated at the lower level under the supervision of a local discrete-event controller for condition monitoring and life extension; the gain-scheduled feedback controller that is used to maintain the specified performance of the turbofan engine is kept unaltered. A global DES controller at the upper level coordinates the local DES controllers for load balancing and health management of the propulsion system.     

Optimal terrain-following for towed-aerial-cable sensors

Towed-aerial cable systems are often used for towing decoys from aircraft and for collecting electromagnetic data from low altitudes. Airborne cable systems are typically controlled by maneuvering the aircraft, which can limit the safe altitude of the towed-sensor package. In this paper, a real-time optimal control strategy for controlling a towed-cable system is proposed that uses cable winch control to control the altitude of the towed-body. The controller is based on a receding horizon control approach, where the aircraft senses the terrain profile ahead of the towed-body with a relatively short time horizon. This information is sent to the controller, which updates the cable winch reel acceleration to safely avoid colliding with the terrain, while keeping the towed-sensor close to the desired altitude for obtaining good measurements. The controller is developed for a simplified system model and implemented in a multibody cable system model that incorporates cable flexibility and elasticity.     

Robust H ∞ and adaptive tracking control against actuator faults with a linearised aircraft application

This article studies the problem of designing adaptive fault-tolerant H _∞ tracking controllers for a class of aircraft flight systems against general actuator faults and bounded perturbations. A robust adaptive state-feedback controller is constructed by a stabilising controller gain and an adaptive control gain function. Using mode-dependent Lyapunov functions, linear matrix inequality-based conditions are developed to find the controller gain such that disturbance attenuation performance is optimised. Adaptive control schemes are proposed to estimate the unknown controller parameters on-line for unparametrisable stuck faults and perturbation compensations. Based on Lyapunov stability theory, it is shown that the resulting closed-loop systems can guarantee asymptotic tracking with H _∞ performances in the presence of faults on actuators and perturbations. An application to a decoupled linearised dynamic aircraft system and its simulation results are given.     

基于干扰抑制控制的飞行器姿态跟踪

本文针对飞行器姿态跟踪控制问题, 考虑系统的内部模型不确定性和外界扰动, 设计了使跟踪误差一致最终有界的控制器. 以四元数为姿态参数, 建立系统的非线性误差模型; 将控制系统分为内环观测器和外环控制器分别设计, 其中, 线性扩张状态观测器作为系统内环将实际系统补偿为标称模型, 而外环非线性控制器则用于镇定非线性标称系统. 最后, 利用Lyapunov理论得到了一致最终有界的稳定性结论, 并基于频域理论, 分析了线性扩张状态观测器阶次对系统性能的影响. 姿态跟踪实验表明, 本文设计的控制系统能够有效实现飞行器的姿态跟踪控制.     

Application of generalised neural network for aircraft landing control system

 It is observed that landing performance is the most typical phase of an aircraft performance. During landing operation the stability and controllability are the major considerations. To achieve a safe landing, an aircraft has to be controlled in such a way that its wheels touch the ground comfortably and gently within the paved surface of the runway. The conventional control theory found very successful in solving well defined problems, which are described precisely with definite and clearly mentioned boundaries. In real life systems the boundaries can't be defined clearly and conventional controller does not give satisfactory results. Whenever, an aircraft deviates from its glide path (gliding angle) during landing operation, it will affect the landing field, landing area as well as touch down point on the runway. To control correct gliding angle (glide path) of an aircraft while landing, various traditional controllers like PID controller or state space controller as well as maneuvering of pilots are used, but due to the presence of non-linearities of actuators and pilots these controllers do not give satisfactory results. Since artificial neural network can be used as an intelligent control technique and are able to control the correct gliding angle i.e. correct gliding path of an aircraft while landing through learning which can easily accommodate the aforesaid non-linearities. The existing neural network has various drawbacks such as large training time, large number of neurons and hidden layers required to deal with complex problems. To overcome these drawbacks and develop a non-linear controller for aircraft landing system a generalized neural network has been developed.     

MIMO conditional integrator control for unmanned airlaunch

A nonlinear MIMO controller based on the conditional integrator technique is designed for the robust stabilization of a new satellite launching strategy called (unmanned) airlaunch. This control technique concerns an integrator performing similar to a sliding mode controller when the system is outside a boundary layer defined by the controller, and performing as a linear controler that provides the integral term when the system enters into the boundary layer. Satellite airlaunch strategy consists in using a two‐stage launching system. The first stage is composed of an airplane (manned or unmanned) that carries a rocket launcher, which constitute the subsequent stages. The control objective is to stabilize the aircraft in the launch phase. It is developed separately for the two nonlinear (one MIMO and one SISO) motion modes of the model, the longitudinal mode and lateral mode, and is then applied to the full model of the aircraft. The considered system is highly nonlinear, mostly as a consequence of a possible large angle of attack, sideslip, and roll angle. Finally, the present work illustrates through simulations, the good performance of the proposed control algorithm. Copyright © 2013 John Wiley & Sons, Ltd.     

飞机俯仰运动自抗扰控制器设计

提出了利用自抗扰控制器在大包线范围内设计飞机俯仰运动控制器的新方法．利用二阶自抗扰控制器补偿系统模型扰动和外扰，实现了纵向运动俯仰角变量的跟踪控制．自抗扰控制器直接依据飞机的非线性模型，符合飞机动力学模型摄动大的特点，在很大的包线范围内不需要改变控制器的结构和参数，简化了飞行控制律的设计过程．大包线范围内的仿真结果表明，系统具有良好的动态和稳态性能，控制器具有很强的鲁棒性，为解决大包线范围内的飞行控制问题提供了一种有效的新途径．     

Observer‐based attack‐resilient control for linear systems against FDI attacks on communication links from controller to actuators

For the adversarial attacks on the communication links from the controller to the actuators, most of the existing attack‐resilient control results focus on denial‐of‐service attacks. Unlike the existing results, this paper studies the observer‐based attack‐resilient control problem for linear systems with false data injection attacks and process disturbances. Due to limited resources, the malicious attacker is assumed to only manipulate a certain number of communication links from the controller to the actuators. A novel control architecture is proposed, which consists of an attack‐resilient state observer, a controller gain scheme, and a supervisory switching strategy. The observer is developed based on the maximin strategy, and state estimation will be used to construct the controller. The switching strategy is designed to pick an appropriate controller gain and prevent the attack signals from entering the plant automatically. It is shown that the closed‐loop system is stable with an attack‐resilient performance. Finally, to verify the effectiveness of the proposed controller, simulation results on a linearized reduced‐order aircraft system and an IEEE six‐bus power system are provided.