飞翼布局无人机控制律设计

以某飞翼布局无人机为设计对象,进行内、外回路的控制律设计.在Matlab/Simulink仿真环境下,建立飞翼布局无人机线性小扰动模型,分析纵向、横航向模态特性,根据本体特性缺陷针对性地设计控制律内回路反馈支路及增益,经反馈补偿后的飞行品质满足GJB 185-1986相关要求.在内回路控制律的基础上设计外回路PI控制器...     

基于线性化反馈的滑模变结构重装空投纵向控制律设计

针对重装空投过程中,重型货物持续移动及瞬间离机严重影响载机的安全性等问题,提出了基于线性化反馈和滑模变结构控制相结合的控制律设计方法,利用非线性多输入多输出反馈线性化完成系统解耦线性化,在此基础上采用滑模变结构控制设计系统内环速度与俯仰姿态跟踪控制器,保证了系统鲁棒性,结合外环PID高度保持控制器完成整个飞行控制系统的设计.最后,仿真验证了该控制器鲁棒性强,且满足空投任务战技指标要求.     

Flight controller design for uncertain and nonlinear plants with pilot compensation

Nonlinear quantitative feedback theory (QFT) is used to design a flight control system for the nonlinear model of the YF-16 aircraft (A/C) with C* as the controlled output. The resulting closed loop stability augmentation system (SAS), P_e(S), becomes part of the outer loop containing the pilot. The Neal-Smith pilot model for a compensatory tracking task is used to develop a technique which allows the designer to synthesize compensation in the outer loop, which includes a free compensator F_p(S). The latter is chosen to minimize pilot workload, increase system bandwidth, and improve handling qualities ratings as per the Neal–Smith criteria, for the tracking task. The available pilot compensation abilities are then available for further increasing of system bandwidth to improve overall capabilities. This approach can be used at the early stages of flight control design, thus saving time and money over the current practice. Simulations in the time and frequency domains demonstrate that the desired performance is attained.     

基于扩张状态观测器和反步滑模法的四旋翼无人机轨迹跟踪控制

为了解决欠驱动四旋翼无人机（UAV）在实际飞行中存在的外界干扰问题,同时提高在系统参数摄动情况下的精确轨迹跟踪效果,设计了一种基于扩张状态观测器（ESO）和积分型反步滑模算法的飞行控制策略。首先,根据系统的半耦合特性和严反馈结构特点,采用反步法设计姿态内环和位置外环控制器;然后,将抗干扰能力较强的滑模控制融入其中,使得系统的鲁棒性得到增强;接着,为了减小系统的稳态误差,引入积分环节;最后,利用ESO实时估算出系统的内、外总扰动并对控制量进行补偿。通过Lyapunov稳定判据,可以说明该系统是一个全局渐进稳定的系统,并通过仿真分析验证了所提控制方法的有效性和鲁棒性。     

Design and Implementation of a Flight Control System for an Unmanned Rotorcraft using RPT Control Approach

In this paper, we apply a so‐called robust and perfect tracking (RPT) control technique to the design and implementation of the flight control system of a miniature unmanned rotorcraft, named HeLion. To make the presented work self‐contained, we will first outline some background knowledge, including mainly the nonlinear flight dynamics model and the inner‐loop flight control system design. Next, the highlight of this paper, that is, the outer‐loop flight control system design procedure using RPT control technique, will be detailed. Generally speaking, RPT control technique aims to design a controller such that (i) the resulting closed‐loop system is asymptotically stable, and (ii) the controlled output almost perfectly tracks a given reference signal in the presence of any initial conditions and external disturbances. Since it makes use of all possible information including the system measurement output and the command reference signal together with all its derivatives (if available) for control, RPT control technique is particularly useful for the outer‐loop layer of an unmanned aircraft. Both simulation and flight‐test results will be presented and analyzed at the end of this paper, and the efficiency of the RPT control approach will be evaluated comprehensively.     

Design of robust redundancy relations for a semi-scale YF-22 aircraft model

This paper presents an “ad hoc” methodology for the design of diagnostic software for the detection and isolation of faults on sensors and actuators of a remotely controlled semi scale YF-22 research aircraft. Starting from the structural analysis of the nonlinear dynamic equations of the aircraft, an algorithm, based on the “variables elimination method”, is proposed to compute a set of residual equations having all the possible fault signatures. The quality of each residual equation has been ranked according to a cost function chosen to represent implementation issues such as the sensitivity to measurement noise in the numerical computation of high order derivatives. An algorithm is then proposed for selecting a subset of residual equations with maximum “failure isolability” and minimum cost, according to the selected performance criteria. The issue of robustification of the residual equations to modeling errors and measurement noise has been addressed through nonlinear uncertainty mapping using Neural Networks in conjunction to FIR filters. The fault detection and isolation method has been applied by injecting simulated faults to flight data collected by a semi-scale YF-22 research aircraft model.     

四旋翼无人飞行器控制算法设计

针对Qball-X4四旋翼无人飞行器的自身特点,建立系统的非线性模型,采用姿态内环和位置外环的双闭环控制算法。线性二次型调节器（LQR）可以快速简便地求解出最优的状态反馈控制率,并且具有良好的鲁棒性,因而利用LQR控制算法来控制姿态内环。由于PID控制算法结构简单、鲁棒性强,因而控制位置外环。通过Matlab/Simulink和飞行试验对控制算法进行仿真和验证,结果表明,设计的控制算法能成功地实现飞行器的悬停控制,并达到较好的控制效果。     

Multi-input,multi-output flight control system design for the YF-16 using nonlinear QFT and pilot compensation

Nonlinear quantitative feedback theory (QFT) and pilot compensation techniques are used to design a 2 × 2 flight control system for the YF-16 aircraft over a large range of plant uncertainty. The design is based on numerical input-output time histories generated with a FORTRAN implemented nonlinear simulation of the YF-16. The first step of the design process is the generation of a set of equivalent linear time-invariant (LTI) plant models to represent the actual nonlinear plant. It has been proven that the solution to the equivalent plant problem is guaranteed to solve the original nonlinear problem. Standard QFT techniques are then used in the design synthesis based on the equivalent plant models. A detailed mathematical development of the method used to develop these equivalent LTI plant models is provided. After this inner-loop design, pilot compensation is developed to reduce the pilot's workload. This outer-loop design is also based on a set of equivalent LTI plant models. This is accomplished by modelling the pilot with parameters that result in good handling qualities ratings, and developing the necessary compensation to force the desired system responses.     

Adaptive control laws for F-8 flight test

This paper describes an adaptive flight control system design for NASA's F-8 digital fly-by-wire research aircraft. This design implements an explicit parallel maximum likelihood identification algorithm to estimate key aircraft parameters. The estimates are used to compute gains in simplified quadratic-optimal command augmentation control laws. Design details for the control laws and identifier are presented, and performance evaluation results from NASA Langley's F-8 Simulator are summarized.     

小型无人直升机悬停小速度段位置控制技术

无人直升机在悬停/小速度飞行阶段具有特殊的物理特性,给控制系统的设计带来了诸多技术难题;针对无人直升机悬停/小速度段位置控制的需求,提出了一种基于"姿态角阻尼内回路"的位置控制结构,该控制结构采用内回路姿态角阻尼增稳,外回路位置控制的控制方式;并且针对增稳回路自适应性、抗风补偿和位置控制精度等问题,分别采用前馈自动配平机制与非线性PID控制方法对常规控制律进行改进;仿真验证表明,所提出的控制策略和控制律设计结果达到了较好的控制效果。     

Application of two‐loop robust control to air‐conditioning systems

This paper presents the design and application of a two‐loop robust controller for temperature control in air‐conditioning systems. A Takagi‐Sugeno fuzzy model with uncertain local models is developed to describe the associated nonlinearities and uncertainties in the operation of the air handling units. Parallel distributed compensation is used to design the global control law. The local control law consists of two loops: an inner‐loop integral controller and an outer‐loop min‐max predictive controller with short prediction horizon. A discounting scheme is developed to weight the contribution of the two loops. Experimental results are presented which show that the proposed strategy can achieve acceptable control performance with a minimum of onsite tuning. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

基于MPU6050和互补滤波的四旋翼飞控系统设计

针对四轴飞行器飞行性能不稳定和惯性测量单元（IMU）易受干扰、存在漂移等问题,利用惯性传感器MPU6050采集实时数据,以经典互补滤波为基础,提出一种可以自适应补偿系数的互补滤波算法,该算法在低通滤波环节加入PI控制器,依据陀螺仪测得的角速度实时调节PI控制器补偿系数。飞行器姿态控制系统采用双闭环PID控制方法,姿态解算的欧拉角作为系统外环,陀螺仪角速度作为系统内环。最后,搭建以NI myRIO为核心控制器的四轴飞行器,通过LabVIEW实现算法和仿真,实验结果表明,自适应互补滤波算法可以准确解算姿态信息,双闭环PID控制超调量小、反应灵敏,控制系统基本满足飞行要求。     

飞行器不确定性建模与μ-H∞鲁棒动态逆控制

针对动态逆方法作为一种先进飞行器控制方法因需被控对象精确的数学模型而难以保证算法鲁棒性的问题,在深入研究飞行器的不确定性模型基础上,将动态逆方法作为鲁棒控制的内环,对模型不确定性进行外环鲁棒控制补偿.在传统H∞控制基础上进行了μ综合的分析与设计,并进行了最差情况分析.从仿真结果可以看出,这种方法既保证了动态逆方法的鲁棒性,又提高了整体控制性能.     

基于RFID技术的四旋翼无人机轨迹跟踪控制系统设计

为促进四旋翼无人机的飞行自主性,增强无人监管情况下飞行器主机所具备的避障行进能力,设计基于RFID技术的四旋翼无人机轨迹跟踪控制系统;采用RFID标签识别技术,调制处理既定控制信号,利用标签识别协议,连接微型四旋翼轨迹控制器与内环姿态控制器,通过数据通信链路,提取轨迹跟踪控制所需的传输电子量,完成轨迹跟踪控制系统硬件设计;利用动力系统中的参数辨识策略,确定与轨迹姿态控制相关的物理规律标注,实现四旋翼无人机轨迹跟踪控制;实验结果表明,与机器视觉型控制系统相比,基于RFID技术的控制系统的SSI避障行进指标数值相对较高,全局最大值达到了 79％,四旋翼无人机滚转角平均值为85°,能够有效抑制四旋翼无人机滚转角的数值上升趋势,增强无人监管情况下飞行器主机避障行进能力.     

DESIGN OF AN AIR-TO-AIR AUTOMATIC REFUELING FLIGHT CONTROL SYSTEM USING QUANTITATIVE FEEDBACK THEORY

Quantitative feedback theory is developed for the design of an automatic station-keeping flight control system to regulate the position of an aircraft receiving fuel relative to the tanker aircraft during air-to-air refueling. A robust flight control system is designed for automating the station-keeping task. A simple outer loop feedback control system is developed that achieves stable position regulation in the presence of wind gusts and fuel transfer related disturbances. The modelling and analysis clearly show the usefulness of QFT in the design of flight control systems for aircraft with large structured parametric uncertainty. Linear and nonlinear simulations are performed to validate the design. © 1997 by John Wiley & Sons, Ltd. This paper was produced under the auspices of the US government and it is therefore not subject to copyright in the US.     

Guidance and nonlinear control system for autonomous flight of minirotorcraft unmanned aerial vehicles

Small unmanned aerial vehicles (UAVs) are becoming popular among researchers and vital platforms for several autonomous mission systems. In this paper, we present the design and development of a miniature autonomous rotorcraft weighing less than 700 g and capable of waypoint navigation, trajectory tracking, visual navigation, precise hovering, and automatic takeoff and landing. In an effort to make advanced autonomous behaviors available to mini‐ and microrotorcraft, an embedded and inexpensive autopilot was developed. To compensate for the weaknesses of the low‐cost equipment, we put our efforts into designing a reliable model‐based nonlinear controller that uses an inner‐loop outer‐loop control scheme. The developed flight controller considers the system's nonlinearities, guarantees the stability of the closed‐loop system, and results in a practical controller that is easy to implement and to tune. In addition to controller design and stability analysis, the paper provides information about the overall control architecture and the UAV system integration, including guidance laws, navigation algorithms, control system implementation, and autopilot hardware. The guidance, navigation, and control (GN&C) algorithms were implemented on a miniature quadrotor UAV that has undergone an extensive program of flight tests, resulting in various flight behaviors under autonomous control from takeoff to landing. Experimental results that demonstrate the operation of the GN&C algorithms and the capabilities of our autonomous micro air vehicle are presented. © 2009 Wiley Periodicals, Inc.     

Multiple model adaptive control for switched linear systems: A two‐layer switching strategy

In this paper, the multiple model adaptive control scheme is first introduced into a class of switched systems. A switched multiple model adaptive control scheme is proposed to improve the transient behavior by resetting the controller parameters. Firstly, a finite‐time parameter identification model is presented, which greatly reduces the number of identification models. Secondly, a two‐layer switching strategy is constructed. The outer layer switching mechanism is to ensure the stability of the switched systems. The inner layer switching mechanism is to improve the transient behavior. Then, by using the constructed jumping multiple Lyapunov functions, the proposed adaptive control scheme guarantees that all the closed‐loop system signals remain bounded and the state tracking error converges to a small ball whose radius can be made arbitrarily small by appropriately choosing the design parameter. Finally, a practical example about model reference adaptive control of an electrohydraulic system using multiple models is given to demonstrate the validity of the main results.     

Robust control law design for lateral-directional modes of an F-16/MATV using μ-synthesis and dynamic inversion

A manual flight control system for the lateral-directional dynamics of a modern fighter aircraft incorporating thrust vectoring is presented. Design goals are posed in terms of maintaining acceptable flying qualities during high angle of attack (α) manoeuvring while also achieving robustness to model parameter variations and unmodelled dynamics over the entire flight envelope. The need for gain scheduling a dynamic controller is eliminated by using an inner loop dynamic inversion/outer loop structured singular value (μ)-synthesis control structure which separately addresses operating envelope variations and robustness concerns, respectively. Performance objectives are based on commanding sideslip angle and stability axis roll rate. Realistic representations of both structured (real parametric) and unstructured uncertainty are included in the design/anlysis process. A flight condition dependent control selector maps generalized controls to physical control deflections, considering actuator redundancy, effectiveness and saturation issues. An angle of attack dependent command prefilter shapes commands to produce desired responses. Structured singular value analysis, low-order equivalent system (LOES) fits, and linear step responses demonstrate satisfaction of design goals. Simulation shows excellent control at both low and high angles of attack. © 1997 John Wiley & Sons. Ltd.     

基于气动参数调节的无人机抗扰动控制算法

无人机飞行受到气动阻尼扰动,从而导致控制稳定性不好。当前采用翼型截面气动参数调节的方法进行无人机抗扰控制,以扭角以及振动方向等参数为约束指标,参数调节的模糊度较大,对气动姿态参数调节的稳定性不好。文中提出基于气动参数调节的无人机抗扰动控制算法。该算法根据无人机的飞行工况构建各阶模态对应的气弹耦合方程,在速度坐标系、体坐标系、弹道坐标系三维坐标系下构建无人机的飞行动力学和运动学模型;采用卡尔曼滤波方法实现对无人机飞行参数的融合调节和小扰动抑制处理,并采用末端位置参考模型进行无人机飞行轨迹的空间规划设计;在卡尔曼滤波预估模型中实现对动力学模型的线性化处理,采用气弹模态参数识别方法进行无人机的飞行扰动调节;将姿态控制作为内环,获得位置环状态反馈调节参数;以无人机的升力系数和扭力系数作为气动惯性参数进行飞行姿态的稳定性调节,从而实现无人机抗扰动控制律的优化设计。采集飞机的俯仰角、横滚角和航向角作为原始数据在Matlab中进行仿真分析,仿真结果表明,采用所提方法进行无人机抗扰动控制的稳定性较好,对气动参数进行在线估计的准确性较高,航向角误差降低12.4%,抗扰动能力提升8dB,收敛时间比传统方法缩短0.14 s,无人机飞行的抗扰动性和飞行稳定性得到提高。所提方法在无人机飞行控制中具有很好的应用价值。     

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.