An experimental study of pilots' control characteristics for flight of an STOL aircraft in backside of drag curve at approach and landing

Abstract

In general, most vehicles can be modelled by a multi-variable system which has interactive variables. It can be clearly shown that there is an interactive response in an aircraft's velocity and altitude obtained by stick control and/or throttle control. In particular, if the flight conditions fall to backside of drag curve in the flight of an STOL aircraft at approach and landing then the ratio of drag variation to velocity change has a negative value (ΔD/Δu<0) and the system of motion presents a non-minimum phase. Therefore, the interaction between velocity and altitude response becomes so complicated that it affects to pilot's control actions and it may be difficult to control the STOL aircraft at approach and landing.

In this paper, experimental results of a pilot's ability to control the STOL aircraft are presented for a multi-variable manual control system using a fixed ground base simulator and the pilot's control ability is discussed for the flight of an STOL aircraft at backside of drag curve at approach and landing.     

Landing Auto‐Pilots for Aircraft Motion in Longitudinal Plane using Adaptive Control Laws Based on Neural Networks and Dynamic Inversion

This paper presents two new automatic landing systems (ALSs) for aircraft motion in longitudinal plane; the model of the landing geometry determines the flight trajectory and the aircraft calculated altitude; the flight trajectory during landing consists of two parts: the glide slope and the flare. Both designed ALSs have an adaptive system (ACS) for the aircraft output's control; for the first ALS, the output vector consists of the flying altitude and the longitudinal velocity, while, for the second ALS, the output variables are the pitch angle and the longitudinal velocity of aircraft. The second variant of ALS also contains an altitude controller providing the calculated pitch angle. The calculated altitude (for the first ALS), the calculated pitch angle (for the second ALS), and the desired flight velocity are provided to the ACS by means of a block consisting of two reference models. ACS is based on the dynamic inversion concept and contains an adaptive controller which includes a linear dynamic compensator, a state observer, a neural network, and a Pseudo Control Hedging block. The paper is focused both on the design of the two ALSs and on their complex software implementation and validation.     

输出重定义方法设计垂直/短距起降飞机高度控制器

垂直/短距起降飞机是一类典型的非最小相位系统.系统的负调特性使得飞机高度响应比较缓慢,并且会在初始阶段响应为负,从而出现不期望的掉高现象.针对该问题,本文设计了新的最小相位输出预估控制器,通过调节近似输出零点的方法提高系统的动态响应;对于负调部分,采用两步参数整定的方法设计PID控制器,达到抑制负调的作用.最后,对飞机的高度俯仰控制进行了仿真验证,结果表明设计的控制器对飞机高度初始负调具有明显的抑制作用,并且缩短了回复上升所需的时间.     

推力矢量垂直短距飞机轨迹优化与控制

推力矢量垂直短距起降(V/STOL)飞机是一种兼顾巡航飞行速度和起降灵活性的新型飞机.本文首先建立了包含执行器饱和的V/STOL飞机动力学模型;然后针对V/STOL飞机在过渡过程阶段面临的强耦合、强非线性的特点,使用梯度下降法进行最优过渡过程轨迹优化并采用适应性矩估计算法(Adam)加速了优化过程;在此基础上,以最优轨迹为基础设计前馈控制器,同时通过对比真实飞行状态与所设计的最优状态给出反馈补偿量,保证了实际的过渡过程沿着最优轨迹进行.经过仿真实验可以发现,该方法具有过渡过程时间短、姿态平稳、鲁棒性强的优点.     

基于瑞萨单片机的四旋翼自主飞行器设计

该四旋翼自主飞行器以瑞萨公司的R5F100LEA单片机为控制核心,包括飞行姿态处理模块,超声波测距模块,红外传感器循迹模块,电机驱动模块以及微处理器模块等.飞行姿态处理由MPU6050加速度计陀螺仪提供,保证飞行器平稳飞行.超声波测距模块和红外传感器循迹模块为飞行器提供导航参数使飞行器可以按照规定航线并以一定高度飞行.本设计中应用了PPM控制方法,PID算法,平滑滤波等,使飞行器实现在一定区域内一键式起飞,稳定飞行,精确降落.并且可以拾取物件,完成空投任务,最终精确降落并停机.     

舰载机纵向容错着舰系统设计

通常发生的舰载机着舰事故中,大多数是由于舰载机纵向航迹控制不好导致的,而造成航迹控制性能下降的最主要因素是航母运动、舰尾流扰动和执行器故障.针对这些特殊情况,提出了一种容错控制方法,应用在纵向着舰系统中.首先采用基于非线性动态逆的滑模控制方法抑制舰尾流扰动影响,然后在此基础上,加入径向基神经网络,利用其对非线性项的万能逼近特性,来补偿执行器故障情况下造成的系统故障,进一步保证了舰载机对理想下滑道的精确跟踪,最后,加入不同类型的执行器故障对此方法进行测试.仿真结果表明,所设计的纵向容错着舰系统不仅具有较强的鲁棒性和容错能力,而且提高了舰载机着舰航迹控制精度.     

模糊自适应的高超飞行器控制与干扰

针对具有超大飞行马赫数、超宽飞行包络、飞行环境复杂等特点的高超声速飞行器,提出了基于模糊自适应的高超飞行器高度控制方法,分别设计了高度和速度控制器.针对所设计的控制器,分析了气动干扰力矩、测量噪声、舵机干扰、气动参数不确定性和飞行器模型参数不确定性对飞行器高度控制和速度控制效果的影响,然后又分析了综合考虑以上干扰和不确定性对飞行器高度控制和速度控制效果的影响.仿真结果表明,对各种干扰和不确定性,所设计的控制器速度和高度控制有较好的跟踪性和鲁棒性,达到了满意的效果.     

Autonomous landing of airplanes by dynamic machine vision

The 4D approach to dynamic machine vision has been validated for the application area of on-board autonomous landing approaches in the visual flight regime with computing technology available today; sensors are a video-camera, inertial gyros and an air velocity meter. The key feature of the method is the reconstruction and servo-maintained adjustment by prediction error feedback of an internal spatiotemporal model about the process to be controlled. This encompasses both the egomotion state of the aircraft carrying the sensors and the relevant geometric properties of the runway and its spatial environment. The efficiency of the approach is proved both in a hardware-in-the-loop simulation and in real test flights with a twin turbo-prop aircraft. For accuracy evaluation of the data gathered, the results of differential GPS and radiometric altitude measurements have been recorded simultaneously.     

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。     

Planning Stable and Efficient Paths for Reconfigurable Robots On Uneven Terrain

This paper proposes a novel path planning method for improving the feasibility of a forced landing. When an aircraft completely loses its thrust, the only measure it can take is to make a forced landing at an adjacent airport as soon as possible. In such a situation, the flight path to the landing point must be safe and viable. This paper details a method which enables safer and easier landing by transferring the benefits of excess altitude to the final approach length. Moreover, by planning the descent angle of final approach to be in the middle of a non-spoiler and a full-spoiler glide angle, this method enables a change in descent angle to correct any tracking errors, without using thrust. To verify the effectiveness of the proposed method, six degrees-of-freedom nonlinear simulations were performed and the results are compared with comparable methods. From the simulation results, it was confirmed that the proposed method could plan a safe path in a sufficiently short time and the aircraft could reach the landing point safely.     

水陆两栖飞机的无线电高度数据处理方法研究

分析了水陆两栖飞机因水上起降和机腹船体构型导致的对无线电高度表数据进行零位基准修正、天线位置修正、负高度显示等特殊的处理要求.提出了零位基准设置的判据,建立了基于坐标变换矩阵,利用姿态角数据对零位基准设置、天线布置偏离零位基准等因素产生的测高误差进行修正的无线电高度数据处理方法,将姿态角的修正从俯仰角扩展到横滚角.应用...     

基于单步最优方法的推力矢量垂直短距飞机过渡过程控制

推力矢量垂直短距起降飞机(V/STOL)具有巡航速度快和起降灵活的特点,近年来受到了广泛的关注.然而,该型飞机需要经历悬停转平飞和平飞转悬停的过渡过程阶段,期间飞机会面临强耦合、强非线性等控制难题,使得传统控制器难以胜任.针对上述问题,通过充分考虑执行器的执行能力,提出一种基于单步最优方法的过渡过程控制策略.所提方法结合推力矢量V/STOL飞机的特点,在确保飞机姿态可控的前提下使飞机水平加速度最大,同时使三轴承推力矢量喷管转角向目标转角不断靠近,从而以最快的速度完成过渡过程,并进行控制器切换.仿真实验验证了所提方法具有过渡过程时间短、姿态平稳的优点.     

The design of smooth switching control with application to V/STOL aircraft dynamics under input and output constraints

This paper presents a smooth switching gain‐scheduled control approach for linear parameter varying (LPV) system dynamics, indexed by a scalar varying parameter. The proposed approach is demonstrated by application to the planar vertical/short takeoff and landing (V/STOL) aircraft dynamics subject to input and output constraints. In the design of switching control, the switch logic determines the switching process between control laws. The usual switching logics use the instantaneous switching manner, which can cause discontinuous chattering control signal. By performing convex weightings between two individual control laws for neighboring subsystems, the proposed smooth switching gain‐scheduled control approach can provide improved performance but does not arouse control signal chattering. For the studied application, the nonlinear aircraft dynamics are represented in the form of LPV systems with parameter dependence on attitude angle. The resulting design is verified by the obtained relative stability and time response simulations. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Autonomous takeoff and landing control for a prototype unmanned helicopter

In this paper, an autonomous takeoff and landing control strategy is designed and implemented for a prototype coaxial unmanned helicopter with ducted fan configuration. The control strategy is designed such that longitudinal and lateral controls use ground forces, attitude and drifting feedbacks. Vertical control employs takeoff and landing decision and vertical velocity control is based on altitude tracking. Ground forces feedback is used to balance longitudinal forces and moments during liftoff effectively cancelling all ground forces. Attitude and drifting feedbacks are used to balance the longitudinal and lateral movements of the helicopter during takeoff and landing. The flight control strategy is successfully verified during flight tests.     

ROBUST GAIN‐SCHEDULED CONTROL OF A VERTICAL TAKEOFF AIRCRAFT WITH ACTUATOR SATURATION VIA THE LMI METHOD

This paper presents a robust gain‐scheduled approach for the control of a vertical/short takeoff. and landing (V/STOL) aircraft. The nonlinear aircraft dynamics exhibit non‐minimum phase characteristics arising from the parasitic coupling effect between the aircraft's lateral force and rolling moment. The undesired coupling effect also causes modelling uncertainy of the aircraft dynamics. The nonlinear aircraft dynamics are considered to be composed of a nominal linear parameter varying (LPV) system and a linear system with a norm bounded uncertainy matrix multiplied by the parasitic uncertain non‐minimum phase coupling parameter. The nominal LPV system is considered to be affinely dependent on a measurable varying parameter. The ranges of the varying parameter and its variation as well as its parasitic induced uncertain matrix are addressed by introducing the parameter‐dependent invariant ellipsoid interpretation for dealing with the issue of affinely quadratic stabilization. In this paper, the relations among the magnitude of actuator saturation, the maximum achievable relative stability, and the sustainable coupling uncertainty are investigated for the considered robust gain‐scheduled design.     

飞行姿态控制系统半物理仿真平台开发

飞行姿态控制系统作为飞机姿态控制的重要组成部分，对飞机起降、空中姿态调整具有重要影响。为快速建立液压作动系统数值计算模型、飞行员操纵及控制单元、舵面及起落架演示单元等实验实物环节，基于 Automation Studio液压设计及仿真专用软件，设计与开发了某型飞机飞行姿态控制系统的半物理仿真实验平台。给出了飞行姿态控制系统半物理仿真平台软总体方案、硬件组成、工作原理及开发和实验流程。最后，以飞机方向舵为例，开发了包括液压油油箱、液压马达、控制阀门、作动筒及管道、溢流阀、限位开关等装置的数值计算模型，液压阀位置数字PID调节器，结合舵面及其加载演示系统PLC控制程序，配合现场人员的实际操控动作，开展了方向舵液压作动随动控制系统半物理仿真实验研究，试验并分析了飞机机翼液压作动系统位置随动过程中的运行工况，并记录关键的实验数据曲线，为飞行姿态控制系统研究提供了一种直观的仿真及分析实验方法。     

小型飞行器高度定位数据融合方法

给出了一种小型飞行器高度定位的数据融合方法。根据飞行器运动方程 ,推导出了高度和飞行状态之间的关系 ,并由所得的飞行状态 ,利用Kalman滤波方法得到高度估计。根据实测值、最优估计值和GPS高度测量值进行数据融合 ,进一步对高度传感器定位误差进行修正。仿真和数据回放结果表明使用此方法可以得到飞行器更准确的定位。     

Fuzzy Logic Based Approach to Design of Autonomous Landing System for Unmanned Aerial Vehicles

This paper is concerned with autonomous flight of UAVs and proposes a fuzzy logic based autonomous flight and landing system controller. Besides three fuzzy logic controllers which are developed for autonomous navigation for UAVs in a previous work as fuzzy logic based autonomous mission control blocks, three more fuzzy logic modules are developed under the main landing system for the control of the horizontal and the vertical positions of the aircraft against the runway under a TACAN (Tactical Air Navigation) approach. The performance of the fuzzy logic based controllers is evaluated using the standard configuration of MATLAB and the Aerosim Aeronautical Simulation Block Set which provides a complete set of tools for rapid development of 6 degree-of-freedom nonlinear generic manned/unmanned aerial vehicle models. Additionally, FlightGear Flight Simulator and GMS aircraft instruments are deployed in order to get visual outputs that aid the designer in evaluating the performance and the potential of the controllers. The simulated test flights on an Aerosonde indicate the capability of the approach in achieving the desired performance despite the simple design procedure.     

Reachability Analysis of Landing Sites for Forced Landing of a UAS

This paper details a method to ascertain the reachability of known emergency landing sites for any fixed wing aircraft in a forced landing situation. With a knowledge of the aircraft’s state and parameters, as well as a known wind profile, the area of maximum glide range can be calculated using aircraft equations of motion for gliding flight. A landing descent circuit technique used by human pilots carrying out forced landings called high key low key is employed to account for the extra glide distance required for an approach and landing. By combining maximum glide range analysis with the descent circuit, all the reachable landing sites can be determined. X-Plane flight simulator is used to demonstrate and validate the techniques presented.