Energy-based approach for flight control systems design

We consider the fundamentals of the energy-based approach to spatial motion control. The resulting energy balance equation establishes quantitative relations between all energy sources and consumers in the system of objects “flying vehicle—thrust system—external environment.” We establish the structure and further modification of an energy-based flight control system. The energy balance equation lets us estimate the level of atmospheric disturbances and formulate the commanding control index for engine thrust under winds of complex structure. For ground-based stages, we show a prediction method for the takeoff energy possibilities with air traffic obstacles; for situations of interrupted takeoff, the possibilities to stop inside the runway.     

Linear-adaptive flight control design for re-entry vehicles

This paper presents a linear-adaptive design technique intended for the very severe parameter variation problems encountered in lifting re-entry vehicles and in flight control of modern aircraft. The technique is illustrated by means of a detailed application to the pitch axis stability augmentation system of the X-15. The problem is to obtain satisfactory vehicle response to command inputs and disturbances, despite the extremely large variations in vehicle parameters, which are encountered when Mach number varies from 6.0 to 0.2 and altitude varies from 160,000 ft to ground level. The given time domain specifications are translated into approximately equivalent frequency response restrictions, enabling the design details to be executed in the frequency domain. This results in the maximum economy in the gain and bandwidth of the system loop transmission. The design is verified by finding the time responses for some of the extreme conditions. The practicality of the design is discussed in terms of the gain and bandwidth demands on the compensating networks, the higher order airframe dynamics and the effects of any overdesign on the system saturation tendencies.     

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.     

磁控小卫星编队飞行的非线性控制

磁控小卫星编队飞行利用磁力和磁力矩对编队小卫星进行位姿调控,不受星载燃料的限制,同时还避免了由推进器羽流造成的光学干扰和精密设备污染。基于磁力研究编队小卫星的相对运动控制问题,介绍了编队卫星的磁力模型和相对运动模型,采用饱和函数方法给出了非线性控制律,利用李雅普诺夫稳定性理论证明了系统的稳定性,最后,利用该方法对两星编队磁力控制进行仿真验证,结果表明：完全依靠电磁力编队卫星是可控的。     

Quaternion-based robust trajectory tracking control for uncertain quadrotors

This paper presents a robust nonlinear controller design approach for uncertain quadrotors to implement trajectory tracking missions. The quaternion representation is applied to describe the rotational dynamics in order to avoid the singularity problem existing in the Euler angle representation. A nonlinear robust controller is proposed, which consists of an attitude controller to stabilize the rotational motions and a position controller to control translational motions. The quadrotor dynamics involves uncertainties such as parameter uncertainties, nonlinearities, and external disturbances and their effects on closed-loop control system can be guaranteed to be restrained. Simulation results on the quadrotor demonstrate the effectiveness of the designed control approach.     

Digital flight control design for a tandem-rotor helicopter

Methods and results in the continuing development of a digital flight control system (DFCS) for a CH-47B helicopter are presented. The helicopter is the research vehicle for the NASA VTOL Approach and Landing Technology (VALT) Program, and it equipped with comprehensive equipment for the investigation of navigation, guidance, and control requirements for future VTOL aircraft. Two control modes (attitude-command and velocity-command) are implemented, and each mode provides ‘Type 1’ response to guidance commands. DFCS design is based upon optimal estimation and control methods, which are found to provide flexible and efficient means for defining practical digital control systems.     

Modular flight control reconfiguration design and simulation

This paper describes a reconfiguring flight control algorithm for damaged aircraft based upon a modular approach. This approach combines real time physical model identification with adaptive nonlinear dynamic inversion (NDI). The sensitivity of NDI to modeling errors is eliminated here by making use of a real time identified model of the aircraft. In failure situations, the damaged aircraft model is identified by the two step method and this updated model is supplied to the model-based adaptive NDI routine, which reconfigures for the fault in real time. Reconfiguration test results for damaged aircraft models indicate good fault handling capabilities of this fault tolerant control set-up, for component as well as structural faults.     

小型无人机飞行控制系统的硬件实现

介绍了基于PC104小型无人机飞行控制系统的硬件实现,给出了系统整体方案的设计和具体的硬件选型,详细地分析了惯性测量单元、电子罗盘、转速传感器、声纳.同时在设计中绝大多数元器件采用最小型号的贴片封装,使该硬件平台具有设计精炼、可靠性高、可移植性强等特点,系统在飞行器多次试飞后,证明是实用的.     

基于xPC的飞行控制系统半实物仿真设计

利用Matlab的xPC目标工具在仿真回路中引入飞控计算机、传感器等实物部件,设计了某型飞机飞行控制系统的半实物仿真系统.根据飞行控制系统的原理特点设计了数据采集卡与信号转换处理电路,并在VC 6.0环境下对系统软件进行了编制.仿真结果表明:该半实物仿真系统具有较高的仿真置信度和可靠度.     

Design of feedback control for quadrotors considering signal transmission delays

For quadrotor types of unmanned aerial vehicles (UAVs), existence of transmission delays caused by wireless communication is one of the critical challenges. Estimation of the delays and analysis of their effects are not straightforward for designing controllers. An estimation method is introduced using experimental data and analytical solutions of delay differential equations (DDEs). Collected altitude responses in the time domain are compared to the predicted ones obtained from the analytical solutions. The Lambert W function-based approach for first-order DDEs is used for such analysis. The dominant characteristic roots among infinite number of roots are obtained in terms of coefficients and the delay. The effects of the time delay on the responses are analysed through the locations of the characteristic roots in the complex plane. Based on the estimation result, proportional plus velocity controllers are proposed to improve transient altitude responses.