Comparative Results on Stabilization of the Quad-rotor Rotorcraft Using Bounded Feedback Controllers

In the recent years autonomous flying vehicles are being increasingly used in both civil and military areas. With the advancement of the technology it has become possible to test efficiently and cost-effectively different autonomous flight control concepts and design variations using small-scale aerial vehicles. In this paper the stabilization problem of the quad-rotor rotorcraft using bounded feedback controllers is investigated. Five different types of nonlinear feedback laws with saturation elements, previously proposed for global control of systems with multiple integrators, are applied and tested to control the quad-rotor rotorcraft roll and pitch angles. The results obtained from autonomous flight simulations and real time experiments with the Draganflyer V Ti four-rotor mini-rotorcraft are analyzed with respect to the structural simplicity of the control schemes and the transient performance of the closed-loop system.     

用局部状态反馈的分散化镇定

本文考虑一般关联大系统的分散镇定问题。通过调节系统的二次型目标函数,我们推导出一种系统的用局部状态反馈的分散镇定方法。这种方法基于子系统模型求解,简单,有效,并用一个数字例子验证了这一方法。     

四旋翼飞行器姿态的非线性控制仿真研究

针对目前国内四旋翼飞行器在电力巡检中的广泛应用,对四旋翼飞行器的姿态控制提出更高的要求.由于四旋翼飞行器存在着非线性、多变量耦合的内部不匹配干扰和风力等的外部干扰,设计了非线性干扰观测器来逼近这些干扰形成反馈补偿,从而抵消各种干扰,主回路采用PID控制器。计算机搭建Matlab仿真模型验证控制器的控制效果,编写三维轨迹和姿态角的GUI监测界面,Simulink仿真结果表明：该非线性干扰观测器能有效抵消干扰。     

Real-Time Digital Image Stabilization Using Kalman Filters

This paper presents a novel, real-time stabilization system that uses Kalman filters to remove short-term image fluctuations with retained smooth gross movements. The global camera motion is defined in terms of constant acceleration motion and constant velocity motion models, and Kalman filtering is employed to facilitate smooth operation. It is shown that the process noise variance has a direct effect on stabilization performance, and that it is possible to implement an efficient and robust stabilization system by adaptively changing the process noise variance value according to long-term camera motion dynamics.     

Real-Time Attitude Estimation by Using Parallax Observation System

With the development of the satellite spatial resolution, high-resolution and high-quality remote sensing images require high stability of the observation satellite platform. Therefore, real-time attitude information is essential to enhance the accuracy and the robustness of the attitude control system in observation satellites. Through the use of the parallax observation system, this paper designs a novel framework to estimate the on-orbit attitude, which includes a complete deconvolution process, a detailed camera motion model, and a support vector regression algorithm to detect the attitude and deal with the latency. The proposed framework is testified by realistically simulated data and remote sensing images from the JL-1 satellite. Simulation and experiment results demonstrate that the proposed framework can detect and predict the attitude in real-time while the error is lower than \(1.125\,\upmu \mathrm{rad}\).     

基于STM32的四旋翼飞行器姿态解算的研究

分析了四旋翼飞行器的姿态解算原理,提出了一种基于 STM32的姿态测量系统。系统由 STM32F407微控制器和捷联惯性测量组件(IMU)组成。利用四元数描述姿态进行坐标换算,采用多传感器数据融合方案,通过互补滤波算法进行数据融合,获取精确的姿态角,并完成姿态解算。实验结果表明,采用互补滤波算法有效融合了捷联惯性测量组件的传感器数据,实现了四旋翼飞行器的高精度姿态解算。     

Real-Time Stabilization of an Eight-Rotor UAV Using Optical Flow

An original configuration of a small aerial vehicle having eight rotors is presented. Four rotors are devoted to the stabilization of the orientation of the helicopter, and the other four are used to drive the lateral displacements. A precompensation on the roll and pitch angles has been introduced so that the attitude dynamics is practically independent of the translational dynamics. This compensation is directly related to the velocity of the lateral motors. The dynamical model is obtained using the Euler–Lagrange approach. The proposed configuration is particularly useful for image processing since the the camera orientation is held constant. The eight-rotor rotorcraft is simpler to pilot than other rotorcrafts. A control strategy is proposed that uses the optical flow measurements to achieve a hover flight that is robust with respect to perturbations like wind. The new aerial configuration and control strategy have been tested in real-time experiments.      

直流电机转速神经网络控制

直流电机速度跟踪控制问题中，由于未知的负载转矩特性存在常规的常值反馈控制不能满足较高的性能指标要求。采用前馈神经网络在线辨识，设计出一种合适的控制率。仿真结果证明此种方法的可行性。     

Stabilization of Approximately Feedback Linearizable Systems Using Singular Perturbation

We consider a stabilization problem of approximately feedback linearizable systems. We introduce a perturbation parameter by applying high-gain feedback and use both the feedback linearization method and the singular perturbation method for the controller design. Through this, we can overcome the rigorous conditions of the feedback linearization method and can reduce the dimension of the slow model of the singularly perturbed system.      

Stabilization of Nonholonomic Robotic Systems Using Adaptation and Homogeneous Feedback

This paper considers the problem of stabilizing nonholonomic robotic systems in the presence of uncertainty regarding the system dynamic model. It is proposed that a simple and effective solution to this problem can be obtained by combining ideas from homogeneous system theory and adaptive control theory. Thus each of the proposed control systems consists of two subsystems: a (homogeneous) kinematic stabilization strategy which generates a desired velocity trajectory for the nonholonomic system, and an adaptive control scheme which ensures that this velocity trajectory is accurately tracked. This approach is shown to provide arbitrarily accurate stabilization to any desired configuration and can be implemented without knowledge of the system dynamic model. Moreover, it is demonstrated that exponential rates of convergence can be achieved with this methodology. The efficacy of the proposed stabilization strategies is illustrated through extensive computer simulations with nonholonomic robotic systems arising from explicit constraints on the system kinematics and from symmetries of the system dynamics.     

基于Anti-windup PID的四旋翼飞行器姿态控制研究

针对四旋翼飞行器姿态控制问题,设计一种Anti-windup PID姿态控制器。结合四旋翼飞行器简化的数学模型,在飞行器在垂直速率、俯仰速率、翻滚速率、偏航速率4个独立通道上分别设计了PID控制器和Anti-windup PID控制器。在MATLAB/SIMULINK环境下,对控制四旋翼飞行器姿态的两种算法进行仿真分析。仿真结果表明,Anti-windup PID控制方法在性能上明显优于PID,对飞行器有良好的控制效果。用Anti-windup PID算法搭建的四旋翼飞行器的物理实验平台更好地验证了该算法的有效性。     

Hovering Flight Improvement of a Quad-rotor Mini UAV Using Brushless DC Motors

This paper present the design of a novel embedded control system for improving attitude stabilization of a quad-rotor mini UAV. The control strategy uses low cost components and includes an extra control loop based on motor armature current feedback. This additional control loop significantly improves the performance of the quad-rotor attitude stability. This technique results in a controller that is robust with respect to external disturbances as has been observed experimentally.     

利用变频器实现异步电动机速度闭环控制

本文介绍利用变频器、测速机和其它电子元件实现异步电动机的速度闭环控制，提出了速度闭环调节器的设计方法。此外，本文还介绍了利用HDH－100型电流互感器实现电动机的电流检测，并用于电动机的力矩控制和过电流保护。     

VC++6.0下用中断实现转速实时测量

本文介绍了在Windows98下利用VxD技术编写中断处理程序．并且利用VC 6．0的多线程技术实现转速的实时测量，并实现了数据存储、再现功能，可用于数据采集，实时控制等领域。     

Euler-Bernoulli梁的反馈镇定

讨论端点带负荷的Bernoulli梁的横向振动的控制问题.分析了系统的谱结构,提出一种非线性边界反馈来镇定梁的横向振动,并证明了相应的闭环系统的渐近稳定性,最后给出了一些数值模拟结果.     

Attitude Stabilization of a Biologically Inspired Robotic Housefly via Dynamic Multimodal Attitude Estimation

In this paper, we study sensor fusion for the attitude stabilization of micro aerial vehicles, particularly mechanical flying insects. Following a geometric approach, a dynamic observer is proposed that estimates attitude based on kinematic data available from different and redundant bioinspired sensors such as halteres, ocelli, gravitometers, magnetic compass and light polarization compass. In particular, the traditional structure of complementary filters, suitable for multiple sensor fusion, is specialized to the Lie group of rigid-body rotations SO(3). The filter performance based on a three-axis accelerometer and a three-axis gyroscope is experimentally tested on a 2-d.o.f. support, showing its effectiveness. Finally, attitude stabilization is proposed based on a feedback scheme with dynamic estimation of the state, i.e., the orientation and the angular velocity. Almost-global stability of the proposed controller in the case of dynamic state estimation is demonstrated via the separation principle, and realistic numerical simulations with noisy sensors and external disturbances are provided to validate the proposed control scheme.     

EKF Based Attitude Estimation and Stabilization of a Quadrotor UAV Using Vanishing Points in Catadioptric Images

In recent years, Unmanned Air Vehicles (UAVs) have become more and more important. These vehicles are employed in many applications from military operations to civilian tasks. Under situations where global positioning system (GPS) and inertial navigation system (INS) do not function, or as an additional sensor, computer vision can be used. Having 360° view, catadioptric cameras might be very useful as they can be used as measurement units, obstacle avoidance sensors or navigation planners. Although many innovative research has been done about this camera, employment of such cameras in UAVs is very new. In this paper, we present the use of catadioptric systems in UAVs to estimate vehicle attitude using parallel lines that exist on many structures in an urban environment. After explanation of the algorithm, the UAV modeling and control will be presented. In order to increase the estimation and control speed an Extended Kalman Filter (EKF) and multi-threading are used and speeds up to 40 fps are obtained. Various simulations have been done to present the effectiveness of the estimation algorithms as well as the UAV controllers. A custom test stand has been designed to perform successful experiments on the UAV. Finally, we will present the experiments and the results of the estimation and control algorithms on a real model helicopter. EKF based attitude estimation and stabilization using catadioptric images has found to be a reliable alternative to other sensor usage.     

挠性欠驱动航天器的姿态镇定方法

针对挠性欠驱动航天器的姿态系统的镇定问题,提出了一种基于自适应观测器的容错控制方法,使得航天器的角速度和姿态收敛到有界的区域．所考虑的挠性航天器几乎是轴对称的,其中小参数ε给出了航天器关于欠驱动轴的非对称性的度量程度．首先,利用齐次系统的思想简化系统的模型,消除部分难以处理的耦合项;其次,设计自适应观测器实现对挠性非线性项的未知信息进行估计,并给出观测值与真值的范数界限;进而设计容错控制器使得系统的输出对于耦合项的估计是输入状态稳定的．最后,仿真结果验证了所提方法的有效性．     

带两控制器刚体飞行器的姿态镇定

已知带两控制器的刚体飞行器系统不能被连续的纯状态反馈局部渐近镇定.有效的解决方法包括时变反馈镇定方法和非连续反馈镇定方法.现有的时变反馈镇定方法设计均较为复杂.已有的光滑时变反馈方法是非指数收敛的.本文通过引入辅助变量以及采用反馈线性化技术设计出光滑时变的控制器.该方法设计简单且保证闭环系统状态是指数收敛的.仿真结果证明了本文方法的有效性.     

任意反馈结构下的分散状态反馈镇定

给定一个系统,在完全分散的状态反馈下,系统可能不能被镇定,这就要求改变系统的反馈结构.本文首先推导出在任意反馈结构下,分散状态反馈可镇定的条件,然后给出一个简单而有效的方法,用以修改原有的反馈结构,使得系统能被镇定.