Nonlinear Adaptive Close Formation Control of Unmanned Aerial Vehicles

This paper treats the question of formationflight control of multiple unmanned aerial vehicles (UAVs). Inclose formation the wing UAV motion is affected by the vortexof the adjacent lead aircraft. The forces produced by these vorticesare complex functions of the relative position coordinates ofthe UAVs. In this paper, these forces are treated as unknownfunctions. For simplicity, it is assumed that the UAVs have autopilotsfor heading-, altitude-, and Mach-hold in the inner loops. Anadaptive control law is derived for the position control of thewing aircraft based on a backstepping design technique. In theclosed-loop system, commanded separation trajectories are asymptoticallytracked by each wing aircraft while the lead UAV is maneuvering.It is seen that an overparametrization in the design is essentialfor the decentralization of the control system. These resultsare applied to formation flight control of two UAVs and simulationresults are obtained. These results show that the wing UAV followsprecisely the reference separation trajectories in spite of theuncertainties in the aerodynamic coefficients, while the leadaircraft maneuvers.     

A Software-in-the-Loop Implementation of Adaptive Formation Control for Fixed-Wing UAVs

This paper discusses the design and software-in-the-loop implementation of adaptive formation controllers for fixed-wing unmanned aerial vehicles (UAVs) with parametric uncertainty in their structure, namely uncertain mass and inertia. In fact, when aiming at autonomous flight, such parameters cannot assumed to be known as they might vary during the mission (e.g. depending on the payload). Modeling and autopilot design for such autonomous fixed-wing UAVs are presented. The modeling is implemented in Matlab, while the autopilot is based on ArduPilot, a popular open-source autopilot suite. Specifically, the ArduPilot functionalities are emulated in Matlab according to the Ardupilot documentation and code, which allows us to perform software-in-the-loop simulations of teams of UAVs embedded with actual autopilot protocols. An overview of realtime path planning, trajectory tracking and formation control resulting from the proposed platform is given. The software-inthe-loop simulations show the capability of achieving different UAV formations while handling uncertain mass and inertia.      

MUAVs系统的混合组织模型

分析多UAV系统的协作控制以及2种基本的组织模型及其优缺点,结合大规模UAVs(MUAVs)系统协作的复杂特征,提出适用于MUAVs系统的几种分级混合网络组织模型以及具有自适应能力的动态杂类混合组织模型。研究结果表明,该方法可有效降低MUAVs系统管理和通信复杂度,提高系统的可靠性与鲁棒性。     

基于行为法多智能体系统构形控制研究

为实现多智能体系统的构形控制,针对二阶多智能体系统,采用了一种基于智能体行为的控制算法,这种控制算法考虑到智能体的驶向目标行为和构形维持行为,可以有效实现智能体相对于期望目标的构形控制,由于采用该算法使得多智能体系统中有明确的队形反馈,因而有利于分布式控制和实时控制。智能体的动力学模型采用多智能体问题研究广泛使用的独轮车模型,通过反馈线性化方法,将这种非线性模型转化成了实用的双积分系统模型。通过Matlab仿真验证了算法的有效性,结果表明控制器参数整定简单,具有很好的稳定性和鲁棒性。     

新型混合励磁导向系统的状态反馈控制

提出一种新型混合励磁导向系统,阐述其结构特点与工作机理,利用等效磁路法得出磁力解析表达式,结合牛顿第二定律和绕组电路方程,推导出混合励磁导向系统的运动方程.建立以气隙、速度、电流为状态变量的线性化电压控制模型,设计出状态反馈控制器并进行仿真.仿真结果表明:新型混合励磁系统的结构是合理的,理论分析和建模方法是切实可行的.设计的反馈控制器在无干扰情况下,控制电流保持为零,在干扰条件下通过调整控制电流能够实现导向系统的稳定导向,研究成果为此类混合励磁导向系统的工业应用提供理论价值和设计参考.     

Input–output invertibility and sliding mode control for close formation flying of multiple UAVs

This paper treats the question of invertibility of input–output maps and the design of a robust control system for formation flying of multiple unmanned aerial vehicles (UAVs). In close formation, the wing UAV motion is affected by the vortex of the adjacent lead aircraft. The forces produced by these vortices are complex functions of relative position coordinates of the UAVs. In this paper, these forces are treated as unknown functions. For trajectory tracking, invertibility of certain input–output maps in the wind axes system are examined. Interestingly, in the wind axes system, the system is not invertible, but in a simplified co‐ordinate system obtained from the wind axes system for which the velocity roll is zero, inverse control of separation co‐ordinates is possible. Variable structure control laws are derived for separation trajectory control of wing aircraft in the simplified wind co‐ordinate system and for the flight control of the lead aircraft. Simulation results for two UAVs are presented which show precise separation trajectory control in spite of the presence of unknown vortex forces, while the lead aircraft maneuvers. Furthermore, these results confirm that when the wing aircraft is positioned properly in the vortex of the lead aircraft, there is a reduction in the required flight power. Published in 2000 by John Wiley & Sons, Ltd.     

基于多任务的无人机编队控制研究

考虑到多架无人机编队飞行的特点,将松散编队及协同思想应用到紧密编队控制中,提出了一个三架无人机协同作战编队的飞行控制系统设计方法;在编队飞行动力学模型的基础上,设计了基于特征结构配置的无人机横侧向控制律,进行指定航路的飞行控制;然后,设计编队控制器,两架僚机可紧紧跟随长机并保持队形稳定;仿真结果表明,设计的控制器可以控制多架无人机进行紧密编队飞行,具有一定的实用性和推广价值。     

Independent Hybrid Force/Motion Control of Constrained Six-Degrees-of-Freedom Manipulators

Controlling the dynamics of a constrained manipulator includesposition tracking as well as stabilization of the contact wrench.In this paper we derive a control scheme, that makes it possible to treat position and force control independently.The approach is based on a mass-orthogonal splitting of the space of joint torques, allowing independent actuation and therefore independent specification of control laws. An appropriate definition of the reference wrenchmakes it possible to achieve independent stability of the position and force loop.     

A Novel Multi-agent Formation Control Law With Collision Avoidance

In this paper a stable formation control law that simultaneously ensures collision avoidance has been proposed. It is assumed that the communication graph is undirected and connected. The proposed formation control law is a combination of the consensus term and the collision avoidance term (CAT). The first order consensus term is derived for the proposed model, while ensuring the Lyapunov stability. The consensus term creates and maintains the desired formation shape, while the CAT avoids the collision. During the collision avoidance, the potential function based CAT makes the agents repel from each other. This unrestricted repelling magnitude cannot ensure the graph connectivity at the time of collision avoidance. Hence we have proposed a formation control law, which ensures this connectivity even during the collision avoidance. This is achieved by the proposed novel adaptive potential function. The potential function adapts itself, with the online tuning of the critical variable associated with it. The tuning has been done based on the lower bound of the critical variable, which is derived from the proposed connectivity property. The efficacy of the proposed scheme has been validated using simulations done based on formations of six and thirty-two agents respectively.      

递阶混合控制系统的分析,综合与证明

提出两类离散事件域的自动机作为控制分析与综合的中间模型，基于广义受控对象的等价事件模型，递阶型的控制器可被系统地综合。为了保证系统分析和综合的正确性，利用Ｈｏａｒｅ逻辑得到一些验证规则。最后以一级倒立摆的控制为例加以说明。     

非线性控制在电力系统中的应用

对多种非线性控制技术的基本原理进行了简要的介绍,在此基础上结合电力系统的具体特性介绍了它们在电力系统中的一些具体应用.最后,指出了电力系统非线性控制的发展趋势.     

非线性控制在电力系统中的应用

对多种非线性控制技术的基本原理进行了简要的介绍, 在此基础上结合电力系统的具体特性介绍了它们在电力系统中的一些具体应用. 最后, 指出了电力系统非线性控制的发展趋势.     

基于方位信息的无人机编队控制设计与验证

本文主要研究了无人机编队的抗扰跟踪控制设计. 针对各无人机只能获取邻机方位信息的情况, 文章设计了一种新的非线性控制器以完成多无人机系统的编队形成与跟踪任务. 考虑到无人机系统易受外界扰动影响的特性, 采用Leader-Follower式编队方法, 通过引入Leader位置信息来矫正基于方位信息的无人机编队系统的位置漂移.将反步法设计结合自适应设计与鲁棒控制设计, 来补偿未知参数与未知外界扰动对多无人机编队系统造成的影响,提高了多无人机方位编队系统的鲁棒性. 然后, 基于Lyapunov分析方法证明了系统的稳定性. 最后, 搭建了四旋翼无人机编队实验平台, 进行了基于方位信息的编队形成与跟踪飞行实验, 并与PD控制器进行了对比实验. 飞行实验结果验证了算法的有效性与实用性.     

Hybrid MARTE statecharts

The specification of modeling and analysis of real-time and embedded systems (MARTE) is an extension of the unified modeling language (UML) in the domain of real-time and embedded systems. Even though MARTE time model offers a support to describe both discrete and dense clocks, the biggest effort has been put so far on the specification and analysis of discrete MARTE models. To address hybrid real-time and embedded systems, we propose to extend statecharts using both MARTE and the theory of hybrid automata. We call this extension hybrid MARTE statecharts. It provides an improvement over the hybrid automata in that: the logical time variables and the chronometric time variables are unified. The formal syntax and semantics of hybrid MARTE statecharts are given based on labeled transition systems and live transition systems. As a case study, we model the behavior of a train control system with hybrid MARTE statecharts to demonstrate the benefit.     

Electro-mechanical Braking Method in Hybrid Electric Vehicles Based on Feedback Control Theory

In this paper, the hybrid electric vehicle braking process is researched, by using variables consists of HEV speed, motor speed, and state of charge established, fimctions of mechanical braking force, regenerative braking force and efficiency of energy recovery are constructed, and the control goal is to maximization the energy recovery efficiency. Under the feedback control strategy, with the constrain condition of braking strength and braking stability, combining experiments in ADVISOR, in different experiments of different working conditions, we can see that in UDDS Cycle, the regenerative braking efficiency is the best. What＇s more, compared with strategies in ADVISOR, strategy proposed in this paper is obviously better.     

基于混合观测器的混合反馈控制

对于一类混合动态系统,研究基于混合观测器的混合反馈控制问题．通过系统线性部分和离散事件部分的Lyapunov函数构造了整个混合系统的Lyapunov函数．据此设计了使整个系统稳定的混合反馈控制且证明了闭环系统的稳定性．仿真实例说明该方法的有效性．     

分布式多无人机编队控制系统仿真

研究一种能够控制多无人机编队的分布式控制方法,采用无人机的动态方程转化为跟随机和领航机间相对运动信号与希望的相对运动信号间的误差模型,然后设计了前馈控制器以使误差模型的平衡点位于坐标原点,最后采用反推法设计了反馈控制器以镇定坐标原点的平衡点。上述方法将领航机的信息视为外部系统产生的信号,为前馈控制器部分设计了内部模型以补偿这些外部信号的作用。同时还设计了能够估计所有误差信号的状态观测器以实现需要全部误差信息的反馈控制器。算例仿真表明了应用编队控制律,各无人机能够较快地形成希望的队列,并按希望队形稳定飞行,验证了前馈加反馈的编队控制方法的有效性。     

混合系统的形式验证技术及其在化工过程控制中的应用

针对PLC等逻辑控制器控制连续对象的可靠性问题。给出了混合系统的形式验证的方法,即用混合矩形自动机建模,通过其商迁移的可达性分析,证明了控制程序的正确性,应用实例表明该方法是可行和有效的。     

一类具有L∞范数有界扰动的非线性系统鲁棒控制

首先针对不确定非线性系统,基于L∞范数定义了鲁棒稳定化和鲁棒跟踪控制问题.然后利用反馈线性化技术和Lvapunov方法,设计了相应的鲁棒控制器.仿真结果验证了控制器设计的正确性.