变速风力发电机组的自适应滑模变桨距控制

在风力发电系统稳定性优化控制的研究中,针对不确定性的变速风力发电机组的变桨距控制方式系统稳定性差的问题,提出了一种自适应全局快速Terminal滑模控制方法.建立变桨距风力发电机组动力学模型,针对模型中的未知环节,设计了自适应模糊逼近系统.采用由Terminal滑动模态和线性滑动模态组成的滑模模态,采用了自适应Terminal滑模变桨距控制器.根据Lyapunov稳定性理论证明了系统稳定性,并给出了具体的自适应律和不确定项边界的估计算法.对自然风下的机组变桨距控制情况进行了仿真,结果表明系统稳定且输出功率平稳.     

四旋翼飞行器建模及其运动控制

针对四旋翼飞行器是一个欠驱动、强耦合、非线性系统,提出了运用反步法解决系统非线性问题,达到对飞行器快速、准确、稳定控制目的.研究了以反步法作为非线性设计工具对飞行器控制系统的设计问题,将飞行控制系统分为内外环2个子系统.建立四旋翼飞行器动力学及运动学方程,并对数学模型进行适当简化.利用反步法求解飞行器内环姿态控制律,实现对目标姿态角的稳定控制;利用比例—积分—微分(PID)作为飞行器外环位置控制律,实现对目标位置的稳定控制.搭建飞行器系统模型,进行Matlab/Simulink仿真实验,结果表明:在小角度飞行和悬停状态下,飞行器的位置与姿态精度得到了有效控制,验证了数学模型与控制律设计的准确性.     

变桨距四旋翼飞行器控制系统设计

变桨距四旋翼飞行器是通过改变旋翼的桨距大小来改变升力的,这种控制策略可使飞行器姿态的响应和控制的延迟都会小很多,同时可以节省资源和能耗。通过分析对比变桨距与传统的变转速四旋翼飞行器的结构和飞行原理,根据其数学模型和控制要求,设计了变桨距四旋翼飞行器的控制系统。该系统采用STM32F427微处理器作为主控制器,使用MPU6000等惯性测量单元及其他传感器用于检测飞行器的位置、姿态;基于四元数方法进行姿态解算;利用PID控制算法对飞行器姿态、高度进行闭环控制。试飞结果表明,变桨距四旋翼飞行器能够稳定飞行,满足系统要求。     

模型参考自适应电动变桨距控制

根据模型参考自适应控制原理(MRAC),以大型风力发电机组直流电动变桨距控制系统为研究对象,设计一个高性能电动变桨距自适应控制系统,并应用李雅谱诺夫稳定性分析法给出自适应系统控制律,通过对所设计系统的性能进行了仿真分析,分析结果表明所设计系统具有很好的跟踪性和伺服性.     

具有输入死区与扰动的四旋翼无人机自抗扰控制

研究了具有输入死区与扰动的四旋翼无人机的姿态控制问题。由于输入死区普遍存在于四旋翼无人机的执行机构,并且易受到扰动的影响。针对具有输入死区与扰动的四旋翼无人机系统,设计基于自抗扰的动态面控制器。采用自抗扰控制算法设计扩张状态观测器估计系统的总扰动,采用动态面方法设计控制律。所设计的控制器使四旋翼无人机实现对期望姿态角跟踪。仿真结果验证了该方案的有效性。     

风扰条件下四旋翼无人机智能控制算法的设计与仿真

为提高四旋翼无人机在风扰条件下的抗扰能力和控制精度,提出一种利用遗传算法优化模糊控制器规则以提高控制器性能的方法。首先,对自然条件下风速的变化特性进行分析,建立相应的数学模型,并将其作为环境噪声引入系统。在四旋翼无人机动力学模型的基础上,设计模糊PID控制器对其进行控制。同时,对模糊控制器中的模糊子集进行基因编码,设计改进型遗传算法来实现对模糊规则的再整定与优化。在Matlab/Simulink仿真环境下的实验结果表明,该算法有效地提高了四旋翼无人机在面对复杂干扰时的抗扰能力和控制精度。     

垂直轴风力发电机的建模与变桨距研究

定桨距垂直轴风力发电机存在启动转矩小和输出效率低的缺点。为了改善垂直轴风电机组的输出特性,在静止和旋转状态下,对6叶片H型垂直轴风力发电机的风轮的受力情况进行了分析。首先建立了H型垂直轴风力机模型,然后对单个叶片变桨距与定桨距下的受力进行了分析,进而对6叶片风力机受力进行了分析。理论分析和仿真结果表明,叶片通过采取变桨距控制,不但有效地改善了H型垂直轴风力机的启动性能,并且减小了输出振动。因此,所提出的变桨距控制方法是可行的。     

基于风速估计的风力机状态反馈滑模容错控制

针对风力机变桨距执行机构突变故障,提出了基于风速估计的自适应状态反馈滑模容错控制策略.首先,设计了基于自适应状态反馈滑模理论的鲁棒主动容错控制器,并结合全阶补偿器对控制律进行设计;然后,利用基于变速灰狼优化算法的组合径向基函数神经网络实现风速估计,可以改善风速测量精度并提高控制系统可靠性;最后,根据线性矩阵不等式和Lyapunov理论对控制器稳定性进行讨论,并与现有控制策略进行比较.仿真结果表明,在健康/故障的变桨距执行机构条件下,所提容错控制方法均能获得较好的控制效果.     

自抗扰fal函数改进及在四旋翼姿态控制中的应用

将自抗扰控制器(ADRC)应用于四旋翼飞行器姿态控制.首先,对扩张状态观测器(ESO)进行理论分析,对扩张状态观测器中的非线性fal函数进行改进,得到改进型faln函数,并对改进后的状态观测器进行收敛性判断;然后,将传统的fal函数与改进型faln函数进行仿真实验对比,以验证改进型faln函数能够更好地达到“大误差,小增益”的效果;最后,将改进的faln函数应用于四旋翼飞行器姿态控制,仿真结果表明,改进后的faln函数具有比传统fal函数更优的抗扰效果.     

具有反馈信息的迭代学习控制律在Lebesgue-p范数意义下的收敛性

针对一类线性时不变系统, 提出了具有反馈信息的PD-型(Proportional-derivative-type)迭代学习控制律, 利用卷积的推广的Young不等式, 分析了控制律在Lebesgue-p范数意义下的单调收敛性. 分析表明, 收敛性不但决定于系统的输入输出矩阵和控制律的微分学习增益, 而且依赖于系统的状态矩阵和控制律的比例学习增益; 进一步, 当适当选取反馈增益时, 反馈信息可加快典型的PD-型迭代学习控制律的单调收敛性. 数值仿真验证了理论分析的正确性和控制律的有效性.     

The category concept: An extension to the entity-relationship model

An enhanced version of the Entity-Relationship (ER) data model called the Entity-Category-Relationship (ECR) data model is presented. The principal extension is the introduction of the concept of a category. Categories permit the grouping of entities from different entity types according to the roles they play in a relationship, as well as the representation of ISA and generalization hierarchies. The structures of the ECR data model are defined, and a graphic representation technique for their display is presented. Language operations to define and use an ECR database are defined. Two realistic examples of the use of the ECR model for database design are demonstrated. The examples show how ECR structures can be directly mapped into relational and network structures. The definition of derived relationships on an ECR database gives the power to phrase higher order recursive queries in a first order query language.     

一类受控Petri网的反馈控制

受控Petri网是离散事件动态系统(DEDS)的一种控制理论模型.通过模型来研究实现 禁止状态避免的最大允许反馈控制是DEDS控制理论中的一个重要课题.文中对受控Petri网 的一个子类(非受控变迁子集的外延子网为TC网)讨论控制综合问题,给出求这类受控网中实 现禁止状态避免的最大允许反馈控制的一个算法.     

基于SIMULINK的永磁同步电机无速度传感器直接转矩控制的仿真建模

永磁同步电机（PMSM）以其高效率、高功率因数、小体积以及节省电能等优点,在许多领域得到了广泛的应用。主要分析了永磁同步电动机的直接转矩控制系统,采用了基于电机转子磁链矢量角的速度估算方法对无速度传感器控制系统的速度进行估计。利用MATLAB中的Simulink仿真工具箱设计并实现了控制系统的仿真,并对仿真结果进行了分析。仿真结果验证了文中采用的转速观测算法的正确性和可行性。     

Motion control algorithms and simulation of the dynamics of multilink robots moving based on the principles of a traveling wave

Multilink robots that simulate the motion of snakes and worms are considered. The motion is a result of the interaction with a supporting surface when the configuration of the robot is changed. Supervisor control algorithms are proposed for which a user (an operator) controls the motion velocity and direction, while the robot configuration that implements the desired motion is changed automatically. Controlled motions of the considered robots were simulated based on their dynamic models. The motions that simulated movements of snakes and worms are compared. Robots of this type can be used as mobile robots.     

Quasi-LPV modeling,identification and control of a twin rotor MIMO system

This paper describes the quasi-linear parameter varying (quasi-LPV) modeling, identification and control of a Twin Rotor MIMO System (TRMS). The non-linear model of the TRMS is transformed into a quasi-LPV system and approximated in a polytopic way. The unknown model parameters have been calibrated by means of the non-linear least squares identification approach and validated against real data. Finally, an LPV state observer and state-feedback controller have been designed using an LPV pole placement method based on LMI regions. The effectiveness and performance of the proposed control approach have been proved both in simulation and on the real set-up.     

Complete dynamic model of the Twin Rotor MIMO System (TRMS) with experimental validation

In this paper we develop a complete dynamic model of the Twin Rotor MIMO System (TRMS) using the Euler–Lagrange method. Our model improves upon the model provided by the manufacturer in the user manual and upon previous models of the TRMS which can be found in the literature. The complete procedure for the model parameters’ estimation and validation is illustrated.     

A multivariable self-tuning controller with integral action

In this paper a novel stochastic self-tuning control algorithm for multivariable linear systems described by Controlled Autoregressive Integrating Moving Average (CARIMA) models is proposed. In particular, the presence of an integral action on each component of the error vector ensures the robust offset rejection for any constant load disturbance acting on the plant. The leading assumption is made that the system interactor matrix is known a priori. The algorithm is derived by resorting to the generalized minimum variance approach. Two simulation examples illustrate the main features of the method.     

网络控制系统的机理描述模型

网络控制系统与工业企业网有着密切的关系。通过对网络控制系统的运行机理进行分析,一个基于Ｅ（事件）、Ｃ（通信）和Ｒ（关系）的三元组模型（ＥＣＲ模型）,可以很好地描述网络控制系统的运行机理。该模型也可以用于指导网络控制系统的设计。     

Electrical contact resistance as a diagnostic tool for MEMS contact interfaces

The electrical contact resistance (ECR) was evaluated as an in situ diagnostic tool for the contact interface behavior of microelectromechanical systems (MEMS). Special polycrystalline silicon (polysilicon) MEMS devices fabricated by surface micromachining were used to study polysilicon/native oxide/polysilicon contact interfaces. ECR measurements obtained during monotonic contact loading and unloading and cyclic contact loading are interpreted in the context of a previous ECR theory. For monotonic contact loading and unloading, the ECR was measured as a function of apparent contact pressure and was found to be on the order of 10/sup 5/ /spl Omega/. The fairly moderate decrease of the ECR with the increase of the contact load is attributed to the intrinsic nonohmic behavior of the native oxide film. Experimental ECR results are correlated with analytical solutions to determine the oxide film thickness. The results indicate that the oxide film remains nearly intact under monotonic contact loading and unloading. Differences in the ECR behavior during unloading are discussed in light of the statistical distribution of asperity nanocontacts and the prevailing deformation mode. During cyclic contact loading, rupture of the oxide film leads to the formation of polysilicon/polysilicon nanocontacts, which produces ECR values in the range of 10/sup 2/-10/sup 3/ /spl Omega/. The erratic behavior of the ECR during cyclic contact loading is related to the pronounced effects of the insulating oxide film and oxide debris trapped at the contact interface.     

基于MATLAB的双旋翼控制系统的优化设计

对于非线性复杂控制系统，传统的求解优化设计问题的方法难以获得良好的控制效果。为解决这一问题，使非线性复杂控制系统中的PID控制器的参数整定更加简单方便，文中分析了MATLAB优化工具箱求解优化问题与传统的求解方法相比的主要优点，提出了一种运用MATLAB优化工具箱中提供的函数，对双旋翼非线性复杂控制系统进行优化设计的方法。仿真结果证明该方法是简单可行的，而且可使设计者将精力完全集中于优化问题的本身，而不是过多地纠缠在具体的算法实现上，计算简单方便，结果可靠。