多变量线性系统解耦控制算法研究

由于耦合现象的存在使得多变量被控对象的控制和分析变得非常复杂,耦合严重时甚至使原来稳定的单回路系统变得发散,无法正常运行;针对这种现象,对多变量耦合被控对象的解耦问题进行了研究,阐述了多变量线性系统基于状态反馈和输入变换的解耦控制理论,详细推导了状态反馈矩阵和输入变换矩阵的构造方法和具体计算步骤,并就此问题给出了一个具有较高实用价值的MATLAB通用程序,仿真结果验证了该程序的有效性;为多变量耦合系统的进一步设计提供了条件.     

VAV空调系统末端解耦控制研究

通过对VAV变风量空调系统的两个末端控制回路之间的耦合进行分析,运用最小二乘法建立被控对象＂送风量—室内温度＂控制回路的数学模型。针对被控对象的特性,采用前馈补偿解耦方法设计解耦网络,并设计单神经元自适应PID控制器。最后,通过MATLAB仿真,证明了所设计的解耦网络和控制器是行之有效的。     

高超声速飞行器再入姿态改进自抗扰控制

针对高超声速飞行器在无动力再入过程中具有复杂非线性、控制通道间强耦合及气动参数不确定性,增加了控制器设计的困难.通过构造连续光滑扩张状态观测器及自抗扰解耦控制技术,设计了高超声速飞行器自抗扰姿态控制器.采用构造qin函数实现了连续光滑扩展状态观测器的设计,可避免自抗扰控制器应用过程中的高频颤振现象.通过自抗扰解耦控制技术设计了姿态角及姿态角速度联合控制器,无需基于奇异摄动理论分为内外环控制,解决了设计飞行器内外环控制器时需忽略内环对外环的耦合影响问题,并且解决了难于获取精确的飞行器被控模型及精确的气动参数、摄动界限等问题.仿真结果表明了改进方法的有效性.     

多变量解耦控制系统设计与仿真

工业生产过程中,被控系统越来越复杂,需要控制的变量通常不止一对,而且相互耦合,较成熟的线性多变量控制理论与设计方法已难以满足实际的多变量生产过程控制。本文针对多变量强耦合带有延迟环节的被控系统,研究了一种简化的串联前馈补偿解耦控制器设计方法。根据被控对象的辨识模型,设计串联前馈补偿解耦器,使系统解耦成单输入单输出模型,进而分别对解耦后输入输出模型设计PID控制器,整定PID控制器参数。仿真结果表明该方法具有较好的解耦能力和鲁棒性,算法简单,易于实现。     

多变量解耦控制系统设计与仿真北大核心CSCD

工业生产过程中,被控系统越来越复杂,需要控制的变量通常不止一对,而且相互耦合,较成熟的线性多变量控制理论与设计方法已难以满足实际的多变量生产过程控制。本文针对多变量强耦合带有延迟环节的被控系统,研究了一种简化的串联前馈补偿解耦控制器设计方法。根据被控对象的辨识模型,设计串联前馈补偿解耦器,使系统解耦成单输入单输出模型,进而分别对解耦后输入输出模型设计PID控制器,整定PID控制器参数。仿真结果表明该方法具有较好的解耦能力和鲁棒性,算法简单,易于实现。     

机动再入飞行器自适应自动驾驶仪设计

解决了机动再入飞行器在气动系数变化范围大和气动耦合严重等恶劣条件下的姿态和过载控制问题. 为了能充分利用飞行器可测量信息提高系统自适应能力, 提出了滚动通道状态方程参数辨识—级点配置—前馈补偿自适应控制和横向通道基于攻角反馈以过载为主控信号的变参数自适应控制的自动驾驶仪设计方法. 通过对某飞行器的制导控制系统仿真, 可以看出该自动驾驶仪使飞行器有很好的飞行性能.     

基于拟连续高阶滑模的高超声速飞行器再入姿态控制

考虑模型参数不确定和外界干扰对再入制导控制性能的影响,基于拟连续高阶滑模控制策略对高超声速飞行器的再入制导控制问题进行了研究.首先,给出再入制导指令的设计过程.其次,基于再入飞行特性对模型进行简化,获得面向控制的姿态模型,在此基础上,通过引入新的控制变量,设计解耦滑模面,实现姿态间的解耦.再次,为了削弱控制抖振,通过引入虚拟控制,对系统进行增广,基于齐次性理论设计拟连续三阶滑模再入姿态控制器,确保系统在有限时间实现对制导指令的稳定跟踪.最后,六自由度再入飞行器的制导控制一体化仿真结果表明,本研究给出的控制策略在不影响系统鲁棒性的同时,能够实现对标称轨迹和再入姿态的综合控制.     

微型飞行器的自抗扰控制器设计

微型飞行器具有高度的非线性特性,且气动参数具有不确定性,难以建立精确的数学模型;为实现其姿态、速度、以及高度的精确鲁棒控制,基于自抗扰控制方法设计了微型飞行器速度回路和高度回路的控制器;首先建立了微型飞行器的非线性模型,然后利用扩张状态观测器对飞行器状态和气动不确定性因素进行了估计,并通过非线性反馈对模型不确定性部分和状态耦合进行补偿,实现了纵向通道的解耦控制;通过仿真对所设计的控制器进行性能验证,结果表明自抗扰控制器能够实现对微型飞行器的快速稳定控制,且不依赖于精确的飞行器数学模型,具有良好的鲁棒性。     

基于虚拟模型的自适应解耦抗扰控制

针对一类多变量非线性耦合系统,提出了一种基于虚拟模型的非线性自适应控制器.首先将非线性系统线性化处理并将其作为虚拟模型,对该模型设计线性自适应控制律.然后将线性控制律分别应用在虚拟系统和受控的实际非线性系统上,根据两者的输出误差设计补偿控制律,以达到对实际被控对象进行自适应解耦抗扰的目的.利用李雅普诺夫稳定理论给出了控制系统稳定性条件.实验仿真验证了控制算法的有效性.     

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。     

Simulation of maglev vehicles riding over single and double span guideways

A magnetically levitated high speed vehicle on an elevated periodically supported guideway is approximated by a single-mass vehicle on a flexible single and double span beam with rigid piers. To describe the distributed parameter system of the flexible guideway, modal analysis technique is used. Because of the coupling of the moving vehicle and the guideway the system is characterized by an ordinary vector differential equation with periodically time varying coefficients and jumping states at the piers. To compensate the static instability the suspension magnets are actively controlled by a suboptimal time invariant control system. For the single span guideway an analog simulation is shown, whereas for the double span guideway a digital simulation is presented. Examples are given comparing the solutions for dynamic displacements of the system when a direct state feedback controller is used an when the vehicle is modelled as a moving mass or a moving force.     

Reentry attitude tracking via coupling effect-triggered control subjected to bounded uncertainties

The attitude tracking control issue for hypersonic reentry vehicle subjected to bounded uncertainties is investigated in this paper. The uncertainties are estimated by a disturbance observer with a simple structure whose parameter tuning methodology is provided to guarantee the system robustness. The coupling effect of the hypersonic reentry vehicle is analysed with a binary form based on a coupling effect indicator. The positive or negative value of indicator represents the harmful or beneficial coupling effect on the system. Then, a coupling effect-triggered control is developed to cancel the harmful couplings while utilising the beneficial couplings. The trigger point in the controller occurs when the property of the coupling effect happens to change. The specific criterion is introduced to quantify the performance improvement via the proposed scheme. Application to the hypersonic reentry tracking is presented to demonstrate the validity of the proposed method.     

Neural network based semi-empirical models for dynamical systems described by differential-algebraic equations

We analyzed the problem of mathematical modeling and computer simulation of nonlinear controlled dynamical systems usually described by differential-algebraic equations. The problem is proposed to be solved in the framework of the semi-empirical approach combining theoretical knowledge for the plant with training tools of artificial neural network field. The results are presented for a semi-empirical model that simulate the reentry hypersonic vehicle and confirm the efficiency of this approach.     

Signal tracking method of GNSS receivers for spinning vehicles

A signal tracking method of GNSS receivers for spinning vehicles is proposed in order to eliminate the influence of spinning to the GNSS signal of a vehicle. In the proposed method, a rotation tracking loop is added into the carrier tracking loop of a conventional GNSS receiver. The proposed method was verified through computer simulations and an experiment for live GPS signals. The results show that the proposed method gives an accurate tracking performance.     

不变结构半弹道式再入飞行器的建模与多模型方法估计

以配平攻角状态再入的不变结构半弹道式再入飞行器(Semi-ballistic reentry vehicle, SBRV)不同于传统的弹道式再入飞行器(Ballistic reentry vehicle, BRV)和机动再入飞行器(Maneuvering reentry vehicle, MaRV), 本文分析了该飞行器再入特征, 提出了新的模型并分析了该模型与传统再入模型间的关系. 对该再入问题的多模型混合状态估计器引入了F-均匀模型集与期望模式补偿(Expected-mode augmentation, EMA)集. 根据SBRV的圆柱体状模式空间的需求, 文中扩展了现有的方法以设计F-均匀模型集, 进而提出一种EMA集的实现形式. 前者在分布最小失配意义下使估计器最优; 后者相比于前者具有更高的估计精度. 仿真结果表明, 相比于传统Monte-Carlo法生成的模型集, 在模型集势相当的情况下这两种模型集对不变结构SBRV再入的初始阶段有更高的模式估计的精度, 在该飞行器状态变化剧烈时有更高的混合状态估计精度.     

Adaptive‐gain multivariable super‐twisting sliding mode control for reentry RLV with torque perturbation

Reusable launch vehicle (RLV) should be under control in the presence of model uncertainty and external disturbance, which is considered as torque perturbation in this paper during the reentry phase. Such a challenge imposes tight requirements to the enhanced robustness and accuracy of the vehicle autopilot. The key of this paper is to propose an adaptive‐gain multivariable super‐twisting sliding mode controller when considering that the bounds of uncertainty and perturbation are not known. The important features of the controller are that the adaptation algorithm can achieve non‐overestimating values of the control gains and the multivariable super‐twisting sliding mode approach can obtain a more elegant solution in finite time. According to the multiple‐time scale features, the dynamics of RLV attitude motion are divided into outer‐loop subsystem and inner‐loop subsystem. On this basis, the controllers are designed respectively to ensure the finite‐time reentry attitude tracking. In addition, a proof of the finite‐time convergence for the overall system is derived using the Lyapunov function technique and multiple‐time scale characteristic. Finally, simulation results of six degree‐of‐freedom RLV are provided to verify the effectiveness and robustness of the proposed controller in tracking the guidance commands as well as achieving a safe and stable reentry flight. Copyright © 2016 John Wiley & Sons, Ltd.     

高超音速导弹的新型控制模式研究

弹头变质心机动控制是通过移动弹头的质心位置,利用气动配平力矩改变弹头的飞行姿态和攻角,从而可实现弹头机动控制.以弹头为例,在推导出质量矩弹头的动力学方程基础上,通过分析其方程组的特点并结合弹头再入过程中的气动、速度等参数变化规律,给出了质量矩弹头再入过程中宜采用的控制模式,为其控制律的设计提供了必要的理论参考.     

Stabilization of Motions of the Descent Vehicle in the Upper Atmosphere

The paper was written in continuation of a series of papers on construction of a control law stabilizing a wide range of motions of the controlled plant. At that, the law in essence must be independent of the plant's dynamic characteristics and the environment. These multimodal (general-purpose) laws must generate the control signal with the minimum computational burden and in the minimum time. These laws have other important characteristics concerning stability of the closed-loop system, its robustness, and so on. The paper studied a controlled plant moving under the action of aerodynamic and other forces. The distinction of the formulated control problem is due to the deficiency of the control actions because it is assumed that the controlled plant has only two control engines. This is the case in the well-known problem of controlling the descent vehicle by stabilizing its lateral motion on the hypersonic leg of flight in the upper atmosphere.     

基于自适应虚拟线圈的多车道车流量检测算法

针对虚拟线圈检测算法在多车道车流量检测中存在误检或者漏检的问题,提出一种基于自适应虚拟线圈的车流量检测算法。根据图像二值化原理,对ViBe算法的前景检测部分进行二次判断,并改变背景更新机制,提出一种改进的ViBe算法,以达到快速消除鬼影的目的,更准确地完成前景目标提取。在道路上设置固定检测区域,根据运动目标在固定检测区域的运动轨迹来建立或者消除非固定虚拟线圈,再进一步使用虚拟线圈的车流量检测算法实现车流量统计。选择三个不同的场景4车道无车辆变道、2车道有车辆变道和3车道有车辆变道且环境突变进行实验,所提算法的车流量检测准确率比传统的虚拟线圈算法分别提高8.9、25和16.6个百分点,且所用时间相当。实验结果表明所提算法更适用于多车道的车流量检测。