基于支持向量机逼近的内模控制系统及应用

针对同步发电机组汽门系统, 文章研究了一种基于支持向量机逼近的内模控制系统. 所研究的控制系统包括两个主要部分: 支持向量机逼近逆控制器、内模框架下的不确定性补偿. 由基于泰勒扩展的输入输出逼近模型计算逆控制律, 并由非线性系统辨识来实现. 同时, 采用一个鲁棒滤波器实现内模框架下的不确定性补偿. 针对汽门系统的仿真实验验证了该控制系统的优良性能.     

电液位置伺服系统内模鲁棒控制器的设计

针对电液位置伺服系统存在一定的参数不确定性和较大的负载扰动等问题,建立了电液位置伺服线性系统的数学模型,并将其转化为H∞性能准则问题.利用H∞鲁棒控制理论,设计了电液位置伺服控制系统的鲁棒状态反馈控制器;基于内模原理的设计方法,设计了跟踪控制器.仿真结果表明,该位置鲁棒跟踪控制系统不仅对于伺服系统的参数不确定性有较好的控制效果,而且可以有效地抑制位置伺服系统负载扰动的影响,并有效地提高系统的跟踪特性,使系统具有良好的动态性能.     

间隙度量与跟踪系统中的鲁棒控制器设计

为定量研究鲁棒控制器允许对象有尽可能大的不确定性.在引入间隙度量的基础上,定义了跟踪系统鲁棒控制器的鲁棒边界,并对某跟踪系统设计了基于间隙度量的鲁棒控制器.该控制器能兼顾对象的不确定性与控制器的不确定性.由仿真结果可以看出,与普通的PID控制器相比,具有较大鲁棒边界的鲁棒控制器不仅具有较强的干扰抑制能力.而且能够在模型加性不确定性存在的情况下具有很好的跟踪性能.     

一类远程控制系统的时延补偿H∞鲁棒控制

针对一类有扰动的多时延不确定模型的远程控制系统,为了有效减少网络时延对系统的影响,提出了一种改进Smith补偿H∞鲁棒控制算法;在给出系统体系结构的基础上,应用改进Smith补偿器将含有网络时延的系统鲁棒性能问题转化为无时延的鲁棒性能问题,并对系统存在的模型不确定性和干扰问题引入H∞混合灵敏度设计方法设计了鲁棒控制器;此方法适用于工业现场为无线传感器网络的远程控制系统,通过对存在乘积性的不确定系统进行仿真研究,证明该算法具有良好的控制品质和动态性能。     

高超声速飞行器非线性鲁棒控制律设计

高超声速飞行器具有模型非线性程度高、耦合程度强、参数不确定性大、抗干扰能力弱等特点,其自主控制具有较大的挑战.论文提出了一种基于鲁棒补偿技术和反馈线性化方法的非线性鲁棒控制方法.文中首先采用反馈线性化的方法对纵向模型进行输入输出线性化,实现速度和高度通道的解耦和非线性模型的线性化.针对得到的线性模型,设计包括标称控制器和鲁棒补偿器的线性控制器.基于极点配置原理,设计标称控制器使标称线性系统具有期望的输入输出特性,利用鲁棒补偿器来抑制参数不确定性和外界扰动对于闭环控制系统的影响.基于小增益定理,证明了闭环控制系统的鲁棒稳定性和鲁棒跟踪性能.相比于非线性回路成形控制方法,仿真结果表明了所设计非线性鲁棒控制算法的有效性和优越性.     

工业过程运行的解耦内模控制方法

工业过程运行控制的目的是实现反映过程整体运行性能的工艺指标. 将常规解耦内模控制(Internal model control, IMC)进行推广, 提出了优化过程运行的解耦IMC方法. 通过对广义解耦内模控制器的设计获得了具有高维解耦能力、鲁棒稳定性和抗干扰能力强的回路设定模型. 该模型能够响应系统的各种不确定性和干扰, 对回路设定值进行调整, 通过控制回路的输出跟踪调整后的设定值, 从而实现期望的工艺指标. 磨矿回路运行的解耦IMC设计实例及仿真验证了所提方法的有效性.     

不确定非线性系统的鲁棒H∞控制分析与综合

讨论一类仿射非线性系统的鲁棒H∞控制问题.针对自由系统,外部干扰输入矩阵和控制输入矩阵都具有加法不确定性的系统,将鲁棒性能的分析和综合归结为求解一组Hamilton-Jacobi不等式,给出了确保非线性控制系统满足鲁棒干扰抑制性能的充分条件,获得了非线性鲁棒控制器的一种形式.一个仿真例子验证了所得结论的正确性.     

双馈风力发电机的内模控制器设计

针对双馈风力发电机(DFIG)中普遍存在的功率耦合问题,设计了一种基于内模原理的电流控制器.首先介绍了内模控制(IMC)理论的系统结构,在此基础上推导出双馈风力发电系统的传递函数,并建立基于内模控制的电流内环数学模型;其次,内模控制器的参数整定参考系统的平方积分误差值,其鲁棒稳定性参考M值的大小;最后利用Matlab仿真平台进行了仿真实验.结果表明,该控制器实现了系统有功和无功的充分解耦,并具有较好的稳态和动态性能.     

基于鲁棒优化理论的电梯群控调度策略

论文针对不确定线性优化问题,研究其不确定集的选择,初始不确定鲁棒优化模型的建立,以及基于该模型的鲁棒对等式转化问题.然后将鲁棒优化建模方法应用于电梯群控调度问题,建立其鲁棒优化模型,解决了交通流不确定性的影响,从而使调度结果更为合理.结合电梯群控虚拟仿真环境,设计了电梯群控鲁棒优化调度算法,并进行仿真验证.通过与其他调度算法的比较,证明了鲁棒优化调度算法在不同交通流F均具有优良的性能和适应能力.实验表明,鲁棒优化调度方法可以解决交通流预测误差的影响,很好地改善电梯群控调度性能.     

一类通讯受限不确定网络控制系统鲁棒H_∞滤波

针对一类通讯受限的不确定网络控制系统,砑究了鲁棒H∞滤波器设计问题.通过引入两个附加的松弛矩阵使Lyapunov矩阵和系统矩阵得到分离,得到了一个新的具有更低保守性的鲁棒H∞性能判据,并基于该判据设计了系统的鲁棒H∞滤波器.当将其应用于具有凸多面体不确定性的网络控制系统时可以得到和系统不确定性相关联的Lyapunov函数,有效降低了设计的保守性.数值算例验证了所提出算法的可行性和优越性.     

Tube‐based robust nonlinear model predictive control

This paper extends tube‐based model predictive control of linear systems to achieve robust control of nonlinear systems subject to additive disturbances. A central or reference trajectory is determined by solving a nominal optimal control problem. The local linear controller, employed in tube‐based robust control of linear systems, is replaced by an ancillary model predictive controller that forces the trajectories of the disturbed system to lie in a tube whose center is the reference trajectory thereby enabling robust control of uncertain nonlinear systems to be achieved. Copyright © 2011 John Wiley & Sons, Ltd.     

A new model reference control architecture: Stability,performance, and robustness

In this paper, we develop a new model reference control architecture to effectively suppress system uncertainties and achieve a guaranteed transient and steady‐state system performance. Unlike traditional robust control frameworks, only a parameterization of the system uncertainty given by unknown weights with known conservative bounds is needed to stabilize uncertain dynamical systems with predictable system performance. In addition, the proposed architecture's performance is not dependent on the level of conservatism of the bounds of system uncertainty. Following the same train of thought as adaptive controllers that modify a given reference system to improve system performance, the proposed method is inspired by a recently developed command governor theory that minimizes the effect of system uncertainty by augmenting the input signal of the uncertain dynamical and reference systems. Specifically, a dynamical system, called a command governor, is designed such that its output is used to modify the input of both the controlled uncertain dynamical and reference systems. It is theoretically shown that if the command governor design parameter is judiciously selected, then the controlled system approximates the given original, unmodified reference system. The proposed approach is advantageous over model reference adaptive control approaches because linearity of the uncertain dynamical system is preserved through linear control laws, and hence, the closed‐loop performance is predictable for different command spectrums. Additionally, it is shown that the architecture can be modified for robustness improvements with respect to high frequency content due to, for example, measurement noise. Modifications can also be made in order to accommodate actuator dynamics and retain closed‐loop stability and predictable performance. The main contribution of this paper is the rigorous analysis of the stability and performance of a system utilizing the command governor framework. A numerical example is provided to illustrate the effectiveness of the proposed architecture. Copyright © 2015 John Wiley & Sons, Ltd.     

A model reference quantitative feedback design theory with application to turbomachinery

A new decentralized robust control design framework, model reference quantitative feedback design (MRQFD), is developed for the design of the MIMO parametric uncertain control systems. An internal model reference loop is proposed to obtain the achievement of generalized diagonal dominance (GDD) and the reduction of uncertainty in the resultant compensated internal loop system. Based on nonnegative matrix theory, a useful design guide is derived to achieve the GDD condition for the internal model reference loop. Then a sensitivity-based quantitative feedback design (QFD) method is developed and used to solve the resulting series of single-loop QFD problems. The MIMO quantitative specifications are guaranteed to be satisfied by the proposed design framework for largely uncertain systems. A successful application to the design of a robust multivariable controller for the Allison PD-514 aircraft turbine engine is presented to demonstrate the effectiveness of the methodology developed here.     

Robust controllability of linear stochastic uncertain systems

The paper extends the concept of robust controllability via linear state feedback to stochastic uncertain systems. We show that the controllability of a stochastic uncertain system can be characterized using solutions to a game-type differential Riccati equation.     

时变非线性不确定系统H∞鲁棒模型预测控制

针对输入受限的时变不确定非线性系统,提出一种H∞鲁棒模型预测控制策略。假设线性化系统矩阵一致有界,将非凸的无穷时域优化问题转化为带有单个线性矩阵不等式(LMI)约束的凸优化问题,降低控制量求解难度。结合滚动优化原理与H∞控制方法在线极小化性能指标,使得闭环系统满足控制性能和约束。在LMI框架下给出H∞NMPC的求解方法及其鲁棒稳定性充分条件。仿真实验对比验证了该策略的有效性。     

基于T-S模型的非线性系统非脆弱极小极大控制

研究一类非线性离散系统的鲁棒非脆弱极小极大控制问题.针对含有不确定项的非线性离散系统,构造T-S模型,引入参数不确定项,使得模糊模型能够更精确逼近原系统.考虑系统和控制器同时含有不确定性,利用线性矩阵不等式(LMI)处理方法和Lyapunov稳定性理论,设计鲁棒且非脆弱的控制器.考虑不确定性使得性能指标最大的情形,得到极小极大鲁棒非脆弱控制器存在的充分条件.引入凸优化算法,求解使闭环系统渐近稳定且性能指标上界最小的最优极小极大鲁棒控制器的参数.最后以著名的truck-trailer模型为例的仿真结果表明所设计的控制器具有良好的鲁棒性和非脆弱性.     

Cooperative robust output regulation of a class of heterogeneous linear uncertain multi‐agent systems

The cooperative output regulation of a linear multi‐agent system can be viewed as a generalization of the leader‐following consensus problem and was studied recently for the case where the system uncertain parameters vary in a sufficiently small neighborhood of their nominal value. This case was handled by the internal model design which converts the problem into a simultaneous eigenvalue placement problem of an augmented multi‐agent system. In this paper, we further consider the cooperative robust output regulation problem for a class of minimum phase linear multi‐agent systems in the sense that the controller allows the system uncertain parameters to vary in an arbitrarily prescribed compact subset. For this purpose, we introduce a new type of internal model that allows the cooperative robust output regulation problem of the given plant to be converted into a robust stabilization problem of an augmented multi‐agent system. We then solve our problem by combining a simultaneous high‐gain state feedback control technique and a distributed high‐gain observer technique. A special case of our result leads to the solution of the leader‐following robust consensus problem for a class of uncertain multi‐agent systems. Copyright © 2013 John Wiley & Sons, Ltd.     

不确定系统混合H2/H∞鲁棒控制的直接迭代LMI方法

设计多胞型不确定系统的控制器时,引入附加变量能够减小设计保守性,但这会使线性矩阵不等式(LMI)的维数大大增加,控制器难以求解.本文阐述了一种基于直接迭代线性矩阵不等式(DILMI)方法的混合H2/H∞鲁棒控制方法.首先借助于仿射二次稳定理论将整个多胞型不确定集合的稳定性问题转化为该集合各顶点的稳定性问题.利用参数依赖Lyapunov方法,给出了一个保证系统鲁棒稳定,并满足混合H2/H∞性能指标的充分条件.随后采用DILMI算法实现了Lyapunov变量和控制增益的解耦,无需引入附加变量就能够求解充分条件中的非凸优化问题.最后,关于F-16多胞型模型的飞行仿真验证了该方法的有效性.     

An improved robust model predictive control approach to systems with linear fractional transformation perturbations

In this paper, a robust model predictive control approach is proposed for a class of uncertain systems with time-varying, linear fractional transformation perturbations. By adopting a sequence of feedback control laws instead of a single one, the control performance can be improved and the region of attraction can be enlarged compared with the existing model predictive control (MPC) approaches. Moreover, a synthesis approach of MPC is developed to achieve high performance with lower on-line computational burden. The effectiveness of the proposed approach is verified by simulation examples.     

具有自适应内模的一类非线性系统输出调节问题

研究一类包含未知非线性项的非线性系统的鲁棒输出调节问题.此类非线性系统由一包含未知参数的线性中性稳定的外系统驱动.首先运用调节器方程组解和标准内模将输出调节问题转化为镇定问题;然后给出控制律镇定闭环系统,同时利用镇定输入项和外系统信息设计出自适应内模方程.控制律使得闭环系统的信号全局最终有界,且误差被调节至预先设定的任意小的精度值.仿真结果验证了所提出设计方法的有效性.