共查询到20条相似文献,搜索用时 15 毫秒
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Investigates robust filtering design problems in H2 and H∞ spaces for continuous-time systems subjected to parameter uncertainty belonging to a convex bounded-polyhedral domain. It is shown that, by a suitable change of variables, both designs can be converted into convex programming problems written in terms of linear matrix inequalities. The results generalize the ones available in the literature to date in several directions. First, all system matrices can be corrupted by parameter uncertainty and the admissible uncertainty may be structured. Then, assuming the order of the uncertain system is known, the optimal guaranteed performance H2 and H∞ filters are proven to be of the same order as the order of the system. A numerical example illustrate the theoretical results 相似文献
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Jun Wu Jian Chu 《Automatic Control, IEEE Transactions on》1999,44(10):1869-1874
The scalar mixed H2/l1 problem for discrete-time systems is considered. The continuity property of the optimal value with respect to changes in the l1 constraint is studied. An upper approximation method and a lower approximation method of the optimal value are given. Suboptimal values and superoptimal values of the problem can be obtained by solving a sequence of finite dimensional quadratic programming problems 相似文献
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For a linear time-invariant system with several disturbance inputs and controlled outputs, we show how to minimize the nominal H2-norm performance in one channel while keeping bounds on the H2-norm or H∞-norm performance (implying robust stability) in the other channels. This multiobjective H2 /H∞-problem in an infinite dimensional space is reduced to sequences of finite dimensional convex optimization problems. We show how to compute the optimal value and how to numerically detect the existence of a rational optimal controller. If it exists, we reveal how the novel trick of optimizing the trace norm of the Youla parameter over certain convex constraints allows one to design a nearly optimal controller whose Youla parameter is of the same order as the optimal one 相似文献
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In certain applications, such as the colocated control of flexible structures, the plant is known to be positive real. Hence, closed-loop stability is unconditionally guaranteed as long as the controller is also positive real. One approach to designing positive real controllers is the LQG-based positive real synthesis technique of Lozano-Leal and Joshi. The contribution of this paper is the extension of this positive real synthesis technique to include an H∞-norm constraint on closed-loop performance 相似文献
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研究了MIMO(多输入多输出)离散时间系统的混合l1/H2优化问题,该问题可描述为最优化一个传递函数矩阵的l1范数同时保证另一个传递函数矩阵的H2范数满足预定的指标.研究了最优目标函数值关于H2范数指标的连续性.证明了MIMO系统混合l1/H2控制问题最优解的存在性.由于基于标定-Q(scaled-Q)方法求解MIMO混合l1/H2问题,避免了进行零点插值运算的困难.通过求解有限维非线性规划问题可得到最优目标值的收敛的上下界. 相似文献
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讨论了混合降阶H2/H∞控制器的设计问题,提出了应用遗传算法设计混合降阶H2/H∞控制器的一种方法.通过遗传算法对次优H∞降阶控制器进行H2性能优化,设计出鲁棒性既强又满足系统性能要求的混合降阶H2/H∞控制器.它分别在H∞降阶和H2性能优化中两次应用遗传算法,遗传算法采用实数编码形式,其算子分别选用排序选择和最佳个体保存相结合的选择算子、实值中间重组的交叉算子及实值变异的变异算子.利用国产某型飞机对该方法进行仿真,其结果表明得到的混合降阶H2/H∞控制器具有良好的H∞性能和H2性能. 相似文献
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This paper presents the ability of electrostatic sprayed tin oxide (SnO2) and tin oxide doped with copper oxide (1, 2, and 4 at.% Cu) films to detect different pollutant gases, i.e., H2S, SO2, and NO2. The influence of a copper oxide dopant on the SnO2 morphology is studied using scanning electron microscopy (SEM) technique, which reveals a small decrease in the porosity and particle size when the amount of dopant is increased. The sensing properties of the SnO2 films are greatly improved by doping, i.e., the Cu-doped SnO2 films have large response to low concentration (10 ppm) of H2S at low operating temperature (100 °C). Furthermore, no cross-sensitivity to 1 ppm NO2 and 20 ppm SO2 is observed. Among the studied films, the 1 at.% Cu-doped SnO2 layer is the most sensitive in the detection of all the studied gases. 相似文献
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This note considers the problem of finding a stable reduced-order model for a given stable model so that its H2 model reduction cost differs by less than a prescribed error from the optimal cost, which may or may not be achievable. It is shown that this new version of the long-standing H2 optimal model reduction problem can be reduced to a well-posed smooth constrained minimization problem whose global solution is guaranteed to exist. In addition, a globally convergent algorithm in the form of an ordinary differential equation is derived 相似文献
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Zhiyong Geng Lin Huang 《Automatic Control, IEEE Transactions on》2000,45(8):1519-1522
This paper studies the problem of H2 norm checking for a MIMO system with parameter uncertainties. Under the assumptions that the coefficients of the numerator polynomial of the system's transfer function are multi-affine functions of the uncertain parameter that varies in a convex polytope, and that the coefficients of the denominator polynomial of the system's transfer function are affine functions of the uncertain parameter which varies in a convex polytope, a vertex checking result is obtained 相似文献
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In this paper we consider the problem of minimizing the H2 -norm of the closed-loop map while maintaining its l1-norm at a prescribed level. The problem is analyzed in the case of discrete-time, SISO closed-loop maps. Utilizing duality theory, it is shown that the optimal solution is unique, and, in the nontrivial case where the l1 constraint is active, the optimal solution has a finite impulse response. A finite step procedure is given for the construction of the exact solution. This procedure consists of solving a finite number of quadratic programming problems which can be performed using standard methods. Finally, continuity properties of the optimal solution with respect to changes in the l1-constraint are established 相似文献
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The effects of the crystallographic orientation on the H2 gas sensing properties were investigated in highly oriented polycrystalline Pd-doped SnO2 films, which were obtained using rf magnetron sputtering of a Pd (0.5 wt%)-SnO2 target on various substrates (a-, m-, r-, and c-cut sapphire and quartz). All the films had a similar thickness (110 nm), root-mean-square (rms) roughness (1.3 nm), surface area, and chemical status (O, Sn, and Pd). However, the orientation of the films was strongly affected by the orientation of the substrates. The (1 0 1), (0 0 2), and (1 0 1) oriented films were grown on (a-cut), (m-cut), and (r-cut) Al2O3 substrates, respectively, and rather randomly oriented films were deposited on (0 0 0 1) (c-cut) Al2O3 and quartz substrates. In addition, the oriented Pd-doped SnO2 films were highly textured and had in-plane orientation relationships with the substrates similar to the epitaxial films. The (1 0 1) Pd-doped SnO2 films on and Al2O3 showed a considerably higher H2 sensitivity, and their gas response decreased with increasing sensing temperature (400–550 °C). The films deposited on and (0 0 0 1) Al2O3 showed the maximum sensitivity at 500 °C. The comparison of the H2 gas response between undoped and Pd-doped SnO2 films revealed that the Pd-doping shifted the optimum sensing temperature to a lower value instead of improving the gas sensitivity. 相似文献
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We consider a semigroup model with jumps in the state that covers distributed parameter systems with impulse control or sampled-data distributed parameter systems with control realized through zero-order or first-order hold. We then introduce the H2 and H∞ problems for this system and give the solutions in terms of the solutions of Riccati equations with jumps 相似文献
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The H2 guaranteed cost control problem for a singularly perturbed norm-bounded uncertain system is addressed using the quadratic stabilizability framework. After defining the corresponding slow and fast uncertain subsystems, the set of quadratic stabilizing composite controls is characterized. Two Riccati equations have to be solved, one for the slow subsystem and the other for the fast subsystem. Choosing appropriately the weighting matrices, it is shown how to pick up in the set of quadratic stabilizing composite controls, a control minimizing an upper bound on the H2 norm of a certain transfer matrix. The case of the guaranteed cost control problem for the reduced system is also investigated 相似文献
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Model quality evaluation in set-membership identification is investigated, In the recent literature, two main approaches have been used to investigate this problem, based on the concepts of n-width and of radius of information. In this paper it is shown that the n-width is related to the asymptotic value of the conditional radius of information of the identification problem with noise free measurements. Upper and lower bounds of the conditional radius of information are derived for the H2 identification of exponentially stable systems using approximating n-dimensional models linear in the parameters in the presence of power bounded measurement errors. The derived bounds are shown to be convergent to the radius for a large number of data and model dimensions. Moreover, a formula for computing the worst case identification error for any linear algorithm is given. In particular, it is shown that the identification error of the least square algorithm may be increasing with respect to the model dimension (“peaking effect”), An almost-optimal linear algorithm is presented, that is not affected by this peaking effect, and indeed is asymptotically optimal 相似文献
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This note proposes a simple linear matrix inequality (LMI) system for the design of static precompensators to reduce the interactions of a multivariable system. The approach is based on minimizing the H2 norm of a modified system and the LMIs are derived from the well known technique of pseudodiagonalisation. The approach is applied to two complex real-life benchmark problems with high levels of interaction. It is shown that its performance is significantly better than previously proposed LMI optimization techniques for designing static precompensators 相似文献
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Recently, a frequency-domain operator called frequency response (FR) operator was defined and shown to represent the transfer characteristics of a stable sampled-data system. Using this novel frequency-domain notion and introducing its extended notion called hybrid FR-operator, we define an H2-norm for sampled-data systems in this paper. Then, sampled-data H2 control problems are formulated and solved, whereby the usefulness of these frequency-domain notions is demonstrated both in the analysis and synthesis aspects of sampled-data systems. For the case of sampled-data systems with hybrid (i.e., both continuous-time and discrete-time) input and output signals, the H2-norm defined by a hybrid FR-operator turns out to be slightly different from that defined in previous studies. The source of the discrepancy is also identified 相似文献