Consistent systems and pole assignment: I

We study the consistency property of a linear time-invariant control system with incomplete feedback and of a bilinear time-invariant control system in connection with the pole assignment problem. We show that consistency is a sufficient and, in some cases, necessary condition for the arbitrary pole assignability of systems with coefficients of a special form.     

双线性系统的无反馈解耦线性化

用现代微分几何方法研究了双线性控制系统的解耦线性化问题，给出了一般双线性系统解耦线性化的充分条件及严格双线性系统解耦线性化的充要条件，并举例说明了本文的结论。     

APPROXIMATE CONTROLLABILITY OF INFINITE DIMENSIONAL BILINEAR SYSTEMS

1.IntroductionRecentlymanyresultshavebeenobtainedfordistributedbilinearsystemsl3'7'8].In[3]thecontrollabilityofabilinearsystem%=Aw(t) p(t)Bw(t)wasstudied,whereAistheindnitesimalgeneratorofaCosemigroupofboundedlinearoperatorsT(t)onaBanachspaceX.B:X-- 5isaboundedlinearoperator,andpELI([0,T];R)isacontrol.TheconditionsforelementsofEtobeaccessiblefromagiveninitialstatecoweregiven.Itisclearthattheystudiedthebilinearsysteminaspecialcase.In[8]theystudiedthesysteminamorespecialcasebecausetheyass…     

Optimization of Bilinear Systems Using a Higher-Order Variational Method

This paper derives some optimization results for bilinear systems using a higher-order method by characterizing them over matrix Lie groups. In the derivation of the results, first a bilinear system is transformed to a left-invariant system on matrix Lie groups. Then, the product of exponential representation is used to express this system in canonical form. Next, the conditions for optimality are obtained by the principles of variational calculus. It is demonstrated that closed-form analytical solutions exist for classes of bilinear systems whose Lie algebra are nilpotent.     

电报方程H~1-Galerkin非协调混合有限元分析

主要研究一类电报方程的H~1-Galerkin非协调混合有限元方法,在任意四边形网格剖分下,其逼近空间分别取为类Wilson元与双线性Q_1元,在不需要满足LBB相容性条件及不采用传统的Ritz投影的情况下,得到了与常规有限元方法相同的L~2-模和H~1-模的误差估计,进一步拓展了H~1-Galerkin混合有限元和类Wilson元的应用范围.     

拟线性双曲方程类Wilson非协调元的高精度分析

主要研究类Wilson元对拟线性双曲方程的逼近.首先证明了当问题的解u∈H~3(Ω)或u∈H~4(Ω)时,u与其双线性插值之差的梯度与类Wilson元空间任意元素的梯度,在分片意义下的内积可以达到O(h~2)这一重要结论.其次运用能量模意义下该元的非协调误差可以分别达到O(h~2)/O(h~3),即比插值误差高一阶/二阶这一性质,并利用对时间t的导数转移技巧,结合双线性元的高精度结果及插值后处理技术,获得了O(h~2)阶的超逼近性和整体超收敛性,从而进一步拓广了该元的应用范围.     

Stabilization of weakly linear systems

The problem of stabilizing bilinear systems, characterized by the presence of a small parameter in the bilinear part of the system, is considered. The result is an approximate method for synthesizing a stabilizing control /1–3/ in bilinear systems, in the case of a performance index. Estimates are derived for the error with respect to the performance index.     

Stabilisation des systèmes bilinéaires homogènes

We deal with the problem of stabilizing the bilinear homogeneous systems. We give sufficient conditions for a bilinear system to be stabilizable with homogeneous feedback of degree zero. The explicit design of the feedback is given.     

基于模糊双线性模型的非线性系统的跟踪控制

研究一种基于T-S模糊双线性系统的跟踪控制器设计及稳定性分析.使用分布并行补偿法(PDC)设计了模糊控制器,得到模糊双线性系统跟踪控制渐近稳定的充分条件,仿真结果验证了该方法改进了闭环系统的性能.     

A connection between multi-linear and Volterra systems

The Volterra system is a non-linear system with the structure of the Volterra series. The Volterra series is attractive from the system-theoretic point of view, since it enables to obtain the output of a class of non-linear systems in terms of the input explicitly rather than involving input-output coupling terms and allows substantial simplifications for the numerical simulation. The Volterra system allows to derive the stability condition as well, i.e. obtain a bound on the output for a given bound on the input function, especially for the bilinear system. The bilinear system possesses the Volterra series. This paper derives the Volterra series formalism from the multi-linear system involving the coupling term attributed to (k-1)th order non-linearity and output function, where 1<k. The bilinear system becomes a special case of the non-linear problem of concern here. The Volterra series formalism of this paper is derived using the discrete counterpart of the phase space analysis for the non-linear non-autonomous system. The main result of the paper, i.e the Volterra series formalism of the multi-linear system of concern here, is somewhat more general, since the Volterra series representations for bilinear and tri-linear systems, etc. can be obtained as its special cases.     

A Sufficient Condition for Stabilization of Bilinear Systems in a Plane

The article considers stabilization of bilinear systems in a plane. A discontinuous-feedback algorithm is proposed. Sufficient conditions for stabilization of bilinear systems are derived. The proposed algorithm stabilizes a system which is not stabilizable in the class of constant controls.     

Controller design for stabilizing bilinear systems with state-based switching

Some nonlinear systems can be approximated by switching bilinear systems. In this paper, we proposed a method to design state-based stabilizing controller for switching bilinear systems. Based on the similarity between switching bilinear systems and switching linear systems, corresponding switching linear systems are obtained for switching bilinear systems by applying state-based feedback control laws. Instead, we consider asymptotically stabilizing the corresponding switching linear system through solving a number of relaxed LMI conditions. Stabilizing controllers for switching bilinear systems can be derived based on the results of the corresponding switching linear systems. The stability of the controller is proved step by step through the decreasing of the multiple Lyapunov functions along the state trajectory. The effectiveness of the method is demonstrated by both a theoretical example and an example of urban traffic network with traffic signals.     

On symmetric algorithms for bilinear forms over finite fields

In this paper we study the computation of symmetric systems of bilinear forms over finite fields via symmetric bilinear algorithms. We show that, in general, the symmetric complexity of a system is upper bounded by a constant multiple of the bilinear complexity; we characterize symmetric algorithms in terms of the cosets of a specific cyclic code, and we show that the problem of finding an optimal symmetric algorithm is equivalent to the maximum-likelihood decoding problem for this code.     

Bilinear Bäcklund transformation and Lax pair for a coupled Ramani equation

In this paper, a coupled Ramani equation is proposed. The bilinear Bäcklund transformation and Lax pair for this equation are derived starting from its bilinear form. Multisoliton solutions to the system can also be obtained.     

A model-order reduction method based on Krylov subspaces for mimo bilinear dynamical systems

In this paper, we present a Krylov subspace based projection method for reduced-order modeling of large scale bilinear multi-input multioutput (MIMO) systems. The reduced-order bilinear system is constructed in such a way that it can match a desired number of moments of multivariable transfer functions corresponding to the kernels of Volterra series representation of the original system. Numerical examples report the effectiveness of this method.     

An overlapping domain decomposition preconditioner for a class of discontinuous Galerkin approximations of advection-diffusion problems

We consider a scalar advection-diffusion problem and a recently proposed discontinuous Galerkin approximation, which employs discontinuous finite element spaces and suitable bilinear forms containing interface terms that ensure consistency. For the corresponding sparse, nonsymmetric linear system, we propose and study an additive, two-level overlapping Schwarz preconditioner, consisting of a coarse problem on a coarse triangulation and local solvers associated to a family of subdomains. This is a generalization of the corresponding overlapping method for approximations on continuous finite element spaces. Related to the lack of continuity of our approximation spaces, some interesting new features arise in our generalization, which have no analog in the conforming case. We prove an upper bound for the number of iterations obtained by using this preconditioner with GMRES, which is independent of the number of degrees of freedom of the original problem and the number of subdomains. The performance of the method is illustrated by several numerical experiments for different test problems using linear finite elements in two dimensions.

     

Improved stability and error analysis for a class of local projection stabilizations applied to the Oseen problem

We consider a class of local projection stabilizations with projection spaces defined on (possibly) overlapping sets applied to the Oseen problem. We prove that the underlying bilinear form satisfies an inf–sup condition with respect to a stronger norm than coercivity suggests. A modification of the stabilization of the convection allows an optimal estimation of the consistency error. A priori estimates in the stronger norm and in the L² norm for the pressure are established. Discontinuous pressure approximations are included in the analysis. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2013     

An analysis of finite element locking in a parameter dependent model problem

Summary. We consider the bilinear finite element approximation of smooth solutions to a simple parameter dependent elliptic model problem, the problem of highly anisotropic heat conduction. We show that under favorable circumstances that depend on both the finite element mesh and on the type of boundary conditions, the effect of parametric locking of the standard FEM can be reduced by a simple variational crime. In our analysis we split the error in two orthogonal components, the approximation error and the consistency error, and obtain different bounds for these separate components. Also some numerical results are shown. Received September 6, 1999 / Revised version received March 28, 2000 / Published online April 5, 2001     

Linear System Structure and Cone Containment for Bilinear Systems

Conditions are derived for a homogeneous bilinear system tohave a proper invariant cone in terms of positivity propertiesof the inverse of an induced linear system.