State-shared model for multiple-input multiple-output systems

This work proposes a method to construct a state-shared model for multiple-input multiple-output （MIMO） systems. A state-shared model is defined as a linear time invariant state-space structure that is driven by measurement signals-the plant outputs and the manipulated variables, but shared by different multiple input/output models. The genesis of the state-shared model is based on a particular reduced non minimal realization. Any such realization necessarily fulfills the requirement that the output of the state-shared model is an asymptotically correct estimate of the output of the plant, if the process model is selected appropriately. The approach is demomtrated on a nonlinear MIMO system - a physiological model of calcium fluxes that controls muscle contraction and relaxation in human cardiac myocytes.     

State-shared model for multiple-input multiple-output systems

This work proposes a method to construct a state-shared model for multiple_input multiple_output (MIMO) systems. A state_shared model is defined as a linear time invariant state_space structure that is driven by measurement signals _the plant outputs and the manipulated variables, but shared by different multiple input/output models. The genesis of the state_shared model is based on a particular reduced non_minimal realization. Any such realization necessarily fulfills the requirement that the output of the state_shared model is an asymptotically correct estimate of the output of the plant, if the process model is selected appropriately. The approach is demonstrated on a nonlinear MIMO system - a physiological model of calcium fluxes that controls muscle contraction and relaxation in human cardiac myocytes.     

Model reduction of systems with zeros interlacing the poles

The problem of reducing a system with zeros interlacing the poles (ZIP) on the real axis is considered. It is proved that many model reduction methods, such as the balanced truncation, balanced residualization, suboptimal and optimal Hankel approximations, inherit the ZIP property. Properties of the Hankel singular values of ZIP systems are also listed.     

On near optimal neural control of multiple-input nonlinear systems

It has been a common consensus that general techniques for stabilization of nonlinear systems are available only for some special classes of nonlinear systems. Control design for nonlinear systems with uncertain components is usually carried out on a per system basis, especially when physical control constraints, and certain control performance measures such as optimum time control are imposed. Elegant adaptive control techniques are difficult to apply to this type of problems. A new neural network based control design is proposed and presented in this paper to deal with a special class of uncertain nonlinear systems with multiple inputs. The desired system dynamics are analyzed and utilized in the process of the proposed intelligent control design. The theoretical results are provided to justify the design procedures. The simulation study is conducted on a second-order bilinear system with two inputs and uncertainties on its parameters. The simulation results indicate that the proposed design approach is effective.     

Autotune identification for systems with right-half-plane poles and zeros

Autotuning based on relay feedback tests have received a great deal of attention recently. The relay feedback tests fail to generate sustained oscillation in some cases. For systems with RHP poles and/or zeros, incorrect autotune identification procedure may give erroneous information and unstable limit cycle. Frequency domain analyses provide a criteria for prediction of the existence of stable limit cycle. Furthermore, a procedure is given to ensure the success of a relay feedback test. The analyses and procedure are illustrated through open loop stable and unstable systems. Results show that, except for some rare occasion, successful relay feedback experiments can be obtained following the proposed procedure.     

Achievable performance of multivariable systems with unstable zeros and poles

This paper examines the fundamental limitations imposed by unstable (right half plane; RHP) zeros and poles in multivariable feedback systems. We generalize previously known controller-independent lower bounds on the H     

On eigenvectors of the canonical matrix for multiple-input controllable systems

The explicit forms of the eigenvectors of the canonical matrix for controllable multiinput systems and the transformation matrix achieving the diagonal matrix are presented.     

一种含噪声不确定多输入多输出非线性时变系统的最优跟踪控制

如何在确保实时性能的前提下,将系统耦合、随机因素、时变特性和不确定非线性的影响一同最小化具有重要意义.为此,本文提出了一种基于自适应多维泰勒网(MTN)的优化控制方案,包括MTN控制器(MTNC)和MTN滤波器(MTNF).首先,设计基于强化学习和自适应动量因子的改进梯度法来调节MTNC权值以快速响应被控对象的不确定性和时变特性,实现最优控制;证明闭环系统稳定性.而后,通过Lyapunov稳定性理论设计MTNF权值更新律,使动态误差指数收敛到零;恰当选择Lyapunov函数来构造具有全局最小值的能量空间并对MTNF的Lyapunov特性进行分析;证明MTNF误差的收敛速度和收敛区域,避免奇点问题.最后,仿真结果表明所提出的控制器和滤波器可在较短的时间内获得更高的精度.     

Global stabilization of linear systems by bounded controls with guaranteed poles

The global stabilization of asymptotically null controllable linear systems by bounded control is considered. A nested type saturation control law is proposed which is a generalization of the existing results reported in the literature. The primary characteristic of this modified control law is that more design parameters, which are the closed-loop eigenvalues when the system is operating in linear form, are introduced and which can be well designed to achieve better system performance. Using this law, the pole locations of the closed-loop systems depending on a linear trans- formation can be placed arbitrarily within certain areas. Numerical example shows that the performance of the closed-loop system under this control law can be significantly improved if the free parameters are properly chosen.     

A robust implicit state observer for multiple-input multiple-output uncertain systems

A new mathematical method of estimating the state for uncertain continuous-time multiple-input multiple-output minimum-phase (with respect to the relation between the disturbance and the output) dynamical systems with arbitrarily relative degrees is presented. For the systems with relative degree one, the state observer which is perfectly robust to disturbances is constructed by using only the input and output information. The estimating error of the state decays to zero exponentially. For the systems with higher relative degrees, the state observer is formulated for the first time, where the input and output information, and the a priori information of the upper and lower bounds of the disturbances are employed. In this case, the estimating error of the state can be controlled to be as small as is needed by the design parameters. The attraction of the proposed observers lies in their robustness to disturbances and insensitivity to the high-frequency noises accompanying the inputs. A design example and its simulation results are presented to illustrate the proposed algorithm.     

A control of particular poles of linear systems

In this work, the conditions under which the given poles of a linear stationary system can be moved to a required position, while the other poles strictly remain at their places, are justified. On the basis of stratification (decomposition) of the initial system, it is shown that to verify the solubility conditions of the problem, it is sufficient to compute a pair of matrices whose dimensions are defined by the number of poles to be corrected and to analyze the controllability of this pair. The structure of the set of controllers providing the control of the chosen poles is justified. The set of all controllers is analytically described for the special case of controlling one real pole. The technique is extended to the case when the invariance to external perturbations and the given placement of the system poles are provided simultaneously. The problem is solved on the basis of the matrix canonization method. An illustrative example is given.     

On standard control problems for systems with infinitely many unstable poles

In this paper, H^∞ control for a class of linear time invariant systems with infinitely many unstable poles is studied. An example of such a plant is a high gain system with delayed feedback. We formulate the problem via a generalized plant which consists of a rational transfer matrix and the inverse of a scalar (possibly irrational) inner function. It is shown that the problem can be decomposed into a finite-dimensional H^∞ control problem and an additional rank condition.     

基于分散模糊推理的多输入多输出系统预测控制

对于动态过程具有明显迟延和惯性的MIMO系统,常规模糊控制难以建立模糊规则,控制效果不理想.针对MIMO控制对象,提出一种基于分散模糊推理的预测控制(predictive control based on decentralized fuzzy inference, DFIPC)方法.构造一组与被控输出相对应的分散模糊推理模块,每个推理模块利用一组分散的模糊推理单元,分别根据各个输出的期望值与预测值之间的偏差进行分散推理.在时间层面,根据动态响应程度对推理结果进行加权综合,获得等效控制输入;进一步,通过对等效控制输入加权综合产生系统实际控制输入增量,从而有效克服模糊推理系统处理多维输入信息时模糊规则难以建立的困难.最后,通过实验验证所提出控制方法对于迟延和惯性明显的MIMO控制对象的有效性和适应性.     

Multiuser detection algorithm based on belief propagation in multiple-input multiple-output systems

In MIMO (multiple-input, multiple-output) systems, signals from differenttransmitting antennas interfere at each receiving antenna and multiuser detection (MUD)algorithms may be adopted to improve the system performance. This paper proposes anovel multiuser detection algorithm in MIMO systems based on the idea of "beliefpropagation" which has achieved great accomplishment in decoding of low-densityparity-check codes. The proposed algorithm has a low computation complexityproportional to the square of transmitting/receiving antenna number. Simulation resultsshow that under low signal-to-noise ratio (SNR) circumstances, the proposed algorithmoutperforms the traditional linear minimum mean square error (MMSE) detector while itencounters a "floor' of bit error rate under high SNR circumstances. So the proposedalgorithm is applicable to MIMO systems with channel coding and decoding. Although inthis paper the proposed algorithm is derived in MIMO systems, obviously it can be appliedto ordinary code-division m     

The design of multivariable systems having zero sensitive poles

A design technique that assigns the maximal number of poles of a linear multivariable system and makes them insensitive to uncertainty in the parameters of the system dynamical matrix is introduced. Its immediate application is in multivariable dominant poles design.     

基于辅助模型正交匹配追踪的多输入系统迭代辨识算法

针对含有未知时滞的多输入输出误差系统的时滞与参数辨识问题,提出一种基于辅助模型的正交匹配追踪迭代算法.首先,由于各输入通道的时滞未知,通过设定输入回归长度,对系统模型进行过参数化,得到一个高维的辨识模型,且辨识模型中参数向量为稀疏向量;然后,基于辅助模型思想和正交匹配追踪算法,在每次迭代过程中,对参数向量和辅助模型的输出进行交互估计,即利用正交匹配追踪算法获得参数向量的估计,再利用参数估计值计算辅助模型的输出,并用辅助模型的输出值代替信息向量中的不可测信息项以更新参数估计;最后,根据参数向量的稀疏特征,获得系统的时滞估计.所提出算法可以利用少量的采样数据信息同时获得系统参数和时滞的估计值.仿真结果表明了所提出算法的有效性.     

L 2-optimization and fixed poles for sampled-data systems with generalized hold

This paper considers the L ₂-optimization problem for a standard sampled-data system with generalized hold of an arbitrary order. The original problem is reduced to the minimization problem of a degenerate quadratic functional, where solution appears nonunique. And finally, the authors propose a polynomial procedure for constructing a set of optimal discrete causal controllers and establish some relevant properties of L ₂-optimal systems in the context of applications.     

H 2-optimization and fixed poles for sampled-data systems with generalized hold

Standard multivariable sampled-data system with generalized hold of arbitrary order is investigated. An algorithm for design of H ₂-optimal digital controller is presented. Some qualitative properties of the H ₂-optimal system are described, which are important in applications.     

On backward shift algorithm for estimating poles of systems

In this paper, we present an algorithm for estimating poles of linear time-invariant systems by using the backward shift operator. We prove that poles of rational functions, including zeros and multiplicities, are solutions to an algebraic equation which can be obtained by taking backward shift operator to the shifted Cauchy kernels in the unit disc case. The algorithm is accordingly developed for frequency-domain identification. We also prove the robustness of this algorithm. Some illustrative examples are presented to show the efficiency in systems with distinguished and multiple poles.