State feedback control of interval type-2 Takagi–Sugeno fuzzy systems via interval type-2 regional switching fuzzy controllers

The interval type-2 Takagi–Sugeno fuzzy systems have been proposed to handle nonlinear systems subject to parameter uncertainties. In this paper, a new type of state feedback controller, namely, interval type-2 regional switching fuzzy controller, is proposed to conceive less-conservative stabilisation conditions, which is switched by basing on the values of system states. To further reduce the conservativeness in the stability analysis, the information of lower and upper membership functions is also considered. Stability conditions for the interval type-2 fuzzy closed-loop systems are presented in the form of linear matrix inequalities (LMIs). Simulation examples are provided to illustrate the effectiveness of the proposed method.     

Robust stability region of fractional order PIλ controller for fractional order interval plant

In this article, by using the fractional order PI^λ controller, we propose a simple and effective method to compute the robust stability region for the fractional order linear time-invariant plant with interval type uncertainties in both fractional orders and relevant coefficients. The presented method is based on decomposing the fractional order interval plant into several vertex plants using the lower and upper bounds of the fractional orders and relevant coefficients and then constructing the characteristic quasi-polynomial of each vertex plant, in which the value set of vertex characteristic quasi-polynomial in the complex plane is a polygon. The D-decomposition method is used to characterise the stability boundaries of each vertex characteristic quasi-polynomial in the space of controller parameters, which can obtain the stability region by varying λ orders in the range (0,?2). These regions of each vertex plant are computed by using three stability boundaries: real root boundary (RRB), complex root boundary (CRB) and infinite root boundary (IRB). The method gives the explicit formulae corresponding to these boundaries in terms of fractional order PI^λ controller parameters. Thus, the robust stability region for fractional order interval plant can be obtained by intersecting stability region of each vertex plant. The robustness of stability region is tested by the value set approach and zero exclusion principle. Our presented technique does not require sweeping over the parameters and also does not need linear programming to solve a set of inequalities. It also offers several advantages over existing results obtained in this direction. The method in this article is useful for analysing and designing the fractional order PI^λ controller for the fractional order interval plant. An example is given to illustrate this method.     

Robust controllability of linear interval systems with multiple control delays

The robust controllability problem for linear interval systems with multiple control delays is studied in this article. The rank preservation problem is converted to the nonsingularity analysis problem of the minors of the matrix in discussion. Based on some essential properties of matrix measures, a new sufficient algebraically elegant criterion for the robust controllability of linear interval systems with multiple control delays is established. A numerical example is given to illustrate the application of the proposed sufficient algebraic criterion.     

Fault detection in non-linear systems based on type-2 fuzzy logic

This paper presents a new method for fault detection (FD) based on interval type-2 fuzzy sets. The main idea is based on a confident span using interval type-2 fuzzy systems. An estimate for upper and lower bounds of output has been taken using the designing of an optimal fuzzy system through clustering. Finally the method has been tested in two non-linear systems, a two-tank with a fluid flow and pH neutralisation process, and it is compared with a well-known method named ANFIS. Furthermore, the mathematical model and the results of simulations prove the effectiveness, usefulness and applications of our new method.     

An efficient LMI approach for the quadratic stabilisation of a class of linear,uncertain, time-varying systems

The purpose of this article is to provide a numerically efficient method for the quadratic stabilisation of a class of linear, discrete-time, uncertain, time-varying systems. The considered class of systems is characterised by an interval time-varying (ITV) matrix and constant sensor and actuator matrices. It is required to find a linear time-invariant (LTI) static output feedback controller yielding a quadratically stable closed-loop system independently of the parameter variation rate. The solvability conditions are stated in terms of linear matrix inequalities (LMIs). The set of LMIs includes the stability conditions for the feedback connection of a unique suitably defined extreme plant with an LTI output controller and the positivity of a closed-loop extremal matrix. A consequent noticeable feature of the article is that the total number of LMIs is independent of the number of uncertain parameters. This greatly enhances the numerical efficiency of the design procedure.     

基于FPGA的扩频通信系统的研究及仿真

扩频通信,被誉为是通信技术的一次重大突破,其用来传输信息的射频带宽远大于信息本身,极大的提高了抗干扰能力,减小了功耗,在现代通信中已经成为了关键的技术.给出了一种基于FPGA的QUARTUS 9.0环境中的数字通信模型的仿真,着重解决了扩频通信系统的调制器的设计实现,并且仿真验证了其正确性,该调制器具有通用性和实现的便...     

协同OFDM系统联合中继选择、子载波配对和功率分配算法

研究了协同OFDM系统中的资源分配问题,提出了一种联合中继选择、子载波配对和功率分配的算法.首先在假定等功率分配的情况下,对中继节点进行选择并对子载波进行配对,然后在此基础上对选定的子载波对进行功率分配.分析结果显示所提算法是一种计算复杂度比较低,且系统容量接近最优容量的算法.     

基于评估和分工合作并行蚁群机器人路径规划

针对复杂环境中移动机器人的导航中存在的问题,提出了一种适用于机器人路径规划的并行蚁群分工合作算法。该方法由控制中心和独立的运算单元组成,每个运算单元中使用分工合作的蚁群进行计算从而从局部和全局两个方面优化蚁群的路径搜索,并将计算发送给处于控制中心的计算机,控制中心则负责处理每个运算单元发送的阶段性的路径搜索结果并利用评估机制对每个计算机得出的结果做最后的决策。从仿真结果可以看出该算法是有效且可行的。