基于混沌变量的模糊控制器设计

本文提出了一种基于混沌变量的模糊控制器设计方法,结合融合技术用以解决模糊控制器的规则爆炸问题。针对二次型最优控制中加权矩阵较难确定的问题,引入混沌大范围粗搜索和局部细搜索相结合,进而搜索出全局最优的权系数,用以提高控制的性能。通过二级倒立摆实物控制实验结果说明该方法是有效可行的。     

Very long-term retention of the control of variables strategy following a brief intervention

Middle school students (n = 354) were tested for their understanding of the control of variables strategy (CVS) 2.5 years after participating in a study comparing three different interventions for teaching CVS. The key finding was that the pattern of effects observed in the 4^th grade continued to be observed in the 6^th grade. This was because (a) students who had mastered CVS in the 4^th grade were likely to continue to perform at mastery levels in the 6^th grade whereas (b) the learning of students who had not mastered CVS in 4^th grade was independent of the teaching intervention they had received in the 4^th-grade study. These findings demonstrate that a brief intervention of direct instruction in CVS can produce long-lasting learning of the principle of controlling variables.     

Delay-dependent robust control for uncertain discrete singular systems with time-varying delay

The design problem of delay-dependent robust control For uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent robust stability condition is derived and expressed in terms of linear matrix inequalities （LMIs）. A suitable robust state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable for all admissible uncertainties. Numerical examples are given to demonstrate the applicability of the proposed method.     

Input-output approach to robust stability and stabilization for uncertain singular systems with time-varying discrete and distributed delays

Based on input-output approach, the robust stability and stabilization problems for uncertain singular systemswith time-varying delays are investigated. The parameter uncertainties are assumed to be norm-bounded and the time-varying delays include both discrete delay and distributed delay. By introducing a new input-output model, the time-delay system is embedded in a family of systems with a forward system without time delay and a dynamical feedback uncertainty. A sufficient and necessary condition, which guarantees the system regular, impulse-free and stable for all admissible uncertainties, is obtained. Based on the strict linear matrix inequality, the desired robust state feedback controller is also obtained. Finally, a numerical example is provided to demonstrate the application of the proposed method.     

Environment map building and localization for robot navigation based on image sequences

SLAM is one of the most important components in robot navigation. A SLAM algorithm based on image sequences captured by a single digital camera is proposed in this paper. By this algorithm, SIFT feature points are selected and matched between image pairs sequentially. After three images have been captured, the environment＇s 3D map and the camera＇s positions are initialized based on matched feature points and intrinsic parameters of the camera. A robust method is applied to estimate the position and orientation of the camera in the forthcoming images. Finally, a robust adaptive bundle adjustment algorithm is adopted to optimize the environment＇s 3D map and the camera＇s positions simultaneously. Results of quantitative and qualitative experiments show that our algorithm can reconstruct the environment and localize the camera accurately and efficiently.     

Multi-objective robust controller synthesis for discrete-time systems with convex polytopic uncertain domain

Multi-objective robust state-feedback controller synthesis problems for linear discrete-time uncertain systems are addressed. Based on parameter-dependent Lyapunov functions, the Gl2 and GH2 norm expressed in terms of LMI （Linear Matrix Inequality） characterizations are further generalized to cope with the robust analysis for convex polytopic uncertain system. Robust state-feedback controller synthesis conditions are also derived for this class of uncertain systems. Using the above results, multi-objective state-feedback controller synthesis procedures which involve the LMI optimization technique are developed and less conservative than the existing one. An illustrative example verified the validity of the approach.     

A robust tolerance design method based on process capability

INTRODUCTIONTolerancedesignisabridgetolinktherequirementofproductperformanceandthemanufacturingprocess;andaffectsnotonlytheproductperformance,butalsothecostoftheproductandthemanufacturingprocess.There foreComputerAidedTolerancing (CAT)be comesthekeytechniqueforintegratingCAD CAPP CAM (WuandYang,1999) .Tradition ally,thetoleranceisassignedtothecomponentdimensionsaccordingtotheminimumcost.Therestrictionofthemanufacturingabilityoftoolsthatthefactoryownsisneglected (Jietal.,1999) .Asa…     

Robust exponential stability analysis of a larger class of discrete-time recurrent neural networks

The robust exponential stability of a larger class of discrete-time recurrent neural networks (RNNs) is explored in this paper. A novel neural network model, named standard neural network model (SNNM), is introduced to provide a general framework for stability analysis of RNNs. Most of the existing RNNs can be transformed into SNNMs to be analyzed in a unified way. Applying Lyapunov stability theory method and S-Procedure technique, two useful criteria of robust exponential stability for the discrete-time SNNMs are derived. The conditions presented are formulated as linear matrix inequalities (LMIs) to be easily solved using existing efficient convex optimization techniques. An example is presented to demonstrate the transformation procedure and the effectiveness of the results.     

Mixed G<Emphasis Type="Italic">l</Emphasis><Subscript>2</Subscript>/G<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> multi-channel multi-objective control synthesis for discrete time systems

This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl ₂ (Gl ₂) and generalizedH ₂ (GH ₂) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl ₂/GH ₂ control problem can be solved less conservatively using computationally tractable algorithms developed in the paper. Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176)