Design and stability analysis of multivariate extremum seeking with Newton method     

Chun Yin  Shanshan Wu  Shiwei Zhou  Jiuwen Cao  Xuegang Huang  Yuhua Cheng 《Journal of The Franklin Institute》2018,355(4):1559-1578

This paper proposes a multivariate extremum seeking with the Newton method (ES-NM) to improve the control performance for multivariable static and dynamic systems. The structure of the proposed ES-NM is designed to speed up the convergence of the scheme without increasing the oscillation. The influence of unknown Hessian matrix on the convergence speed existed in conventional methods is effectively eliminated in the proposed ES-NM approach. The stability analysis of the proposed ES-NM is given in detail for static and dynamic systems. Comparisons to the existing Gradient based extremum seeking control (ESC) and the Newton based ESC reveal that the proposed ES-NM has a higher probability of improving the convergence speed as well as reducing the chattering performance. Simulation results show advantages of the proposed ES-NM by comparing the multivariate Gradient based and Newton based ESC.  相似文献   

Improving the multimodal probabilistic semantic model by ELM classifiers     

Yu Zhang  Ye Yuan  Fangda Guo  Yishu Wang  Guoren Wang 《Journal of The Franklin Institute》2018,355(4):1967-1990

The multi-modal retrieval is considered as performing information retrieval among different modalities of multimedia information. Nowadays, it becomes increasingly important in the information science field. However, it is so difficult to bridge the meanings of different multimedia modalities that the performance of multimodal retrieval is deteriorated now. In this paper, we propose a new mechanism to build the relationship between visual and textual modalities and to verify the multimodal retrieval. Specifically, this mechanism depends on the multimodal binary classifiers based on the Extreme Learning Machine (ELM) to verify whether the answers are related to the query examples. Firstly, we propose the multimodal probabilistic semantic model to rank the answers according to their generative probabilities. Furthermore, we build the multimodal binary classifiers to filter out unrelated answers. The multimodal binary classifiers are called the word classifiers. It can improve the performance of the multimodal probabilistic semantic model. The experimental results show that the multimodal probabilistic semantic model and the word classifiers are effective and efficient. Also they demonstrate that the word classifiers based on ELM not only can improve the performance of the probabilistic semantic model but also can be easily applied to other probabilistic semantic models.  相似文献   

HOG-assisted deep feature learning for pedestrian gender recognition     

Lei Cai  Jianqing Zhu  Huanqiang Zeng  Jing Chen  Canhui Cai  Kai-Kuang Ma 《Journal of The Franklin Institute》2018,355(4):1991-2008

Pedestrian gender recognition is a very challenging problem, since the viewpoint variations, illumination changes, occlusion, and poor quality are usually encountered in the pedestrian images. To address this problem, an effective HOG-assisted deep feature learning (HDFL) method is proposed in this paper. The key novelty lies in the design of HDFL network to effectively explore both deep-learned feature and weighted histogram of oriented gradient (HOG) feature for the pedestrian gender recognition. Specifically, the deep-learned and weighted HOG feature extraction branches are simultaneously performed on the input pedestrian image. A feature fusion process is subsequently conducted to obtain a more robust and discriminative feature, which is then fed to a softmax classifier for pedestrian gender recognition. Extensive experiments on multiple existing pedestrian image datasets have shown that the proposed HDFL method is able to effectively recognize the pedestrian gender, and consistently outperforms the state-of-the-art methods.  相似文献   

In-depth cross-coupling analysis in high-performance induction motor control     

Luis A. Amézquita-Brooks  Carlos E. Ugalde-Loo  Eduardo Licéaga-Castro  Jesús Licéaga-Castro 《Journal of The Franklin Institute》2018,355(5):2142-2178

High-performance field oriented control (FOC) of induction motors (IMs) relies on the accurate control of their electrical dynamics. In particular, perfect decoupling control of the stator currents should be ideally achieved for a FOC scheme to be efficient. However, the decoupling effectiveness afforded by most stator currents controllers may be influenced not only by the parameters and the operating condition, but also by the specific controller structure and the adopted coordinate system. A measure to assess decoupling effectiveness is non-existent in the IM control literature. To bridge this gap, an in-depth analysis of the cross-coupling inherent characteristics of the electrical subsystem of IMs under different well-known control structures is presented in this paper. Specifically, four control strategies previously studied and experimentally validated in the literature are critically assessed in this work: (1) stationary frame proportional-integral (PI) control, (2) synchronous frame PI control, (3) synchronous frame PI control with decoupling networks, and (4) improved stationary frame diagonal control. The decoupling capabilities of controllers in stationary and synchronous coordinates are examined, with a detailed insight on the role of decoupling methods. The analysis is performed in the frequency domain under the framework of individual channel analysis and design (ICAD). By application of ICAD, the decoupling effectiveness of FOC schemes is clearly exposed and quantified, with an assessment of the effects of parametric uncertainty being carried out for completeness. The effect of the inverter dynamics over cross-coupling is also treated using digital simulations. The results are useful to determine the conditions in which each control strategy has either advantages or disadvantages. Additionally, it is possible to determine the effect of several operating parameters over the stator currents cross-coupling such as nominal flux and torque levels.  相似文献   

Neural network adaptive control design for robot manipulators under velocity constraints     

Hamed Rahimi Nohooji  Ian Howard 《Journal of The Franklin Institute》2018,355(2):693-713

This paper studies the neural adaptive control design for robotic systems with uncertain dynamics under the existence of velocity constraints and input saturation. The control objective is achieved by choosing a control Lyapunov function using joint error variables that are restricted to linear growth and furthermore by introducing a secant type barrier Lyapunov function for constraining the joint rate variables. The former is exploited to bind the forward propagation of the position errors, and the latter is utilized to impose hard bounds on the velocity. Effective input saturation is expressed, and neural networks are employed to tackle the uncertainty problem in the system dynamics. Feasibility conditions are formulated, and the optimal design parameters are obtained by solving the constrained optimization problem. We prove that under the proposed method, semi-global uniform ultimate boundedness of the closed-loop system can be guaranteed. Tracking errors meanwhile converge to small neighborhoods of the origin, and violations of predefined velocity constraints are avoided. Finally, numerical simulations are performed to verify the effectiveness of the theoretical developments.  相似文献   

Lag synchronization for fractional-order memristive neural networks with time delay via switching jumps mismatch     

Lingzhong Zhang  Yongqing Yang  Fei wang  Xin sui 《Journal of The Franklin Institute》2018,355(3):1217-1240

This paper studies drive-response synchronization in fractional-order memristive neural networks (FMNNs) with switching jumps mismatch. A comparison theorem for fractional-order systems with variable order is provided first. Theories of fractional order Filippov differential inclusions are used to treat FMNNs because the parameters of FMNNs are state dependent and the FMNNs has discontinuous right hand sides. Based on Laplace transform and linear feedback control, some lag quasi-synchronization conditions are obtained with variable order α: 0?<?α?<?1 and 1?<?α?<?2. The error level is estimated and the larger synchronization regain is discussed. Finally, two numerical examples are presented to illustrate the effectiveness of our proposed theorems.  相似文献   

Observer-based fault detection for uncertain nonlinear systems     

Huayun Han  Ying Yang  Linlin Li  Steven X. Ding 《Journal of The Franklin Institute》2018,355(3):1278-1295

This paper addresses L₂ observer-based fault detection issues for a class of nonlinear systems in the presence of parametric and dynamic uncertainties, respectively. To this end, three different types of uncertain affine nonlinear system models studied in this paper are described first. Then, the integrated design schemes of L₂ observer-based fault detection systems are derived with the aid of Hamilton–Jacobi inequalities (HJIs), respectively. Numerical examples are also provided in the end to demonstrate the effectiveness of the proposed results.  相似文献   

Fault-tolerant anti-windup control for hypersonic vehicles in reentry based on ISMDO     

Yizhen Meng  Bin Jiang  Ruiyun Qi  Jianwei Liu 《Journal of The Franklin Institute》2018,355(5):2067-2090

Due to the extreme large flight scale of Hypersonic Vehicle (HSV), the system inevitably possesses strong nonlinearity, coupling, fast time-variability and is also sensitive to disturbance and fault. The method of external anti-windup system combined with the terminal sliding mode control law (TSMC) is presented for the nonlinear control problem under the restriction of control surfaces for HSV. It can realize the compensation for the control surface saturation and let the HSV smoothly track the command signals. Then, the improved sliding mode disturbance observer (ISMDO) is proposed to estimate unknown parameters and strong external disturbance as well as the unknown actuator fault. This method does not need the information of disturbance and the fault bounds and has fewer learning parameters, which makes it suitable for the real-time control. Finally, the simulation test of attitude control for the reentry HSV is conducted, and the results show the effectiveness and robustness of the proposed scheme.  相似文献   

Multiple switching-time-dependent discretized Lyapunov functions/functionals methods for stability analysis of switched time-delay stochastic systems     

Shixian Luo  Feiqi Deng  Wu-Hua Chen 《Journal of The Franklin Institute》2018,355(2):949-964

This paper presents novel approaches for stability analysis of switched linear time-delay stochastic systems under dwell time constraint. Instead of using comparison principle, piecewise switching-time-dependent discretized Lyapunov functions/functionals are introduced to analyze the stability of switched stochastic systems with constant or time-varying delays. These Lyapunov functions/functionals are decreasing during the dwell time and non-increasing at switching instants, which lead to two mode-dependent dwell-time-based delay-independent stability criteria for the switched systems without restricting the stability of the subsystems. Comparison and numerical examples are provided to show the efficiency of the proposed results.  相似文献   

The benefits of multivariate singular spectrum analysis over the univariate version     

Paulo Canas Rodrigues  Rahim Mahmoudvand 《Journal of The Franklin Institute》2018,355(1):544-564

Singular Spectrum Analysis (SSA) is a relatively simple and powerful method in the area of time series analysis that is mainly based on matrix analysis. In this paper, we present a methodological comparison between the univariate and multivariate versions of SSA. Additionally, we explore the advantages of multivariate SSA in terms of theoretical results and with application to a real data set on currency exchange rates.  相似文献