Dehua Shi^1,4, Shaohua Wang^1,2,*, Yingfeng Cai¹, Long Chen¹, ChaoChun Yuan¹, ChunFang Yin³

Intelligent Automation & Soft Computing, Vol.26, No.1, pp. 27-39, 2020, DOI:10.31209/2018.100000062

Abstract Model predictive control (MPC), owing to the capability of dealing with nonlinear and constrained problems, is quite promising for optimization. Different MPC strategies are investigated to optimize HEV nonlinear energy management for better fuel economy. Based on Bellman’s principle, dynamic programming is firstly used in the limited horizon to obtain optimal solutions. By considering MPC as a nonlinear programming problem, sequential quadratic programming (SQP) is used to obtain the descent directions of control variables and the current control input is further derived. To reduce computation and meet the requirements of real-time control, the nonlinear model of the system is approximated… More >

Guobao Zhang^a,b, Jing-Jing Xiong^a,b, Yongming Huang^a,b, Yong Lu^a,b,c, Ling Wang^a,b

Intelligent Automation & Soft Computing, Vol.24, No.3, pp. 541-551, 2018, DOI:10.31209/2018.100000021

Abstract This paper investigates the delay-dependent stability problem of recurrent neural networks with time-varying delay. A new and less conservative stability criterion is derived through constructing a new augmented Lyapunov-Krasovskii functional (LKF) and employing the linear matrix inequality method. A new augmented LKF that considers more information of the slope of neuron activation functions is developed for further reducing the conservatism of stability results. To deal with the derivative of the LKF, several commonly used techniques, including the integral inequality, reciprocally convex combination, and free-weighting matrix method, are applied. Moreover, it is found that the obtained stability criterion has a lower… More >

Hong-Sen Yan^1,2, Jiao-Jun Zhang^1,2, Qi-Ming Sun^1,2

Intelligent Automation & Soft Computing, Vol.25, No.3, pp. 487-507, 2019, DOI:10.31209/2018.100000037

Abstract MTN optimal control scheme of SISO nonlinear time-varying discrete-time systems based on multi-dimensional Taylor network (MTN) is proposed to achieve the real-time output tracking control for a given reference signal. Firstly, an ideal output signal is selected and Pontryagin minimum principle adopted to obtain the numerical solution of the optimal control law for the system relative to the ideal output signal, with the corresponding optimal output termed as desired output signal. Then, MTN optimal controller (MTNC) is generated automatically to fit the optimal control law, and the conjugate gradient (CG) method is employed to train the weight parameters of MTNC… More >

D. Vijeswaran^1,*, V. Manikandan²

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.3, pp. 801-813, 2019, DOI:10.32604/cmes.2019.07793

Abstract In a cyber-physical micro-grid system, wherein the control functions are executed through open communication channel, stability is an important issue owing to the factors related to the time-delay encountered in the data transfer. Transfer of feedback variable as discrete data packets in communication network invariably introduces inevitable time-delays in closed loop control systems. This delay, depending upon the network traffic condition, inherits a time-varying characteristic; nevertheless, it adversely impacts the system performance and stability. The load perturbations in a micro-grid system are considerably influenced by the presence of fluctuating power generators like wind and solar power. Since these non-conventional energy… More >

V. Venkatachalam^{1, *}, D. Prabhakaran¹

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 321-334, 2018, DOI:10.3970/cmes.2018.114.321

Abstract This paper presents, using Lyapunov-Krasovskii functional technique combined with reciprocal convex lemma is considered for a networked control temperature control system with additive time-varying-delays. In the stability analysis, a new LK functional is assumed, and take the time-derivative of the (LK) functional, using reciprocal convex combination technique was employed to obtain less conservative stability criteria. Finally, the proposed stability analysis culminates into a stability criterion in the LMI (linear matrix inequalities) framework. The results obtained are in accordance with the theoretically obtained in the temperature control system and they are closer to the standard benchmark temperature-control system. More >

Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 157-176, 2007, DOI:10.3970/cmes.2007.020.157

Abstract In many engineering applications the Lie group calculation is very important. With this in mind, the subject of this paper is for an in-depth investigation of time-varying linear systems, and its accompanied Lie group calculations. In terms of system matrix A in Eq. (11) and a one-order lower fundamental solution matrix associated with the sub-state matrix function A_s^s, we propose two methods to nilpotentlize the time-varying linear systems. As a consequence, we obtain two different calculations of the general linear group. Then, the nilpotent systems are further transformed to a unique new system Ż(t) = B(t)Z(t), which having a… More >

Chein-Shan Liu¹

CMC-Computers, Materials & Continua, Vol.10, No.1, pp. 97-116, 2009, DOI:10.3970/cmc.2009.010.097

Abstract A new numerical method is proposed for solving the delay ordinary differential equations (DODEs) under multiple time-varying delays or state-dependent delays. The finite difference scheme is used to approximate the ODEs, which together with the initial conditions constitute a system of nonlinear algebraic equations (NAEs). Then, a Fictitious Time Integration Method (FTIM) is used to solve these NAEs. Numerical examples confirm that the present approach is highly accurate and efficient with a fast convergence. More >