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A multi-strategy enhanced African vultures optimization algorithm for global optimization problems
Zheng Rong,Hussien Abdelazim G,Qaddoura Raneem,Jia Heming,Abualigah Laith,Wang Shuang,Saber Abeer 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.1
The African vultures optimization algorithm (AVOA) is a recently proposed metaheuristic inspired by the African vultures’ behaviors. Though the basic AVOA performs very well for most optimization problems, it still suffers from the shortcomings of slow convergence rate and local optimal stagnation when solving complex optimization tasks. Therefore, this study introduces a modified version named enhanced AVOA (EAVOA). The proposed EAVOA uses three different techniques namely representative vulture selection strategy, rotating flight strategy, and selecting accumulation mechanism, respectively, which are developed based on the basic AVOA. The representative vulture selection strategy strikes a good balance between global and local searches. The rotating flight strategy and selecting accumulation mechanism are utilized to improve the quality of the solution. The performance of EAVOA is validated on 23 classical benchmark functions with various types and dimensions and compared to those of nine other state-of-the-art methods according to numerical results and convergence curves. In addition, three real-world engineering design optimization problems are adopted to evaluate the practical applicability of EAVOA. Furthermore, EAVOA has been applied to classify multi-layer perception using XOR and cancer datasets. The experimental results clearly show that the EAVOA has superiority over other methods.
Multitap coherence-free photonic RF filter employing semiconductor optical amplifier
Zheng, Rong,Alameh, Kamal,Lee, Yong Tak,Wang, Zhenglin Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.5
<P>A novel multitap coherence-free photonic bandpass RF filter utilizing the cross-gain modulation property of the semiconductor optical amplifier to convert a coherent RF-modulated laser carrier to a low-coherence light that is sliced and delayed to realize a stable transversal RF filter. An 8-tap photonic RF bandpass filter operating at 2.25 GHz with more than 15 dB rejection is experimentally demonstrated. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1103–1106, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22352</P>
Delay-dependent robust stability criterion for Lurie-type system
Zhengrong Zhao,Wei Wang 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-
The delay-dependent robust stability of Lurie-type control system with delay is concerned, the delay is assumed constant and unknown. The uncertainties under consideration are norm bounded, and possibly time varying. Based on the Lyapunov method, a new stability criterion in terms of linear matrix inequalities (LMIs) is presented, the LMIs can be easily calculated. An example shows that the stability criterion in this paper is less conservative than others.
Active Disturbance Rejection Control Applied to High-order Systems with Parametric Uncertainties
Zhengrong Chu,Christine Wu,Nariman Sepehri 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6
Active disturbance rejection control (ADRC) is an emerging control technique known for its simplicity and good disturbance rejection ability. It has been applied to first- and second-order systems in many areas. However, the application of the ADRC to high-order systems is few and also challenging because the existing bandwidth tuning method is unable to determine proper controller parameters to achieve desired system performance. To address this problem, a new method is proposed to tune the ADRC for controlling high-order systems. First, the ADRC is decomposed into a controller and a prefilter in the frequency domain. Second, they are tuned to satisfy prescribed performance specifications. Two applications of the ADRC to high-order hydraulic systems are presented. It is shown that the proposed method greatly improves the performance of the ADRC compared to the bandwidth tuning method.
Zhengrong Wang,Rennian Li,Gaoping Xu,Wei Han,Mingkuo Bian,Weiwei Zhou,Qinjiang Sun 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.4
Simulation models of permanent magnet brushless DC motor with cam rotors and two kinds of uniform air gap motor determined by two limit arcs of the cam rotor were established on the basis of JMAG software. These simulation models were used to determine the influence of regularly varying air gap, which is formed during the rotation of the two cam rotors of the hydraulic motor pumps integrated with a cam rotor vane pump and a permanent magnet brushless DC motor, on the electromagnetic performance of the motor. The electromagnetic performance of the three kinds of motors were simulated and compared under rated and variable loads, respectively. Finally, the cam rotor motor prototype was developed for experimental research. Results show that the starting time of cam rotor motor under rated load is 20% shorter, and its output torque ripple is 23% smaller than those of the uniform air gap motor determined by the minimum limit arc of the cam rotor. However, the air gap flux density curve of the cam rotor motor weakens obviously amongst the three motors. Under different loads, the efficiency of the cam rotor motor is the highest amongst the three motors, and its mechanical property is hard. The research results can lay a theoretical foundation for the development of cam rotor motor pumps.
Catenary Equation-Based Approach for Force Finding of Cable Domes
Zhengrong Jiang,Xiaowei Liu,Kairong Shi,Quanpan Lin,Zijian Zhang 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.1
Cable forces along the cable length direction vary with deadweight. An invariant that is horizontal component force along the cable length, is introduced to characterize prestress distribution of cable domes. A new approach named catenary equationbased component force balancing method, is proposed for force fi nding. In the method, the relationship between the form and the horizontal component force of the cable is determined according to catenary equation of the cable. Based on the horizontal component force of one cable, the horizontal component forces of other cables can be solved from the nodal equilibrium relationship. Take the Geiger cable dome as an example, the results of force fi nding show that the proposed method has clear mechanical concept, high calculation accuracy and simple solving process. Thus, it can provide a new general idea for force fi nding of cable domes. In addition, the diff erence of the results of force fi nding is large between with deadweight considered and with deadweight ignored. Therefore, deadweight should be considered during the prestress design of cable domes.
Shuo Li,Zhengrong Xiang,Hamid Reza Karimi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.4
This paper investigates the problem of fault detection observer design for positive switched systems with time-varying delay via delta operator approach. A new fault sensitivity measure, called l– index, is proposed. The l– fault detection observer design and multi-objective l– /l1 fault detection observer design problems are addressed. Based on the average dwell time approach and the piecewise co-positive type Lyapunov-Krasovskii functional method in delta domain, sufficient conditions for the existence of such two kinds of fault detection observers are firstly given, and then the design methods are presented. Finally, two examples are provided to show the effectiveness and the applicability of the proposed methods.
Finite-time H∞ Control for Switched Systems with Time-varying Delay using Delta Operator Approach
Chen Qin,Zhengrong Xiang,Hamid Reza Karimi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.6
Finite-time H∞ control for switched systems with time-varying delay using delta operator approach is investigated in this paper. Firstly, by using the average dwell time approach and delta operator theory, sufficient conditions for H∞ finite-time boundedness of the underlying systems are derived. Then a state feedback controller is proposed such that the resulting closed-loop system is H∞ finite-time bounded. All the obtained results are formulated in terms of linear matrix inequalities (LMIs). Finally, an example is presented to show the validity of the proposed results.
Stabilization of Positive Switched Systems with Time-varying Delays under Asynchronous Switching
Mei Xiang,Zhengrong Xiang,Hamid Reza Karimi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.5
This paper investigates the state feedback stabilization problem for a class of positive switched systems with time-varying delays under asynchronous switching in the frameworks of continuous-time and discrete-time dynamics. The so-called asynchronous switching means that the switches between the candidate controllers and system modes are asynchronous. By constructing an appropriate co-positive type Lyapunov-Krasovskii functional and further allowing the functional to increase during the running time of active subsystems, sufficient conditions are provided to guarantee the exponential stability of the resulting closed-loop systems, and the corresponding controller gain matrices and ad-missible switching signals are presented. Finally, two illustrative examples are given to show the effec-tiveness of the proposed methods.
Acoustic Noise of Brushless DC Motors Induced by Electromagnetic Torque Ripple
Kun Xia,Zhengrong Li,Jing Lu,Bin Dong,Chao Bi 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4
Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.