Transactions of the Institute of Measurement and Control

Jiali, Yu; Chaoying, Xia

doi: 10.1177/0142331218817087pmid: N/A

Modular multilevel converter (MMC) is especially appropriate in high-voltage constant-frequency systems due to its modularity and scalability. But, so far MMC has not been widely used in motor drives applications. Since the capacitor voltage fluctuation is proportional to the output current amplitude and inversely proportional to the output frequency under constant torque load, at the low-speed, the excessive sub-module (SM) capacitor voltage fluctuation is one of the major obstacles for MMC applied in motor drives. To suppress the SM capacitor voltage fluctuation, an effective solution is to inject a high frequency zero sequence voltage to the three-phase output voltages of MMC and control the circulating current per phase reasonably. However, the introduced high frequency and high amplitude common voltage at the motor side is harmful. In this paper, a hybrid MMC with cascaded full-bridge SMs (HMMC-CFB) topology is used in the medium-voltage motor drives. The high frequency and high amplitude common mode voltage is absorbed by the cascaded full-bridge SMs. Besides, the capacitor voltage fluctuations of each arm and the cascaded full-bridge SMs is easily limited within a reasonable range. Finally, the state space model of HMMC-CFB system is established and a stable state-error feedback control law is given. By the passive theory, the necessary and sufficient condition for the globally uniformly asymptotical stability of the HMMC-CFB closed-loop system is deduced. Simulation results confirm the superiority of this novel topology and the validity of the proposed control strategy.

Lochan, Kshetrimayum; Roy, Binoy Krishna; Subudhi, Bidyadhar

doi: 10.1177/0142331218819700pmid: N/A

The problem of chaotic tip trajectory tracking control for a planar assumed modes modelled two-link flexible manipulator is addressed. Tracking of such an apparently random-like (chaotic) desired trajectory is a challenging task. Initially, a PID-type sliding surface is designed in terms of the tip trajectory tracking error, then a second-order integral-type fast terminal sliding mode control is designed using the above-designed sliding surfaces. The desired chaotic trajectory is generated from a four-dimensional chaotic hyperjerk system. The proposed controller guarantees fast tracking performance with lower steady-state error and less control input. The model of a two-link flexible manipulator is obtained using the assumed modes method. The robustness of the proposed control method is evaluated in the presence of matched uncertainty and variability of payload. The performances of the proposed control technique are verified in terms of low tracking error and fast tip deflection suppression. The effectiveness of the proposed technique is validated using numerical simulations, and compared with the normal second-order sliding mode control (SMC) and another controller reported recently in the literature.

Guo, Jianguo; Li, Yifei; Zhou, Jun

doi: 10.1177/0142331218819713pmid: N/A

A novel observer-based continuous adaptive sliding mode guidance (OCASMG) is proposed for homing missiles. First, a new sliding mode guidance law is derived from the nonlinear dynamics describing the pursuit situation of a missile and a target in the two-dimensional space, where a continuous adaptive function is introduced to overcome the chattering problem in sliding mode. Second, to improve the accuracy of target interception, a new nonlinear extended state observer (NESO) is presented to estimate target acceleration and compensate for the sliding mode guidance law. The stability of observer-based closed-loop system is proved by Lyapunov theory. Finally, simulations are conducted on the nonlinear longitudinal missile model and results demonstrate the effectiveness of proposed method.

Ege, Emre; Ankarali, Mustafa Mert

doi: 10.1177/0142331218822698pmid: N/A

In this paper, we propose a new motion planning method that aims to robustly and computationally efficiently solve path planning and navigation problems for unmanned surface vehicles (USVs). Our approach is based on synthesizing two different existing methodologies: sequential composition of dynamic behaviours and rapidly exploring random trees (RRT). The main motivation of this integrated solution is to develop a robust feedback-based and yet computationally feasible motion planning algorithm for USVs. In order to illustrate the main approach and show the feasibility of the method, we performed simulations and tested the overall performance and applicability for future experimental applications. We also tested the robustness of the method under relatively extreme environmental uncertainty. Simulation results indicate that our method can produce robust and computationally feasible solutions for a broad class of USVs.

Yu, Xiaolei; Zhou, Yujun; Liu, Zhenlu; Zhao, Zhimin

doi: 10.1177/0142331218823864pmid: N/A

In this paper, a multi-tag optimization method based on image analysis and particle swarm optimization (PSO) neural network is proposed to verify the effect of radio frequency identification (RFID) multi-tag distribution on the performance of the system. A RFID tag detection system is proposed with two charge coupled device (CCD). This system can automatically focus on the tag according to its position, so it can obtain the image information more accurately by template matching and edge detection method. Therefore, the spatial structure of multi-tag and the corresponding reading distance can be obtained for training. Because of its excellent performance in multi-objective optimization, the PSO neural network is used to train and predict multi-tag distribution at the maximum reading distance. Compared with other neural networks, PSO is more accurate and its uptime is shorter for RFID multi-tag analysis.

Nasri, Mohamed; Saifia, Dounia; Chadli, Mohammed; Labiod, Salim

doi: 10.1177/0142331218824385pmid: N/A

This paper presents an H∞ static output-feedback control of electrical power steering (EPS) subject to actuator saturation. It deals with different practical problems in designing control of EPS systems, such as unavailability for measurement of the sideslip angle, friction effect, disturbances and the assist motor input current optimization. In order to guarantee good and stable driving, the nonlinear model of the EPS combined with bicycle model of electrical vehicles is used. Firstly, a new Takagi-Sugeno model is established, then using a fuzzy Lyapunov function, an H∞ static output-feedback is designed in terms of linear matrix inequalities. Finally, the proposed control schemes are applied to an EPS system. Simulation results and comparison with previous works show the effectiveness of the proposed control methods.

Ladhari, Taoufik; Khoja, Intissar; Msahli, Faouzi; Sakly, Anis

doi: 10.1177/0142331218824384pmid: N/A

Parameter identification plays a key role in systems’ modeling and control. This paper deals with a parameter identification problem for an activated sludge process used in wastewater treatment. The considered model is a nonlinear one inspired from the well-known ASM1. Nature-inspired algorithms have gained significant attention over the last years as useful means to solve parameter identification problem. The proposed approach in this paper is the cuckoo search algorithm based on both the fascinating brood parasitic behavior and the lévy flights. The advantages of this method are its simplicity and robustness, but it requires a good tuning of its parameters to have the best results. The comparison of the simulation results with the Nelder-Mead method, genetic algorithm, and particle swarm optimization proves the capability of this method to identify the model’s parameters with high precision.

Liang, Jinxia; Wu, Baowei; Liu, Lili; Wang, Yue-E; Li, Changtao

doi: 10.1177/0142331219826333pmid: N/A

Finite-time stability and finite-time boundedness of fractional order switched systems with 0<α<1 are investigated in this paper. First of all, by employing the average dwell time technique and Lyapunov functional method, some sufficient conditions for finite-time stability and finite-time boundedness of fractional order switched systems are proposed. Furthermore, the state feedback controllers are constructed, and sufficient conditions are given to ensure that the corresponding closed-loop systems are finite-time stable and finite-time bounded. These conditions can be easily obtained in terms of linear matrix inequalities. Finally, two numerical examples are given to show the effectiveness of the results.

Sun, Shaoxin; Zhang, Huaguang; Han, Jian; Liang, Yuling

doi: 10.1177/0142331219826655pmid: N/A

In this paper we investigate the fault estimation problem against local unknown nonlinear dynamics, sensor and actuator faults for a class of Takagi–Sugeno (T-S) fuzzy systems. In addition, the exogenous disturbances and measurement noise are considered, which are presented in the operation of the systems and are various and independent of the systems. A novel double-level observer is designed to estimate the system states and faults. Compared with the current research results, the proposed observer has a wider range of application. By designing a fuzzy augmented system and a Kalman filter as the first-level observer, the estimations of system states, sensor faults and actuator faults can be obtained simultaneously. The second-level observer can estimate the unknown nonlinear dynamic function by establishing generalized fuzzy hyperbolic model. The robust stability of the estimation error systems is considered by H∞ performance. Finally, three simulation examples are provided to demonstrate the effectiveness of the proposed fault estimation method.

Sönmez, Şahin; Ayasun, Saffet

doi: 10.1177/0142331219826653pmid: N/A

This paper investigates the effect of gain and phase margins (GPMs) on stability delay margin of a two-area load frequency control (LFC) system with constant communication delay. A gain-phase margin tester (GPMT) is introduced to the LFC system as to take into GPMs in delay margin computation. A frequency domain exact method, Rekasius substitution, is proposed to compute the GPMs-based stability delay margins. The method aims to calculate all possible purely complex roots of the characteristic equation for a finite positive time delay. The approach first transforms the characteristic polynomial of the LFC system with transcendental terms into a regular polynomial. Routh-Hurwitz stability criterion is then implemented to compute the purely imaginary roots with the crossing frequency and stability delay margin. For a wide range of proportional–integral controller gains and GPMs, time delay values at which LFC system is both stable and has desired stability margin measured by GPMs are computed. The accuracy of complex roots and delay margins are verified by using an independent algorithm, the quasi-polynomial mapping-based root finder and time-domain simulations. Simulation studies indicate that delay margins must be determined considering GPMs to have a better dynamic performance in term of fast damping of oscillations, less overshoot and settling time.