1,256 publications from this institution
In this paper, a Model Predictive Control (MPC) based tracking control design method for air-breathing hypersonic vehicles (AHVs) with input constraints is proposed. The tracking controller design problem is challenging because the relationship between flight dynamics and the control input is not so clear, especially when the input is subject to input constraints. Since the upper and lower bound of the constrained function are not symmetric, the anti-windup design method is not suitable. For the tracking control objective, an optimization based reference reconfiguration method is given. Through the reconfiguration, a new reference command, which can be realized by the constrained system, is constructed. A MPC based controller reconfiguration method is proposed with respect to the new command and input constraints. Finally, simulations are given to show the effectiveness of the proposed control method.
No abstract is provided for this article.
In this article, we address a convex optimisation approach to the problem of state-feedback H ∞ control design for vibration reduction of base-isolated building structures with delayed measurements, where the delays are time-varying and bounded. An appropriate Lyapunov–Krasovskii functional and some free-weighting matrices are utilised to establish some delay-range-dependent sufficient conditions for the design of desired controllers in terms of linear matrix inequalities. The controller, which guarantees asymptotic stability and an H ∞ performance, simultaneously, for the closed-loop system of the structure, is then developed. The performance of the controller is evaluated by means of simulations in MATLAB/Simulink.
This paper is devoted to the modeling and simulation of a full-scale commercially available magnetorheological (MR) brake installed in a semi-active suspension (SAS) system. The analysis of the Bouc-Wen and Dahl mathematical models of MR damper is presented. Influence of their parameters on the response is explored. Subsequently, by using the neural networks, the parameters characterizing each model are estimated. This makes it possible to perform the comparative analysis of the suggested damper models responses with the measured experimental results. The novelty of the presented methodology is the application of artificial intelligence methods to estimate model parameters of a MR brake utilized in a SAS system. The results of this approach have a strong potential to be successfully utilized in the area of model-based control of semi-active vibration suppression systems.
The potential of multi-antenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11x is investigated. The medium access control in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA), which itself is a powerful tool for the mitigation of intra-system interference. However, due to the spatial dependence of radio signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation algorithms at the PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers, and are evaluated in this paper via cross-layer simulations. It is shown that the uplink throughput can potentially be substantially increased with the use of two-antenna interference cancellation at the access point
This paper investigates the problem of observer‐based sliding mode control (SMC) of stochastic uncertain Markov jump systems using dual‐driven event‐triggered mechanism (ETM). The ETM is implemented not only in the system output to the observer channel but also in the feedback channel, forming a dual ETM, which can effectively reduce communication load. By designing a state observer, the error dynamics is derived, and subsequently, sliding mode dynamics (SMD) are formulated by proposing a specific type of integral sliding surface. Moreover, a SMC law is put forward to guarantee the attainment of the sliding surface by the system state within a finite time and to maintain the state within the domain of the sliding surface. Furthermore, sufficient conditions for the closed‐loop system are established to ensure both the stochastic stability and a prescribed performance through linear matrix inequalities. Finally, two examples are provided to demonstrate the effectiveness of the proposed results.
This paper investigates a defect appearing in “Finite-time <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX"> $H_{\infty }$</tex></formula> fuzzy control of nonlinear jump systems with time delays via dynamic observer-based state feedback,” which the observer-based finite-time <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$H_{\infty }$</tex></formula> controller via dynamic observer-based state feedback could not ensuring stochastic finite-time boundedness, and satisfying a prescribed level of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$H_{\infty }$</tex></formula> disturbance attenuation for the resulting closed-loop error fuzzy Markov jump systems. The corrected results are presented, and the improved optimal algorithms and new simulation results are also provided in this paper.
No abstract is provided for this article.
No abstract is provided for this article.
This paper is concerned with the problems of stability analysis and l 2-gain control for a class of two-dimensional (2D) nonlinear stochastic systems with time-varying delays and actuator saturation. Firstly, a convex hull representation is used to describe the saturation behavior, and a sufficient condition for the existence of mean-square exponential stability of the considered system is derived. Then, a state feedback controller which guarantees the resulting closed-loop system to be mean-square exponentially stable with l 2-gain performance is proposed, and an optimization procedure to maximize the estimation of domain of attraction is also given. All the obtained results are formulated in a set of linear matrix inequalities (LMIs). A numerical example is given to illustrate the effectiveness of the proposed method.
This paper investigates the problem of automatic speed tracking control of an electric vehicle (EV) that is powered by a permanent-magnet synchronous motor (PMSM). A reconfiguration scheme, based on higher order sliding mode (HOSM) observer, is proposed in the event of sensor faults/failures to maintain a good control performance. The corresponding controlled motor output torque drives EVs to track the desired vehicle reference speed for providing uninterrupted vehicle safe operation. The effectiveness of the overall sensor fault-tolerant speed tracking control is highlighted when an EV is subjected to disturbances like aerodynamic load force and road roughness using high-fidelity software package CarSim. Experiments with a 26-W, three-phase PMSM are presented to demonstrate the validity of the proposed fault-detection scheme.
The problem of H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control design for vibration reduction of a base isolated structure with limited wireless communication capacity is studied in this paper. The network under consideration is subjected to measurement quantization, signal transmission delay, and data packet dropout, which appear typically in a network environment. Based on Lyapunov-Krasovskii functional (LKF) theory, some delay-range-dependent conditions are established for the existence of desired controllers such that the resulting closed-loop system is asymptotically stable and its performance is kept within a prescribed level. Finally, some simulation results are given to illustrate the effectiveness of our method.
This paper discusses the problem of the fuzzy sliding mode control for a class of disturbed systems. First, a fuzzy auxiliary controller is constructed based on a feedback signal not only to estimate the unknown control term, but also participates in the sliding mode control due to the fuzzy rule employed. Then, we extend our theory into the cases, where some kind of system information can not be obtained, for better use of our theoretical results in real engineering. Finally, some typical numerical examples are included to demonstrate the effectiveness and advantage of the designed sliding mode controller.
No abstract is provided for this article.
The paper delves into the problems of stability analysis and state-feedback controller design for discrete-time switched nolinear systems (SNSs), employing mode-dependent average dwell time (MDADT). Dependent on parameter-sensitive discontinuous switching Lyapunov functions and several fundamental lemmas, the key objective is to formulate a controller for the system under consideration to secure stability,and adjusting to the sector's conditions to handle the nested actuator saturation. Then the necessary conditions and the initial zone securing the local exponential stability(LES) of the switched system are put forth. By solving the Linear Matrix Inequality(LMI) conditions, the controller gain is devised, and the system is given a stable attraction domain. The proposed methodology's effectiveness is validated through two illustrative examples.
This paper describes the modeling, simulation and the instrumentation of High Pressure Roller Crusher (HPRC) for the production of silicon carbide grains. The study is to make a model and then simulate a High Pressure Roller Crusher. Selection of sensors for the HPRC is also important in this study. A High Pressure Roller Crusher (HPRC) is an important part in the production of silicon carbide, where the grains are crushed into powder form and then sieved into specified sizes based on its usage. This paper will present a model based on Johanson's theory for roller compactors, considering all the delays. The non-linearity or delays were handled in matlab using. Conclusions were drawn at end of the paper.
Distributed fiber optic vibration sensing system has been widely used in safety monitoring with distinct advantages, and the feature extraction and classification methods of fiber optic signals directly determine the real-time performance and reliability of the monitoring system. The existing research feature extraction methods are unidimensional and time consuming, which cannot balance the goals of high accuracy and low time consumption for safety monitoring systems. In this paper, we propose an efficient recognition framework for fusing signal time-frequency features, called TFF-CNN, based on Gramian Angular Difference Fields(GADF) and FFT co-generation matrix(FFTT) to manually extract two-dimensional time-frequency image features of fiber optic signals, taking the significant advantages of CNN in image processing and combining a two-channel model and a fusion module that simulates human decision-making behavior. The accuracy of TFF-CNN is 99.30% and the detection response time is only 0.6s. Compared with other methods in this field, TFF-CNN has the advantages of low false alarm rate and short time consumption, which is more suitable for deployment in security monitoring field with distributed fiber optic sensing system. Index Terms: Distributed optical fiber vibration sensing system(DVS), Two-dimensional multi-feature, CNN, intrusion detection, real-time monitoring