1,256 publications from this institution
This brief focuses on the sliding mode control (SMC) design for nonlinear stochastic switching systems subject to semi-Markov switching parameters and signal quantization. The aim of this brief is to design an efficient SMC scheme under quantization error effect. To this end, a mode-independent sliding surface is adopted to avoid the potential repetitive jumping effects. Then, based on the weak infinitesimal operator theory, sufficient conditions are given for the corresponding stochastic stability criteria. Furthermore, an appropriate SMC law is proposed to drive the state signals onto the predefined manifold and the effect of quantization error can be effectively attenuated. Finally, a single-link robot arm model is provided to illustrate the effectiveness of the theoretical findings.
In this paper we study packet scheduling algorithms which exploit multi-radio transmission diversity in a multi-radio access network. We view the packet scheduling process as a combination of user ...
The consensus problem has a crucial role in theoretical and practical aspects of interconnected systems, for instance in smart computing field. This paper is concerned with the observer-based H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers. In the addressed observer-based H∞ consensus problem, measurement outliers can affect the estimation accuracy and thus affect the consensus performance. To assuage the impact of measurement outliers, a control protocol based on an observer containing a saturation function with variable saturation limits is proposed. The purpose of this paper is to find a solution to the addressed H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers by designing an observer-based control protocol such that multi-agent systems can fulfill the H∞ consensus performance over a finite horizon. With the aid of Lyapunov theory, the sufficient condition is established to guarantee that the consensus error dynamic system satisfies the H∞ consensus performance. Then, the linear matrix inequality (LMI) approach is used to obtain the desired parameters of the observer-based control protocol. Finally, the effectiveness of the proposed control protocol is verified in a simulation environment. Aim: The purpose of this study is to find a solution to the addressed H∞ consensus problem for a class of linear multi-agent systems subject to measurement outliers. Methods: By choosing a suitable Lyapunov function, the sufficient condition is obtained, which can guarantee the consensus error dynamic system satisfying the given H∞ consensus performance. The LMI approach is employed to design the desired controller. With Matlab LMI toolbox, a numerical example was conducted to demonstrate the effectiveness of the proposed observer-based control protocol in the simulation environment. Results: A satisfactory consensus performance can be guaranteed for multi-agent systems subject to measurement outliers under the proposed observer-based control protocol. The constructed saturation function with variable saturation limits can mitigate the effect of measurement outliers by dynamically regulating saturation limits. Compared with the traditional observer-based control protocol, in this paper, the proposed observer-based control protocol shows robustness against measurement outliers. Conclusion: A solution to the addressed multi-agent consensus problem subject to measurement outliers was found by designing an observer-based consensus controller. The obtained results can be extended to sensor networks, neural networks, and nonlinear multi-agent systems.
The objective of this chapter is to study the problem of vibration control analysis and synthesis in a vehicle engine-body vibration structure. It is assumed that the actuator is subject to a time-varying delay for control of bounce and pitch vibrations. Based on a Lyapunov-Krasovskii functional and using some free weighting matrices, delay-dependent sufficient conditions for designing desired state- and output-feedback controllers are given in terms of linear matrix inequalities (LMIs). The state- and output-feedback controllers, which guarantee asymptotic stability with a prescribed γ-level L2-gain (or H∞ performance), are then developed directly instead of coupling the second-order model to a first-order system. The controller gains are determined by convex optimization over LMIs. Simulation results are included to demonstrate the validity and applicability of the technique.
No abstract is provided for this article.
1 School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia 2 College of Engineering and Science, Victoria University, Melbourne, VIC 8001, Australia 3 Department of Engineering, Faculty of Technology and Science, University of Agder, 4898 Grimstad, Norway 4 School of Control Science and Engineering, Shandong University, Jinan 250061, China 5 School of Automation, Chongqing University, Chongqing 400044, China
This paper is concerned with the problem of global finite-time control for switched nonlinear systems whose nonlinear terms satisfy homogenous growth conditions. At first, we design homogenous output feedback controllers for nominal switched nonlinear systems by adding a power integrator method. Then, we employ the homogeneous domination approach to scale homogeneous observers and controllers to render switched nonlinear systems with lower-triangular homogenous growth condition globally finite-time stable. Finally, the proposed control method can be extended to switched nonlinear systems satisfying with upper-triangular homogeneous growth condition. Two examples are provided to demonstrate the effectiveness of the proposed control scheme.
No abstract is provided for this article.
The problem of finite-time control for attitude tracking maneuver of a rigid spacecraft is investigated. External disturbance, unknown inertia parameters are addressed. As stepping stone, a sliding mode controller is designed. It requires the upper bound of the lumped uncertainty including disturbance and inertia matrix. However, this upper bound may not be easily obtained. Therefore, an adaptive sliding mode control law is then proposed to release that drawback. Adaptive technique is applied to estimate that bound. It is proved that the closed-loop attitude tracking system is finite-time stable. The tracking errors of the attitude and the angular velocity are asymptotically stabilized. Moreover, the upper bound on the lumped uncertainty can be exactly estimated in finite time. The attitude tracking performance with application of the control scheme is evaluated through a numerical example.
No abstract is provided for this article.
This paper deals with an experimental study on the modeling and identification of the hysterical behavior of inerters. Unlike existing methods that can only consider a constant inertance to capture a static model of the device, we develop three different dynamic models for a ball-screw type inerter. To eliminate the effects of the measurement noise, an empirical mode decomposition (EMD) method is proposed. Then, three dynamic models—the Dahl, LuGre and Bouc–Wen model—are used in order to model the friction behavior of the device. Using the least-square optimization method, the parameters of the models are estimated. The results of the tuned models are compared together within different frequencies. The good agreement between predicted and measured data shows that LuGre and Bouc–Wen models can be effective for modelling the hysteretic behavior of friction inside the inerter mechanism. It is also shown that the Bouc–Wen model has better correlation with the experimental results in all test frequencies and amplitudes.
The stability analysis and stabilization of Takagi-Sugeno (T-S) fuzzy delta operator systems with time-varying delay are investigated via an input-output approach. A model transformation method is employed to approximate the time-varying delay. The original system is transformed into a feedback interconnection form which has a forward subsystem with constant delays and a feedback one with uncertainties. By applying the scaled small gain (SSG) theorem to deal with this new system, and based on a Lyapunov Krasovskii functional (LKF) in delta operator domain, less conservative stability analysis and stabilization conditions are obtained. Numerical examples are provided to illustrate the advantages of the proposed method.
The potential of multi-antenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC) 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 received 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 physical (PHY) layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semi-blind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. This is illustrated by cross-layer simulations in open access network (OAN) scenarios involving intra- and (impolite) inter-system interference.
The vehicle crash is a complex process with nonlinear large deformation of structures. The analysis of the crash process is one of the challenges for all vehicle safety researchers. In this paper, the Ensemble Empirical Mode Decomposition (EEMD) method is applied in the analysis of crash responses in order to achieve some meaningful results. With the help of EEMD, the crash responses are decomposed into a trend signal and some high frequency fluctuations. By studying the load path of vehicle design, each component is corresponding to the structure of vehicle body. Consequently, some parameters of vehicle crash model can be identified. A frontal crash of Toyota Yaris is employed for demonstration.
No abstract is provided for this article.
In this article, an event-triggered robust fuzzy adaptive prescribed performance finite-time control strategy is presented for a class of strict-feedback nonlinear systems with external disturbances. The relative-threshold-based event-triggered signal is introduced to reduce communication burden, and the dynamic surface control technique is applied to address the computational complexity problem. A disturbance observer is designed to estimate the compounded disturbances, which are composed of external disturbances and fuzzy approximation errors. The proposed control strategy can guarantee that the closed-loop system is semiglobally practically finite-time stable, and the tracking error converges to a small residual set by incorporating the prescribed performance bound in finite-time. Finally, simulation results are provided to verify the effectiveness of the proposed robust fuzzy control strategy.
