# International Journal of Robust and Nonlinear Control

Publisher: Wiley

## Journal description

The intention of the International Journal of Robust and Nonlinear Control is to encourage the development of analysis and design techniques for uncertain systems. The Journal will provide a natural forum for papers on the theory and application of robust control system design including contributions on the H and loop transfer recovery design philosophies. Papers will also be welcome on methods of improving the robustness of well-established design procedures such as the Inverse Nyquist Array Sequential Return Difference Characteristic Loci and Linear Quadratic Gaussian methods. The wider issues of modelling and identifying uncertain systems will also be addressed and analysis procedures such as the Structured Singular Value will be of interest. Papers on applications will be particularly encouraged. Control techniques based on Heuristic or rule based design methods for uncertain systems will be considered together with procedures based on fuzzy set theory. Contributions on the design of controllers for nonlinear systems will be included particularly where these involve robust design issues. The main thrust of the Journal is on the control of uncertain systems but it is recognized that nonlinearities cause robust design problems of a similar nature.

## Impact Factor Rankings

2015 Impact Factor Available summer 2016 3.176 2.652 1.9 1.554 1.495 1.906 1.56 1.637 1.108 1.048 0.772 0.792 1.021 0.84 0.657 0.426 0.256 0.624 0.762 0.623

## Impact factor over time

Impact factor
.
Year

5-year impact 2.94 5.30 0.45 0.01 1.16 International Journal of Robust and Nonlinear Control website International journal of robust and nonlinear control (Online), International journal of robust and nonlinear control, Robust and nonlinear control 1099-1239 44069290 Document, Periodical, Internet resource Internet Resource, Computer File, Journal / Magazine / Newspaper

## Publisher details

• Pre-print
• Author can archive a pre-print version
• Post-print
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• Restrictions
• 12 months embargo
• Conditions
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• If OnlineOpen is available, BBSRC, EPSRC, MRC, NERC and STFC authors, may self-archive after 12 months
• If OnlineOpen is available, AHRC and ESRC authors, may self-archive after 24 months
• Publisher last contacted on 07/08/2014
• This policy is an exception to the default policies of 'Wiley'
• Classification
yellow

## Publications in this journal

• ##### Article: Finite-time stabilization of a class of switched stochastic nonlinear systems under arbitrary switching
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ABSTRACT: This paper investigates the finite-time stabilization of a class of switched stochastic nonlinear systems under arbitrary switching, where each subsystem has a chained integrator with the power r (0 < r < 1). By using the technique of adding a power integrator, a continuous state-feedback controller is constructed, and it is proved that the solution of the closed-loop system is finite-time stable in probability. Two simulation examples are provided to show the effectiveness of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 08/2016; DOI:10.1002/rnc.3398
• ##### Article: The Nyquist stability criterion in the Nichols chart
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ABSTRACT: The Nyquist stability criterion is a widely used technique for determining in the complex s-plane the stability of a dynamical system with feedback. This paper presents a practical and comprehensive method to compute the Nyquist stability criterion directly in the Nichols (magnitude/phase) chart. The proposed method also gives guidelines to design controllers to stabilize unstable plants when dealing with frequency domain techniques like the quantitative feedback theory robust control. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3465
• ##### Article: Adaptive finite-time control for nonlinear teleoperation systems with asymmetric time-varying delays
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ABSTRACT: This paper addresses the adaptive finite-time control problem of nonlinear teleoperation system in the presence of asymmetric time-varying delays. To achieve the finite-time position tracking, a novel adaptive finite-time coordination algorithm based on subsystem decomposition is developed. By introducing a switching-technique-based error filtering into our design framework, the complete closed-loop master (slave) teleoperation system is modeled as a special class of switched system, which is composed of two subsystems. To analyze such system, a finite-time state-independent input-to-output stability criterion is first developed for some normal switched nonlinear delayed systems. Then based on the classical Lyapunov–Krasovskii method, the stability of complete closed-loop systems is obtained. It is shown that the proposed scheme can make the position errors converge into a deterministic domain in finite time when the robots continuously contact with human operator and/or the environment in the presence of asymmetric time-varying delays. Finally, the simulation results are given to demonstrate the effectiveness. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3462
• ##### Article: Energy compensation-based approach for solving the HJI equation in the nonlinear H∞ synthesis
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ABSTRACT: The H∞ framework provides an efficient and systemic method for the design of controllers for both linear and nonlinear systems. In the nonlinear controller synthesis, however, the limitation of this method is usually associated with the existence of a solution to the Hamilton–Jacobi–Isaac (HJI) equation. In this paper, an innovative energy compensation-based approach to the solution of the HJI equations is presented and compared with the existing methods relying on Taylor series expansion. This new approach provides an efficient methodology that ensures the existence of a solution to the HJI equation. Numerical application to spacecraft attitude control is presented to validate the developments. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3463
• ##### Article: Consensusability of linear multi-agent systems with time delay
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ABSTRACT: This paper studies the consensusability of a continuous-time linear time-invariant multi-agent system (MAS) with time delay in an undirected network with N nodes. We show that the MAS can achieve consensus if and only if N − 1 time-delay subsystems associated with the eigenvalues of the Laplacian matrix of the network are simultaneously asymptotically stable. By employing a linear matrix inequality (LMI) method, we present a controller design method for a MAS to reach consensus. We also obtain a bound on the maximum time delay for consensusability for a MAS with first-order integrator dynamics by using frequency-domain analysis. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3458
• ##### Article: Design of an RMPC with a time-varying terminal constraint set for tracking problem
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ABSTRACT: This paper presents a robust model predictive control algorithm with a time-varying terminal constraint set for systems with model uncertainty and input constraints. In this algorithm, the nonlinear system is approximated by a linear model where the approximation error is considered as an unstructured uncertainty that can be represented by a Lipschitz nonlinear function. A continuum of terminal constraint sets is constructed off-line, and robust stability is achieved on-line by using a variable control horizon. This approach significantly reduces the computational complexity. The proposed robust model predictive controller with a terminal constraint set is used in tracking set-points for nonlinear systems. The effectiveness of the proposed method is illustrated with a numerical example. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3464
• ##### Article: Integrated adaptive robust control for multilateral teleoperation systems under arbitrary time delays
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ABSTRACT: With the increasing industrial requirements such as bigger size object, stable operation, and complex task, multilateral teleoperation systems extended from traditional bilateral teleoperation are widely developed. In this paper, the integrated control design is developed for multilateral teleoperation systems, where n master manipulators are operated by human to remotely control n slave manipulators cooperatively handling a target object. For the first time, the control objectives of multilateral teleoperation including stability, synchronization, transparency, and internal force distribution are clarified systematically. A novel communication architecture is proposed to cope with communication delays, where the estimated environmental parameters are transmitted from the slave side to the master, to replace the traditional environmental force measurement in the communication channel. A kind of nonlinear adaptive robust control technique is used to deal with nonlinearities, unknown parameters, and modeling uncertainties existing in the master, slave, and environmental dynamics, so that the excellent tracking performance is achieved in both master and slave sides. The coordinated motion/force control is designed in the slave side by the optimal internal force distribution among n slave manipulators, and the impedance control is designed in the master side to realize the target transparency behavior. In summary, the proposed control algorithm can achieve the guaranteed robust stability, the excellent synchronization and transparency performance, and the optimal internal force distribution simultaneously for multilateral teleoperation systems under arbitrary time delays and various modeling uncertainties. The simulation is carried out on a 2-master/2-slave teleoperation system, and the results show the effectiveness of the proposed control design. Copyright
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3472
• ##### Article: Robust H∞ deconvolution filtering for uncertain singular Markovian jump systems with time-varying delays
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ABSTRACT: The problem of H∞ deconvolution filter design for a class of singular Markovian jump systems with time-varying delays and parameter uncertainties is considered in this paper. By constructing a more comprehensive stochastic Lyapunov-Krasovskii functional, novel delay-dependent conditions are established to guarantee the filtering error system is not only stochastically admissible, but also satisfies a prescribed H∞-norm level for all admissible uncertainties. The desired filter parameters can be obtained by solving a set of strict linear matrix inequalities. Two examples and an electrical RLC circuit example are employed to verify the effectiveness and usefulness of the proposed methods in the paper. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3461
• ##### Article: Robust optimal estimation over networks: Application to battery state of charge estimation
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ABSTRACT: In this paper, we provide a general framework for robust optimal estimation over a lossy and delayed network. A threshold principle is introduced to integrate network-induced uncertainties into packet losses, which are modeled with a Bernoulli process. Based on stability conditions derived from two Riccati equations, we show the existence of critical observation arrival probabilities below which the optimal estimator stochastically fails to converge. Moreover, the result is extended to a real system with variable process disturbance, which has an indicator for its admissible bound in terms of a given restriction of estimation accuracy. The proposed method is experimented on a specific automobile application, the battery state of charge estimation. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3455
• ##### Article: Call for submissions: Special issue on consensus-based applications in networked systems

International Journal of Robust and Nonlinear Control 10/2015; DOI:10.1002/rnc.3471
• ##### Article: New Results on Stability of Singular Stochastic Markov Jump Systems with State-Dependent Noise
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ABSTRACT: This paper aims to develop the stability theory for singular stochastic Markov jump systems with state-dependent noise, including both continuous-time and discrete-time cases. The sufficient conditions for the existence and uniqueness of a solution to the system equation are provided. Some new and fundamental concepts such as non-impulsiveness and mean square admissibility are introduced, which are different from those of other existing works. By making use of the -representation technique and the pseudo inverse E+ of a singular matrix E, sufficient conditions ensuring the system to be mean square admissible are established in terms of strict linear matrix inequalities, which can be regarded as extensions of the corresponding results of deterministic singular systems and normal stochastic systems. Practical examples are given to demonstrate the effectiveness of the proposed approaches. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3401
• ##### Article: New interpolation solution and application in system modeling and optimal control with prescribed distance to instability
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ABSTRACT: We present a system theoretic interpretation of a two-sided interpolation problem with a stable rational matrix ${\boldsymbol U}$ (interpolant) without constraints on its norm. It is known that all solutions ${\boldsymbol U}$ of that problem can be expressed as ${\boldsymbol U}={\boldsymbol U}_{\rm h}+{\boldsymbol U}_{\rm p}$, where ${\boldsymbol U}_{\rm h}$ ranges in the set of all solutions of the associated homogeneous problem, and ${\boldsymbol U}_{\rm p}$ is a particular solution. We present a new solution for ${\boldsymbol U}_{\rm p}$, and prove that it is actually the minimal ${\mathscr H}_2$-norm interpolant in the set of all interpolants. We apply these results in system modeling and in optimal ${\mathscr H}_\infty$ control of one-block plants, with a prescribed bound on the distance to instability of the closed loop system. The applications are illustrated by examples. Interesting connections to the augmented Basic Interpolation Problem (aBIP), to the Nehari's problem, and to the stability of one-block plants with multiple unstable invariant zeros, are given.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3459
• ##### Article: A synchronization-based state observer for impact oscillators using only collision time information
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ABSTRACT: We present the design of a state observer for Lagrangian systems subjected to frictionless geometric unilateral constraints. A master–slave synchronization setup is used in which the unidirectional coupling only consists of the information of the impact time instants. After a brief synchronization phase, the obtained observer replicates the full state of the observed system, independently of the initial conditions and even in the presence of accumulation points (Zeno behavior).The key idea is that the (virtual) observer system is subjected to switched kinematic unilateral constraints such that it may enjoy the property of incremental stability when the impact law is maximal monotone. The main inequality impact laws for hard unilateral constraints, that is, the generalized Poisson's and Newton's impact law, are under mild assumptions maximal monotone, which is a stronger condition than dissipativity. The results are applied to two different examples of mechanical impact oscillators. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3460
• ##### Article: Nonlinear output regulation for invertible nonlinear MIMO systems
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ABSTRACT: In this paper, we address the problem of output regulation for a broad class of multi-input multi-output (MIMO) nonlinear systems. Specifically, we consider input–affine systems, which are invertible and input–output linearizable. This class includes, as a trivial special case, the class of MIMO systems which possess a well-defined vector relative degree. It is shown that if a system in this class is strongly minimum phase, in a sense specified in the paper, the problem of output regulation can be solved via partial-state feedback or via (dynamic) output feedback. The result substantially broadens the class of nonlinear MIMO systems for which the problem in question is known to be possible. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3454
• ##### Article: Output feedback quantized observer-based synchronization of linear multi-agent systems over jointly connected topologies
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ABSTRACT: The synchronization problem of linear over-actuated multi-agent systems with unmeasurable states is studied in this paper, under both limited communication data rate and switching topology flows. A class of adaptive quantized observer-based encoding–decoding schemes and a class of certainty equivalence principle-based control protocols are proposed. By developing the graph-based space decomposition technique and analyzing the closed-loop quantized dynamic equations, it is shown that if the network topology flow is jointly connected, the communication channels are periodic active, and the agent dynamics is observable, and with the orthogonal system matrix, the proposed communication and control protocols can ensure the closed-loop system to achieve synchronization exponentially fast with finite bits of information exchange per step. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3453
• ##### Article: Static anti-windup design for a class of Markovian jump systems with partial information on transition rates
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ABSTRACT: This paper investigates the problem of static anti-windup design for uncertain continuous-time Markovian jump systems with partially unknown transition rates in the face of actuator saturation. The underlying system is subject to time-varying and norm-bounded parameter uncertainties in both the state and input matrices. It is assumed that a set of stabilizing dynamic output-feedback controllers have been designed for the system in the absence of control saturation. The objective is to design anti-windup compensation gains for the given controllers such that the system can still be stabilized, irrespective of whether actuator saturation appears or not. To obtain a maximum estimation of the domain of attraction of the resulting closed-loop system, a convex optimization problem in the linear matrix inequality framework is formulated. Furthermore, the results are extended to the cases of the systems with completely known transition rates and with completely unknown transition rates. Finally, the usefulness of the developed method is demonstrated through simulation examples. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3456
• ##### Article: A new model reference control architecture: Stability, performance, and robustness
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ABSTRACT: In this paper, we develop a new model reference control architecture to effectively suppress system uncertainties and achieve a guaranteed transient and steady-state system performance. Unlike traditional robust control frameworks, only a parameterization of the system uncertainty given by unknown weights with known conservative bounds is needed to stabilize uncertain dynamical systems with predictable system performance. In addition, the proposed architecture's performance is not dependent on the level of conservatism of the bounds of system uncertainty. Following the same train of thought as adaptive controllers that modify a given reference system to improve system performance, the proposed method is inspired by a recently developed command governor theory that minimizes the effect of system uncertainty by augmenting the input signal of the uncertain dynamical and reference systems. Specifically, a dynamical system, called a command governor, is designed such that its output is used to modify the input of both the controlled uncertain dynamical and reference systems. It is theoretically shown that if the command governor design parameter is judiciously selected, then the controlled system approximates the given original, unmodified reference system. The proposed approach is advantageous over model reference adaptive control approaches because linearity of the uncertain dynamical system is preserved through linear control laws, and hence, the closed-loop performance is predictable for different command spectrums. Additionally, it is shown that the architecture can be modified for robustness improvements with respect to high frequency content due to, for example, measurement noise. Modifications can also be made in order to accommodate actuator dynamics and retain closed-loop stability and predictable performance. The main contribution of this paper is the rigorous analysis of the stability and performance of a system utilizing the command governor framework. A numerical example is provided to illustrate the effectiveness of the proposed architecture. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3416
• ##### Article: Geometric modeling and local controllability of a spherical mobile robot actuated by an internal pendulum
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ABSTRACT: In this paper, we present the modeling and local equilibrium controllability analysis of a spherical robot. The robot consists of a spherical shell that is internally actuated by a pendulum mechanism. The rolling motion of the sphere manifests itself as a nonholonomic constraint in the modeling. We derive the dynamic model of the system using Lagrangian reduction and the variational principle. We first compute the Lagrangian and identify the symmetry with respect to a group action. The system Lagrangian and the rolling constraint are invariant with respect to the group isotropy and hence permit a reduced dynamic formulation termed as the nonholonomic ‘Euler-Poincaré’ equation with advected dynamics. Using Lie brackets and symmetric products of the potential and control vector fields, local configuration accessibility and local (fiber) equilibrium controllability are presented. Copyright © 2015 John Wiley & Sons, Ltd.
International Journal of Robust and Nonlinear Control 09/2015; DOI:10.1002/rnc.3457