Online ISSN
1751-8652
Print ISSN
1751-8644
IET Control Theory & Applications
Volume 3, Issue 7, July 2009
Volumes & issues:
Volume 3, Issue 7
July 2009
-
- Author(s): R. Ritala
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 789 –798
- DOI: 10.1049/iet-cta.2007.0489
- Type: Article
- + Show details - Hide details
-
p.
789
–798
(10)
A bistable system with a desirable and an undesirable state exhibits transitions between the states because of stochastic actions on the system. Selecting the operational point of a bistable system is a tradeoff between expected performance of the system and risk of transition to an undesired state. Hence control of a bistable system must consider the probability density function of the state. Measurement about state reduces state uncertainty according to the Bayesian rule. The author analyses how the measurement frequency and uncertainty affect the tradeoff between performance and risk, and thus seek for optimal measurement design. The author discretises the time by Euler integrating the stochastic differential equation describing the bistable system over an interval much shorter than any deterministic time scale, and discretise state to describe the system as a Markov chain. Measurements are made infrequently – every 50–100 time steps – and their uncertainty is Gaussian. The tradeoff problem is formulated by maximising system performance subject to constraint on the probability of undesired transition. The tradeoff is then obtained by varying the constraining probability. Similar tradeoffs are obtained either by frequent but uncertain and less frequent but more accurate measurements. Our analysis is motivated by the control of bioreactors. - Author(s): G. Garcia ; S. Tarbouriech ; J.M. Gomes da Silva ; D. Eckhard
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 799 –812
- DOI: 10.1049/iet-cta.2008.0221
- Type: Article
- + Show details - Hide details
-
p.
799
–812
(14)
This study addresses the control of linear systems subject to both sensor and actuator saturations and additive ℒ2-bounded disturbances. Supposing that only the output of the linear plant is measurable, the synthesis of stabilising output feedback dynamic controllers, allowing to ensure the internal closed-loop stability and the finite ℒ2-gain stabilisation, is considered. In this case, it is shown that the closed-loop system presents a nested saturation term. Therefore, based on the use of some modified sector conditions and appropriate variable changes, synthesis conditions in a ‘quasi’- linear matrix inequality (LMI) form are stated in both regional (local) as well as global stability contexts. Different LMI-based optimisation problems for computing a controller in order to maximise the disturbance tolerance, the disturbance rejection or the region of stability of the closed-loop system are proposed. - Author(s): Y. Liu and Y.M. Jia
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 813 –822
- DOI: 10.1049/iet-cta.2008.0329
- Type: Article
- + Show details - Hide details
-
p.
813
–822
(10)
An adaptive H∞ controller is designed for a class of non-linear dynamical systems by using neural networks (NNs) to approximate the unknown system function. It is shown that under bounded initial conditions, the H∞ performance from the external disturbance to the controlled output is achieved with a prescribed attenuation level. A systematic design procedure is then developed for the synthesis of the adaptive H∞ controller by solving two linear matrix inequalities (LMIs). Finally, a numerical example is included to demonstrate the effectiveness of the proposed controller. - Author(s): G.I. Kalogeropoulos ; A.D. Karageorgos ; A.A. Pantelous
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 823 –833
- DOI: 10.1049/iet-cta.2008.0098
- Type: Article
- + Show details - Hide details
-
p.
823
–833
(11)
Two main goals are to discretise the solution of an autonomous linear singular continuous-time system and to compare the discretised with the continuous solution at fixed time moments. Practically speaking, we are interested in such kind of systems, since they are inherent in many physical, economical and engineering phenomena. The complex Kronecker canonical form decomposes the singular system into five sub-systems, whose solutions are obtained. Moreover, in order for the norm of the difference between the two solutions to be smaller than a fully pre-defined, acceptable bound, the sampling period should be arranged in a particular interval. A numerical example is also available. - Author(s): L. Zhang and E.-K. Boukas
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 834 –842
- DOI: 10.1049/iet-cta.2008.0023
- Type: Article
- + Show details - Hide details
-
p.
834
–842
(9)
A class of extended continuous-time Markov jump linear systems is proposed in this study. The generality lies in that the discrete dynamics of the class of systems is described by a Markov stochastic process, but with only partially known transition probabilities, which relax the traditional assumption in Markov jump systems that all the transition probabilities must be known a priori. Moreover, in contrast with the uncertain transition probabilities studied recently, no structure (polytopic ones), bounds (norm-bounded ones) or ‘nominal’ terms (both) are required for the partially unknown elements in the transition rate matrix. The sufficient conditions for H∞ control are derived via the linear matrix inequality formulation such that the closed-loop system is stochastically stable and has a guaranteed H∞ noise-attenuation performance. A tradeoff can be built using our approach between the difficulties to obtain all the transition probabilities and the systems performance benefits. A numerical example is provided to show the validity and potential of the developed theoretical results. - Author(s): H. Wu
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 843 –851
- DOI: 10.1049/iet-cta.2008.0269
- Type: Article
- + Show details - Hide details
-
p.
843
–851
(9)
In this study, the problem of memoryless adaptive robust state observer design is considered for a class of uncertain nonlinear time-delay systems. It is supposed that the upper bounds of the uncertainties, including delayed states, are assumed to be unknown. An improved adaptation law with σ-modification is employed to estimate such unknown bounds. Then, by making use of the updated values of these unknown bounds, a class of memoryless adaptive robust state observers is proposed for uncertain nonlinear time-delay systems. It is also shown that by employing the proposed adaptive robust state observer, the observation error between the observer state estimate and the true state can converge asymptotically to zero in the presence of significant uncertainties and time delays. Finally, a numerical example is given to demonstrate the validity of the results. - Author(s): Z.-J. Yang ; Y. Fukushima ; S. Kanae ; K. Wada
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 852 –864
- DOI: 10.1049/iet-cta.2008.0253
- Type: Article
- + Show details - Hide details
-
p.
852
–864
(13)
A robust non-linear output-feedback controller by the K-filter approach is proposed for position-tracking problem of a magnetic levitation system, where only the position measurement is available for control. Instead of the popular adaptive control techniques, a disturbance observer (DOB) is merged into the K-filter-based output-feedback controller to compensate the external disturbance and model mismatch, so that a much simpler controller is constructed. Rigorous stability of the non-linear control system is established. Experimental results are included to show the excellent performance of the designed controller. - Author(s): J. Zhang ; Y. Xia ; M.S. Mahmoud
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 865 –876
- DOI: 10.1049/iet-cta.2008.0146
- Type: Article
- + Show details - Hide details
-
p.
865
–876
(12)
This study is concerned with the generalised ℋ2 and the ℋ∞ static control problems for discrete-time fuzzy systems with time-varying norm-bounded parametric uncertainties. Based on the solutions to certain linear matrix inequalities LMIs, static output feedback controllers are designed, which can ensure the asymptotic stability and the generalised ℋ2 and ℋ∞ performance level, respectively. Differenting from the existing results, the design conditions in this study are derived in terms of LMIs directly, and the local output matrices are allowed to be different. Three illustrative examples are provided to demonstrate the effectiveness and the reduced conservatism of the proposed methods. - Author(s): R. Orjuela ; B. Marx ; J. Ragot ; D. Maquin
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 877 –890
- DOI: 10.1049/iet-cta.2008.0148
- Type: Article
- + Show details - Hide details
-
p.
877
–890
(14)
This study addresses the analysis and design of unknown input observer in order to provide both state and unknown input estimations of complex systems modelled with the help of a particular class of multiple model. The proposed observer uses the multi-integral strategy successfully employed in the classic linear control theory and known for its robustness properties. The observer design is based on the representation of the system via a particular multiple model, known as ‘decoupled multiple model’. This structure of multiple model allows to use submodels with different number of states and this feature constitutes the main advantage of the proposed observer with respect to the classic multiple model structure where the submodels have the same dimension. It is shown how the gains of the suggested observer can be obtained by solving a linear matrix inequality optimal problem. An academic example is also proposed in order to illustrate the proposed methodology. - Author(s): M. Tanelli ; L. Piroddi ; S.M. Savaresi
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 891 –906
- DOI: 10.1049/iet-cta.2008.0287
- Type: Article
- + Show details - Hide details
-
p.
891
–906
(16)
Tire–road friction characteristics are deeply interlaced with all vehicle dynamics control systems, as road conditions strongly affect the control schemes behaviour. This work aims at the real-time estimation of the wheel slip value corresponding to the peak of the tire–road friction curve, in order to provide anti-lock braking systems (ABS) with reliable information on its value upon activation. Different techniques based on recursive least squares and the maximum likelihood approach are used for friction curve fitting and their merits and drawbacks thoroughly examined. In addition, since one of the main issues in slip-based friction estimation during braking is vehicle speed estimation, an effective algorithm for addressing this task is developed. The proposed peak slip value estimation strategy is analysed and tested both in simulation and on data collected on an instrumented test vehicle. In the latter case, the vehicle speed estimation algorithm is used, and the estimated vehicle speed provided as input for friction estimation. Practical applicability constraints posed by typical ABS systems are also considered. - Author(s): Q. Zhong ; Y. Zhang ; J. Yang ; J. Wu
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 907 –916
- DOI: 10.1049/iet-cta.2008.0038
- Type: Article
- + Show details - Hide details
-
p.
907
–916
(10)
There are many uncertainties and unmodelled dynamics in active power filters (APFs) because loads may vary all the time and the high switch frequency of solid-state devices has not been modelled in detail so far. Considering the difficulty of creating an accurate mathematic model for APF, auto-disturbance rejection control (ADRC) is an alternate non-linear robust method, which is fully based on the system inputs and outputs. The design procedure for an ADRC controller of parallel APF systems is proposed and discussed. Three main parts of ADRC are analysed and the adjustment of the controller parameters is discussed in details. Furthermore, simulation and experiment are carried out to prove the dynamic performance and robustness of the proposed controller. The result proves the validity of the control strategy. The analogue signal detected in the ADRC controller is less than in the other control strategies. - Author(s): Y. Zhao ; J. Wu ; P. Shi
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 917 –928
- DOI: 10.1049/iet-cta.2008.0272
- Type: Article
- + Show details - Hide details
-
p.
917
–928
(12)
The problem of robust H∞ control for Takagi–Sugeno (T–S) fuzzy systems with norm-bounded parameter uncertainties and a time delay in the state is investigated. Attention is focused on the design of robust H∞ controllers via the parallel distributed compensation scheme such that the closed-loop fuzzy time-delay system is asymptotically stable and the H∞ disturbance attenuation is below a prescribed level. By utilising the instrumental idea of delay partitioning, a new Lyapunov–Krasovskii functional is introduced, and some novel ideas for achieving delay dependence and basis dependence have been employed, which guarantee the obtained conditions to be much less conservative than most existing results in the literature. These conditions are formulated in the form of linear matrix inequalities (LMIs), based on which, the controller design is cast into a convex optimisation problem subject to LMI constraints. Finally, two examples are illustrated to show the feasibility and effectiveness of the obtained results. - Author(s): H. Li ; M.-Y. Chow ; Z. Sun
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 929 –940
- DOI: 10.1049/iet-cta.2008.0260
- Type: Article
- + Show details - Hide details
-
p.
929
–940
(12)
This study addresses the state feedback stabilisation problem for networked control systems (NCSs) with time delays and packet losses. By introducing the concept of ‘effective sensor packet’, a new discrete-time switched model is formulated, and the sufficient conditions for the asymptotical stability of the closed-loop system are derived. An iterative algorithm is proposed to design the corresponding stabilising controller, and the synthesis method is also extended to the servo control case. The proposed method can be easily implemented to various applications, since it is simple and has no assumptions on the time delays model and the packet losses model. Simulation and experimental results are given to demonstrate the effectiveness of the proposed approaches. - Author(s): S.S. Ge ; B. Ren ; K.P. Tee ; T.H. Lee
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 941 –956
- DOI: 10.1049/iet-cta.2008.0103
- Type: Article
- + Show details - Hide details
-
p.
941
–956
(16)
In this study, the altitude and yaw angle tracking is considered for a scale model helicopter, mounted on an experimental platform, in the presence of model uncertainties, which may be caused by unmodelled dynamics, or aerodynamical disturbances from the environment. To deal with the uncertainties, approximation-based techniques using neural network (NN) are proposed. In particular, two different types of NN, namely multilayer neural network and radial basis function neural network are adopted in control design and stability analysis. Based on Lyapunov synthesis, the proposed adaptive NN control ensures that both the altitude and the yaw angle track the given bounded reference signals to a small neighbourhood of zero, and guarantees semiglobal uniform ultimate boundedness of all the closed-loop signals at the same time. The effectiveness of the proposed control is illustrated through extensive simulations. Compared with the model-based control, approximation-based control yields better tracking performance in the presence of model uncertainties. - Author(s): P. Lin and Y. Jia
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 957 –970
- DOI: 10.1049/iet-cta.2008.0263
- Type: Article
- + Show details - Hide details
-
p.
957
–970
(14)
This study investigates consensus problems for networks of second-order agents, where each agent can only access the relative position information from its neighbours. We first introduce two new protocols with and without time-delay. Then we provide a convergence analysis in three cases: (a) networks with fixed topology; (b) networks with switching topology; (c) networks with switching topology and time-delays. Several conditions are presented to make all agents asymptotically reach consensus while accomplishing some tasks such as moving to a common value and moving together with a constant velocity or with a constant acceleration. Finally, simulation results are provided to demonstrate the effectiveness of our theoretical results. - Author(s): J. Raouf and E.K. Boukas
- Source: IET Control Theory & Applications, Volume 3, Issue 7, p. 971 –982
- DOI: 10.1049/iet-cta.2007.0451
- Type: Article
- + Show details - Hide details
-
p.
971
–982
(12)
In this study, the problems of stability and stabilisation of singular Markovian jump systems with external discontinuities and saturating inputs are addressed. A design procedure is proposed to determine simultaneously a state feedback controller and an associated domain of safe admissible states for which the regularity, the absence of impulsive behaviour and the stochastic stability in mean square sense of the closed-loop systems are guaranteed. This design procedure is based on linear matrix inequality technique (LMI) and the sequential linear programming matrix method (SLPMM). A numerical example is provided to demonstrate the effectiveness of the proposed methods.
Value of measurement frequency and accuracy in control of a stochastic bistable system
Finite ℒ2 gain and internal stabilisation of linear systems subject to actuator and sensor saturations
Adaptive H∞ control for a class of non-linear systems using neural networks
Discretising effectively a linear singular differential system by choosing an appropriate sampling period
H∞ control of a class of extended Markov jump linear systems
Memoryless adaptive robust asymptotic state observers for a class of nonlinear time-delay systems
Robust non-linear output-feedback control of a magnetic levitation system by K-filter approach
Robust generalised ℋ2 and ℋ∞ static output feedback control for uncertain discrete-time fuzzy systems
On the simultaneous state and unknown input estimation of complex systems via a multiple model strategy
Real-time identification of tire–road friction conditions
Non-linear auto-disturbance rejection control of parallel active power filters
H∞ control of non-linear dynamic systems: a new fuzzy delay partitioning approach
State feedback stabilisation of networked control systems
Approximation-based control of uncertain helicopter dynamics
Further results on decentralised coordination in networks of agents with second-order dynamics
Stabilisation of singular Markovian jump systems with discontinuities and saturating inputs
Most viewed content for this Journal
Article
content/journals/iet-cta
Journal
5
Most cited content for this Journal
-
Finite-time stability of interconnected impulsive switched systems
- Author(s): Guangdeng Zong ; Hangli Ren ; Linlin Hou
- Type: Article
-
Event-based security control for discrete-time stochastic systems
- Author(s): Derui Ding ; Zidong Wang ; Guoliang Wei ; Fuad E. Alsaadi
- Type: Article
-
Survey on semi-tensor product method with its applications in logical networks and other finite-valued systems
- Author(s): Jianquan Lu ; Haitao Li ; Yang Liu ; Fangfei Li
- Type: Article
-
Optimal control for networked control systems with disturbances: a delta operator approach
- Author(s): Yuan Yuan ; Huanhuan Yuan ; Zidong Wang ; Lei Guo ; Hongjiu Yang
- Type: Article
-
Filtering-based iterative identification for multivariable systems
- Author(s): Yanjiao Wang and Feng Ding
- Type: Article
