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# IET Control Theory & Applications

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Displaying Results 1 - 20 of 20
• ### Combined optimal pulse width modulation and pulse frequency modulation strategy for controlling switched mode DC–DC converters over a wide range of loads

Publication Year: 2012, Page(s):1973 - 1983
Cited by:  Papers (6)
| | PDF (1454 KB)

This paper develops a combined optimal pulse width modulation (PWM) and pulse frequency modulation (PFM) strategy for controlling switched mode DC-DC converters. The peak ripple magnitudes of both the output-voltages and -currents during all operating modes over a wide range of loads are minimised subject to specifications on the minimum efficiency bounds of the converters. This problem is posed a... View full abstract»

• ### PID controller adjustment using chaotic optimisation algorithm for multi-area load frequency control

Publication Year: 2012, Page(s):1984 - 1992
Cited by:  Papers (8)
| | PDF (1060 KB)

The early aim of the automatic generation control is to regulate the power output of the electrical generator within a prescribed area in response to changes in system frequency, tie-line loading, so as to maintain the scheduled system frequency and interchange with the other areas with predetermined limits. The purpose of this study is to propose a PID optimised by the lozi map-based chaotic algo... View full abstract»

• ### Robust H/spl infin/ control in nano-positioning

Publication Year: 2012, Page(s):1993 - 2001
Cited by:  Papers (3)
| | PDF (855 KB)

This study considers the use of robust H tracking control in a nano-positioning system. The nano-positioning system uses a high-performance monolithic multilayer piezoelectric stack actuator connected in series with an external capacitor, which is used to provide a measured voltage proportional to the charge on the piezoelectric actuator. The electrical energy applied to ... View full abstract»

Publication Year: 2012, Page(s):2002 - 2008
Cited by:  Papers (2)
| | PDF (1602 KB)

This study is devoted to the adaptive consensus problem of multi-agent systems with partly unknown parameters and bounded external disturbances, under the guidance of an active leader with a reference input signal. Firstly, a distributed adaptive protocol is proposed for the system without disturbances by adopting the model reference adaptive control method. Then it is extended to the disturbed sy... View full abstract»

• ### Decentralised adaptive output feedback synchronisation tracking control of spacecraft formation flying with time-varying delay

Publication Year: 2012, Page(s):2009 - 2020
Cited by:  Papers (2)
| | PDF (1081 KB)

This study deals with the problem of decentralised cooperative position tracking with time-varying delays of interconnect communication in the leader-follower spacecraft formation flight. More specifically, a class of low-pass linear filters is developed to derive a control law without absolute and relative velocity measurement, which is significant for practical applications with low-cost configu... View full abstract»

• ### Block backstepping controllers design for a class of perturbed non-linear systems with m blocks

Publication Year: 2012, Page(s):2021 - 2030
Cited by:  Papers (6)
| | PDF (739 KB)

Based on the Lyapunov stability theorem, a design methodology of adaptive block backstepping controller is proposed in this study for a class of multi-input systems with mismatched perturbations to solve regulation problems. According to the number of blocks (m) in the plant to be controlled, m-1 virtual input controllers are firstly designed from the first block to the (m-1)t... View full abstract»

• ### Output-feedback quantised control of decentralised systems

Publication Year: 2012, Page(s):2031 - 2040
Cited by:  Papers (3)
| | PDF (724 KB)

The problem of designing decentralised &Hscr; feedback control for a class of linear interconnected continuous-time systems with quantised signals in the subsystem control channels is fully examined. The system has unknown-but-bounded couplings and interval delays. A decentralised static output-feedback controller is designed at the subsystem level to render the closed-loop ... View full abstract»

• ### Global H/spl infin/ consensus of multi-agent systems with Lipschitz non-linear dynamics

Publication Year: 2012, Page(s):2041 - 2048
Cited by:  Papers (18)
| | PDF (505 KB)

This study addresses the global consensus problems of a class of non-linear multi-agent systems with Lipschitz non-linearity and directed communication graphs, by using a distributed consensus protocol based on the relative states of neighbouring agents. A two-step algorithm is presented to construct a protocol, under which a Lipschitz multi-agent system without disturbances can reach global conse... View full abstract»

• ### Tolerance of intermittent faults in spacecraft attitude control: switched system approach

Publication Year: 2012, Page(s):2049 - 2056
Cited by:  Papers (5)
| | PDF (828 KB)

This study models a spacecraft attitude control system (ACS) process with intermittent controller faults by a stochastic switched system, whose stability is shown to be equivalent to the fault tolerability of the ACS. A global dissipativity concept is first introduced for the stochastic switched system to derive its stability condition, which can be checked easily via the proposed `gain techniqu... View full abstract»

• ### Stabilisation for a class of non-linear uncertain systems based on interval observers

Publication Year: 2012, Page(s):2057 - 2062
Cited by:  Papers (1)
| | PDF (189 KB)

Feedback stabilisation for a class of non-linear uncertain systems is devoted in this study. An interval observer is given to estimate admissible values of the state. A linear control law is designed such that the equilibrium point of the interval observer is asymptotically stable. By the linear control law, the uncertain system is asymptotically stable at the equilibrium point. An application of ... View full abstract»

• ### Approximate dynamic programming for continuous-time linear quadratic regulator problems: relaxation of known input-coupling matrix assumption

Publication Year: 2012, Page(s):2063 - 2075
Cited by:  Papers (4)
| | PDF (616 KB)

This study proposes an approximate dynamic programming (ADP) scheme which solves approximately the continuous-time (CT) infinite horizon, linear quadratic (LQ) optimal control problems (OCPs) online for CT linear time-invariant (LTI) systems whose model is not exactly given a priori. In order to relax the assumption of the perfectly known input-coupling matrix, a cheap OCP consisting of a dynamic ... View full abstract»

• ### Estimating the stability domain of spacecraft attitude with delayed feedback

Publication Year: 2012, Page(s):2076 - 2082
| | PDF (384 KB)

This study deals with the estimation of the stability domain of the spacecraft attitude control system with delayed feedback. For autonomous functional-differential equations, by using the invariance principle, a general estimation theorem is established to explicitly estimate the stability domain. Furthermore, based on the estimation theorem and an applicable Lyapunov functional, an estimation cr... View full abstract»

• ### Non-linear decoupling control of vehicle plane motion

Publication Year: 2012, Page(s):2083 - 2094
Cited by:  Papers (2)
| | PDF (531 KB)

This article studies the decoupling control strategies for a quasi-linearised vehicle model consisting of three degrees of freedom. The key feature of the model is that it preserves strong non-linearities and inherent coupling effects between longitudinal acceleration/braking force, steering angles and state variables of the vehicle, based on which two kinds of decoupling controllers are presented... View full abstract»

• ### Control of linear discrete-time systems by quantised feedback

Publication Year: 2012, Page(s):2095 - 2102
Cited by:  Papers (3)
| | PDF (499 KB)

In this study the authors, we investigate the problem of designing quantised H feedback control for a class of discrete-time systems with and without bounded uncertainties. The quantiser has arbitrary form. A linear matrix inequality-based method using static and dynamic quantised output-feedback controller are designed to render the closed-loop system asymptotically stable with... View full abstract»

• ### Task priority approach to the coordinated control of a team of flying vehicles in the presence of obstacles

Publication Year: 2012, Page(s):2103 - 2110
| | PDF (1077 KB)

This study describes the application of the task priority null-space behavioural technique to the coordinated control of a team of flying vehicles with hovering capabilities, such as helicopters or quadrotors, in the presence of obstacles and no-fly zones. Once a flight mission is assigned to the team in terms of a target region to reach, each flying vehicle is required to accomplish four tasks wi... View full abstract»

• ### Solving periodic Lyapunov matrix equations via finite steps iteration

Publication Year: 2012, Page(s):2111 - 2119
| | PDF (239 KB)

Periodic Lyapunov matrix equations play important roles in stability analysis and stabilisation of discrete-time periodic systems. In this paper, an iterative algorithm for solving periodic Lyapunov matrix equations is established. It is shown that the proposed iteration converges to the unique solution of the considered matrix equations at finite steps with arbitrary initial condition despite the... View full abstract»

• ### Observer-based partial differential equation boundary control for a flexible two-link manipulator in task space

Publication Year: 2012, Page(s):2120 - 2133
Cited by:  Papers (9)
| | PDF (1198 KB)

This study addresses the problem of trajectory control of a flexible two-link manipulator on the basis of the partial differential equation (PDE) dynamic model. One of the key contributions of this study is that a novel non-linear PDE observer is proposed to estimate distributed positions and velocities along flexible links, which cannot be achieved by the typical ordinary differential equation ob... View full abstract»

• ### Global adaptive stabilisation of feedforward systems by smooth output feedback [Brief Paper]

Publication Year: 2012, Page(s):2134 - 2141
Cited by:  Papers (4)
| | PDF (411 KB)

The authors address the problem of global output-feedback stabilisation for a class of feedforward nonlinear systems. The system satisfies linear growth condition with an unknown growth rate. Using the dynamic gain scaling technique and introducing a new adaptive law, it is proved that global adaptive stabilisation of the feedforward systems can be achieved by smooth output feedback. The gain matr... View full abstract»

• ### Robust cooperative output regulation problem for non-linear multi-agent systems [Brief Paper]

Publication Year: 2012, Page(s):2142 - 2148
Cited by:  Papers (5)
| | PDF (220 KB)

In this study, the author considers a robust cooperative output regulation problem for a class of uncertain non-linear multi-agent systems. The dynamics of each agent can be represented by a non-linear system with unknown parameters. It is assumed that only some of the agents are able to access the exosystem, and thus the problem has to be solved by cooperation among different agents. An internal ... View full abstract»

• ### Relaxed inequality approach to robust H/spl infin/ stability analysis of discrete-time systems with time-varying delay [Brief Paper]

Publication Year: 2012, Page(s):2149 - 2156
Cited by:  Papers (3)
| | PDF (219 KB)

This study aims at deriving a less conservative delay-dependent criterion for the robust H stability analysis of discrete-time systems with interval time-varying state delay. To this end, an appropriate Lyapunov-Krasovskii functional containing triple summation terms is established and a relaxed inequality approach is proposed to address the induced double summation inequality a... View full abstract»

## Aims & Scope

IET Control Theory & Applications is devoted to control systems in the broadest sense, covering new theoretical results and the applications of new and established control methods.

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