C. Edwards

C. Edwards
University of Exeter | UoE · College of Engineering, Mathematics and Physical Sciences

BSc (Mathematics) Warwick

About

424
Publications
39,090
Reads
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16,243
Citations
Additional affiliations
July 2012 - present
University of Exeter
Position
  • Professor
Description
  • I began began his academic career in the department of Engineering at the University of Leicester as a Lecturer in 1996. I was promoted to Senior Lecturer in 2004, Reader in 2008 and awarded a Personal Chair in 2010.
September 1996 - June 2012
University of Leicester
Position
  • Professor

Publications

Publications (424)
Article
Full-text available
As the UK, together with numerous countries in the world, moves towards a new phase of the COVID-19 pandemic, there is a need to be able to predict trends in sufficient time to limit the pressure faced by the National Health Service (NHS) and maintain low hospitalisation levels. In this study, we explore the use of an epidemiological compartmental...
Article
In this work, the problem of online secure state estimation and attack reconstruction in the face of offensives that corrupt the sensor measurements and modify the actuator commands of cyber–physical systems is investigated for designing a resilient controller for the system. The states of cyber–physical system and its actuator attacks are estimate...
Article
Full-text available
A linear parameter varying sliding mode fault reconstruction scheme is proposed. Compared with other conventional sliding mode observer designs, the estimate emerges quite naturally from the equations governing the sliding motion, and although the process may be viewed as a filtering of the discontinuous injection, there is no phase lag introduced...
Article
Full-text available
Abstract In this paper, a quasi‐linear parameter varying sliding mode control allocation law is proposed for the fault tolerant control of an octorotor. In the event of rotor faults/failures, an allocation law redistributes the control effort among the remaining healthy rotors. The sliding mode control law is designed to guarantee asymptotic tracki...
Article
This brief develops a sliding mode sensor fault-tolerant control scheme for a class of linear parameter varying (LPV) systems. It incorporates a sliding mode observer that reconstructs the unknown sensor faults based on only the system inputs and outputs. The reconstructed sensor faults are used to compensate for the corrupted sensor measurements b...
Article
Full-text available
In this brief, a novel sliding mode (SM) observer-based scheme is proposed to achieve frequency regulation and economic dispatch (ED) in power grids composed of interconnection of generators and load buses. The ED problem is addressed in two steps. Assuming only the voltage phase angles are measured, in the first step a network of heterogeneous SM...
Article
Full-text available
In this paper a novel distributed adaptive dual-layer super-twisting sliding mode observer-based scheme is designed to isolate, reconstruct and mitigate the effects of disturbances and a class of communication attacks affecting both generator nodes and load nodes in power networks. Voltage phase angles are measured at each node by means of Phasor M...
Article
Full-text available
The problem of resilient control of linear cyber‐physical systems with cyber‐attacked sensor measurements and actuator commands is studied in this article. Online reconstruction of unknown cyber‐attacks is accomplished by an adaptive sliding mode observer with a novel injection term in the form of a dynamically extended equivalent control. Then, th...
Article
This paper proposes a first order sliding mode observer for the purpose of simultaneously estimating the unknown input time delay and reconstructing the loss of effectiveness in a model of an actuator. The adaptive algorithm is driven by the ‘equivalent output error injection’ signal associated with the sliding motion. Sufficient conditions are giv...
Conference Paper
Full-text available
In this paper, a Sub-Optimal Sliding Mode (SOSM) guidance scheme is proposed to induce boundary tracking behaviours in autonomous vehicles. The spread of an environmental feature in 2-dimensional space is modelled as a scalar field characterised by an unknown spatial gradient. It is assumed that a single autonomous vehicle is deployed and this prov...
Article
Full-text available
This paper presents a novel form of control allocation, designed within a sliding mode framework, for the fault tolerant control of over‐actuated systems. The control allocation is designed in such a way as to allow a subset of the actuators to remain inactive under nominal fault‐free conditions. In the event that the active set of actuators become...
Conference Paper
Due to the unconventional layout of a Blended Wing Body aircraft the available actuators provide little control authority: this situation is exacerbated in situations where the actuators are subject to actuator faults and failures. This paper proposes an optimised integral sliding mode scheme, with control allocation, to ensure that the actuators p...
Article
In this work, we consider the problem of simultaneously estimating the system states and unknown inputs in a linear sampled-data system, whose dynamics is influenced by external disturbances and uncertainties. Hardware limitations prevent an estimation scheme for a sampled-data system from achieving finite-time convergence, which is a typical prope...
Chapter
This chapter presents a review of sliding-mode estimation techniques recently proposed by the authors in the area of power systems. The power grid is interpreted as a large-scale system, composed of an interconnection of generator nodes and load nodes. The analysis starts at the local level by considering a single generator node for which two dynam...
Article
Full-text available
This paper develops a sliding mode fault tolerant control scheme based on a Linear Parameter Varying (LPV) system representation of the plant. The scheme includes a control allocation component, which is capable of utilizing the available healthy actuators in the face of actuator faults/failures, in an effort to retain close to nominal fault free p...
Article
Full-text available
This paper proposes an integrated fault tolerant control scheme for a class of systems, modelled in a linear parameter-varying (LPV) framework and subject to sensor faults. The gain in the LPV sliding mode observer (SMO) and the gain in the LPV static feedback controller are synthesized simultaneously to optimize the performance of the closed-loop...
Article
Full-text available
In this paper, the problem of output feedback sliding mode control of linear sampled-data multi-input multi-output systems is considered. Existing sliding mode control schemes can attenuate the influence of an external disturbance by driving system states onto a sliding surface. However, they can exhibit high gains during transients, which can be w...
Conference Paper
Full-text available
This paper deals with the design of a variable gains super-twisting sliding mode-based decentralized control scheme with application to large-scale modular systems. The system under consideration is composed by a interconnection of so-called active nodes, where the control signal acts, and nonactive nodes, which are not subjected to control actions...
Article
Full-text available
This paper considers the application of higher order Sliding Mode (SM) observers to robustly and dynamically estimate the unmeasured state variables in modern power grids, in which both traditional and renewable energy sources coexist. In particular, a power grid composed of traditional, wind and inverter-based sources connected with dynamical load...
Article
Full-text available
In this paper, a sliding mode-based guidance strategy is proposed for the control of an autonomous vehicle. The aim of the autonomous vehicle deployment is the study of unknown environmental spatial features. The proposed approach allows the solution of both boundary tracking and source-seeking problems with a single autonomous vehicle capable of s...
Preprint
Full-text available
In this paper, the problem of output feedback sliding mode control of linear sampled-data multi-input multi-output systems is considered. Existing sliding mode control schemes can attenuate the influence of an external disturbance by driving system states onto a sliding surface. However, they can exhibit high gains during transients, which can be $...
Article
Full-text available
This paper proposes a linear parameter-varying sliding mode observer for the purpose of simultaneously estimating the system states and reconstructing sensor faults. Furthermore, some of the measured scheduling parameters are also assumed to be unreliable, and the corresponding values used in the observer are adapted to maintain the performance lev...
Preprint
With far greater fuel economy and reduced noise, the Blended Wing Body is an efficient alternative to the conventional aircraft layout which, up to this point in time, has dominated commercial aviation. However, the combination of highly coupled effectors, limited control authority, poor intrinsic stability and significant mechanical redundancy res...
Conference Paper
Full-text available
This paper deals with the design of a distributed super-twisting sliding mode observer-based scheme to isolate and reconstruct faults affecting both generator nodes and load nodes in power networks. It is assumed that voltage phase angles are measured at each node using Phasor Measurement Units (PMUs). Based on this information, an interconnection...
Article
Full-text available
This brief presents a novel estimation scheme for power grids based on distributed observers. Assuming only the generator voltage phase angles are measured and the electrical load active power demands are specified, we design an observer for each bus of the power grid, exploiting only knowledge of local information about the power system. In partic...
Conference Paper
Full-text available
This paper implements a sliding mode control scheme combined with control allocation on a multirotor UAV. The controllers were designed to be applicable to both fault-free and faulty conditions. The implementation was done using the Simulink Pixhawk support package for rapid and automatic build-and-deploy control algorithms. The designed controller...
Chapter
The chapter considers so-called integral sliding modes (ISM) and how they can be employed in the context of fault tolerant control. Two distinct classes of problems are considered: firstly a fault tolerant ISM controller is designed for an over-actuated linear system; secondly an ISM scheme is retrofitted to an existing feedback control scheme for...
Article
Full-text available
This paper develops novel fault‐tolerant integral sliding mode control allocation schemes for a class of an overactuated affine nonlinear system. The proposed schemes rely on an existing baseline controller, and the objective is to retain the nominal (fault‐free) closed‐loop performance in the face of actuator faults/failures by effectively utilizi...
Conference Paper
Full-text available
This paper deals with data-based assessment of a recently proposed super-twisting-like sliding mode observer for frequency estimation and reconstruction in power systems, and the earlier observer further develops in this paper. We make use of both the historical measurement data of frequency and information about faults which have taken place in th...
Article
Full-text available
This paper deals with the design of a robust sliding mode observer for dynamic state estimation applied to synchronous generators in power systems. Assuming only the frequency deviation of the generator is measured via Phasor Measurement Units (PMUs), we use a robust sliding mode estimation technique to dynamically reconstruct the rotor angle and t...
Article
Full-text available
In this study, a linear parameter varying (LPV) sliding mode sensor fault detection and isolation (FDI) scheme is proposed wherein knowledge of the measurement redundancy is utilised to achieve FDI in multiple channels simultaneously. Such a situation is common in some state-of-the-art aircraft fault diagnosis systems where information is generally...
Article
Complex control systems and some preliminary background knowledge of variable structure control are introduced in this chapter. Some of the sources of system complexity dealt with in this book are discussed. Specifically, the basic concepts and fundamental methodology of sliding mode control and decentralised control are provided. Core notions are...
Article
Some examples, as an echo of the discussion about the source of complexity in Chap. 1 at the beginning of the book, are presented to further confirm the complexity of the systems considered in this book. Some suggestions for future work are presented. It is shown that study of complex control systems is a long term task for researchers and control...
Article
Full-text available
This paper describes the development, application, and evaluation of a linear parameter-varying integral sliding mode control allocation scheme to the Reconfiguration of Control in Flight for Integral Global Upset Recovery benchmark model to deal with an actuator failure/fault scenario. The proposed scheme has the capability to maintain close to no...
Article
This study proposes a two-sliding mode (SM) observer to detect and reconstruct a certain class of load altering faults in a power network. The observer design is based on the recently proposed multivariable super-twisting structure. The IEEE benchmark power networks used to test the scheme are modelled as a semi-explicit class of differential algeb...
Conference Paper
Full-text available
In this paper an estimation scheme for a power grid based on distributed observers is presented. Assuming that the only measurements available are the generator phase angles, our approach allows us to consider an observer for each bus of the power grid, exploiting on only knowledge of local information about the power system. In particular, we desi...
Article
Full-text available
This paper describes the optimisation of a nano-positioning stage for a Transverse Dynamic Force Microscope (TDFM). The nano-precision stage is required to move a specimen dish within a horizontal region of 1 micron × 1 micron and with a resolution of 0.3 nm. The design objective was to maximise positional accuracy during high speed actuation. This...
Article
This paper presents the design process for the optimisation of a nano-precision actuation stage for a Transverse Dynamic Force Microscope (TDFM). A TDFM is an advanced type of Atomic Force microscope (AFM) that does not contact the specimen and therefore has potential for increased accuracy and decreased damage to the specimen. The nano-precision s...
Article
In this technical note, a distributed observer structure is proposed to estimate the states of a large scale network of semi-linear systems interconnected by a positive, time varying coupling strength. The distributed observer comprises distinct sub-observers which require only local node level information and exchange their local state estimates w...
Article
The problem studied in this paper is one of improving the performance of a class of adaptive observer in the presence of exogenous disturbances. The H∞ gains of both a conventional and the newly proposed sliding-mode adaptive observer are evaluated, to assess the effect of disturbances on the estimation errors. It is shown that if the disturbance i...
Article
This paper presents a sliding mode fault detection scheme for linear parameter varying (LPV) systems with uncertain or imperfectly measured scheduling parameters. In the majority of LPV systems, it is assumed that the scheduling parameters are exactly known. In reality due to noise or possibly faulty sensors, it is sometimes impossible to have accu...
Article
Full-text available
The problem of output feedback sliding mode control for sampled-data systems in the presence of external disturbances is considered. The proposed output feedback control strategy helps obtain a quasi sliding mode with an O(T 3) boundary layer, where T is the sampling period. This outperforms the O(T 2) result induced by the one-step delayed disturb...