Stephen Duncan

Stephen's research concentrates on the design and implementation of feedback control systems for a range of applications. Many of these applications are distributed parameter processes, where the properties vary in both space and time. The resulting controller is typically multi-input and multi-output and of high dimension and often there is a high degree of uncertainty in the response of the process, which makes the implementation of these systems particularly challenging.

Fast Orbit Feedback Stabilisation System for a Synchrotron. Diamond Light Source is the UK's national synchrotron facility. Synchrotrons produce beams of intense electro-magnetic radiation across a broad spectrum of wavelengths by deflecting electrons that are travelling at close to the speed of light. The radiation is used in a wide range of applications from new medicines and treatments for disease to innovative engineering and cutting-edge technology. We have designed the system for controlling the position of the electrons in the main ring of the synchrotron and are designing the controller for the planned upgrade, Diamond-II.

Design of a New Generation of Battery Electrodes. As part of the Nextrode project, funded by the Faraday Institution, we are using ideas from control theory and optimisation to design new structured electrodes for Lithium-ion batteries. These electrodes can be manufactured using novel spraying techniques and improve the performance of the batteries and increase their lifetime.  

Monitoring Overhead Line Equipment for Electrified Railways. Ensuring a reliable service on an electrified railway requires the overhead line equipment to be continually monitored in order to predict and detect faults. We have developed a camera based system called OLErt, which uses image processing techniques to monitor the position of the overhead wires and to estimate the contact force between the pantograph, the device that transfers the power to the train, and electrified line. The system has been developed in conjunction with Incremental Solutions and is being installed on trains on the UK rail network.

Analysis of Nonlinear Control Systems. We have been investigating the absolute stability of Lurie systems, which are a class of nonlinear systems. Although most of this work is theoretical, many of the results have been exploited in the design of battery electrodes and in analysing the stability of fluid flows.