The Future Electrical Machines Manufacturing Hub team

Professor Geraint Jewell

Department of Electronic and Electrical Engineering, University of Sheffield

Dr Laura O’Keefe

Department of Electronic and Electrical Engineering, University of Sheffield

Professor Ashutosh Tiwari
Department of Automatic Control and Systems Engineering, University of Sheffield

Michael Ward

Dr Michael Ward

Advanced Forming Research Centre (AFRC), University of Strathclyde

Professor Zi-Qiang Zhu
Department of Electronic and Electrical Engineering, University of Sheffield

Dr Glynn Atkinson

Electrical Power Research Group, Newcastle University

Dr Jill Miscandlon

Advanced Forming Research Centre (AFRC), University of Strathclyde

Dr Alasdair McDonald
Department of Electronic & Electrical Engineering, University of Strathclyde

Professor Barrie Mecrow

Electrical Power Research Group, Newcastle University

Ben Morgan
Advanced Manufacturing Research Centre, University of Sheffield

Professor Jiabin Wang
Department of Electronic and Electrical Engineering, University of Sheffield

Dr Gladys Benghalia

Advanced Forming Research Centre (AFRC), University of Strathclyde

Professor Rab Scott

Advanced Manufacturing Research Centre (AMRC), University of Sheffield

Dr Robin Purshouse

Department of Automatic Control and Systems Engineering, University of Sheffield

Dr Xiao Chen

Department of Electronic and Electrical Engineering, University of Sheffield

Dr Michael Farnsworth

Department of Automatic Control and Systems, University of Sheffield

Dr Divya Tiwari


Department of Automatic Control and Systems, University of Sheffield

Dr Lloyd Tinkler

Advanced Manufacturing Research Centre (AMRC), University of Sheffield

Dr Sheena Mackenzie

Advanced Forming Research Centre (AFRC), University of Strathclyde

Dr Nabeel Ahmed

Electrical Power Research Group, Newcastle University

Ryan Diver AMRC

Ryan Diver 

Advanced Manufacturing Research Centre (AMRC), University of Sheffield

Steve Forrest - University of Sheffield

Dr Steve Forrest

Department of Electronic and Electrical Engineering, University of Sheffield

Georgios Yiannakou
Department of Electronic and Electrical Engineering, University of Sheffield
Leigh Paterson
Advanced Forming Research Centre (AFRC), University of Strathclyde

Gianmarco Pisanelli

 Advanced Manufacturing Research Centre (AMRC), University of Sheffield

Professor Geraint Jewell – Hub Director

Department of Electronic & Electrical Engineering, University of Sheffield

Professor Jewell is a graduate of Sheffield (BEng- 1988; PhD 1992) and has been a member of the academic staff in the Department of Electronic and Electrical Engineering in Sheffield since 1994. He held an EPSRC Advanced Research Fellowship (2000-2005) and a Royal Society Industry Fellowship at Rolls-Royce (2006-2008). He has been Director of the Rolls-Royce University Technology Centre in Advanced Electrical Machines since 2006. Alongside his academic roles within the Department, he served as the Faculty of Engineering’s first Director of Research and Innovation from 2008-2011 and was Head of the Department from 2013-2019.

His research interests cover many aspects of electromechanical devices including electrical machines (permanent magnet, switched reluctance, synchronous reluctance) and linear actuators. Much of this research in recent years has been directed towards aero-engine applications in collaboration with Rolls-Royce. This research has included high temperature devices (many around 400 °C but with one up to 800 °C) and several demonstrator starter-generators for aero-engines. He have supervised some 20 PhD students to completion across a wide range of electromagnetic and electro-mechanical topics.

Dr Laura O’Keefe – Hub Manager

Department of Electronic & Electrical Engineering, University of Sheffield

Laura O’Keefe an experienced Manager with a demonstrated history of working in higher education. Prior to her current position at the University of Sheffield, she spent 8 years at The University of Manchester in positions within the Faculty of Science and Engineering, EPSRC Supergen Bioenergy hub and the Tyndall Centre for Climate Change Research.

Professor Ashutosh Tiwari

Airbus/RAEng Research Chair in Digitisation for Manufacturing, The University of Sheffield

His research focuses on real-time digitisation, simulation and optimisation of skill-intensive manufacturing processes, such as wing manufacture and engine assembly, with a vision to develop a digitised factory that requires no setups and inspections for manufacturing part variants.

He has secured around £7m of research funding and is an executive committee member of the EPSRC Future Electrical Machines Manufacturing Hub. He has completed 36 PhD theses supervision, and produced 316 publications including 137 journal and 125 conference papers. He is a Fellow of IMechE and IET, a Chartered Engineer, and an executive committee member of EPSRC Connected Everything Network Plus.

He is an associate editor of Artificial Intelligence for Engineering Design, Analysis and Manufacturing Journal, a review editor of Applied Soft Computing Journal, and an editorial board member of IMechE Journal of Engineering Manufacture.

Dr Michael Ward

Research Director,  Advanced Forming Research Centre, University of Strathclyde. 

Michael has spent a quarter of a century in the field of manufacturing  innovation. This has included several years at Rolls-Royce, where he had roles in capability acquisition, the Trent 1000 programme, and process modelling. In his early career Michael worked with ABB Daimler Benz Transportation in the petrochemical processing industry.

Professor Zi-Qiang Zhu

Professor of Electrical Machines and Control Systems, Department of Electronic and Electrical Engineering, University of Sheffield

Professor Zi-Qiang Zhu graduated with a BEng degree (1982) and an MSc degree (1984) from Zhejiang University, Hangzhou, China, and a PhD degree (1991) from The University of Sheffield, UK.
After working as a Lecturer/Assistant Lecturer at Zhejiang University from 1984 to 1988, he joined The University of Sheffield in 1988. Initially as a Visiting Research Fellow sponsored by the British Council (1988-1989) and a Research Associate working on an EU funded project in co-operation with Philips (1989-1992), then on an established university post as a Senior Research Scientist/Officer (1992-2000). He is currently a Professor on Electrical Machines and Control Systems in the Department of Electronic and Electrical Engineering (2000- present). He holds the Royal Academy of Engineering/Siemens Research Chair (2014- present) and is the Head of the Electrical Machines and Drives Research Group (2008- present).

Prof Zhu’s research interests include the design and control of novel high torque/power density and high efficiency permanent magnet machines and drives for applications ranging from electric vehicles through domestic appliances to wind power generation and more electric aircraft. By way of example, his research activities over last >35 years cover (a) novel permanent magnet machines including Halbach machines, fractional slot machines, stator wound field machines, switched flux machines, magnetically geared machines, multi-3-phase machines, segmented stator machines, ultra-high speed machines, and novel linear machines; (b) theories, and analytical and numerical modelling techniques of permanent magnet machines; (c) novel PWM, sensorless, and vector and direct torque control techniques; (d) acoustic noise and vibration in electrical machines and drives. These research activities have been sponsored by the UK/EU government and the global industries based in the UK, Germany, Japan, Denmark, France, and China, with research funding of >£20M. He is the Founding Academic Director of Sheffield Siemens Wind Power Research Centre on direct-drive permanent magnet wind power generators, the Founding Director of CRRC Electric Drives Technology Research Centre on the power trains for fast train propulsion, and the Founding Director of Midea Electric Machines and Controls Research Centre on low cost high performance electric motors and drives for domestic appliances.

Dr Glynn Atkinson

Electrical Power Research Group, University of Newcastle. 

Glynn is Senior Lecturer and the Faculty Associate Dean for Postgraduate Research. His research interests include soft magnetic composites, fault tolerant machines for aerospace and design and analysis of electrical machines for a wide variety of domestic and industrial applications.

Dr Jill Miscandlon

The Advanced Forming Research Centre (AFRC), University of Strathclyde

Dr Jill Miscandlon graduated from the University of Strathclyde with a PhD in Mathematics and BSC (Hons) First Class in Mathematics. Jill has worked at the AFRC since May 2013 on advanced forming and forging technologies.

She started her career working on a variety of forming processes, including superplastic forming and incremental sheet forming, before specialising in cold, incremental technologies. Her technology research interests include flow forming, shear forming, rotary forging, and radial forging. Jill has worked for the last 5 years predominantly on flow forming, leading large scale CR&D projects including the SAMULET (Strategic Affordable Manufacturing in the UK through Leading Environmental Technologies) and Manufacturing Portfolio projects.

Jill has joined the FEMM hub team from a manufacturing background and will bring her knowledge and experience of advanced forming techniques, method of manufacture optimisation, and supply chain development to the group.

Dr Alasdair McDonald

Senior Lecturer, Institute for Energy and Environment, Department of Electronic & Electrical Engineering, University of Strathclyde

Dr Alasdair McDonald is a Senior Lecturer in the Institute for Energy and Environment, Department of Electronic & Electrical Engineering, University of Strathclyde. He is an electrical machine designer with a particular interest in lightweight design for mass sensitive applications.

He studied Electrical and Mechanical Engineering at the University of Durham in 2004 and completed a PhD at the Institute of Energy Systems at the School of Engineering & Electronics at the University of Edinburgh in 2008. Subsequently Alasdair worked as a postdoctoral researcher in Edinburgh on a number of projects on lightweight design of direct-drive generators for wind and marine energy. In 2009, he co-founded the spin-out company NGenTec to commercialise research of a novel air-cored generator for wind. Dr McDonald was Chief Engineer at the company in 2010-2012, during which time the company designed, built and tested a 1MW demonstrator. Alasdair has worked as a consultant on the design of permanent magnet generators for direct-drive wind turbines.

At Strathclyde he is Training Manager for the EPSRC Wind and Marine Energy Systems Centre for Doctoral Training. He is PI of the UK-China MOD-CORE project, which looks at offshore renewable energy powertrain modelling, optimisation, design and control.

Professor Barrie Mecrow

Professor of Electrical Power, School of Engineering, Newcastle University.

Barrie commenced his career as a Turbogenerator Design Engineer with NEI Parsons, Newcastle upon Tyne, U.K., where he completed his PhD on 3-D eddy-current computation in large electrical machines. He became a Lecturer in 1987 and a Professor in 1998 with Newcastle University. He was Head of the School of Electrical and Electronic Engineering, Newcastle University, from 2012-2017, where he is also a Professor of Electrical Power Engineering. His research interests include fault-tolerant drives, high-performance permanent-magnet machines and novel switched reluctance drives. He has close links with Dyson and a number of automotive and aerospace companies, and is a fellow of the Royal Academy of Engineering.

Ben Morgan MEng CEng FIMechE

Head of the Integrated Manufacturing Group, AMRC
Ben Morgan is Head of the Integrated Manufacturing Group at AMRC and is responsible for the £43m Factory 2050. He leads a multi-disciplinary team of over 70 engineers carrying out transformative research for UK manufacturing industry. Factory 2050 is the world’s first fully reconfigurable assembly and component manufacturing facility for collaborative research and the venture has increased the group’s ability to transform research into high tech solutions for some of the world’s leading aerospace and engineering companies.

Ben has previously been PI on a number of large innovation projects including VIEWS (£2.2m of £30m, Innovate UK), Spirit AeroSystems Aerostructures Factory of the Future (£2.3m, Innovate UK), Meggitt M4 (£1m of £6m, Innovate UK) and Airbus Factory of Aircraft Future (£1.8m of £15m, Innovate UK). Morgan has won several BAE Systems Chairman’s Business Innovation awards developing automated solutions for aircraft manufacture. Morgan also sits on the board for the EPSRC Machining Industrial Doctorate Centre.

Professor Jiabin Wang

Professor, Department of Electronic and Electrical Engineering, University of Sheffield

Professor Jiabin Wang graduated with a BEng in 1982 and MSc in 1996 from Jiangsu University in China, and a PhD in 1996 from the University of East London, UK, respectively, all in Electrical Engineering. He was an academic staff in Jiangsu University, from 1982 to 1983 and from 1986 to 1991, and a visiting academic researcher in Liverpool University, UK, from 1991 to 1992. After working on multi-degrees of freedom rotary and linear electromagnetic actuation systems as a post-doctoral research associate at the University of Sheffield from 1997 to 1998, he joined the EEE department in the University of East as Senior Lecturer in 1998. Since 2001, he has been with the EEE Department at the University of Sheffield, being promoted to Reader in 2007 and to Professor in 2010.

His research encompasses advanced control techniques for electrical drives, novel rotary and linear machines and drives, advanced electrical power-trains and ‘more-electric’ technologies and energy management strategies for electric and hybrid vehicles, and aircraft. Currently, his research focuses on high integrity, fault tolerant and high efficiency electric drives and associated condition monitoring techniques for applications in aerospace, automotive and household appliances.

Dr Gladys Benghalia

Strategic Programme Lead – Electrification at The Advanced Forming Research Centre (AFRC), University of Strathclyde 

Dr Gladys Benghalia graduated from the University of Strathclyde with a BEng (Hons) First Class in Mechanical Engineering with International Study in 2011 before commencing a PhD in the Weir Advanced Research Centre at the University of Strathclyde.

Gladys has worked at the AFRC since July 2015, initially as a Research Associate in materials science and residual stress. She led research programmes on the characterisation of residual stress due to quenching and machining processes in collaboration with a number of industrial partners, as well as leading the development of non-destructive residual stress measurement using ultrasonic means.

Gladys then progressed onto the role of Strategic Programme Lead for Electrification at the AFRC and joins the FEMM Hub team to coordinate interactions between the Hub, the University of Strathclyde and the UK manufacturing field to ensure that FEMM Hub technology developments are embedded in a ready and willing industrial supply chain.

Professor Rab Scott

Professor of Industrial Digitalisation. Head of Digital at the AMRC.

Professor Rab Scott has been a member of the AMRC staff since its beginning in 2001, after heading up the Virtual Reality and Simulation activities he now leads on the strategic development and implementation of digital manufacturing solutions across the whole organisation.

Rab is the operational chair of the High Value Manufacturing Catapult’s Digital Strategy Team. He sits on the Steering Committee of Immerse UK (the UK’s body for immersive technologies), the IET’s Digital Panel and their Applied Visualisation Forum. He is also the IET’s spokesman for Virtual Reality. Rab has recently been made a Visiting Professor in the Department of Design, Manufacturing and Engineering Management at the University of Strathclyde.

Dr Robin Purshouse

Reader in Decision Modelling and Optimisation, Department of Automatic Control and Systems Engineering, University of Sheffield

Robin Purshouse received the MEng degree in Control Systems Engineering in 1999 and a PhD in Control Systems in 2004 for his research on evolutionary many-objective optimisation under the supervision of Peter Fleming. Commercial experience includes Logica plc (1999-2000), PA Consulting Group (2003-2007) and Rolls-Royce plc (2007-2008). He returned to the University of Sheffield in 2008 – initially as a Research Fellow in the School of Health and Related Research and, since 2010, as a Lecturer in the Department of Automatic Control & Systems Engineering. Robin was a principal architect of the Sheffield Alcohol Policy Model, alongside Alan BrennanRachid Rafia, and Petra Meier. He was the holder of an ESRC Future Research Leaders grant award (October 2012 – September 2014) and, with Peter Fleming and Carlos Fonseca, was General Chair of the seventh international conference in the world-leading series on Evolutionary Multi-Criterion Optimization (EMO) held in Sheffield in March 2013.

Dr Xiao Chen

Lecturer in Electrical Machines, Department of Electronic and Electrical Engineering, University of Sheffield
Xiao Chen is currently a lecturer in EMD group, EEE department, University of Sheffield. He received his PhD degree in electrical machines from University of Sheffield in Dec 2015, before working as a research associate in the same group until May 2018. Then, he joined Dyson Technology Limited as an advanced motor drive engineer from July 2018 to Sep 2019, before coming back to University of Sheffield in Sep 2019.
His current research interests include manufacturing-led innovation in electrical machines, multi-phase fault tolerant electrical machines for more electric aircraft, digital twin of electrical machine and drive, high-speed electrical machines for traction, low-cost electrical machines, and powertrain energy management for electric vehicles.

Dr Michael Farnsworth

Research Associate, ACSE, University of Sheffield

I graduated originally from the biological sciences having pursued a BSc in Biochemistry at Cardiff University before undertaking a MSc in Computer Science at the University of the West of England (UWE). I continued with my interest in biologically inspired computation, undertaking a PhD at Cranfield University on the evolutionary design optimisation of Micro-Electro-Mechanical Systems (MEMS). I continued on with this theme as a researcher of a number of projects throughout my time at Cranfield University, ranging from autonomous maintenance and robotics, self-healing systems, manufacturing informatics and process optimisation.

In my current role as a research associate within ACSE I research and develop digital, electronic and robotic solutions for automation within manufacturing and shop floor environments. I am developing a research theme concerned with digital manufacturing and how the distributed resources of IoT and ‘Smart Products’ can augment robotic cognition in this field. The core of this research is centred on my interests in biologically inspired computing, whether it be evolutionary computation, machine learning and AI, or robotics and cognitive neuroscience.

Dr Divya Tiwari

Research Associate, ACSE, University of Sheffield

Dr Divya Tiwari is a Research Associate working in the area of Digital Manufacturing within the department of ACSE at the University of Sheffield. Her work focuses on sensors and simulation for high value manufacturing processes.

She has a background in optical fibre sensing technology and was awarded a fellowship by Royal Academy of Engineering and Daphne Jackson Trust in 2013 for the development of novel photonic sensors for industrial applications. She was awarded a degree of PhD in 2010 by Cranfield University. Before joining academia, Divya worked in an electronics industry on the development of sensors for aerospace and automotive applications in the UK.

Dr Nabeel Ahmed

Research Associate,  Electrical Power Research Group, Newcastle University

Nabeel received his BEng in Electrical and Electronic Engineering from Newcastle University in 2012. He completed his Ph.D. degree from Newcastle University in 2016 in which he designed several Flux switching modulated pole machine topologies to reduce cogging torque in futuristic electric vehicles.

Nabeel began his career with Jaguar Land Rover where he worked as a Lead Power Electronics Design Engineer in Electrification Department. He now works as a member of the Electrical Power Research Group in Newcastle University and specialises in high speed electrical machine design and FE simulation, linear motors, 3D machine topologies for aerospace and railway engineering and manufacturing process.

Presently working at EPSRC Future Electrical Machines Manufacturing Hub which combines expertise in electrical machines and manufacturing for the first time.  Previously, Nabeel was working on a UK funded project (called Z_LIM) investigating predictable and optimised braking for rail systems applying the concept of a linear induction motor. Instead of using an integrated primary and secondary unit, it separates them using the existing running rails as the secondary, placing the primary component attached to the bogie in the fashion of a eddy current brake. This allows for the generation of forces that are independent of the level of adhesion between wheel and rail, effectively providing a zero wheel-slip effect.

Prior to this, Nabeel worked extensively in the development of drives for use in a variety of aerospace applications. He was particularly involved in the manufacturing of a calorimetric system for testing high efficiency, low mass motors for use in solar powered aircraft applications. These projects involved QinetiQ, Boeing and Airbus, and saw motors designed which achieved new levels of efficiency whilst being designed to operate at altitudes above 50kft and at temperatures below -50degC.

Dr Lloyd Tinkler

Advanced Manufacturing Research Centre (AMRC), University of Sheffield
Dr Lloyd Tinkler is a Senior Project Engineer at the Advanced Manufacturing Research Centre (AMRC). Lloyd holds a MEng (Hons) degree in electronic engineering from the University of Hull and a PhD from the University of Sheffield for his research on the optical nonlinearities of semiconductor waveguides.

In his role at the AMRC, Lloyd has led numerous projects for aerospace companies on topics including the robotic application of sealants and adhesives, and the use of autonomous mobile robots for internal logistics. He has also led the research on reconfigurable and flexible manufacturing systems for high-value products, culminating in the design and construction of a state of the art reconfigurable robot assembly cell. This cell, designed to allow rapid changeover between processes and products, is used as a test-bed for automation projects and research into flexible and reconfigurable manufacture.

Dr Sheena Mackenzie

Advanced Forming Research Centre (AFRC), University of Strathclyde

Sheena MacKenzie is the Future Business Manager for the Advanced Forming Research Centre (AFRC), part of the University of Strathclyde and one of seven centres in the UK’s High Value Manufacturing (HVM) Catapult.

The AFRC has a range of production scale manufacturing equipment, laboratory facilities and the breadth and depth of knowledge to take manufacturing research through to production scale implementations. The centre has a recently established Digital Manufacturing team which is growing rapidly. The team has expertise in virtual reality, Industry 4.0, robotics and automation in addition to working with Scottish Enterprise and the Scottish Manufacturing Advisory Service to support Scottish companies interested in adopting these technologies.

Sheena has spent 30 years working at the interface between engineering research and its application and is passionate about bringing research and new technologies into real, practical use. She worked in academia for 10 years with companies including ICI, BP and Rolls-Royce before moving into industry in 1997, where she worked for the UK’s defence evaluation research agency as the organisation privatised into QinetiQ and diversified into new industries. She has led multidisciplinary teams, shaping, bidding, winning and delivering highly successful programmes for a range of industries including manufacturing, energy, aerospace, defence and process control.

She joined the AFRC in February 2012 and heads up the development of collaborative Research and Development programmes and projects with industry.

Dr Steve Forrest

Research Fellow in Electrical Machines and Drives, Department of Electronic and Electrical Engineering, University of Sheffield

Steve is an experienced researcher in the field of Electrical Machines and Drives, having spent many years as a post-doctoral research fellow within the Rolls-Royce University Technology Centre in Advanced Electrical Machines and the wider department. Historically his research interests have focused on both electrical machine and grid facing power converters, primarily for Aerospace applications, including advanced topologies and control methods. His PhD was concerned with a novel, low energy storage, power converter to control a multi-phase switched reluctance machine in an Aerospace application. More recently, Steve’s research interests have focused on failure analysis and fault mitigation methods for coil based faults in permanent magnet machines and thermal management of power dense permanent magnet machines in Aerospace applications.

A graduate of Sheffield, Steve initially gained a BSc in Physics, before moving to the department of Automatic Control and Systems Engineering and completing an MSc, in order to gain entry to the field of Engineering. Following an initial role as a research assistant in the department of Electronic and Electrical Engineering, investigating a control strategy for electromagnetic valve actuation, he went on complete his PhD in 2011, under the Rolls-Royce Technology Centre.

Ryan Diver

Head Of Technology, Advanced Manufacturing Research Centre (AMRC), University of Sheffield

Ryan Diver is the Head of Technology for the Integrated Manufacturing Group based at the Advanced Manufacturing Research Centre. Within the Factory 2050 facility he is responsible the research strategy and project delivery for 60 multidisciplinary research engineers. His research teams focus on: Robotics and automation; Control systems and integration technologies; Augmented and virtual reality; AI and manufacturing informatics; In-process metrology and inspection. Ryan graduated from The University of York with a BEng in Computer Science and worked in embedded electronic design before joining the AMRC. Over the past 5 years, he has delivered the Spirit AeroSystems Aerostructures Factory of the Future programme (£2.3m, Innovate UK) and Airbus UK Factory of the Aircraft Futures programme (£1.8m, Innovate UK) both from a project management and research delivery perspective. These programmes were both focused on the manufacture of high value, low volume components and assemblies utilising robotics, smart factories and digital manufacturing technologies.

Georgios Yiannakou

Research Associate, University of Sheffield 

Georgios Yiannakou graduated from the University of Sheffield in 2015 with a BEng (Hons) in Electrical Engineering. He currently is at the final stage of his Ph.D. studies developing a novel electromagnetic process for the internal polishing of complex metallic structures as-built by Additive Layer Manufacturing. This is an EPSRC Industrial CASE award with Rolls-Royce involved as the industrial collaborator. He has joined the EPSRC FEMM hub in September 2019 and his work focuses on the properties of advanced soft magnetic materials, in what extend these properties are affected during the various stages of electrical machine manufacturing and finally how these may influence the overall in-service performance of these machines.

Leigh Paterson

PhD Student,  AFRC  

PhD title: Circular Design and Sustainable Manufacture of Permanent Magnet Machine Components.

Leigh’s PhD is concerned with alleviating the environmental impact from the component parts of an electrical machine by looking at implementing a circular economy design route. She graduated from the University of Strathclyde in 2014 with a first class honours degree in Product Design & Innovation. After working as a product development engineer within the medical industry for a number of years, she returned to the University to undertake this PhD in a topic she is passionate about.

Gianmarco Pisanelli

Control Engineer, AMRC

Gianmarco is a Control Engineer at the Advanced Manufacturing Research Centre (AMRC). He was awarded an MEng (Hons) in Mechatronic and Robotic Engineering at the University of Sheffield. His thesis proposed a novel methodology to control Collaborative Robots using natural language interfaces. He has previously conducted research on intuitive interfaces for Human-Robot Interaction applications. He worked alongside audio-visual artist Mark Fell to develop an interactive robotics art installation for the Festival of the Mind 2018. He has also collaborated with Sheffield Robotics to develop choreographic performances with robotic swarms for public events.