|
University home > Mechanical Engineering > People > Personal Details
|
|
|
Research
Summary
I am an accomplished control
engineer with extensive experience in the development and implementation of
novel control schemes. My research interests are in the area of nonlinear and
linear robust control. Emphasis is given towards the development of novel
theoretical methods which can be practically validated. A result of my
MSc-thesis was a journal publication on an improved approach of Pyragas’ method
for stabilization of unstable orbits in chaotic systems. During my PhD, I
developed significant expertise in the area of sliding mode control and the
theoretical investigation of discrete implementations of nonlinear
continuous-time control systems. Case studies have been carried out for a
realistic 270 state nonlinear simulation of a chemical process. After my PhD, I
developed novel servo-control methods at the A*Star Data-Storage Institute. I
have worked in collaboration with the University of Leicester on novel
anti-windup methods which have been successfully applied to hard disk drive
servo systems to allow for faster seek-settling time using secondary actuators
in hard disk servos. I am also interested in intelligent adaptive neural
network control approaches.
Recently, significant research
effort has been directed towards important industrial issues of networked control systems.
I am leading the Nonlinear Robotics Control Group (NRCG) at the Bristol Robotics Laboratory.
Novel intelligent and robust
control approaches are being applied to probe-microscopes which require nano-precision.
I am an Associate editor of the International Journal of Social Robotics and a Technical Editor
of the IEEE/ASME
Transactions on Mechatronics.
Link
to all Publications (Journal, Conference Papers, Book Chapters; chronological
order; excluding those which are in print)
Projects
High Precision Control Approaches for Bristol’s Probe
Microscopes
Advanced control and estimation algorithms for the transverse dynamic atomic
force microscope: Observing the dynamic behaviour and interactions
of single biomolecules is a long-standing goal to facilitate bio-medical
research. Standard practice is to use one of several scanning probe microscopes
(SPMs), principally atomic force microscopy (AFM). While AFMs can provide
sub-molecular resolution of biomolecules under physiological conditions (cf.
electron microscopy which uses a vacuum) there are two significant
disadvantages of AFMs still to be overcome.- slow imaging rates: A typical
256x256 pixel image takes 60 seconds to produce.- excessive interaction forces
during imaging: A significant challenge to imaging biomolecular interactions is
that the forces typically present between the probe and the sample disturb or
even damage the biomolecules.To counter these issues, we will combine the
latest advances in control theory with the novel SPM instrumentation, currently
in development in Bristol, to produce a new scanning probe microscope capable of imaging these
fragile samples without damaging them.
This project is in
collaboration with Professor Mervyn Miles (University of Bristol, Physics, see example publication), Professor Stuart C. Burgess
(University of Bristol, see example
publication), Professor
Christopher Edwards (University of Exeter, see example publ), where I have the project lead.
Human(oid) control approaches
for the Bristol Robot
The BRL humanoid robot torso is a multiple-redundant
actuation system of impressive proportions. It is a heavily distributed system
with sensors, actuators and micro-processor system communicating with each
other over a Controller Area Network (CAN) interface. Each actuator, from
finger-digit to shoulder requires to be controlled to create an overall
human(oid) movement pattern. All this is to be brought to bear on
'active-touch' finger-tip investigations of object surface shape and texture.
This research project has been ongoing since October
2007, considering the PhD-research of 5 PhD-students: Dr
This project is carried out at the Bristol Robotics
Laboratory (BRL, http://www.brl.ac.uk/), a collaborative research partnership funded by the
University of
PhD-student
project in the press!! Web / Softcopy / ANDy - Anthropomorphic natural dynamics
Link to Human-Robot Interaction Movie integrating some of the techniques above
Link to my research group on nonlinear control in robotics
Networked Control Systems (see poster)
In a
Networked Control System (NCS), sensors and actuators are connected to a
feedback controller through a shared communication medium which inevitably
limits the amount of communication supported by the NCS, introduces delays and
may become nondeterministic. On the other hand, NCSs increase modularity,
flexibility and allow quick and easy maintenance at low cost. They are
essential to automotive industry, avionic systems, robots and automated manufacturing systems to reduce
hardwiring and costs of installation and implementation and to increase safety.
Significant theoretical problems are being solved in collaboration with
industry to allow for safe and reliable integrated control dynamics. This
project is in close collaboration with various industrial companies, the Royal
Society and the Beijing Institute of Technology.
Dr. Stefano Longo, received the IET 2011 Control PhD Award
for his work on "Optimal and Robust Scheduling for Networked Control
Systems"
Book: Optimal and Robust Scheduling for Networked Control Systems:
Longo, S. , Su, T. , Herrmann, G. & Barber, P. 19-Apr-2013 CRC Press,
Taylor & Francis. 280 p. (Control Series).
Parameter Estimation in Vehicular Systems
In collaboration with engineers from Jaguar Land Rover (e.g. Dr Phil
Barber), methods for real-time parameter estimation are being developed. Other
close collaborators are from Beijing
Institute of Technology (Dr Jing Na and Professor
Dynamic Gain Scheduling
A controller
designed for linearizations at various trim/operating points of a nonlinear
system using linear approaches is not necessarily well-performing or stable
once scheduled with a state to retain the scheduled control law design close to
the current operating point. Dynamic gain scheduling (DGS) is a technique aimed
to resolve this controller scheduling issue for rapidly changing dynamics and
states. It
entails scheduling the control law gains with a fast varying state variable
rather than with a slowly varying state. It has been applied to aircraft system
models successfully in a single-input-single output fashion, allowing also for
nested loops. The aim of this work is to extend dynamic gain scheduling to
general multi-variable nonlinear control systems. This work is carried out in
close collaboration with Dr. Mark Lowenberg and several collaborators from NUDT,
Constrained control methods
with recent applications to Substructuring:
A significant body of research has been obtained on the
problem of constrained control systems considering non-linear constraints at
the input and at the output of a plant. In particular, override and anti-windup
compensation methods where considered in a research collaboration with Dr. Matthew Turner and Professor
Current
PhD-Students
Mr.
Mr.
Mr. Nasiruddin Mahyuddin
Other Current
Postgraduate Students/Collaborators
Mrs.
Mrs. Wei Wei Yang, currently at NUDT, China (common supervision with Dr. Mark Lowenberg and Professor Xiaoqian Chen)
Current
Post-Doctoral Researcher
Dr. Said Khan, link to personal website,
link to BRL,
works on the transverse dynamic atomic
force microscope project
Former
PhD-Students advised at the University of
Bristol
Dr. Jamaluddin Jalani
Dr. Said Khan, link to personal website; link to Human-Robot Interaction movie (supervised together with Dr.
Dr. Nadjib Hammoudi, University of Bristol, (Supervisor Dr. Mark Lowenberg; co-advisory support, collaboration on
dynamic gain scheduling)
Dr. Stefano Longo, link to personal website@Cranfield, link to personal website@Imperial, link to poster
IET 2011 Control PhD Award for his work on "Optimal
and Robust Scheduling for Networked Control Systems"
Dr Jing Na
Dr.
Former and
Current Postdoctorate Visitors
Dr. Li Jian, visiting
from NUDT, China, November 2010-October 2011
Dr Jing Na & Professor
Link
to Group Photo
Some
Recent and Current Grants:
2012-2015 MYOROBOTICS A framework for
musculoskeletal robot development
(EU-FP7, Project Reference: 288219) Co-Investigator
Jaguar Landrover funded
PhD-studentship, Principal Investigator
2011 Nov-2014 Oct Robustness and adaptivity: advanced
control and estimation algorithms for the transverse dynamic atomic force
microscope, EPSRC (Ref.: EP/I034882/1+EP/I034831/1) Principal Investigator and Project lead on both projects
2010 Oct-2011 Sep Optimisation of nonlinear Networked
Control Systems for advanced Network Scheduling, Jaguar & Landrover, Principal
Investigator
2010 Apr-2012 Apr Sensor-Reduced Adaptive Observation and
Control in Vehicular Systems – International Joint Project – NSFC (China) Royal Society Research Grants (Ref.:
RG2474 / JP090823) Principal
Investigator
2008 Apr-2009 Apr A hardware in the loop tool for control
optimized communication in distributed control Royal
Society Research Grants (Ref.: RK6923) Principal Investigator
Overall Value as PI: £ 747,000
Total: £ 3,272,200
Conferences:
General Chair of FIRA-RoboWorld Cup and FIRA-Roboworld Congress together with TAROS-Conference
in Bristol in 2012
General Chair of International Conference on Social Robotics in Bristol in
2013
Co-Authored
Books:
Optimal and Robust Scheduling for Networked Control Systems: Longo, S. , Su, T. , Herrmann, G. & Barber, P.
19-Apr-2013 CRC Press, Taylor & Francis. 280 p. (Control Series).
Edited Books:
Advances in Autonomous Robotics: Joint Proceedings of the 13th Annual
TAROS Conference and the 15th Annual FIRA RoboWorld Congress, Herrmann, G. , Studley, M. , Conn, A. T. , Melhuish,
C. R. , Witkowski, M. , Kim, J-H. & Vadakkepat, P. 2012 Springer-Verlag,
Berlin Heidelberg. 466 p. (Lecture Notes in Computer Science, Lecture Notes in
Artificial Intelligence).
Teaching –
Selection of 3rd Year projects
|
|
link to poster
link to poster, movie 1 & 2
link to poster
link to poster
link to poster
link to poster
link to poster
link to poster, movie
link to poster
link to poster
link to poster
link to poster
link to poster
link to poster
link to poster
|
Teaching - 4th year project
|
|
link to poster, paper
link to poster, paper
link to poster, movie
link to poster, Website
|
,