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.
Novel intelligent and robust control approaches are being applied to probe-microscopes which require nano-precision.
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.
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
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
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.
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
Mr. Nasiruddin Mahyuddin
Dr. Wei Wei Yang, NUDT, China (common supervision with Dr. Mark Lowenberg and Professor Xiaoqian Chen)
Dr. Jamaluddin Jalani
Dr. Nadjib Hammoudi, University of Bristol, (Supervisor Dr. Mark Lowenberg; co-advisory support, collaboration on dynamic gain scheduling)
IET 2011 Control PhD Award for his work on "Optimal and Robust Scheduling for Networked Control Systems"
Dr Jing Na, graduated at BIT, China, funding from the Chinese Scholarship Council
Dr. Li Jian, visiting from NUDT, China, November 2010-October 2011
Dr Jing Na & Professor
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
General Chair of International Conference on Social Robotics in Bristol in 2013
System Modelling and Controller Design of an Electric Power Steering System (2007/2008),
Electro Mechanical Design of a Power Assisted Steering System (2007/2008),
Design of an Adaptive Cruise Control System for model vehicle (2008/2009),
Design and Control of a uniaxially moving force feedback joystick for a haptic device (2008/2009),
Design and Control of a uniaxially moving force sensor for a haptic joystick / force sensor couple (2008/2009)
Design And Manufacture a 3-DoF Constrained Link Robotic Arm (2009/2010)
Mathematical Modelling and Control of a Lightweight Robotic Arm (2009/2010)
Design and Manufacture of a Flywheel Driving System for an Electrically Powered Vehicle (2009/2010)
Investigation into traction control and slip analysis of a longitudinal speed controlled car (2009/2010)
Design and building of Nano Positioning Stage (2009/2010)
Biped Humanoid Gait Control For The FIRA Robot Games (2010/2011)
Design of a Humanoid Robot (2010/2011)
The Dynamics and Control of a Humanoid Robot Arm (2010/2011)
Design, Manufacture & Optimisation of a Robotic Arm & End Effector for the FIRA Robotic Games (2010/2011)
An Investigation into Alternative Control Methods for a Robotic Arm (2010/2011)
link to poster, movie 1 & 2
Design Of A Longitudinal Speed Controlled Car With Gradient And Weight Estimation, (2008/2009),
Design and Manufacture of an Interactive Three-Dimensional Swept Volumetric Display (2009/2010),
Design and Testing of a Torque Vectoring Controlled Vehicle (2010/2011)
Construction and Development of a Humanoid Robot (2011/2012)