M. Farsi

Newcastle University, Newcastle-on-Tyne, England, United Kingdom

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Publications (50)14.95 Total impact

  • Source
    K.J. Zachariah · John W. Finch · Mohammad Farsi
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    ABSTRACT: Results from a collaborative research and development program devoted to turbine generator (TG) control are described. Digital self-tuning excitation controllers were designed for a generator during the initial phase of the project, with the design subsequently extended to cover multivariable control of the TG, which is the topic of this paper. Simulations and tests on a laboratory-scale machine have been accomplished successfully and a prototype multivariable self-tuning controller has been built. A set of typical results is given, covering responses to fault conditions of the power system. The multivariable self-tuning controller is shown to have good potential for commercial use for the TG.
    Full-text · Article · Jul 2009 · IEEE Transactions on Energy Conversion
  • Source
    J.W. Finch · K.J. Zachariah · M. Farsi
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    ABSTRACT: Results are presented from new self-tuning controllers for turbogenerators. Simulations and micromachine tests have been successful, with a prototype self-tuning controller being manufactured. This is intended as a direct replacement for a conventional AVR, so a more conventional fixed parameter controller is also considered, serving as a comparison of performance. Typical results are given for normal set point changes and fault dynamics. An additional modification which could be introduced if a power signal were available, a form of power system stabiliser, is also covered. These new controllers are shown to have good potential for practical application
    Full-text · Article · Oct 1999 · IEEE Transactions on Energy Conversion
  • M. Farsi · K. Ratcliff · M. Barbosa
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    ABSTRACT: The controller area network is a well-established networking system specifically designed with real-time requirements in mind. Developed in the 1980s by Robert Bosch, its ease of use and low cost has led to its wide adoption throughout the automotive and automation industries. However, for the beginner using CAN may seem somewhat bewildering. This article goes some way into explaining how CAN is used both at the hardware and the software levels
    No preview · Article · Sep 1999 · Computing and Control Engineering
  • M. Farsi · K. Ratcliff · M. Barbosa
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    ABSTRACT: CANopen is a truly open protocol that has not been developed by one company alone. Several working groups, consisting of many different device manufacturers and end-users, have co-operated to produce the CANopen standards, now under the supervision of the CAN in Automation organisation. CANopen has been produced as a result of EU funding. This article gives an overview of some of the fundamental concepts of CANopen communication and of CANopen implementation.
    No preview · Article · Sep 1999 · Computing and Control Engineering
  • M. Farsi · K. Ratcliff
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    ABSTRACT: Fieldbus systems have become an important factor in communication between industrial control devices. In this paper, the authors report how, since originating as an Esprit project, CANopen has evolved to become an increasingly popular real-time networking system
    No preview · Article · Oct 1998 · IEE Review
  • M. Farsi · K. Ratcliff · J. Doran · M. Crocker
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    ABSTRACT: CANopen based on the popular controller area network (CAN) represents an ideal networking system for distributed control systems and overcomes the limitations inherent in conventional master/slave and peer-to-peer networks. The paper discusses the benefits of using CANopen and describes its implementation on a distributed motion control system
    No preview · Conference Paper · Apr 1998
  • M. Farsi · K.Z. Karam · A.J. Moon
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    ABSTRACT: The paper presents a study of a flexible structure that may be applied to a robotic head in building services. The equations that govern the deflections of a beam are well studied. Essentially they are a series of differential equations, which can include nonlinear terms. The beam is assumed to be “thin”: that is its thickness (in the direction of loading) is small in comparison to its length. The two properties of the beam that are important in these equations are: the value of the Young's Modulus of Elasticity for the material E, and the Second Moment of Area of the cross section of the beam (sectioned perpendicular to its length). The second moment of area is a measure of how the geometry of the beam resists bending
    No preview · Conference Paper · Jan 1998
  • M. Farsi · K. Ratcliff
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    ABSTRACT: The Controller Area Network (CAN) provides the user with many powerful features, including multi-master functionality and the ability to broadcast/multicast telegrams. The low cost of CAN components, high data reliability and short reaction times, together with the huge user base will ensure that the future of CAN is safe for an extremely long time to come. However, to ensure inter-operability between CAN components, several higher-layer protocols have been developed to allow devices to communicate in a standardised manner. CANopen is one of these protocols and has already seen wide adoption within industry and other sectors, such as building automation and public transport. This paper discusses various aspects of CANopen communication and gives a general overview of some of its powerful features
    No preview · Conference Paper · Nov 1997
  • M. Farsi · K. Ratcliff
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    ABSTRACT: The paper describes an European field bus communication standard developed during ESPRIT IV project 7302 and subsequently has become known as CANopen. CANopen Configure Device and Test (CDT) software has been developed by Newcastle University (UK) to facilitate the configuring and testing of CANopen devices. The CDT is further enhanced to perform conformance testing of I/O devices. To operate the software requires a PC running Windows and a CAN card supporting CANopen. It allows the use of any CANopen compliant object dictionaries to communicate with the device. Any object can be read or written, for both service data and process data communications. Synchronisation messages can be generated automatically, with real time display and control of synchronous data. Full CANopen network management services and life guarding are implemented and there is an object dictionary editing facility
    No preview · Conference Paper · Nov 1997
  • M. Farsi · K. Ratcliff
    [Show abstract] [Hide abstract]
    ABSTRACT: The Controller Area Network or CAN provides the user with many powerful features including multi-master functionality and the ability to broadcast/multicast telegrams. The low cost of CAN components, high data reliability and short reaction times together with its huge user base will ensure future of CAN is safe for an extremely long time to come. However, to ensure inter-operability between CAN components, several higher layer protocols have been developed to allow devices to communicate in a standardised manner. CANopen is one of these protocols and has already seen wide adoption within industry and other sectors such as building automation and public transport. This paper discusses various aspects of CANopen communication and gives a general overview of some of its powerful features
    No preview · Conference Paper · Aug 1997
  • M. Farsi · K.J. Zachariah · J.W. Finch
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    ABSTRACT: Power system stability is one of the most important considerations in turbine generator control. Traditionally, efforts to improve transient performance of a turbine generator have been concentrated only on excitation control. Although a significant enhancement in the system damping can be obtained through excitation control, there are limits to which improvements in the stability limit can be achieved by this means. The use of a power system stabiliser to derive a supplementary stabilising signal which acts through the AVR is also subject to such limits. Since the governor gives a second input, multivariable control can therefore be considered for stability improvement. This is achieved by considering two co-ordinated control loops to optimise the improvement in the stability of the system
    No preview · Conference Paper · May 1997
  • M. Farsi · K.J. Zachariah · J.W. Finch
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    ABSTRACT: The paper describes the design and implementation of a self-tuning automatic voltage regulator (STAVR) based on the generalised predictive controller (GPC). When implementing self-tuning controllers on industrial systems such as turbogenerators it is pertinent to consider several potential problems before a reasonable design can evolve. For example, in actual industrial plants, the quality of the plant signals used for feedback purposes is far from perfect, which may be attributed to sensor noise, sensor lag, aliasing, quantisation error, etc. These issues, along with the robustness, unmodelled dynamics, disturbances, steady-state offsets and nonlinearities, are considered
    No preview · Article · Feb 1997 · IEE Proceedings - Control Theory and Applications
  • J.W. Finch · K.J. Zachariah · M. Farsi
    [Show abstract] [Hide abstract]
    ABSTRACT: Results from a research and development programme devoted to turbogenerator control are described. Digital self-tuning controllers are covered, although fixed parameter controllers have also been considered. Simulations and tests on laboratory scale machines have been accomplished successfully, with a prototype self-tuning controller being manufactured. A set of typical results is given, covering responses to normal set point changes and fault dynamics. These new controllers are shown to have good potential for practical application
    No preview · Article · Oct 1996 · IET Proceedings - Generation Transmission and Distribution
  • M. Farsi · K.J. Zachariah · J.W. Finch
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    ABSTRACT: Concerns the implementation of the GPC self-tuning control on the excitation system of a turbo generator, taking into account several potential problems. The plant signals used for feedback are far from perfect. Although, robustness has received some consideration in self-tuning field, techniques most suitable for the control of excitation problem had to be identified and chosen for implementation. Problems such as unmodelled dynamics, disturbances, steady state offsets and nonlinearities have a considerable effect on the robustness and hence need attention during design. The popular assumption of a persistently exciting plant is generally not true. Hence ways to make the parameter estimator of the self-tuning controller handle those periods during which very little dynamic information about the plant is available, should be carefully considered. Many researchers have attempted to increase the range of applicability of linear self-tuner which include: use of variable forgetting factors for improved adaptivity while also reducing the possibilities of numerical instability; covariance resetting techniques for improved alertness, providing rapid adaptation. Other issues such as cautious least squares estimators, facilitating the input of an element of engineering knowledge, state variable techniques for smoother control via noise rejection and long prediction horizon of the system output have also received attention
    No preview · Conference Paper · Apr 1996
  • M. Farsi · K.Z. Karam · H.H. Abdalla
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    ABSTRACT: A knowledge-based system is used to incorporate the existing heuristics in the control systems domain in order to supervise and choose between a number of control strategies running in parallel in a practical implementation environment. Fuzzy set theory is used to assess the performance constraints of each controller in order to set a platform for the expert system to select the appropriate controller based on qualitative and quantitative measures. The measures include the assessment of the system response using performance criteria. These criteria are composed of energy consumption, output variance and meeting user specifications in terms of overshoot and settling time. Implementation and practical application results are also presented.
    No preview · Article · Apr 1996 · Fuzzy Sets and Systems
  • M. Farsi
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    ABSTRACT: Design and implementation of a low cost flexible production unit for assembly, inspection and other sequential tasks while maintaining an open system architecture is explained. All components of the cell are connected to the production unit controller, a PLC, via the installation bus controller area network (CAN). The design is flexible to accept a number of sensors with different functionality such as pressure, temperature, bar-code readers etc. which may be connected to the bus individually or via an intelligent peripheral device
    No preview · Conference Paper · Jul 1995
  • H.H. Abdalla · K.Z. Karam · M. Farsi
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    ABSTRACT: The purpose of the paper is to present a concept utilising a knowledge-based system approach to a multi-faceted control system. The knowledge based system monitors the performance of a number of parallel running controllers with different control strategies. A decision to make use of the most appropriate controller is made on the basis of primary user specified objectives as well as secondary considerations such as actuator energy, potential robustness and regulation capability
    No preview · Conference Paper · Sep 1994
  • M. Farsi
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    ABSTRACT: The paper describes the design and implementation of low cost flexible production units for assembly, inspection and other sequential tasks while maintaining an open system architecture. Using device profiling all components of the cell are connected to the installation bus. Bus communications are managed by the production unit controller supervising the cell operation. Information are passed to higher layers of automation via an intelligent gateway
    No preview · Conference Paper · Sep 1994
  • M. Farsi · A. Abdulaziz
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    ABSTRACT: The paper deals with self-tuning control of Hammerstein type nonlinear systems that contain linear parameters and a nonlinear quasi-input function of the real input signal. Linear estimation algorithm has been used to estimate the linear parametric part, whilst a neural feedforward net is employed to estimate the remaining nonlinearity. The performance of the controller is illustrated by a hybrid algorithm simulation.
    No preview · Conference Paper · Aug 1994
  • Source
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    ABSTRACT: Window cleaning is a two-stage process; application of cleaning fluid, which is usually achieved by using a wetted applicator and removal of cleaning fluid by a squeegee blade without spillage on to other areas of the facade or previously cleaned areas of glass. This is particularly difficult for example if the window is located on the roof of a building and cleaning is performed from inside by the human window cleaner. Simulation studies were conducted to demonstrate the feasibility of a robot system to act and mimic the human operator; an end effector had to be designed to accommodate different tools such as applicator and squeegee; the pay load for tool handling, sensory feedback requirements; force and compliance control; and finally the cost of the overall system had to be feasible. As a result of the studies it was conceived that the end effector should contain a combined datuming/cleaning head. This arrangement would allow automatic datuming and location of the window pane relative to the robot using a specially designed and constructed compliant head. One advantage of a combined head being the elimination of tool changes between the datuming and wiping operation. A dedicated XYZR robot system was designed which makes use of an Industrial IBM PC connected to a DELTA-7AV systems PMAC card to drive the robot and to: coordinate its actions with those of the OCS roof mounted gantry delivery carrier system.
    Preview · Conference Paper · Aug 1994

Publication Stats

175 Citations
14.95 Total Impact Points

Institutions

  • 1985-1999
    • Newcastle University
      • School of Electrical and Electronic Engineering
      Newcastle-on-Tyne, England, United Kingdom
  • 1984-1998
    • University of Newcastle
      • Department of Electrical Engineering
      Newcastle, New South Wales, Australia
  • 1990
    • The Newcastle upon Tyne Hospitals NHS Foundation Trust
      Newcastle-on-Tyne, England, United Kingdom
  • 1987
    • University of Oxford
      • Department of Engineering Science
      Oxford, ENG, United Kingdom
    • National Technical University of Athens
      Athínai, Attica, Greece