J.O. Gray

PLANNING AND BEHAVIOURS - A HYBRID ARCHITECTURE FOR MOBILE ROBOTS

Abstract The paper discusses a hybrid predicitve-behavioural architecture being developed by the Mobile Robotics Research Group at Salford University for cooperating mobile robots. The test bed used for experiments is described, the multi-agent framework for the hybrid architecture is explained and the behavioural and predictive components are presented. Issues of division of responsibility, communication nd the relationship between the two styles of architecture are described.

Frequency Domain Functionals for the Assessment of Interaction Effects in Multivariable Feedback Systems

Abstract This paper is concerned with a numerical method of accurately determining three interaction functionals in the frequency domain. These functionals have a useful graphical interpretation which enable interaction effects in any loop to be determined qualitatively and act as an aid in any subsequent design procedure. An example is given of the computation of these functionals for a feedback configuration and the results are compared with alternative methods of specifying interactions in the frequency domain.

A Formal Computer Based Design Environment for Aircraft Engine Control Systems

Abstract Manufacturers of modern aerospace systems often use formalistic design methods, frequently of a modular and hierarchical nature to specify the model of the system in question. This often takes the form of a graphical representation, and hence the development of a graphical interface to the variety of software tools used would enhance the productivity and consistency of such work. In this paper a graphical operating system (ARGOS) is used as an interface for the time response package TSIM in the investigation of jet engine control system performance.

The Classification of Sample Defects in Electromagnetic Non Destructive Testing

Abstract An adaptive estimation technique is proposed for the automatic classification of defects in metal tubes during a high speed eddy current inspection process. The technique makes use of a bank of Kalman filters with each filter being matched to a specific hypothetical defect and the residual behaviour of each filter monitored via a simple nonlinear calculation to determine a best fit to actual measurements from the inspection coils. A lumped parameter model of the eddy current test phenomenon is presented which is amenable to state variable presentation and which matches an exact system performance based on solutions to the classical Helmholtz equations. This model has a unique property of accurately representing specific fault conditions within a sample volume and also enables a rigorous analytical investigation to be undertaken of the effects of a range of excitation waveforms of arbitrary complexity.

A POWERED HIP ORTHOSIS - AN INTEGRATED SYSTEMS APPROACH

Abstract This paper describes a project that applies intelligent control to an electrically powered orthosis to assist the gait restoration of paraplegic subjects. This device uses a modified Reciprocating Gait Orthosis to which are attached two electrical actuators providing power at the hip joints. Control of the device will be achieved using an adaptive control scheme implemented upon a small network of microcontrollers integrated with the modified device, where these handle the motor control, coordination and user/patient input. The principal design features of the powered orthosis are presented in detail and anticipated future control requirements are discussed.

Mobile Path Planning: A Hierarchical Approach

Abstract This paper presents the approach taken by the UK National Advanced Robotics Research Centre to develop an advanced mobile vehicle. The method of fusing the vehicles range sensor data into a mapof the surrounding environment in real-time is discussed. This map is dynamically updated as the vehicle moves and fonns the data used by the hierarchical path planner to control the movement of the vehicle

Economic Optimisation of Gas Networks

Abstract Efficient management of the natural gas grids involve a complex optimisation task to resolve conflicting operational objectives to maintain cost of effective transmission services all year round. Typical computer software aids for this task divide the optimisation into several parts which are treated separately before the results are brought together for expert assessment and decision. A single, integrated suite of programs to address all aspects of the optimisation task would have obvious attractions. In this paper we describe HERO, a dynamic non-cooperative games framework for such development.

Information Management Requirements of Integrated Cacsd Environments - a Forward Look

Abstract CACSD has been the subject of much discussion for at least twenty years; beginning with the use of computers as numerical processors to the present development of general purpose graphical interactive CACSD environment Yet, in spite of the great strides made in the quantity and availability of CACSD appications, the control communitys ability to integrate applications with the overall design process is still very undeveloped. Engineering support is more effective if the design environrnent is integrated and each tool works within an organisational context. This paper addresses the issues involved in information managetment in an integrated CACSD environment. The need for integration is etnphasised, various ditnensions of integration in an engineering design environment are defined and a repository-based unifying framework is proposed as a preferred direction for CACSD developrnent.

The Computer Aided Design of Nonlinear Feedback Systems

Abstract A range of methodologies which are currently used in the development of computer aided control system design procedures for nonlinear systems is surveyed and the facilities available in a number of mature packages are outlined. Future trends are indicated which include the evolution of comprehensive integrated packages and the use of expert systems to assist the user.

Graphical Data Interpreter for Control System Computer Aided Design Environment

Abstract There is a current trend to develop anthropo-morphic user interfaces for computer aided control system design packages in order to utilise graphical or scratchpad methods for dynamical data input. The advantage lies in the ability to input the manipulate system data in a familiar domain without undue requirements for re arrangement or abstraction. The procedures are suitable for modern graphical work stations. Current generic work at Salford is described and future trends outlined. A video film is available to support the presentation.