David A. Bradley

The Development, Control and Operation of an Autonomous Robotic Excavator

The excavation of foundations, general earthworks and earth removal tasks are activities which involve the machine operator in a series of repetitive operations, suggesting opportunities for the automation through the introduction of robotic technologies with subsequent improvements in machine utilisation and throughput. The automation of the earth removal process is also likely to provide a number of other benefits such as a reduced dependence on operator skills and a lower operator work load, both of which might be expected to contribute to improvements in quality and, in particular, the removal of the need for a local operator when working in hazardous environments.The Lancaster University Computerised Intelligent Excavator or LUCIE has demonstrated the achievement of automated and robotic excavation through the implementation of an integrated, real-time, artificial intelligence based control system utilising a novel form of motion control strategy for movement of the excavator bucket through ground. Having its origins in the systematic observation of a range of machine operators of differing levels of expertise, the control strategy as evolved enables the autonomous excavation of a high quality rectangular trench in a wide variety of types and conditions of ground and the autonomous removal of obstacles such as boulders along the line of that trench.The paper considers the development of the LUCIE programme since its inception and sets out in terms of the machine kinematics the evolution and development of the real-time control strategy from an implementation on a one-fifth scale model of a back-hoe arm to a full working system on a JCB801 360° tracked excavator.

Reproducing oscillatory behaviour of a hydroelectric power station by computer simulation

Abstract This paper describes a complex simulation of a pumped-storage hydroelectric power station. Dinorwig power stations fast response is essential for controlling the electricity supply frequency on the national grid in Great Britain. The paper describes the stations key physical features and it is shown that the plant is nonlinear, multivariable and time-varying. The details of a Simulink® model, which is valid over a wide range of operating conditions, are presented. The improved understanding of the stations dynamic characteristics is illustrated by using the simulation to investigate an incident of oscillatory behaviour in its power output.

Do community alarm users want telecare

Previous surveys have suggested that community alarm users are in general satisfied with the service provided. However, there is also evidence that users would like additional options that could be provided by a telecare system. Inner-city users of community alarms were consulted about their current systems and the extension of these to incorporate telecare options. The users lived in 160 homes in three multistorey apartment blocks. The average age of the 176 users surveyed was 76 years. Seventy-seven per cent of users were interested in automatic fall detection, 68% in lifestyle monitoring, 57% in telemedicine and 46% in videoconferencing. Nineteen of those interviewed (11%) did not want any of the suggested enhancements. The survey showed that elderly people are not technophobes, since 58% possessed either a microwave oven or a video-recorder, and also showed that the majority were prepared to accept new technologies that would support their independence.

Design, modelling, simulation and integration of cyber physical systems

Presentation of a systematic classification of systems and new CPS paradigms.Analyses of literature conducted across a range of different perspectives.A systematic review of CPS-design literature was carried out, with an emphasis on the design, modelling, simulation and integration of CPS.An architectural and behavioural paradigm for CPS.Compilation of different viewpoints referring to applications at different levels of granularity. The main drivers for the development and evolution of Cyber Physical Systems (CPS) are the reduction of development costs and time along with the enhancement of the designed products. The aim of this survey paper is to provide an overview of different types of system and the associated transition process from mechatronics to CPS and cloud-based (IoT) systems. It will further consider the requirement that methodologies for CPS-design should be part of a multi-disciplinary development process within which designers should focus not only on the separate physical and computational components, but also on their integration and interaction. Challenges related to CPS-design are therefore considered in the paper from the perspectives of the physical processes, computation and integration respectively. Illustrative case studies are selected from different system levels starting with the description of the overlaying concept of Cyber Physical Production Systems (CPPSs). The analysis and evaluation of the specific properties of a sub-system using a condition monitoring system, important for the maintenance purposes, is then given for a wind turbine.

Future systems for remote health care

As the number of elderly people in society increases, the use of technology to support the care system is being examined. However, there is no agreed model of a technology-based health-care system that fully integrates the technical and social aspects to meet the needs of both clients and care providers. This paper examines a possible model from the perspective of both the client and the service provider, and estimates the costs, and hence the potential savings, associated with the introduction of a health-care system based on this model. Cost data are presented in the context of an installation as might be anticipated within a city such as Birmingham, UK. Installation costs of an advanced telecare system would be higher than the set-up costs of conventional systems. Expected savings in control centre costs and emergency services costs would be small. However, a reduction in the average annual length of hospital stay by one day and a reduction in the proportion of elderly people being treated in hospital from 32.4% to 32.0%, directly as a result of the use of advanced telecare, would produce significant savings. A financing scheme with a 5-year or 10-year repayment period would then be financially viable for a 10,000-home advanced telecare system.

Safety and risk issues in using telecare

The increasing adoption of technology to support independent living at home through the extended use of community alarms and, ultimately, second-generation telecare systems poses some safety problems. The implications of any failure of the technology must be addressed in order to provide a safe and reliable care service. The risks of using home-based technology can be assessed by standard techniques under three categories: environmental factors; human factors; and technological factors. A safety classification system for telecare devices is proposed leading to a range of design guidelines which represent good practice. An example of the use of these design principles is a prototype second-generation telecare system, MIDAS, which is currently undergoing trials. In order to reduce the risks associated with device failure, the system incorporates distributed intelligence, built-in self-testing and redundancy. Potentially hazardous situations can therefore be controlled.

Artificial intelligence in the control and operation of construction plant - the autonomous robot excavator.

Abstract The paper describes a significant development in the intelligent automatic control of an adaptive robot. The particular application concerns the problem of autonomous excavation, and the subtlety of the approach lies in the fact that the machine can cope with highly variable ground conditions and even underground obstructions without human interference. The nature of the excavation problem is first described. The development of a working fifth-scale model of an excavator—LUCIE—the Lancaster University Computerised Intelligent Excavator. The hardware systems are briefly described, but the main emphasis of the paper concerns the method by which the AI technique of a rule-based “production system” is used to control the tip of the excavator bucket. The software is in two distinct parts; a low-level velocity controller and a high level “activities manager” which contains the rules. It is concluded that the best way to achieve subtle, human-like, automatic control is by means of simple rules and heuristics, and not complex control algorithms. Finally the paper reports field trials of LUCIE, and goes on to describe proposed future developments.

Controlling an intelligent excavator for autonomous digging in difficult ground.

This paper reports on the recent advances made in developing an autonomous robot excavator. Previous work on a fifth-scale model was reported at earlier symposia, but the technology has now been transferred to a real excavator LUCIE Lancaster University Computerised Intelligent Excavator. The paper concentrates on the architecture of the software control which enables the machine to modify its behaviour to cope with highly varying ground conditions. A single powerful processor controls the low-level motion of the excavator arm, as well as high level tactical and strategic behaviour. An A.I. rule-based approach has been adopted for high-level functions. Successful field trials are reported.

What is Mechatronics and Why Teach it

Despite a world-wide interest in mechatronics education, there is no clear and consistent understanding of what mechatronics is, nor how, and at what level, it should be taught. The key challenge for mechatronics course designers is seen as that of ensuring an appropriate balance between depth and breadth while providing opportunities to enable students to practise integration. The paper discusses this in relation to a number of mechatronic themes. Factors influencing the design, structure and content of a mechatronics programme are discussed and suggestions made as to the possible core content of such a programme.

A standard method for specifying the response of hydroelectric plant in frequency-control mode

Abstract The paper proposes a specification for the transient and steady-state responses of a hydroelectric power station operating in frequency-control mode. It can be used during design, testing and commissioning as well as forming the basis for contractual agreement on performance during normal operation. The specification gives a generic definition of how the electrical power should respond to step, ramp and random changes in frequency. The rationale for the proposed specification is discussed. A prototype transfer function is proposed as an aid to formulating a step response specification. The length of record required during random testing is discussed. The use of the specification is illustrated by considering the response of the Dinorwig pumped-storage hydroelectric station.