机器人移动控制

Department of Cybernetics, University of Reading, Whiteknights, Reading RG6 6AY, UK E-mail: k.warwick@ E-mail: i.c.b.goodhew@ *Corresponding author
E-mail: b.d.hutt@
Abstract: In this paper, the discussion is focused on the concept of a personal robot system, which is capable of tracking and following a human operator. A prototype robot has been designed and constructed to function externally within a human-centric environment, and this is introduced. The main features of its operation are described and some specific problem areas, due to the nature of the robot, are considered. In particular the robot’s method of tracking is given in detail, initially by considering the realistic options available before the final method was selected. Some important features of the robot’s construction are outlined, again with reference to alternatives available and reasons for the final selection. The method of tracking control employed by the robot thus far is discussed and an indication is given of future possible procedures, which could be tried. Finally, some experimental results are given, with a particular focus on the robot’s head tracking performance. Keywords: personal robots; autonomous robots; ultrasonic sensors; target tracking; PID control; robot head. Reference to this paper should be made as follows: Goodhew, I.C.B., Hutt, B.D. and Warwick, K. (2006) ‘Control and experimentation of a personal robot tracking system’, Int. J. Modelling, Identification and Control, Vol. 1, No. 1, pp.4–12. Biographical notes: Iain Goodhew has graduated with a degree in electronic and electrical engineering in 1992 from the University of Leeds and is currently employed as a Senior Research Fellow in the School of Systems Engineering, the University of Reading. His main areas of research include mobile autonomous robots, global positioning systems, smart sensors, intelligent systems, wireless networking and ambient intelligence. While undertaking research, he also enjoys an active role in public communication of science, helping to raise the profile of robotics and artificial intelligence to the general public. Benjamin Hutt has been a researcher in the Department of Cybernetics at the University of Reading since 1999. He was awarded his PhD for his work on novel evolutionary algorithms applied to the design of neural networks used for the control of robotic systems. Before obtaining his PhD he gained a first-class honours degree from the University of Cybernetics and Control Engineering. His long-term research interests focus on the application of modern machine learning techniques to the control of robotic systems, and also include genetic algorithms, evolutionary robotics, biologically plausible neural networks, machine learning, artificial life and artificial intelligence. Kevin Warwick is a Professor of Cybernetics at the University of Reading, where he carries out research in artificial intelligence, control, robotics and biomedical engineering. He is also Director of University KTP Centre, which links the university with small-to-medium enterprises and raises over £2 million each year in research income for the university. He obtained his first degree at Aston University, followed by a PhD and a Research Post at Imperial College, London. He subsequently held positions at Oxford, Newcastle and Warwick Universities before being offered the Chair at Reading. He has been awarded higher doctorates (DScs) both by Imperial College and the Czech Academy of Sciences, Prague. He has been presented with The Future of Health Technology Award from MIT (USA), has been made an Honorary Member of the Academy of Sciences, St. Petersburg and received The IEE Achievement Medal in 2004. In 2000, he presented the Royal Institution Christmas Lectures.
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Int. J. Modelling, Identification and Control, Vol. 1, No. 1, 2006

Control and experimentation of a personal robot tracking system I.C.B. Goodhew, B.D. Hutt and K. Warwick*
Copyright © 2006 Inderscience Enterprises Ltd.
immediate and responsive impact from the technology around it (Cochrane, 2004). A key aspect of this, and one of rising criticality, is the apparently seamless, adaptive interface required between human individuals and the technology (Brooks, 2002; Gasson et al., 2002;
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Introduction
In recent years, the field of domestic robotics has increased rapidly in importance, particularly in terms of research and development, as an ageing society demands more of an
Control and experimentation of a personal robot tracking system Menzel and D’Aluisio, 2001). In light of this, the study described here considers in detail the design and control of a mobile, (relatively) autonomous robot, which has the ability to follow a human individual at potentially high speeds, in an external or internal environment, yet which retains a high degree of accuracy in its tracking characteristics. Essentially, we consider here a personal robot. Clearly as such personal robots are developed, the control aspects involved play a vital role. Not only are there the more obvious low-level control decisions normally associated with mobile robots but, as the robot is required to operate in a world designed primarily for humans, controller features also need to take into account (what the robot may perceive through its complex sensory system as) hazardous conditions and safety dependant operations in terms of not damaging (either through design or inadvertently) objects, such as humans, around the robot. At the same time a major consideration must be the concern that what may be extremely easy for a human to do, may not be so trivial for the robot – if for no other reason than its physical presence. The potential application range for personal robots is immense. Even restricting consideration to present day environments opens up a variety of possibilities such as a shopping helper, a golf caddy or an airport porter. It is expected, however, that once such robots become readily available this application range will develop nicely along with further requirements in terms of human–robot interaction and the accuracy of robot positioning. But the introduction of new robot devices such as this throws up new and exciting challenges for technological innovation. As an example, requiring a robot to follow an individual human at a respectable (perhaps steady) distance does not involve a simple target-tracking exercise, rather the distance of separation depends on the relative and absolute velocities of the human, a past history and future prediction of human intent, involving possible acceleration and deceleration and spatial and temporal awareness. On top of this, the general environmental conditions surrounding the robot, including the unpredictable behaviour of both other humans and weather and surface consistency, make the problem complex and multiobjective. Surprisingly, directly related research in this area has not, to this point, been extensive, most likely due to the difficult nature of the problem. Nevertheless in terms of robot tracking using ultrasonic sensory input, some very useful results (Kuang and Morris, 1999a,b, 2000) have been obtained, also general coverage of autonomous robot exploration in new environments can be found (e.g. Anderson and Cheng, 2003). Perhaps by far the most extensive coverage in relation to the problems faced here can be found in regard to different approaches to path planning (examples being Ge and Cui, 2000; Wu et al., 1997; Zhang et al., 2004). This is though of relatively little direct value in our own studies, apart from the possible use of rerouting procedures when unexpected obstacles are encountered. In general the actual target for the robot is, in our case, a straightforward one – follow that human!