9R18. Strategies for Collective Minimalist Mobile Robots. Engineering Research Series No 6. - C Melhuish (Fac of Eng, Univ of the West of England, UK). Professional Eng Publ, Suffolk, UK. 2001. 222 pp. ISBN 1-86058-318-0. $150.00.

Reviewed by JE Cochran (Dept of Aerospace Eng, Auburn Univ, 211 Aerospace Eng Bldg, Auburn AL 36849-5338).

A swarm of bees has a collective intelligence different from, and in many ways, superior to that of each of its members. Working together, wasps construct nests that a single wasp probably cannot even envision. Individual ants forage for food, but the ant colony brings in the harvest, using several modes of communication. Can the techniques and principles used by these insects help scientists and engineers design simple, or minimalist robots that are less prone to disabling malfunctions because they are so simple. Can such robots in large swarms collectively accomplish complex tasks even if a large number of the individual members of the swarm are disabled during the process? In short, “[Is it] possible to construct a collection of simple mobile robots that can reproducibly perform tasks that transcend the capability of the individual?” Addressing this question is the purpose of the author of this monograph, which is Volume 6 in the publisher ’s Engineering Research Series. Several other volumes in this series focus on the use of characteristics of animals, especially insects, to design robots. The underlying idea seems to be that through the process of evolution, nature has provided solutions that are collectively minimal (optimal for large numbers of actors) and that these solutions “[potentially] can provide the advantages of robustness, redundancy, scalability, emergent self-organization…”

According to Webster, minimalist means “one who favors restricting…the achievement of a set of goals to a minimum.” Minimalistic action, decentralized control, self-organization, redundancy, emergence, and stigmergy (indirect communication) are characteristics that the author proposes for developing robots. In Chapter 2, he describes how these characteristics provide explanations for the application of these characteristics as principles. Minimalistic robots necessarily have minimal computational, communication, and sensory capabilities (Ch 3). Simulation plays a large role in the development of algorithms and experiments are used to test the abilities of actual minimalistic robots to operate under non-ideal environmental conditions. The robots in a swarm are tasked to home on a beacon. A gradient type algorithm based on the sensed proximity of the beacon is used for control. In Chapter 4, some of the robots are secondary signal generators. As a robot so endowed gets closer to the beacon, the signal it emits grows stronger. A number of robots very close to the beacon collectively make an effectively larger beacon. Homing on the beacon is improved, but the robots are less minimal.

Another assault on the minimality is made in Chapter 5 by adding to the communication abilities of the robots. However, the additional capability is relatively simple and allows the robots to form work gangs.

Indirect communication is introduced in Chapter 6, and in Chapters 6–8, real robots are used to carry out experiments. The ideas of blind bulldozing with minimalistic sorting and segregation are extended in Chapter 8. Conclusions are drawn in Chapter 9.

The author’s study does demonstrate “that it is possible to implement collective minimalist strategies, based on biological principles, on simulated and real robots.” His minimalist locomotion strategies and ideas of secondary swarming, control of work gangs, and stigmergic mechanisms should be of interest to investigators in the robotics field.

Libraries at universities and colleges with engineering and/or industrial design programs should consider purchasing the collection of monographs in the Engineering Research Series. Individuals working in the robotics area, especially those using biological models to develop algorithms, should also be interested in Strategies for Collective Minimalist Mobile Robots.