Page 31 - Electric Drives and Electromechanical Systems

Chapter 1 Electromechanical systems 23

FIG. 1.11 An artist’s impression of the rover Spirit on the surface of Mars. The robotic arm used to position scientific
instruments and the moveable camera mast are clearly visible. Credit: Image reproduced courtesy of NASA.

While many mobile robots operate independently, either autonomously or as a
teleoperated system, swarm robotics is an approach that involves coordination of large
numbers of robots and are used to study how a large number of relatively simple
physically embodied agents can be designed such that a desired collective behaviour
emerges from the local interactions among agents and between the agents and the
environment (Bayindir and Sahin, 2007). Swarm robotics has its origins in the study of
social insects where they work collaboratively, to achieve tasks that could not be ach-
ieved individually, for example, a colony of ants can cross wide void or pull leaf edges
together to form a nest; bees and wasps build nests and termites build nests with
remarkable heights and complexity (Bonabeau et al., 1999). With these characteristics
(Beni, 2005), swarm robotic systems can be differentiated from other multi-robot sys-
tems by having the following key aspects: autonomous mobility, limited sensing and
communication abilities, simplicity, decentralised control or coordination mechanism,
homogeneity and scalability, Fig. 1.12. They also have to aim the following advantages
(Doriigo et al., 2013): robustness where the system should be able to continue to operate
when there are failures in the individuals or disturbances in the environment, flexibility
where the system should be able to adapt to the dynamics of the number of robots and
the change of tasks, and scalability where the system should be able to operate with
different numbers of robots.

1.3.4 Walking robots

While many mobile robots are wheeled, there is increasing interest in legged systems,
partly due to increased research activity in the field of biologically inspired robotics and
biomechanical systems. A walking robot are more versatile than wheeled robots and can
traverse many different terrains, however these advantages require increased complexity
and power consumption. Many legged designs have been realised, ranging from military
logistic carriers to small replicas of insects. These robots, termed biometric robots,