A new approach to classification of devices and its application to classification of in-pipe robots

This paper provides a classification of in-pipe robots or robotic mechanisms in literature with the help of axiomatic design theory (ADT). The existing classification of these designs focuses on either their mobility or contact of the robot with the pipe inner surface. Such classification fails to provide a framework to guide the design of such robots. In this paper, we first propose a new approach to the devices classification and then apply it to the classification of in-pipe robots. This new approach has three features. The first feature is that classification of a device includes the function along with the context of the device. The second feature is that classification of a device starts with classification based on the operating principle of the device. The third feature is that classification of a device based on the complexity of the device especially the coupling property of the device. Classification of a device or system is an important step towards a more rational and systematic analysis and evaluation of the system, which is conducive to design innovation for discovery of new operating principles and new devices. Indeed, the future direction of research on in-pipe robots is discussed in this paper based on the proposed classification of in-pipe robots.