17 Biologically Inspired Robots

The idea of building machines that emulate features of animals that we see around us has a long history. Leonardo da Vinci’s drawings of machines that fly like birds are one familiar example. It was not until the middle of the 19th century, however, that scientific knowledge had advanced enough for realistic and realizable plans for such machines to be made (Raibert, 1986) and truly successful attempts to make walking or crawling robots proliferated only in the last few decades of the 20th century (e.g., Raibert, 1990). In the sense that any machine that swims, flies, or walks can be said to be inspired by fish, birds, or legged animals, every mobile robot that employs one of these means of locomotion can be said to be biologically inspired. However, the term biologically inspired and the current concept of biologically inspired robotics originated in the last few decades of the 20th century. The first use of the phrase in the title of a journal article appears to have been by Beer et al. (1997). In this article, Beer and his colleagues make a distinction between merely emulating some general feature of an animal like legs or wings and a more considered approach in which specific structural or functional elements of particular animals is emulated in hardware or software. Because animals are both structurally and functionally complex, it is obvious that a complete reproduction of any animal in hardware and software is not possible. Hence, there is some debate among bioroboticists about where to draw the line. Some researchers take the approach of Ritzmann and colleagues (Ritzmann et al., 2000), who suggested that as many features of an animal should be incorporated into a robot as possible, even if the functional advantage of any particular feature is not clear (e.g., Cham et al., 2004; Dillmann et al., 2007). In recent years, this approach has sometimes been called biomimetic robotics (e.g., Ayres & Witting, 2007). The argument is that many of these features actually do confer useful attributes to the robot even if that usefulness is not immediately apparent. Other researchers take a more conservative approach, even arguing that including too many animal-like features into a robot can impair performance (e.g., Yoneda & Ota, 2003). Biorobotics has a second element as well. In addition to arguing that using biological principles as a source of inspiration for the construction of robots, some researchers have argued that studying robots can advance biologists’ knowledge and understanding of those same biological principles (Beer et al., 1998; Ritzmann et al., 2000; Webb, 2006). The idea is that any attempt to implement in hardware and software specific features of a real animal can only improve our understanding of those features because such an attempt will immediately expose any part of our understanding that is incomplete or that when O pe n A cc es s D at ab as e w w w .ite ch on lin e. co m