Page 42 - Introduction to Autonomous Mobile Robots

Locomotion

Figure 2.14 27
The Spring Flamingo developed at MIT [123]. Image courtesy of Jerry Pratt, MIT Leg Laboratory.

gait. Sony recently invested several million dollars to develop a four-legged robot called
AIBO (figure 2.15). To create this robot, Sony produced both a new robot operating system
that is near real-time and new geared servomotors that are of sufficiently high torque to sup-
port the robot, yet back drivable for safety. In addition to developing custom motors and
software, Sony incorporated a color vision system that enables AIBO to chase a brightly
colored ball. The robot is able to function for at most one hour before requiring recharging.
Early sales of the robot have been very strong, with more than 60,000 units sold in the first
year. Nevertheless, the number of motors and the technology investment behind this robot
dog resulted in a very high price of approximately $1500.
Four-legged robots have the potential to serve as effective artifacts for research in
human-robot interaction (figure 2.16). Humans can treat the Sony robot, for example, as a
pet and might develop an emotional relationship similar to that between man and dog. Fur-
thermore, Sony has designed AIBO’s walking style and general behavior to emulate learn-
ing and maturation, resulting in dynamic behavior over time that is more interesting for the
owner who can track the changing behavior. As the challenges of high energy storage and
motor technology are solved, it is likely that quadruped robots much more capable than
AIBO will become common throughout the human environment.

2.2.2.4 Six legs (hexapod)
Six-legged configurations have been extremely popular in mobile robotics because of their
static stability during walking, thus reducing the control complexity (figures 2.17 and 1.3).