Page 39 - Introduction to Autonomous Mobile Robots

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Specifications: Chapter 2

Weight: 7 kg
Height: 58 cm
Neck DOF: 4
Body DOF: 2
Arm DOF: 2 x 5
Legs DOF: 2 x 6
Five-finger Hands

Figure 2.11
The Sony SDR-4X II, © 2003 Sony Corporation.

The paper of Ringrose [125] demonstrates the very important duality of mechanics and
controls as applied to a single-legged hopping machine. Often clever mechanical design
can perform the same operations as complex active control circuitry. In this robot, the phys-
ical shape of the foot is exactly the right curve so that when the robot lands without being
perfectly vertical, the proper corrective force is provided from the impact, making the robot
vertical by the next landing. This robot is dynamically stable, and is furthermore passive.
The correction is provided by physical interactions between the robot and its environment,
with no computer or any active control in the loop.

2.2.2.2 Two legs (biped)
A variety of successful bipedal robots have been demonstrated over the past ten years. Two
legged robots have been shown to run, jump, travel up and down stairways, and even do
aerial tricks such as somersaults. In the commercial sector, both Honda and Sony have
made significant advances over the past decade that have enabled highly capable bipedal
robots. Both companies designed small, powered joints that achieve power-to-weight per-
formance unheard of in commercially available servomotors. These new “intelligent”
servos provide not only strong actuation but also compliant actuation by means of torque
sensing and closed-loop control.