Page 255 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

11.1 Tripod gait, at rest

11.2 Tripod gait, first move forward

Figure 11.1 shows our creature at rest. All feet are on the ground.
From the resting position our creature decides to move forward. To
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step forward, it lifts three of its legs (see Fig. 11.2, white circles),
leaving its weight on the remaining three legs (dark circles). Notice
that the legs supporting the weight (dark circles) are in the shape of
a tripod. This is a stable weight-supporting position. Our creature is
unlikely to fall over. The three lifted legs (white circles) are free to
move, and they move forward.
Figure 11.3 illustrates where the three lifted legs move. At this point,
the creature’s weight shifts from the stationary legs to the movable
legs (see Fig. 11.4). Notice that the creature’s weight is still sup-
ported by a tripod position of legs. Now the other set of legs move
forward and the cycle repeats. This is called a tripod gait, because
the creature’s weight is always supported by a tripod positioning
of legs.

Creating a walker robot

There are a lot of little wind-up toy walkers around. These toy
walkers move their legs up and down, back and forth, using a ro-
tary cam mechanism. While these walkers work, and some are sur-
prisingly fast, our task is to build a walker that does not use a
rotary cam to imitate walking.

Team LRN
Chapter eleven