Hexapod Walker

Legged walkers are a c lass of robots that imitate the locomotion of animals

and insects, using legs. Legged robots have the potential to transverse rough

terrains that are impassable by standard wheeled vehic les. It is with this in

mind that robotists are developing w alker robots.

Imitation of Life

Legged walkers may imitate the locomotion style of insects , crabs, and sometimes

humans. Biped walkers are still a little rare , requiring balance and a

good deal more engineering science than multilegged robots . A bipedal robot

walker is discussed in detail in Chap . 13. In this c hapter we will build a sixlegged

walker robot.

Six Legs—Tripod Gait

Using a sixlegged

model, we can demonstrate the famous tripod gait used by

the majority of legged creatures. In the following drawings a dark circle means

the foot is firmly planted on the ground and is supporting the weight of the

creature (or robot). A light circle means the foot is not supporting any weight

and is movable.

Figure 10.1A shows our walker at rest. All six feet are on the ground. From

the resting position our w alker decides to move forw ard. To step forw ard, it

leaves lifts three of its legs (see F ig. 10.1B, white circ les), leaving its entire

weight distributed on the remaining three legs (dark circ les). Notice that the

feet supporting the weight (dark circ les) are in the shape of a tripod. A tripod

is a very stable weightsupporting

position. Our walker is unlikely to fall over.

The three feet that are not supporting any weight may be lifted (white circles)

and moved without disturbing the stability of the walker. These feet move forward.