93

(a)

(b)

(c)

Figure 5.18 - Bent-over walking
(a) straight to bent transition
(b) walking bent-over
(c) bent to straight transition

Figure 5.18 shows the transitions into and out of the bent-over walk and a few steps of the bent-

over walk. Both transitions are performed over two steps, with a different scaling parameter used

for each intermediate step. The arm perturbations are included in order to make the biped's arms

appear to hang by its side in a "natural" position while the body is bent-over.

In retrospect, a

better approach would be to reduce

the

stiffness

and

damping

parameters

of

the

shoulder

actuators, letting physics determine a more appropriate arm position for the walk.

This would

require variable joint stiffness and damping parameters which are not currently supported.

5. 5. 3

Ducking

By combining the bent-knee and bent-over perturbations with an additional bend of the neck, it is

possible to form a relatively simple composite "ducking" perturbation which could potentially be