94

Figure 5.19 shows the composite perturbation for the human

used to avoid overhead obstacles.

model used with the bent-over perturbation.

transition
info

0 0 0 0 0 0

DOF:

state

1

5
5
5
5
5
5

2

40
40
40
40
40
40

3:03:13:2

4

20
20
20
20
20
20

5:05:16:06:16:2

7

20
20
20
20
20
20

8:08:1

9

-52
-52
-52
-42
-33
-33

10

-5
-5
-5
-5
-5
-2

11

-42
-33
-33
-52
-52
-52

12

-5
-5
2
-5
-5
-5

13

15
15
15
15
15
15

S1
S2
S3
S4
S5
S6

0
0
0
0
0
0

-20
-20
-20
-20
-20
-20

0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

-20
-20
-20
-20
-20
-20

0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

Figure 5.19 - Composite bent-knee, bent-over and bent-neck perturbation

Figure 5.20shows the transitions to and from "ducking".

Note

that

while

the

bent-knee

perturbation was originally designed for a slower rate walk which uses speed control, it also

works well when applied to a different basic walk (bent-over) without speed control.

(a)

(b)

Figure 5.20 - Ducking
(a) straight to ducking transition
(b) ducking to straight transition

While the ducking perturbation is demonstrated here in an open loop configuration, one can

imagine using feedback to provide the biped with the ability to automatically duck under obstacles

in its path.