Page 151 - Biomimetics : Biologically Inspired Technologies

Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c004 Final Proof page 137 21.9.2005 9:37am

Evolutionary Robotics and Open-Ended Design Automation 137

Synapse
Linear
Actuator Neuron
Bar
Control
(Brain)
Morphology
Ball Joint
(Body)
Infinite
Plane

(a) (b)

(c) (d)

(e)

(f)
Figure 4.4 (See color insert following page 302) Evolving bodies and brains: (a) schematic illustration of an
evolvable robot, (b) an arbitrarily sampled instance of an entire generation, thinned down to show only significantly
different individuals, (c) phylogenetic trees of two different evolutionary runs, showing instances of speciation and
massive extinctions from generation 0 (top) to approximately 500 (bottom), (d) progress of fitness versus gener-
ation for one of the runs. Each dot represents a robot (morphology and control), (e) three evolved robots, in
simulation (f) the three robots from (e) reproduced in physical reality using rapid prototyping. (From Lipson, H.,
Pollack, J. B. (2000) Nature, 406, 974–978. With permission.)

shown here) used a sort of a crawling bi-pedalism, where a body resting on the floor is advanced
using alternating thrusts of left and right ‘‘limbs.’’ Some mechanisms used sliding articulated
components to produce crab-like sideways motion. Other machines used a balancing mechanism
to shift friction point from side to side and advance by oscillatory motion. Taylor and Massey
(2001) provide a review of several works on evolution of morphologies.