Graphics Reference
In-Depth Information
A Passive-Walking Robot
A current area of robotics research is
passive walking
. This is the study of the way that walking can be accom-
plished by means of a repetition of “controlled falls,” where the walker simply follows the forces of physics at
certain points in the walk cycle and then exerts itself at key points to adjust its balance and ensure that it is in
the right position to take the next step. In fact, this kind of passive walking is an important part of how humans
actually walk and a big reason why human walking is so fluid and smooth when compared to the way most
current robots walk. Rather than controlling every movement with our muscles, a lot of what we do is to allow
the forces of physics to work for us.
Passive walking is closely related to ragdoll behavior, and it is possible to construct ragdoll-like walkers that
can carry out passive walking in Blender. Yuta Fuji (Hans), a researcher who studies passive walking, has done
just this with his intriguing Bullet/Blender passive-walking robot.
Thisvisualizationusesathree-leggedrobot,asshownin
Figure8-72
.
Asyoucanseeinthefigure,therobot's
natural joints are represented by Hinge constraints, just as they were in the ragdoll example in the previous sec-
tion.
Figure 8-72
The passive-walking robot
Theartistusesconstraintsinafewotherinterestingways.Therobot'srightlegismadetofollowitsleftleg's
motion by means of two orthogonal Hinge constraints, as shown in
Figure 8-73
. The left leg is also constrained
by a Generic constraint with no target, set to be unrestricted on all degrees of freedom except Y rotation, which
