|
For
the applications that we are interested in, the main challenge in
designing these robots deals with putting actuated joints in a tight
volume were we minize the length of the stages and their cross sectional
areas. Therefore, the main concept of our design, as well as many
others, is to stack two degree-of-freedom joints on top of each
other, forming a snake robot. There are three main schools
of designs for these kinds of robots: actuated universal joint,
angular swivel joints and angular bevel joint.
The
simplest design that first comes to mind is stacking simple revolute
joints as close as possible to each other and this led to the actuated
universal joint design. However these kinds of designs tend to be
bulky and slow, hence not appropriate of lots of snake robos
applications. Another kind of bulky two DOF joints are pnuematic
snakes.
The
second design that evolved was the angular swivel joints, which
is present in the JPL Snake Robot. These are much more compact
two DOF joints. The design is simple: starting with a sphere, then
slicing the sphere into two parts such that the slice plane is transversal
to the south-north pole axis of the sphere. Now rotate one half
sphere with respect to the other and notice the motion of the north
pole as it traverses a cone of revolution. Conneting two adjacent
snake bays via a passive universal joint and then by coordinating
the rotation of the two spherical cups generalted two degrees of
freedom: In-plane bending and orientation.
This
is the most compact joint design till now. However here we are trying
to develop a new compact two DOF joints. We work on optimizing the
size, strenght, reachability and flexibility of these joint. so
far we have designed three new types of joints. We have already
design and built many prototypes. Please check the different designs
we have been working on by clicking on the specific link on the
top left corner of this page. [Top]
|
