The Robot Group
PROTO-ANDROID PROGRESS REPORT No.1  
by David Santos
Printed in Pulse  Vol.2  July 16, 1992

-the cruel reality of   
 engineering and art in collision.

This report covers current work on the robot's mechanics and structure.  The design/build team implicated includes Joe and David Perez, David Hutchings,
and the author. Another report will cover the related subject of gross kinematics.  Particulars can also be found in the wishful Specification Draft.

The Proto Android (Pa) physical concept calls for an apelike platform of superstrong aircraft alloy driven by oversized pneumatics giving monstrous power
and speed. Impulse to begin work on the frame was strengthened by experience with Varmint its carcass served as bait for more control engineering talent
(Mark Dommers) and further funding.

The challenge with this approach is to anticipate the concerns of control engineers.  This means severely restricting computational complexity by the careful
choice of geometry, actuator counts, and other specifications  (nevertheless, control of the android will be a nightmare and is still largely and open job for
daring souls) .Months of debate as to the specific implications of engineering expediency led to two concepts; the "Beauty" and the "Beast".  The Beauty is a
refined humanoid advanced by Tim Sheridan.  What we are building is the Beast, with its brutally reduced actuator count, forced modularity and recursivity,
and a marbling of ad hoc desperation.  It costs less, is quicker to design and build, and may thereby enable success.  

The Beast concept envisions the recursive use of generic three Degree Of Freedom (DOF) driven joints throughout the platform, which vary only in scale and
handedness.  The joint itself is made of  repeating parts sliced like salami from a milled alloy billet (we call them "bones").  The payoff of this approach is
conceptual simplicity and economics of scale, even at the cottage level, as we build many joints for general use across many platforms.

These, then were the basic specifications:

	-Extreme stylization of the control math.  A single 30 degree module defines all parameters of motion, orthogonality of multiple axises, etc., for all
joints multiple or not.  This means each DOF ranges 60 degrees, its axis centers at 90 degrees to the other two and each joint hinge plate is staggered 30
degrees from the next.

	-Maximal recursion of structure.  Each individual DOF is mechanically identical; two basic parts and two sub-parts combine to build everything and
joints of different size and power scale true (minor differences in structural efficiency due to scaling are negligible at present).

	-High-strength, light-weight and compact design. A novel tri-tetrahedral geometry to the 3DOF joint promised the greatest structural efficiency; close
packing of elements achieved by painstaking refinement of motion paths. We have since found academic research pointing toward this approach but rather far
behind our attainments.

	-Standardization to pneumatic components.  In this case Bimba's since they are the biggest manufacturers and are formally contributing hardware
through J.P. Mason of Shepherd Controls. 

Consequences of the Design Philosophy:

The resulting design resembled an hyper-dimensional oriental puzzle.   Prolonged contemplation of its mysteries as embodied in the many scale models we built
caused alarming hallucinations and dementias.

We began to cut metal in a befuddled state.  With almost two centuries of shop experience we could only advance painfully, stopped again and again by
hilarious counterintuitive surprises.  All involved now know why driven 3DOF joints have been commercially unavailable in this Age of Technology.

Our progress is real and we are the final stages of manufacture of the large waist joint for the PA.  Each of its cylinders will be able to kick at 600 lbs. at
normal pressure or, if we ever lose our minds, 1500 lbs at Pa's highest legal pressure.

We are smug, with the initial hill climb done.  It will be straight forward to "clone" the original  at 3/4 scale for the shoulders and hips and a 1/2 scale for the
head.  Like fools we now look forward the next unending phase of work on Pa.

Thanks for flying PolyCosmos. Join us again.