[archiver]

Posted by Joe Johnson at 04/25/2001 7:04 PM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: Re: Reflected Inertia?
Posted by Paul Copioli on 04/25/2001 1:00 PM EST:



Paul,

Thanks for the introduction.

I have some questions though.

I have always used either speed consideration or torque
consideration to design my gear ratios, not reflected
inertia.

I why do we want a 1 to 1 ratio?

What good things does it do for us if we can get a 1 to
1 ratio?

Finally, does it make sense to add mass to the armature
of the motor in order to improve the reflected inertia
ratio? If I can get good things for the extra work, I
may end up doing it.

I have always blamed my main problems with controlling
large robot arms on 3 main problems:

1) Inability to easily implement a PID control
algorithm on the current STAMP2 CPU.

2) The dead band in the Victors (a PWM output value of
127 +/- 10% yeilds 0 Volts output -- very annoying).

3) My poor design skills preventing me from properly
counter-balancing the arm so that the arm is more or
less neutrally balanced over a large range of motion.

I try, but weight limits, time limits and incompetent
engineering on my part always have conspired to leave
the arm falling or auto rising over most of its range
of motion.

So...

My question is now, maybe there is some other culprit
that I should be blaming as well.

I am anxious to hear your reply.

Joe J.