Posted by Andy Baker at 05/22/2001 10:09 AM EST
Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.
In Reply to: my opinions
Posted by Scott England on 05/21/2001 10:46 PM EST:
Scott,
Thank you for your kind words. I'll try to explain how the process went for our double-drive motors.
After concepting our robot's design for one week, our team decided that we will need alot of power, as much traction as possible, and the ability to switch gears.
We wanted to use four motors on our drive system, but we still wanted to use the Bosch drillbox to switch gears, since we had success with that method over the past two years.
One of our team's engineers, Mark Koors, had the idea of attaching the output shaft of the Fisher-Price (FP) Motor to the back end of the Drill Motor. The rest of the team thought he was crazy. We were thinking... "yeah, right". But he still wanted to try it, and we decided as a team to take the risk, since Mark's ideas usually work very well.
Now, for the detailed design work, here's how it went: Mark conveyed his ideas to me and I designed the assembly in Unigraphics CAD. Since we had a similar drive motor system from last year, I just had to add some things to it to incorporate the FP motor. The print package was done in 2-3 days, and I released the prints.
Many of the parts on this assembly needed to be well aligned in order the the motors to work well together and not "wobble" too much. In order to keep the coupling in place, we had to make sure the motors were well-aligned. Many of the parts had dimensions that had to be very tightly held... as tight as 4-places (+/- 0.0005"
.
All of the fabricated parts for this assembly were made by our school's machine trades class. This class of students used their skills to make these parts correctly, and within 10 or so days. And, they made enough for 2 spare assemblies (4 assemblies total).
Myself and another engineer, Kit Gerhart, supervised the assembly of the drives, as 5-6 of our students got lessons on how to assemble, debug and maintain these assemblies. Throughout the year, these students checked the assemblies, changed the motors, and made sure everything was in working order before each match.
As we did last year with our "Gear Switching and Motor Mount Design", we will publish this mechanical design during the off season (within a few weeks).
This assembly was not trouble-free. We had to change out 3 Drill motors and 4 FP motors, due to losing a weld on our coupling between the two motors. It was a risky design, but it was the foundation of our machine, and it was worth the effort. Luckily, all of these coupling failures happened while practicing in our shop and not at a competition.
I'll keep you posted on when I'll publish this design. Again, thanks for your interest.
Andy B.