Quote:
Originally Posted by DampRobot
Very cool. It'SS an amaSSing SShaker RoboticSS robot as uSSual!
Can you talk a little bit more about your arm gearbox? What happened at WPI, and how do you mean it's repairable in place?
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Yes we have actually done a lot to improve on our arm gearbox design in this itteration. For those who don't know we were number one seed at WPI. We went undefeated for all of qualification matches. In our last qualification match our arm gearbox (which adjusted the shooter and picked up the robot) sheared 1/2 of the teeth on the last stage pinion gear. With the short turn around time of finals and a poor maintenance design we were never able to be 100% again and ended up coming in second overall.
This year we have a reduction of about 500:1 over 6 stages. That is a lot of stages for the amount of reduction. Last year we were able to be close to 1000:1 with only 5 stages. The reasoning behind this, is we wanted to have lager pinions this year, especially at our later stages. Lager pinions create less force on the gear teeth. Our last stage is a 50:84 reduction. The 50 tooth pinion is a AM steel gear (versus a 20 tooth vex gear from last year). This was our first concern when redesigning the system.
Next, we made changing out last reduction much easier. We can now change gears out in less than 20 minutes. We did not think of maintenance last year, and it was so difficult we avoided changing the gears. This year we are adding a maintenance schedule for the last stage. During lunch on Saturday we will replace the last stage of gear. Also we will change gears before our second regional and again before finals. Mind you, our gears sheared at WPI which was our second regional last year, so we are confident that this schedule along with our updates to the system is more than adequate.
Finally, we added a dampening spring to the system (not shown in picture). We use a gas spring to absorb shocks to the gears from momentum and impacts with other robots. We believe that the abrupt movement prematurely wore the gears last year. We are happy to report that the dampening system is working better than expected.
We really liked the gear driven arm last year, when it worked, it worked great. Our current iteration should prove to make a big difference in performance this year.