pic: 2007 FRC Team 548 Robostangs Robot Pic2

[Cory]

Originally Posted by Gabe

The lift is to raise and lower the wheels for the different speeds. A larger diameter wheel will make the robot travel faster at a definite RPM compared to a smaller diameter wheel because the larger wheel will travel farther (circumference) per rotation than a smaller wheel.

The amazing thing is to see a theoretical idea actually put into play and at the same time very well implemented. I can't wait to so this bot on the field!!!

I think you are in for some recognition by FIRST...

980 was actually the first to do this that I can remember--back in 2003.

[Alex Cormier]

Originally Posted by Cory

980 was actually the first to do this that I can remember--back in 2003.

67 also had somehting familiar for '04.

[Nuttyman54]

190 used this type of system in their first and only regional winning robot, the SpiderGoat, in 2001

[robostangs548]

Gabe came the closest... we lift up our robot completely off the ground in order to achieve low gearing, and high torque.... this is how it works.... We create 290lbs. of torque because of an all student designed drive train that instead of using a two speed transmission uses a custom working trans. like this... In high speed (Low Torque) two big diameter small width wheels on the ground and two scrubber wheels.... In low speed (High Torque) Four wheels with a smaller diameter and larger width come slamming to the ground to lift the entire robot and speed wheels off the ground to create an amazing amount of force on the opposing object (shall i say robot) we have found that if we put our 2006 bot sideways we can push it with amazing ease.

[robostangs548]

And also... yes we have seen this before, but we have never seen it carried out to this caliber... This idea may have been used before, but we think that so far this will be one of the most powerful ways of creating this design. This design was mainly based off the question of how can we make a high torque, high speed, and 0 turn robot. After lots of deliberation we finally found our answer. Also like I had said before this drive train works great, and it is like a tank without the treads, loss of speed, and slower turning capabilities...

[AdamHeard]

Originally Posted by robostangs548

Gabe came the closest... we lift up our robot completely off the ground in order to achieve low gearing, and high torque.... this is how it works.... We create 290lbs. of torque because of an all student designed drive train that instead of using a two speed transmission uses a custom working trans. like this... In high speed (Low Torque) two big diameter small width wheels on the ground and two scrubber wheels.... In low speed (High Torque) Four wheels come slamming to the ground to lift the entire robot and speed wheels off the ground to create an amazing amount of force on the opposing object (shall i say robot) we have found that if we put our 2006 bot sideways we can push it with amazing ease.

Are there supposed to be two more of the large wheels in the picture?

[robostangs548]

Nope.... it is has two large front wheels, and two scrubber wheels in the back, which act as a lighter version of two more drive wheels, and also add a zero turning capability and low lag or (jitter) while turning the bot. If you look at the next picture it will show you what the bot currently looks like, and will help you better understand the drive trains intentions.

[Ben Piecuch]

Buzz (FRC175) built a "kicker wheel" design in 2000, and used the Van Door motor to rotate a smaller, higher traction wheel downward to lift the main driving wheels (8" skyways) off the ground. This was only a 2wd system.

The Bobcats (FRC177) built a similar "kicker wheel" design in 2002, but used the old seat motors with their 2" lead screws to drive the smaller wheel down. This design used a swingarm, made of 1.5" box aluminum, to lower a similar smaller, higher traction wheel downward to lift the main driving wheels (12" custom) off the ground. Again, this was only a 2wd system.

The HOT Bot (FRC67) also used a smaller, higher traction wheel design in 2002. However, their design was more static in nature, in that their robot weight was shifted onto these rear wheels when it grabbed a goal. It looked sort-of like a tractor pull when the front end got lifted a good 6-12 inches off the ground.

Clearly, the use of pneumatics was not as prominent back in the day. Today, it's a bit easier to implement such a system with the pneumatics. Grady, when are you going to give us a FIRST 101 on the origins of 2-speed robots?

BEN