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!!!
Hey Robostangs, I think you are in for some recognition by FIRST…
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.
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…
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.
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?
Sorry about that David I had missed your comment. I apologize. When we score we have a tower that goes from the 4 feet level all the way up to making the top tier… we do not have the tower on in this picture, but as you can see the brackets are there to mount the tower to the base. If you reference the next picture you will see how the tower ended up, and what it currently looks like before we shipped. The tower has an arm that goes up and down it and can grab tubes with a death grip and place them on the tower with no problem at all. One of the problems that we had was that I hardly have any of the pictures, because we leave all of the pictures with the website management, so if you are interested in learning more about the design of our robot feel free to visit www.robostangs.com Thanks for the question, and again I am sorry about skipping it on the answers.
They always look to pretty before adding in all the ugly wiring, motors and such. Looking pretty sharp guys, even with all that other stuff.
We actually have a long history of doing stuff like this. The 1999 robot looked very similar but the arms were used to elevate the robot to drive on to the puck. We did a pair of high torque, high traction wheels on the '02 bot where we tipped the robot to engage them when lifting the goal. As someone mentioned, our '04 robot had two of these also. I’ve always liked the setup too. Very robust.
Jim, you know that your designs have influenced almost every part of this robot… The thing is that I can only hope of being able to create some designs as good as I am used to with the hot bot. When you grow up working with the hot team, it kinda has a way with sticking with you. Over the 6 or 7 years I have worked with team 67 I have learned what works good and what doesn’t… sometimes it takes a little while for my team to believe me that things work, but it always seams to come back to saying… "Believe me the hot team did is in 200X I know that it works awesome… and now if there is any problems I just say… Jim Meyer tried this before and believe me it works great… So just to let you know the design of this bot was influenced very much by team 67’s designs, and also incorporates some of your highly influential designs… My dad always tells me that you “Think out side of the box” and that is what I want to be able to do. This year I think that I somewhat leaned my team toward thinking outside the box, and I think that the outcome was amazing. I have taken everything that I have learned over the years from one of the highest respected teams, team 67, and applied it to this team, team 548, to try to transform it into a team that could compete at the high level. So I want to say thanks Jim, Dave, Kenny, Tom, Walt, Lori, Rodney, and all other mentors that have helped me develop the true “Thinking outside the box” attitude, and I just want you to know that what you do really does reflect on the kids that grew up working with your team. Thanks for taking the time to check out our robot, and thanks even more for being an extremely large part of my engineering experience. I want to wish you and team 67 the best this year. I will see you all at the great lakes regional! Hopefully I wont have to drive against the team that I grew up with.
P.S. Anyone who isn’t really sure that the HOT team lives up to all the hype, and isn’t sure that they deserved the chairmans award in 2005, believe me they do!