pic: Two bot side balance

[JABot67]

Originally Posted by Nathan Streeter

Agreed... This is fundamentally the exact same mechanism of "grasping" the sidewall as 118 used if the CG isn't over the bridge surface, like you said. The only solutions physics could allow for this Free Body Diagram (that I can think of) would involve either "gluing" yourself to the surface of the bridge or "grasping" the sidewall of the bridge similar to how 118 did.

I don't have that hard a time believing this one wasn't ruled illegal, though... This one looks to basically be sitting on the bridge. 118 looked to be hanging off the side. So much of how the GDC ends up ruling things is based off how the solution looks. If they see something they don't like, it seems like they then figure out how to rule it illegal... * sigh *

I watched this team's alliance triple balance on the practice field. If there is any more weight on the side off the bridge, the robot will fall off. It does not "grasp" the bridge. It does not apply force to two or more sides of an arena element. The notch is there for alignment.

[jblay]

People need to relax a bit before coming to conclusions on this and ask questions.

Hey cptopher, can you explain how this works because it's legality might be questionable? If it is legal though that is some clever work and I commend you for pulling this off.

[lnader]

I was able to see this robot in action. It is steel ballast on the edge. The parts you see under the robot are alignment guides, and do not touch the sides the the rail when it is on the bridge. I believe (not being certain) that there is a surface which rides on top of the rail.

It would be no different than if a robot got bumped off the side of the bridge and they were resting on their chassis.

The head referee checked at the end of each match to make sure there was no lateral contact on the bridge.

[cptopher]

It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.

This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too.

Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts.

Chris
Team 3534 ME Mentor

[Tom Bottiglieri]

Wow, cool! It's hard to tell from the photo that there is ballast on the bridge side of the robot, thanks for clearing that up.

Are you going to champs?

[Madison]

Originally Posted by cptopher

It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.

This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too.

Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts.

Chris
Team 3534 ME Mentor

Cool.

Do you have any pictures showing the drive train from below? I'd like to see the belt and drive shaft more closely.

[Nathan Streeter]

Originally Posted by cptopher

It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.

This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too.

Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts.

Genius! Again, congratulations! You guys clearly put a tremendous amount of work into this - I hope it succeeds!

[jblay]

Originally Posted by cptopher

It is just a a simple CG trick. 98 lbs on the right side wheels, 20 on the left. We sit on the rail, with a simple guide that its twice the width of the flange for alignment only. The belt drive gives us traction on the top surface only.

This was a huge design commitment for the team. All 4 Cims and gearboxes are on the right side with a driveshaft to the left wheels. The belt is driven by this shaft, geared for the same linear speed as the wheels. We have 30lbs of balast weight on the right side C rail. And a sliding battery tray. The super low CG also makes us a good stable two bot regular balancer too.

Thanks to all for the interest. We were honored to receive the Creativity Award at Livonia districts.

Chris
Team 3534 ME Mentor

That is an incredible design comitment. This is one of the most creative things I have ever seen in my time in FIRST. Will you guys be at championships? I would love to take a closer look at this robot.

[Peck]

man, that is cool. great job

[Brandon Holley]

Wow, kudos on a very unique design! That is quite a commitment. I always enjoy seeing outside the box, yet legal, designs.

[RobotMom]

I love seeing what other teams come up with each year. Very creative!

Was your team able to do a triple balance like this during competition?

[Joe Ross]

Here's a description of another team that does something similar: http://www.chiefdelphi.com/forums/sh...9&postcount=11

[PAR_WIG1350]

I'm glad that this worked for you; it is really cool. In 2010, My team, 1350, built a robot that functioned identically when completely inverted (it didn't have a top, just two bottoms joined at their bumper zones). It worked, but not particularly well, especially after the frame started to bend.

[Ken Streeter]

WOW! Very well done! Building your entire robot with this design constraint is a remarkable accomplishment!

Very deserving of the creativity award!

[cptopher]

Unfortunately we are on the bubble to get into the state championship. We probably won't get in. We performed poorly at Kettering but had a great weekend at Livonia. Our first time in eliminations and going to semi finals far surpassed our goal this season.

We are disappointed because we really wanted to pull off a 3 long bot balance in competition at Livonia. When we fell off the bridge once, it broke a belt pulley side which eventually broke our lower chain.

The bot will balance without the side guides. It rests on the belt vertically only. Its all very simple weight and balance calculations. The side guides just help to keep us on the center of the belt and lined up. They are fixed and do not move. They don't grab the sides of the rail to stabilize.

The inspiration came from a rail grind sliding move in skateboarding, or riding the pipe in snowboarding. Just needed the belt for more traction. I'll post some photos soon.

Thanks to everyone for the positive comments.