Moment of inertia and turning performance

[IKE]

Try adding about 10 lbs to the front, center, then rear. High and low. Take notes about how thw cg movement effects driving performance. These 6 trials will tell you a lot and will make a good experiment.

[MichaelBick]

Another problem, that I noticed this year, was the field. I think many fields were not completely level due to maybe a budget decrease. I know for a fact we were "bouncing", with an 1/8 in drop, and very stiff chassis(we overbuilt the drivetrain, using 3 x 1 tubing instead of 2 x 1). Furthermore, I even saw teams that are known for their drive bouncing(ie. 1538 Holy Cows).

[jwfoss]

Originally Posted by MICHAELABICK

Another problem, that I noticed this year, was the field. I think many fields were not completely level due to maybe a budget decrease. I know for a fact we were "bouncing", with an 1/8 in drop, and very stiff chassis(we overbuilt the drivetrain, using 3 x 1 tubing instead of 2 x 1). Furthermore, I even saw teams that are known for their drive bouncing(ie. 1538 Holy Cows).

I believe that the bouncing you saw in 1538s drive was caused by their use of pneumatic wheels.
I noticed many teams this year with the same condition.

[PAR_WIG1350]

Originally Posted by jwfoss

I believe that the bouncing you saw in 1538s drive was caused by their use of pneumatic wheels.
I noticed many teams this year with the same condition.

We had it, it was reduced when we switched from a gamepad to a pair of joysticks.
Our wheel base was probably only about 14" due to our use of 12 inch wheels on a wide robot, but we were not in danger of tipping over. In one match we were up at nearly a 45 degree angle on a tilted bridge and we still recovered and balanced the bridge. The only time we tipped was when we drove off the side of a bridge in Boston.

[Chinmay]

Originally Posted by IKE

Try adding about 10 lbs to the front, center, then rear. High and low. Take notes about how thw cg movement effects driving performance. These 6 trials will tell you a lot and will make a good experiment.

great idea. This will help us see if our suspicions were correct. I will post the results here. It's really a pretty complex problem with a ton of variables, but I like your idea to isolate a few situations and compare them

[roystur44]

Chinmay,

Try some smaller wheels and drop the bumper as low as you can get it. Geared correctly with the smaller wheels you will find the robot accelerates quickly. We design in the placement of the wheels close to the perimeter of the frame. The frame needs to be very stiff if you want the robot to run fast and turn gracefully. Try to keep the weight of the robot as low as possible and between the front and rear axles.

Here are some pictures of our 6 wheel sheetmetal chassis for 2012:

https://picasaweb.google.com/1177698...12BuildSeason#

One of 971 summer projects is to invite local teams to a question and answer to our design process, materials, fabrication methods. Shoot us a email if you are interested.


Roy

[Chinmay]

Originally Posted by roystur44

One of 971 summer projects is to invite local teams to a question and answer to our design process, materials, fabrication methods. Shoot us a email if you are interested.

Thanks for the offer I'm in CT right now and will be here for the next 10 weeks still in school doing research, but I'll have some of the kids on the team shoot you guys an email and take a closer look at your drive train. I'd love to see the facility and the robot in person near the end of summer when i get back home I'll be in touch...