# What is T-boning?

Now I know what t-bone is, Where a team collides with you on the side forming a right angle or a “T”, but I’m not sure what is the effect is especially in FRC. Also I’m trying to understand how some teams avoid T-bones or get out of those situation. If someone could please explain and provide some examples of how team get out of these situation it would be much appreciated. Thanks!

The effect of T-boning is (usually) that your robot cannot move due to friction. Some team have countered this through slippery bumpers and unusual chassis shapes. The cheesy poofs use slippery bumpers and 971 uses a slightly angled chassis.

Simbotics used drop down omni wheels this year to allow their robot to get out of T-Bones.

Actually T-boning in Frc isn’t exactly where the robot can’t move. It’s where a robot pushes another robot that is moving forward/backwards on its side and the t-boned robot’s wheels spinning and the sideways force from the other robot causes the t-boned robot to lose traction and then the defending robot can push the t-boned robot sideways. If the robot being t-boned does not move, the robot trying to t-bone won’t be able to move it sideways because sideways force by itself isn’t enough to overcome the traction of the t-boned robot.

Interesting, never knew it could also refer to a case where the robot being 'boned is moved sideways. Thanks for the info!

According to 254, the alternate bumper material makes t-bones far less of a concern. They can just drive past them. I believe they use sail cloth for their bumpers.

I think you’re confused, because t-bone exclusively refers to when the robot being boned is moved sideways, or at least pushed from the side. Pins in general are not T-bones, nor is “wall defense”.

Oh I see. Sorry, I had previously thought that t boning referred to a t shaped pin! Thanks for the information.

T-boning can be a t-shaped pin. It can have the effect of the robot being t-boned moved sideways, or it can be against a wall.

T-Boning is generally creating bumper-to bumper contact with another robot with the front end of your robot pushing the other robot perpendicular to that robot’s direction of motion.

The effect it has is often preventing motion in the desired direction, and thereby keeping the affected robot from scoring.

This can be better explained by someone smarter than me.

You can see it in most FRC matches this year that had effective defense.

T-bones are very hard to get out of especially when using mecanem wheels. The wheels have such little traction that you can’t drive out of a t-bone like 254. Without using different bumper material or chassis, the best way is to have your driver get stuck in a few and then learn how to avoid them or drive spin or drive well enough to get out of them. I was caught in tons in the first district I drove and then was not caught in them hardly at all after. In my opinion the easiest way to avoid them is to be constantly moving. Also if you know that one is coming you can essentially spin out of it, if they do not hit you directly in the middle of your bumpers. Spin the corner the your robot the same direction that the robot is coming at you. Watch at about 1:04 when 3663 gets pinned by 1983.

If you have your mecanum programmed properly and your drivers know how to take advantage of its holonomic capabilities i dont understand how you can possibly get t-boned. When somebody comes along side you all you need to do is translate away.

This.
Although not directly comparable, 33 this year was a good example of why having a low sideways cof could make it easy to slip out of t-bones. Given, this is all dependent on good driving, I’m sure it would have been easy to take advantage of 33’s drivetrain when defending had they had poor driving ability.

Gearing is also important. You need to be able to apply force to the ground while your wheels are being backdriven and your rollers are spinning due to the pushing force. Ideally, you’re right - translating away from the pin will allow you to escape. Just be sure to do some testing when implementing your mecanum drive as this kind of stuff can be hard to model accurately. Lots of factors involving play at the rollers, construction of the wheels, rigidity of the frame, etc. are at play.

There are a surprising number of mecanum robots that are not actually programmed to go sideways; they simply use mecanum wheels in a tank drive setup…

So like a normal omni-tank drive, but with 4 wheel independent gear-trains. Sounds expensive.

I doubt many such configurations are planned. It’s probably more a case of not getting the software (and/or hardware) working correctly, and tank steering being a contingency plan.

Just because they don’t EVER move sideways, doesn’t mean they’re not programmed to do so. It is bad scouting to make an assumption like this…

*Or that the driver can use this capability effectively.

This blows my mind. With code available online that does the work for you, how do teams let this happen to them?

While this is possible, our Mecanems couldnot strafe or go fast enough sideways to get out of it.