Advantages to a long bot?

[Laaba 80]

Long robots are able to fit through smaller gaps. In my experience it was harder to defend a long robot than a wide one.

[F22Rapture]

Longbots are inherently more stable in the forward-backward axis. Thus, they can accelerate and decelerate quickly with less sway. Consider also that if you're crossing a barrier, like this year, a longbot would be far less likely to flip while crossing it perpendicularly. Since you're much more likely to experience instability in the forward-backward axis than the side-side axis during an FRC match, longbots are generally the better choice.

However, there are a few scenarios in which a widebot configuration might be beneficial. This year, if you didn't go for an over-the-bumper solution for ball capture, a widebot would have provided quite a bit more room for balls picked up. In pushing or highly defensive games, a widebot would provide a slight traction advantage and can turn a bit easier.

Usually though, speed is more useful than pushing power, and stability more than ease of turning, so the longbot comes out on top. A properly-done West-Coast Drive can negate several of the advantages of a widebot while also coming out ahead in speed.

[Peyton Yeung]

As a driver, my favorite bots to drive were long bots because ours didn't turn in a circle as fast. This helped refine control of the robot so when we went to a wide base for this year it wasn't that hard to control.

Peyton

[Gregor]

Originally Posted by F22Rapture

...in pushing or highly defensive games, a widebot would provide a slight traction advantage...

How so?

[FrankJ]

Not really game related, but long bots are easier to get through door ways.

[MARS_James]

In all honesty my team has only ever made long bots, after our rookie year. We like them more since it is easier to control for a driver, you can fit more wheels in a standard drive, and when we tried a wide bot with mecanums it responded weird when driven diagonally (this could have been our programming but we just didn't like it). One year where I think it was really good to use a wide bot was 2009 since it made it much easier to pick up moon rocks.

[F22Rapture]

Originally Posted by Gregor

How so?

Traction is probably the wrong word, but it's easier to deflect the force of a longbot than it is a widebot, and most longbots have drop-centers so depending on the wheel types (some teams like to put omni's in the front) and whether or not it's 6wd or only has the back 2 sets powered, a longbot on a drop-center pressed up against another robot may or may not have the same footing that a widebot which usually wouldn't have the drop-center would have.

[edit] that was a terrible run-on sentence

[Gregor]

Originally Posted by F22Rapture

Traction is probably the wrong word, but it's easier to deflect the force of a longbot than it is a widebot.

Why?

Originally Posted by F22Rapture

most longbots have drop-centers so depending on the wheel types (some teams like to put omni's in the front) and whether or not it's 6wd or only has the back 2 sets powered, a longbot on a drop-center pressed up against another robot may or may not have the same footing that a widebot which usually wouldn't have the drop-center would have.

If there are omni-wheels, then yes traction will be effected.

Drop center longbots wont be effected if they are hit from the front or back, but yes they could "spin out" if it from the side, due to the shorter wheelbase.

What does

may or may note have the same footing

mean?

[MichaelBick]

This was mentioned earlier but not explicitly stated. long bots will turn faster than a wide bot.

[IndySam]

Originally Posted by MICHAELABICK

This was mentioned earlier but not explicitly stated. long bots will turn faster than a wide bot.

Really, you sure about that?

One of the things that makes a wide bot hard to drive is the fact that it turns so quickly.

[Peyton Yeung]

Originally Posted by IndySam

Really, you sure about that?

One of the things that makes a wide bot hard to drive is the fact that it turns so quickly.

Quoted for truth

[dellagd]

a) Is "Turns too fast" really a legitimate reason not to do a wide bot? That is so easily fixed in code. Even if you dont want to loose any control throw, throw some exponential rates in there for some fun.

b) For this year, we found long bot beneficial as it was basically impossible for us to tip backwards when going over the bump even though we didnt have a low center of gravity. Wide would have been a different story.

[MichaelBick]

Originally Posted by IndySam

Really, you sure about that?

One of the things that makes a wide bot hard to drive is the fact that it turns so quickly.

If you think about it, for robots with the same effective wheelbase, the robot with the wider track width will turn slower. This is because the wheels are further out so they have to travel a farther distance to achieve the same amount of rotation. Sorry I should have clarified that.

[IndySam]

Originally Posted by MICHAELABICK

If you think about it, for robots with the same effective wheelbase, the robot with the wider track width will turn slower. This is because the wheels are further out so they have to travel a farther distance to achieve the same amount of rotation. Sorry I should have clarified that.

Correct, long bots have shorter effective wheelbases so they will generally turn quicker.

This has always made me wonder if an 8 wheel drive long robot could give you the stability of long with the shorter quicker turning of a wide bot?

[apalrd]

Originally Posted by MICHAELABICK

If you think about it, for robots with the same effective wheelbase, the robot with the wider track width will turn slower. This is because the wheels are further out so they have to travel a farther distance to achieve the same amount of rotation. Sorry I should have clarified that.

4wd wide robots generally have an aspect ratio (ratio between side/side wheel spacing and front/back wheel spacing) that is the same as a 6wd drop center, leading to less turning scrub. A 6wd drop center long robot will have substantially less turning scrub because the aspect ratio will be half of a normal 6wd drop center.

Thinking about turning scrub is important if you want to turn. It also has a huge effect on how squirrely a robot is.