Scouting Advice? FTC to FRC help?

[rs201496]

Hi there, I'm currently on a FTC team but recently began interested in watching local FRC competitions. This interests me a lot, but unfortunately I am newer to my robotics team and do not know a lot. A friend of mine explained scouting to me in detail a while back, but he lives farther away so I did not get to far. This is why I have come here for help.

I just have a few questions that I hope could be answered, thanks.

One question I have is are the types of drive trains that are used in FRC?
How can you tell what type drive train a robot is running just by looking at the robot?

Another question I have is about wheels. I just want to know more about the wheels used, and how each is different. (ex, omni, mecanum)

I'm new to the whole robotics scene in general, so please don't be too rough on me for not knowing this stuff Thanks again folks!

[xXhunter47Xx]

I can help you on drive trains.
Usually, from just observation, you can only determine if it's a dual gearbox system or a holonomic setup.
If the robot rotates and goes forward at high speeds, it usually is a dual gearbox system.
If the robot can strafe (move side to side without rotation), it's most likely a holonomic drive.

In a holonomic drive, you can have mecanum wheels or omni wheels.
Mecanum wheels have rollers positioned at 45 degree angles on the wheels, and will overcome the motors when they are moving against each other.
Omniwheels have free spinning rollers, and operate similarly to mecanum except you have to set it up in an "x" orientation as opposed to the regular wheel configuration to mecanum wheels. You can also use 5 omniwheels and set it up as a regular wheel configuration with the 5th driven in the center of the bot.

[rs201496]

Thanks, this helped a lot. How about west coast/jump/swerve drive trains? Are there any others?

[xXhunter47Xx]

WCD is a 2 gearbox type of drivetrain.
Swerve drive is like an over complicated holonomic drive, although it does provide a more detailed driving experience and has a greater degree of movement as opposed to holonomic, it tends to be very pricey and difficult to program for.

[Canon reeves]

A lot of teams run tank drive, which is basically each side of the robot operates individually and most every team has atleast 4 CIM motors on their drive train, an quite a few have 6 causing for some very fast robots or some very powerful ones. If a team has a shifter than they can go from a gear ratio that is higher meaning more for speed, to a lower ratio for pushing power. I've seen teams do different things with tank however, one of my favorites is not dropping the center wheel and adding omni wheels on the outsides. The reason for dropping the center wheel lower than the others is so that when it is turning it is only turning on 4 wheels vs 6 causing much better turns.

[Abby341]

Tank drives often opt. for wheels with higher traction, their almost always round, nothing too special about them, they are better for pushing . Omni wheels are just round wheels with smaller wheels laying perpendicularly on the wheel it allows for easier turning. Mechanum wheels look like wheels are slicing into the larger wheel, they are supposed to make changing directions easier, they are the most obscure looking out of all the wheels. Drop center drives are fairly common, wheels are slightly lower in the middle making turning tighter.

[EricH]

A "jump" drive, as I recall, switches between two drive systems. The most common are the "octocanum" or "butterfly" drivetrains, which switch between a traction wheel and a mecanum wheel, or occasionally an omni wheel.

Just to give a little more detail into swerve or crab drive, there are a number of different subtypes, but in the interest of simplicity: the robot can go in any direction without turning. Some internal wheel-turning configurations can turn the robot, some cannot. Some require lots of chain, some do not.

And, to elaborate on West Coast Drive (WCD): A "true" WCD is 6WD, dropped center wheel directly driven from a 2-speed gearbox on each side, with chain runs to the outer wheels, and all wheels cantilevered outside of the frame. They've been used for over 10 years, and have been very effective the whole time. There are a number of variations and tweaks; the most common is to move the wheels inside of the frame and use chain drive on all of them. 8-wheeled WCDs have been cropping up as well.