Re: omni drive vs tank
 

ya you get just as much traction with the pneumatic wheels with those big CIMs it wont be necessary to use tank treads and if any team is smart they will use a pneumatic brakepad system to hold their ground while shooting at the center goal

Re: omni drive vs tank
 

I'll bite. This year's game will not be friendly to omni wheel drives (unless you can shoot extremely accurately on the fly). It will also not be friendly to tank treads, although I am not sure that is what you meant. Tank does not mean tank treads you guys. It could mean a skid steer system, which would be good, unless you want to go ramp climbing. Although after last year and 116's incredibly wicked sweet drive, I'm sure you can think of something cool.

Re: omni drive vs tank
 

Im not saying it wont be friendly to tank treads im just saying it wont be neccessary your better off going witha 6 wheel pneumatic tire drive train, that ramp isnt going to be to hard to get on. other then that its all about speed, traction, and movability. A functional holonomic drive train is fast as h*** and nice manevability if you practicle driveing but if u get pushed you got zero traction, we even replaced the wheels and added tire treds we literally glued on with some industrial glue the traction increased but if you get pushed you slide.

Re: omni drive vs tank
 

it is possible for a crab drive or an omni drive to get up the ramp with the help of another robot. There will be plenty of tankbots that can push them ramp, just make those wheel/motor assemblies strong.

Re: omni drive vs tank
 

I think a crab could get up in its own but an omni would need the assistance of a dropdown high traction roller of some sort.

I think a crab is perfect for the game, but I don't think my team wants to go that way.

Re: omni drive vs tank
 

Omni wheel drives, when not being useful while climbing the ramp, will probably prove to be extremely valuable when a team is positioning itself to shoot the balls into the corner goal. Lets say you have positioned your robot in front of the goal to shoot and you find yourself a little too far left. Without Omni wheels its given that u will turn right, go forward a little and turn left again to face the goal. Precious time lost...which wont be if you use an omni drive system.

My team has used a four wheel drive system with doubled up wheels wrapped in tread(from McMaster Carr) and two pneumatically activated castor wheels. If all four wheels are on the floor the robot has a LOT of traction and works well as a defensive robot. If the castors are actuated and pushes the front wheels up, it gives it the manuevarability required in the FIRST games. We have found this to work quite well.

On the topic on tank drives, it is a very hard thing to perfectly execute. Tank drives require a lot of work and the result is not very much advantageous over a normal four wheel drive system.

These are just my thoughts. The game dynamics on the field will also have a great say on the reliability and advantages of each of these different systems.

Good Luck

Re: omni drive vs tank
 

Omni bots will have a place in this year's game, although I dont know if 116 will use a holonomic drive again. More advanced programming teams may like omni-drives to "shoot on the fly", especially if they dont develope a turret system for their launcher. Agility and speed will be essential in reaching the corner goals/HP stations, because you CANNOT power your way to them (youll just jam the opponent into the corner, and its gonna be near impossible to get them out).
It is POSSIBLE to create an active suspension system, although very difficult, for a holonomic or mechanum drive to get up the ramp.

Re: omni drive vs tank
 

if it werent our "first" year doing this we would push for omni or crab drive... and it would be nice if the "shooter" were ALWAYS pointed at the goal. no matter which way the joystick is puished the robot moves int the x/y accordingly but the programming keeps the front faced towards the goal.
i guess a rotating top would do as well

Re: omni drive vs tank
 

regarding the tank treads- it's not so much that they're slow, it's that they're not good for turning, which will probably end up being an important part of this game.

Re: omni drive vs tank
 

That was the first thing that I thought of once I saw that green light. Set the camera to home in on the light and rotate the firing mechanism.

I'm pretty sure that team 648 is going with a crab steer system and that is the perfect drive system for that design idea. This will also be our first year for crab but we have been testing design and coding on the Robovation bot.

Re: omni drive vs tank
 

if you do it correctly, they can turn just as easily as a tank drive.

Re: omni drive vs tank
 

The thing about tracks is that I haven't seen proof that you can get more traction with them than with a good treaded wheel. And unless you are climbing a stair, I haven't seen a good reason for why you need them. And there are a few excellent reasons not to have them.

Re: omni drive vs tank
 

sounds like a good offseason project to me. Make two identically geared drives, make one with treads, one with wheels using the same belt material. See which pushes the other.

Even if it turns out treads aren't better...you'll know how to use them for the future. And you can teach new kids a bunch about drivetrains. :)

Re: omni drive vs tank
 

I made a 1min video on the Speed, Power and Traction of tank treads..


Introducing: Speed, Power and Traction of Tank Treads

I made a 1min turning video

EDIT: Introdicing: Sooo Tracks Can't Turn?

Re: omni drive vs tank
 

bump