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#1
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pic: DiscoBots Nano-killough
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#2
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Re: pic: DiscoBots Nano-killough
Nice!! it looks great! I'm just curious why y'all went with the omni side of this game?
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#3
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Re: pic: DiscoBots Nano-killough
We did a game analysis and came to two ideas we could either build a drive train that is more powerful than other robots or we could build a robot that is more maneuverable. We also decided that speed was a crucial component in getting as many tubes hung as possible.
With that we would either need to build a six wheel drive train with a shifting gearbox or go with omni-directional and have lots of speed and be able to get around defenders quickly. We also knew that when in the our zone we will be able to position ourselves to hang without defender interference unlike 2007. Strafing in your zone to be able to get to the proper peg without exiting your zone is important so defenders can not affect you. Swerve drive may be a better option (to have more power and still get maneuverability) but we have never prototyped swerve modules so we went with what we considered to be the best method to accomplish our game strategy that we could complete in the six weeks. |
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#4
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Re: pic: DiscoBots Nano-killough
1745 did this type of design in 2008. it worked out well but I would suggest some sort of suspension. we found places in the carpet arnt as level as others and if all the wheels arnt applying the same pressure and traction to the floor it can mess with handling.
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#5
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Re: pic: DiscoBots Nano-killough
that is one interesting chassis. the only thing i'm worried about is stability. it seams that without suspension, as stated above, that the robot will be very prone to tipping over. Use suspension and distribute the weight effectively, and you will have one heck of a robot there!
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#6
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Re: pic: DiscoBots Nano-killough
Having built a robot like this last year, i woud warn again the omni drive configuration... we realized (too late in the build season) that even the smallest bump or unevenness of the playing field would cause the robot to turn violantly, no matter how much the software tries to compensate for it.
- Bochek |
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#7
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Re: pic: DiscoBots Nano-killough
Quote:
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#8
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Re: pic: DiscoBots Nano-killough
I am not so sure what the tipping thing is about either, our chassis is 1.125" from the ground and we will have bumpers extending from that. Tipping over the bumpers will be pretty difficult.
However the traction problem is something we are definitely considering. We have several solutions in mind both mechanical and software to try to fix any problems that we might have. Thanks for the comments and tips. |
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#9
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Re: pic: DiscoBots Nano-killough
It won't absorb the force of a hit from another bot as well. Plus, suspension will keep it stable while maneuvering at faster speeds.
Also guys, a rookie on my team was wondering how stable this will be when you mount the other parts like the elevator, minibot/minibot deployment, etc. on it? |
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#10
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Re: pic: DiscoBots Nano-killough
Stability is something we are definitely testing. One of the things we know is that we should never be driving at high speeds with our lift up. So the vast majority of our weight besides the outer lift rails will be low to the ground when driving.
Stability is a problem every team has and our frame is the same length as most teams narror dimension. |
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#11
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Re: pic: DiscoBots Nano-killough
Sounds good. Here's another tip that helped my team last year: make your center of gravity very low, so put all your heavy stuff towards the bottom of the robot.
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#12
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Re: pic: DiscoBots Nano-killough
How did this work out for you? We are building something very similar as our off season project. This style chassis is extremely stiff and has a very low center of gravity so I doubt you had the predicted stability problems nor needed a suspension.
The major difference with ours is we went asymmetric - meaning we put the wheels at a 30deg toe-in instead of standard 60deg. This gives us more usable torque front to back (87% vs swerve) and less lateral (50% vs swerver). 45deg would give 70% vs swerve in all orthogonal directions. Did you do robot centric or field centric controls? What sensors did you use and would you use them again? Quote:
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#13
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Re: pic: DiscoBots Nano-killough
Haven't seen this thread in awhile. I was a discobots mentor when we built this robot and was in charge of the control systems team.
Was it a fun challenge, yes. Would I ever build it for competition again, NO. You absolutely need some form of suspension or you will be struggling to get all your wheels to touch the ground at the same time. If you use driver centric instead of robot centric controls it helps alleviate some of the problems with wheels slipping. Even the smallest imperfection in the floor will make your robot turn drastically, the plates around the mini-bot poles in 2011, were a huge problem for this drivetrain. The only sensor we really used was a gyro, to keep us oriented. We had "Halo" style controls, so one joystick was for strafing and forwards and backwards and the other was for rotation. We also implemented quick position buttons on the top the turn joystick so you could quickly go to any 90 deg offset from strait ahead. By our 2nd event, we had it working well enough for us to be the 2nd overall pick and make it the finals before losing to 118 and 1477. Very few games allow for you to give up that much of a traction advantage and still play well. |
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#14
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Re: pic: DiscoBots Nano-killough
What was the magic change that made the second event better? 2nd pick is fairly good, obviously your arm must have been great and your scoring was probably enhanced by the strafe capability.
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#15
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Re: pic: DiscoBots Nano-killough
Quote:
We also increased the speed of the drivetrain by changing the gears in the tough boxes, that helped a lot. |
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