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Bjenks548 09-06-2010 20:20

Crazy Drive Train Ideas
 
A few members of our team are working on crazy drive train ideas. While we have plenty to work with currently, I hope to get through them and onto more. If you have any weird drive train ideas please post them here and do your best to describe them. I don’t want anything that’s already been seen around such as nona-drive and kiwi, I want brand new ideas. We plan to CAD and build all these drive trains using the kit of parts c-channel this summer. Please post any ideas, thanks.

,4lex S. 09-06-2010 20:29

Re: Crazy Drive Train Ideas
 
BALL DRIVE!!!

One large ball with a traction wheeled motor rolling said ball in the y direction, and another in the x. I can't see this ever being practical, but it would be fun to build and program.

Chris is me 09-06-2010 20:42

Re: Crazy Drive Train Ideas
 
I have a really crazy drivetrain idea. Instead of 4 wheels, put 6 wheels on a robot, and make the center one lower! That way, robots will have a shorter wheelbase for turning but high traction all around! :rolleyes:

Of course I'm kidding, but I've always wondered why people take the "let's do something weird for the sake of it" approach to prototyping, rather than engineering a drivetrain that tackles a design aspect differently. I think you should totally build a crazy drivetran, don't get me wrong - but maybe it would be a better exercise to figure out what current drivetrains you use don't do very well, and then figuring out a new drivetrain optimized toward different design criteria than the bog standard.

The latest innovative drivetrain in FIRST (nonadrive) probably wasn't thought of by going "hey dude, what if we did THAT?". I imagine they specifically looked at a way to accomplish something not present in a 6wd (strafing) without some of the drawbacks of drivetrains designed for that (swerve, mecanum). Maybe you can do the same thing - and come up with something incredibly crazy, but useful too!

BrendanB 09-06-2010 20:48

Re: Crazy Drive Train Ideas
 
Well, since Winnovation stole an idea I had in 2007 of 6 wheel crab drive I guess 8 wheel crab drive is the next new thing of the future! :D

ttldomination 09-06-2010 20:58

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Chris is me (Post 966050)
The latest innovative drivetrain in FIRST (nonadrive) probably wasn't thought of by going "hey dude, what if we did THAT?".!

I don't know, but that sounds perfectly plausible to me. Some of the best ideas on my team have come from people just talking about hypothetical ideas or things that would be cool, and then someone sees the implementation in their head, and it just takes off.

- Sunny

dodar 09-06-2010 21:03

Re: Crazy Drive Train Ideas
 
i think it would be cool to see a crab-drive tankdrive robot :ahh:

Arefin Bari 09-06-2010 21:04

Re: Crazy Drive Train Ideas
 
Here is a link to the ball drive Team 45 came up with back in 2003. Also, search for ball drive under CD-Media to see more pictures.

Team 179 and 1345 collaborated in 2009 and built a crab drive. The crab drive also drove like a tank drive. Is this what you meant?

BrendanB 09-06-2010 21:12

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by dodar (Post 966057)
i think it would be cool to see a crab-drive tankdrive robot :ahh:

I believe team 2342 Team Pheonix from Nashua/Merrimack New Hampshire did a design in 2009. It was a standard crab drive robot but with added code allowing to act as a crab, tank, and ackerman steering and even some slight combined variations.

Is that sort of what you were thinking of?

Chris is me 09-06-2010 21:16

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by BrendanB (Post 966061)
I believe team 2342 Team Pheonix from Nashua/Merrimack New Hampshire did a design in 2009. It was a standard crab drive robot but with added code allowing to act as a crab, tank, and ackerman steering and even some slight combined variations.

Tons of crab drives do that. Not to take anything away from the 5 or 6 teams each year that tell me their drivetrain is a crab drive AND a tank drive, but that's pretty standard.

I think he meant swerving tank treads or something.

BrendanB 09-06-2010 21:19

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Chris is me (Post 966064)
Tons of crab drives do that. Not to take anything away from the 5 or 6 teams each year that tell me their drivetrain is a crab drive AND a tank drive, but that's pretty standard.

I think he meant swerving tank treads or something.

Yah I was confused as well thinking of the same thing, "aren't all crabs tank drives?"

I think it is just one of many things that makes me crack up back on pit scouting or alliance strategy. "Our robot has a very low center of gravity!" That is great, but how does that large heavy steel arm play into that?

mwtidd 09-06-2010 21:23

Re: Crazy Drive Train Ideas
 
4 wheel crab with actuator legs (http://www.youtube.com/watch?v=IMmJtw0XYzk)

lets make the legs 3-position pneumatics.

and while we're at it, figure out some way to mount the bumper is its '10 legal.

or the beautiful rotating mecanums would be nice
i have a design that could be driven by one set of motors and still be holonomic

Hawiian Cadder 09-06-2010 21:42

Re: Crazy Drive Train Ideas
 
Hoover-craft....

i would actually like to see a robot with a bike drive train, even the most basic bicycles have at least a couple different gear ratios, and there are some bikes with upwards of 24.

jamie_1930 09-06-2010 22:15

Re: Crazy Drive Train Ideas
 
I think I have exactly what you are thinking of this was one of our programmer's, dana, idea in 2009. He called it serpentine drive and was designed to slide across the regolith, similarly to a snake. I hope I can explain this well enough for some people to get, and I'll try and follow it up with some of dana's prototyping of the drivetrain. You make multiple wheel assemblies that would include two wheels, parallel to one another and unpowered, with a center pivot in the middle of the two. Now you would have the center pivot offset from the center of a gear, then put a series of this in a line with eachother, connected with springs to the front and back of each and idler gears inbetween to maintain direction. Each of the assemblies would then be offset slightly so that when the whole thing was powered by a single motor the wheel assemblies would travel in a wave.

Hawiian Cadder 09-06-2010 22:39

Re: Crazy Drive Train Ideas
 
i just came up with another one, make a robot that is entirely encased in a hollow sphere with omni wheels on every corner facing outward, to drive the main part of the robot drives the inside of the sphere, if we ever get a water competition this would be highly helpful i think.

Aren_Hill 10-06-2010 00:21

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by BrendanB (Post 966054)
Well, since Winnovation stole an idea I had in 2007 of 6 wheel crab drive I guess 8 wheel crab drive is the next new thing of the future! :D

The Idea has been lurking around in my head for longer than that, Dillon just made it feasible by making tiny modules ;)

Jared Russell 10-06-2010 07:59

Re: Crazy Drive Train Ideas
 
You have to be careful that you think about this in the right way. There have been all sorts of crazy drive trains in FIRST. Ball drives. All sorts of swerves. Active and passive suspensions (especially this year). Walking file cards. Ball differentials. CVTs. 2 speed (AM-style), 3 speed (DeWalt + 222 ball lock shifter), 4 speed transmissions (33). Brakes. Triwheels. Traction wheels, inflatable wheels, omni wheels, mecanum wheels, treads. Nonadrive. The list grows every year.

Some of the above have been used to great effect on certain robots. Others tend not to do as well. What's the difference?

The teams that succeed on the field don't generally seek to innovate their drive systems for innovation's sake - they instead analyze the game and what they want their robot to do well and use that analysis to drive their choice of drive system. In other words, before trying to think of off the wall ideas, think of what possible situations would cause the "tried and true" FIRST drive trains to fall short.

Steps? Driving on sand? The return of regolith? What if you decide you need holonomic/swerve-like agility with extreme pushing power (especially if you decide that your team isn't a good fit for swerve, either financially or because of fabrication resources)? How can you ensure that nobody can cause your robot to turn if you don't want it to?

(I'm speaking about drive systems you would actually want to use on a competition robot here. In the offseason, or for demo purposes, sure, anything goes. But the teams that succeed on the field more often than not have competition on their minds before they go and prototype.)

Bjenks548 10-06-2010 08:16

Re: Crazy Drive Train Ideas
 
While I know that this is not the best idea as far as making a game applicable off season part, with summer coming and the GDC refusing to give me a game hint to work with, I am bored and need something to do. Please do not criticize what we are doing and keep the post to drive train ideas and discussion.

JesseK 10-06-2010 09:38

Re: Crazy Drive Train Ideas
 
To sum up the critics of this thread:
"An innovation needs to be set to a strategy, solve a specific problem and be practical before the design even starts."

Thank God DaVinci didn't think that way, nor did these guys
<Philosophy>
The methodology of complex innovation has been around since the Rennaisance Era, and didn't start with a specific problem to solve. The problems are abstract, even in the FRC Drive Train realm: design a drive train that is both agile and has high tractive power. The reality is that solving the problem is an excellent lesson in Innovation itself and the lessons learned will carry further than just the FRC season. The biggest lesson is that there is never a silver bullet to solve every problem in a mechanical system. Given that now is the Prototyping Season, this is a fun discussion with perfect timing.
</Philosophy>

I don't understand why all teams want the drive train to do everything for mobility. If the rules allow for it, why has no one even prototyped something like a tethered Quad Rotor that lifts off and gets the game object? Sure, the thing would probably get beat up during a finals match but the sheer success in prototype will spur a LOT of creative thought come build season. Of course just implementing a quad rotor with limited amounts of motors is a feat and requires its own innovations worthy of patents and PHD's, heh. Then there's the control component, which many programmers would salivate at the chance to do, and the sensor feedback component which boggles the mind of even the smartest professionals.

0.02

Jared Russell 10-06-2010 09:52

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Bjenks548 (Post 966106)
While I know that this is not the best idea as far as making a game applicable off season part, with summer coming and the GDC refusing to give me a game hint to work with, I am bored and need something to do. Please do not criticize what we are doing and keep the post to drive train ideas and discussion.

I'm sorry if I came off as criticizing - I think that no matter what you decide to do, prototyping in the off season is very beneficial and a lot of fun! True innovation doesn't necessarily require a concrete problem first, but history shows that necessity is the mother of invention quite often.

I was just throwing out that if you want to prototype for fun and to for practice, why not also practice analyzing a FIRST-like game challenge. While the GDC hasn't given hints towards 2011 yet (and given past history, they are unlikely to do so until much closer to kickoff), history shows that elements of past games tend to be re-used in new and slightly different ways. Pick a game that you aren't familiar with, analyze some of the technical challenges, and think of ways to solve them.

Either way, you'll have fun and learn a lot.

Andrew Schreiber 10-06-2010 10:02

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JesseK (Post 966115)
To sum up the critics of this thread:
"An innovation needs to be set to a strategy, solve a specific problem and be practical before the design even starts."

An idea need not solve a specific problem but a design should. That problem can be completely off the wall or it can be realistic. A water game, not so realistic for FRC but figuring out how to navigate under water would be useful for NURC.

I suppose there are two ways of looking at this, either you can define a problem and develop a solution or you could define a solution and develop a problem. Personally, I prefer knowing my problem first as it means I can more easily break it down into sub problems to be solved.

As for crazy drive trains, why not do a definitive test 14 wheel drive (703) compared to 6wd or 8wd or 2wd? It might be that having more wheels has benefits that we can't see easily.

As far as problems you might want to look into solving I would suggest climbing stairs (6" or more) or navigating on a narrow area (see 2004 field centerpiece for example). These are challenges a lot of FRC teams have never faced and none of the students still on teams have faced.

Bill Beatty 10-06-2010 10:53

Re: Crazy Drive Train Ideas
 
Speaking about wild drives, does anyone remember and have any information on a wild drive I saw on a web cast a few years ago? It had three flats driven between two disks. I think the robot was decorated to look like a cow. I still haven't figured out just how that thing worked. A picture would be great.

Mr. Bill

MrForbes 10-06-2010 11:42

Re: Crazy Drive Train Ideas
 
Speaking of stairs, designing an FRC sized legged robot would be a great exercise, and if you can figure it out, might even work in a real game.

My son's friend Matt made a smaller one, and although the mechanics would probably have to be quite different (crankshafts/connecting rods for legs?) the programming could be similar. You never know where this kind of thing will lead.

http://www.technewsarizona.com/Artic...0091220&t=0600

Alex Cormier 10-06-2010 11:44

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Bill Beatty (Post 966122)
Speaking about wild drives, does anyone remember and have any information on a wild drive I saw on a web cast a few years ago? It had three flats driven between two disks. I think the robot was decorated to look like a cow. I still haven't figured out just how that thing worked. A picture would be great.

Mr. Bill

That would be team FRC 276. I had the pleasure of competing against them in 2003, 2004, and 2005 at Buckeye.

http://www.chiefdelphi.com/media/photos/15308

Mr. Tech Vike 10-06-2010 12:54

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by dodar (Post 966057)
i think it would be cool to see a crab-drive tankdrive robot :ahh:

my team did that this year we programed for a skid-steer and crab. all we had to do is make sure the wheels were lined up and in hae right direction (you can get turned around pretty easy) but all we had to do is hold down a button on our joy sticks.

JamesCH95 10-06-2010 13:31

Re: Crazy Drive Train Ideas
 
I've seen teams with two sets of tank drives oriented 90deg apart with the ability to switch between the two. That is an interesting problem to think through or build.

Can you make a robot that moved like an inch worm?

What about a tread design like The Pack Bot? Talk about being robust...

Have fun with your prototyping!

Hawiian Cadder 10-06-2010 14:54

Re: Crazy Drive Train Ideas
 
looking at the challenges up above i believe i have found a form of locomotion that would satisfy all of them.

a robot that uses Augers to contact the ground.


http://www.youtube.com/watch?v=1uynmApjhWI

better yet, a robot of this type would be somewhat holonomic if the augers were separately driven, it would also have incredible amounts of traction, even more than tank treads i believe. it could go up stairs if the auger diameter were large enough, and if the Augers were hollow or could float, it might contribute to a water game. i suspect that depending on the pitch of the augers, not much gear reduction would be needed for a working robot, a single AM stack-box would probably do the trick.

EricH 10-06-2010 16:45

Re: Crazy Drive Train Ideas
 
Build a drivetrain that can handle corn. You just might need it...

jamie_1930 10-06-2010 18:16

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 966081)
i just came up with another one, make a robot that is entirely encased in a hollow sphere with omni wheels on every corner facing outward, to drive the main part of the robot drives the inside of the sphere, if we ever get a water competition this would be highly helpful i think.

This is a drive train I've been pondering for a while and I would love to make it.

CENTURION 10-06-2010 19:32

Re: Crazy Drive Train Ideas
 
This is basically what I've been doing for the past few weeks straight :P

Specifically, I've been attempting to find a way of making a demo/promotional robot that our team can show off to schools, potential sponsors, and the general public (especially when we do recruiting for our summer camp).

I personally have been wanting to tackle the problem of an off-road sort of drivetrain, so I've been experimenting.

For now my favorite solution is off-road swerve/crab drive, using two wheels on each pod (ok, I'll admit, the two-wheels part is mostly to make it look cooler, but it would have it's benefits: traction, weight distribution on soft material, etc)
Each pod would be individually rotated via an FP or Window motor, and would raise and lower via a pneumatic piston and some guide bars. (the pistons could be pressurized somewhat to create a passive suspension system).

I will upload some sketches and better explanations later...

548swimmer 10-06-2010 20:00

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by jamie_1930 (Post 966191)
This is a drive train I've been pondering for a while and I would love to make it.

http://xkcd.com/413/

'nuff said.

Chris is me 10-06-2010 20:00

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by CENTURION (Post 966201)
For now my favorite solution is off-road swerve/crab drive, using two wheels on each pod (ok, I'll admit, the two-wheels part is mostly to make it look cooler, but it would have it's benefits: traction, weight distribution on soft material, etc)
Each pod would be individually rotated via an FP or Window motor, and would raise and lower via a pneumatic piston and some guide bars. (the pistons could be pressurized somewhat to create a passive suspension system).

You may be interested in this whitepaper. 1114 made a swerve drive somewhat similar to this in 2004.

jamie_1930 10-06-2010 22:12

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by 548swimmer (Post 966205)

That is actually infuriating that is exactly how I wanted to go about it, minus the webcam although it is a nice addition.

NickE 10-06-2010 22:26

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 966081)
i just came up with another one, make a robot that is entirely encased in a hollow sphere with omni wheels on every corner facing outward, to drive the main part of the robot drives the inside of the sphere, if we ever get a water competition this would be highly helpful i think.

Have fun putting bumpers on that robot. ;)

daltore 11-06-2010 02:16

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by 548swimmer (Post 966205)

First let me say that I dearly love XKCD and Randal Munroe. But he got it wrong. Just take a good look at those "omni wheels". They're mecanum...

I've been looking into making a drive train I recently read about in Servo magazine: Melty Brain. Basically, it's an effectively holonomic robot (overall it is, but instantaneous moments it isn't) that can be driven with only one wheel and one motor, but you can technically use as many wheels and motors as you want if you've got a fast enough processor. This site has a good explanation:

http://www.spambutcher.com/meltyb.html

I want to preface this description with the note that this drive train is absolutely terrifying, but if it's crowds you want, then crowds you'll have. The robot spins up really fast in a circle (no gear reduction on the wheels, in fact depending on wheel diameter, the CIM's might be a little slow) using the motor[s], and very precise timing allows you to vary the motor speed at specific points in the circle to effect a net vector that allows the robot to move around. If you think of it in terms of a polar graph, to go forward, you'e have a base speed, at 0, the motor would be going faster than that base speed, at PI/2 and 3PI/2, the motor would be spinning at the base speed, and at PI, the motor would be slower than base speed.

This is a fairly easy drive train to build (although it's harder with the size of robot you're building, you have to make sure the center of mass is relatively stable and all of your frame connections are very solid, otherwise the robot might try to rip itself apart). The hard part of this type of drive train is the code. You have to have either one accelerometer and know its radius away from the center of mass (the axis of rotation), or two accelerometers inline and know the distance apart (I like that one because it means you can change batteries without necessarily recalibrating). You measure the centripetal acceleration with the accelerometers, and with the radius information, you can figure out angular velocity. You effectively integrate that (multiply the calculated angular velocity in one loop by the amount of time between loops, then do it again next time and keep a running sum), and you'll end up with your angle. The angle is used to calculate wheel speed. The motor control is very simple, and can in fact be done with a PWM-capable pin and a large Darlington transistor or power transistor and a gate driver (the Darlington transistor is usually used because you can pick one up at Fry's for under $5).

I'd suggest making a small one (at least at first, probably a good size to keep it though) out of a small piece of 1/4" Lexan or plywood and a Fisher-Price motor and a Lite-Flite or equivalent high-traction wheel, and seeing how it goes before you think about moving up to anything bigger and more dangerous. It's been done before, but all for antweight (and one beetleweight) combat robots, so it would be cool to see what you guys come up with to do with it. An idea I had was to use a line of LED's and write messages in the air while it's spinning, but there are probably lots of other things you could do with it.

Chris is me 11-06-2010 07:32

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by jamie_1930 (Post 966224)
That is actually infuriating that is exactly how I wanted to go about it, minus the webcam although it is a nice addition.

Why is it infuriating?

Anyway, if you want a crazy drivetrain idea... Figure out a 4wd drivetrain that is not vulnerable to pushing that goes over the bumps that can turn. I wish I figured that one out...

JamesCH95 11-06-2010 08:53

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Chris is me (Post 966248)
Figure out a 4wd drivetrain that is not vulnerable to pushing that goes over the bumps that can turn. I wish I figured that one out...

One that uses ackerman steering with zero mechanical trail :)

Chris is me 11-06-2010 08:54

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 966253)
One that uses ackerman steering with zero mechanical trail :)

It also has to zero point turn, sorry. :P

I saw one solution this year. Very forehead-slap moment for me. (Edit: I think with some adaptations, that same drivetrain could outperform a Nonadrive. Wait... I think I just inspired myself. CAD time!)

JamesCH95 11-06-2010 08:58

Re: Crazy Drive Train Ideas
 
Pictures of the solution? Or Nonadrive for us un-initiated?

Chris is me 11-06-2010 09:18

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 966255)
Pictures of the solution? Or Nonadrive for us un-initiated?

*spoiler alert for teams that want to guess :)*

The pictures available don't show it, but 195 had a drivetrain with 4 high traction wheels. To turn, they had drop down omni wheels in line with the back wheel axles. It was an extremely clever solution that I feel stupid for not thinking of when I wanted a 4wd this year.

As for the adaptation, let me work on that one for a bit.

Andrew Remmers 11-06-2010 09:38

Re: Crazy Drive Train Ideas
 
I would like to make an adaptable drive train that is easily suited for most kinds of game play or game types

JesseK 11-06-2010 11:00

Re: Crazy Drive Train Ideas
 
What do you mean by "outperform" the nonadrive? Considering that the nonadrive effectively addresses a multitude of issues with both omni and 4wd while combining their strengths (and even manipulating a perceived weakness of 4wd), saying a drive train will outperform the nonadrive is a very broad, boastful statment...

Additionally, until you've driven a drive train with "modes" (linkage in 2008/09, nonadrive as implemented in '10), you really don't get a feel for the true power of a manipulatable center of rotation.

Chris is me 11-06-2010 20:32

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JesseK (Post 966268)
What do you mean by "outperform" the nonadrive? Considering that the nonadrive effectively addresses a multitude of issues with both omni and 4wd while combining their strengths (and even manipulating a perceived weakness of 4wd), saying a drive train will outperform the nonadrive is a very broad, boastful statment...

Additionally, until you've driven a drive train with "modes" (linkage in 2008/09, nonadrive as implemented in '10), you really don't get a feel for the true power of a manipulatable center of rotation.

The random idea I thought of when I made the post had the capability of doing particular features better than a Nonadrive base. It was rashly typed, yes, but also an example of the kind of thinking that could get you to think up your next "creative" drivetrain. Start looking at drives that arent 6-drop and what advantages they have, and how to work around their drawbacks. Evolution is innovation.

CENTURION 14-06-2010 00:17

Re: Crazy Drive Train Ideas
 
ok, here's a few sketches if you care to take a look:

This is 8-wheel swerve drive, with modules that can be raised and lowered (you can ignore pretty much all of the math and notes on there, that was me doing figuring on amounts of material for the whole bot)

(I will hopefully have Sketchup models done soon)

http://s226.photobucket.com/albums/d...rent=001-3.jpg

This is a triangular(ish) robot, with a single swerve module in the middle, and basically a kiwi drive around it (three omni's, each powered by a FP/Window Motor). The only reason the omni's are powered is to keep the robot from spinning wildly when you try to rotate the swerve module.

http://s226.photobucket.com/albums/d...rent=002-1.jpg

548swimmer 23-06-2010 01:12

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Chris is me (Post 966257)
*spoiler alert for teams that want to guess :)*

The pictures available don't show it, but 195 had a drivetrain with 4 high traction wheels. To turn, they had drop down omni wheels in line with the back wheel axles. It was an extremely clever solution that I feel stupid for not thinking of when I wanted a 4wd this year.

As for the adaptation, let me work on that one for a bit.

We used that method as well, and it made so much sense once someone said it that everyone else was amazed they didn't figure it out themselves. Though, if you want to be picky, it is technically a 6 wheel drivetrain.

Bjenks548 23-06-2010 14:24

Re: Crazy Drive Train Ideas
 
So I have another drive train running through my head. I was wondering what gear ratio would be used to power an individual wheel using a ban bot moter and what it would be for a fisher price moter. Also I thought i remebered that we only get 2 bb and 2 fp moters, is that right?

JamesCH95 23-06-2010 16:56

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Bjenks548 (Post 967439)
So I have another drive train running through my head. I was wondering what gear ratio would be used to power an individual wheel using a ban bot moter and what it would be for a fisher price moter. Also I thought i remebered that we only get 2 bb and 2 fp moters, is that right?

ban bot motor? err... :confused:

Yes, teams typically get 2 FP motors.

What sized wheel?
How fast do you want to go?

Divide the circumference of the wheel by 85% of the motors free speed (a rough approximation for full speed under load) then multiply by the gear ratio (1:15 reduction would mean multiplying by 1/15th) and there's your top speed.

Generally 5ft/s is a good pusher robot, 8ft/s is quick with good acceleration, and 11ft/s is FAST with moderate acceleration.

Chris is me 23-06-2010 17:04

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 967453)
ban bot motor? err... :confused:

For example, this year's RS-555's that no one used.

Quote:

Generally 5ft/s is a good pusher robot, 8ft/s is quick with good acceleration, and 11ft/s is FAST with moderate acceleration.
With 4 CIM motors. Your acceleration will take a hit as will your pushing ability *using other motors*

Hawiian Cadder 23-06-2010 22:19

Re: Crazy Drive Train Ideas
 
if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

Chris is me 23-06-2010 22:25

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 967476)
if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

Unfortunately, the metal or plastic digging into the carpet would have been an illegal traction device this year, if I understand correctly.

Alan Anderson 23-06-2010 22:34

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 967476)
if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

Use mecanum wheels. They work based on almost exactly the same effect, and they have two major advantages. First, they are carpet-friendly. Second, they will actually work. :rolleyes:

M.Wong 23-06-2010 23:13

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by ,4lex S. (Post 966049)
BALL DRIVE!!!

One large ball with a traction wheeled motor rolling said ball in the y direction, and another in the x. I can't see this ever being practical, but it would be fun to build and program.

We did this for a community outreach robot. Instead of treaded wheels we used omni wheels. At first, he was designed to balance on it, but we decided to put some casters on him. The large basketball we used got worn down to the fabric.

548swimmer 23-06-2010 23:42

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by M.Wong (Post 967481)
We did this for a community outreach robot. Instead of treaded wheels we used omni wheels. At first, he was designed to balance on it, but we decided to put some casters on him. The large basketball we used got worn down to the fabric.

How did you secure the ball? That's the only issue I have with ball drives.

Lil' Lavery 23-06-2010 23:48

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JesseK (Post 966115)
I don't understand why all teams want the drive train to do everything for mobility. If the rules allow for it, why has no one even prototyped something like a tethered Quad Rotor that lifts off and gets the game object? Sure, the thing would probably get beat up during a finals match but the sheer success in prototype will spur a LOT of creative thought come build season. Of course just implementing a quad rotor with limited amounts of motors is a feat and requires its own innovations worthy of patents and PHD's, heh. Then there's the control component, which many programmers would salivate at the chance to do, and the sensor feedback component which boggles the mind of even the smartest professionals.

If only a tether wouldn't prevent them from doing this...

Hawiian Cadder 23-06-2010 23:54

Re: Crazy Drive Train Ideas
 
augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

Collin Fultz 24-06-2010 07:21

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 967488)
drives would achieve holonomicacy.

/tangent/

I'm not 100% sure this is a word, but if not, it should be. Or would it just be holonomicy? Either way, it's finding it's way into my vocab.

/tangent/

Jared Russell 24-06-2010 07:50

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 967488)
augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

Think of the interactions between the "ribs" of the auger and the ground. In order to move, there will necessarily be slip. Slip means that you have (sometimes significantly) less available tractive force - remember the differences between static and dynamic friction. So you will accelerate more slowly - and push with less force - than with a mecanum wheel.

Additionally, it is hard to find a material that can slip against the carpet, yet still have traction, yet won't destroy either the carpet or itself very quickly. The analogy would be if you made a "kiwi" drive (wheels at 45 degree angles to the body) with regular wheels - everything would scrub the ground all the time. It kills your wheels, it kills the carpet, and it kills your efficiency.

All of this goes out the window (somewhat) if you are driving in sand, but otherwise I would think long and hard before implementing this.

gblake 24-06-2010 08:46

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Collin Fultz (Post 967513)
/tangent/
it's finding it's way into my vocab.
/tangent/

/tangent//tangent/

Argh!!!!!! Please say it isn't so!

Good words already exist. Take the time to discover and use them. Vocabulary and writing skills are important. Practice using existing words precisely instead of cluttering your vocabulary with ambiguous jargon that only creates the illusion of technical information.

FYI - Most good employers care greatly about this....

/tangent//tangent/

Blake

JesseK 24-06-2010 09:26

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Lil' Lavery (Post 967487)
If only a tether wouldn't prevent them from doing this...

Make an offseason t-shirt bomber and it can do that ;). Make it a gimbaled tilt-quadrotor and then it can do spins while flying on it's side to wow the crowd in a match. Heh, make it a gimbaled quad-tiltrotor powered from a single motor and you can write your meal ticket for life almost. (It's theorectically mechanically feasible, but quite complex to do.)

Then there's the element of autonomous maneuvers that the driver could command the quadrotor to do during the match. It brings about a systems range of questions, ranging from how the user inputs the command at the driver's station to how the quadrotor interprets an executes the maneuver regardless of its current orientation or flight path.

lim shi hao 28-06-2010 07:15

Re: Crazy Drive Train Ideas
 
how about combining all the omni-directional drive together??

Tom Ore 29-06-2010 17:23

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Hawiian Cadder (Post 967488)
augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

Not sure if this link has been posted earlier in the thread but here it is:

http://www.youtube.com/watch?v=L3NGCL-efRM

Chris is me 29-06-2010 17:29

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Tom Ore (Post 967897)
Not sure if this link has been posted earlier in the thread but here it is:

http://www.youtube.com/watch?v=L3NGCL-efRM

You'll note the machine in the video is running on a surface that deforms under the auger-wheels. How do kinematics when the surface fails work differently than on a stable carpeted surface?

Ian Curtis 29-06-2010 22:15

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Chris is me (Post 967898)
You'll note the machine in the video is running on a surface that deforms under the auger-wheels. How do kinematics when the surface fails work differently than on a stable carpeted surface?

This video seems to say it works just as well. :)

If any team wants to mold some enormous Archimedes screws like those, I'd bet you win some kind of technical award. Making weight would be fun though... :p

Jared Russell 30-06-2010 07:26

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by iCurtis (Post 967914)
This video seems to say it works just as well. :)

If any team wants to mold some enormous Archimedes screws like those, I'd bet you win some kind of technical award. Making weight would be fun though... :p

Nobody is saying you can't get a screw drive to move - just that it will be much, much more inefficient than just about anything else on terrain that isn't sand or snow.

JamesCH95 30-06-2010 07:36

Re: Crazy Drive Train Ideas
 
With 130+lbs on the screws good luck not damaging the carpet from driving or getting pushed around.

Tom Ore 30-06-2010 16:28

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 967935)
With 130+lbs on the screws good luck not damaging the carpet from driving or getting pushed around.

From the video, it looks like a rather high lead thread is required to get the speed ratios correct (fore/aft versus sideways). Maybe a multi start thread could be used to keep the lead high but provide more surface area in contact with the ground.

gblake 30-06-2010 16:37

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 967935)
With 130+lbs on the screws good luck not damaging the carpet from driving or getting pushed around.

Maybe someone can have fun making an omni/mechanum auger. Get a big hollow drum and mount (or cut slots to hold) a ribbon of ball bearings, or of rollers, in a barber-pole spiral around the drum's outer surface.

I'm not saying it would be ideally suited for any games other than those containing the fabled FRC water hazards; but it could be fun to make. If you chose the materials carefully, you might be able to create a fun off-road machine that isn't stymied by swampy terrain, and that is also at home on FRC carpets.

Blake

Bjenks548 30-06-2010 21:29

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by iCurtis (Post 967914)
This video seems to say it works just as well. :)

If any team wants to mold some enormous Archimedes screws like those, I'd bet you win some kind of technical award. Making weight would be fun though... :p

Any idea on how it would work on corn?

JamesCH95 11-07-2010 23:18

Re: Crazy Drive Train Ideas
 
How about this?

DinerKid 12-07-2010 06:42

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 968771)

This will be my favorite robot of the day. That is totally sick. My mom walked by while i was watching it and thought it was real. I want to know what snake makes that sound though.

~DK

penguinfrk 14-07-2010 20:14

Re: Crazy Drive Train Ideas
 
Cam drive. Worst mobility, best entertainment quality. You can only rotate the wheels in one direction, and if the wheels are placed on out of phase, you have this crazy tumbling thing. If put on in phase, you have a sort-of robot low rider that can pounce onto objects. If put on reflected, it's like a carousel.

How cool!

Bjenks548 17-07-2010 10:57

Re: Crazy Drive Train Ideas
 
Haha as cool as some of these ideas are, like the snake one :yikes: , i was more looking for odd wheel arrangements like the close center wheel 6 wheel that 548swimmer posted a few weeks ago. We were also planing on making a jump drive before it even came on chief delphi, stuff like that.

gblake 17-07-2010 13:25

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 968771)

Why is the snake surrounded by a blurry aura in that video? It is using a prototype cloaking device or...

Is the video perhaps a fake?

JamesCH95 17-07-2010 21:55

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by gblake (Post 969206)
Why is the snake surrounded by a blurry aura in that video? It is using a prototype cloaking device or...

Is the video perhaps a fake?

I think that's an artifact of the video compression.

I highly doubt that the video is a fake, here is the inventor's website, with all of the earlier and later versions.

penguinfrk 13-09-2010 02:27

Re: Crazy Drive Train Ideas
 
Gallop (Cam) Drive

(Change the phase difference for Low Rider drive!)

Katie_UPS 13-09-2010 19:51

Re: Crazy Drive Train Ideas
 
I always wanted to see a big-wheel robot. :P

theprgramerdude 13-09-2010 20:27

Re: Crazy Drive Train Ideas
 
With high gear reductions and large wheels instead of small wheels and low reductions?

Turbo-fan powered drive?

Bjenks548 13-09-2010 20:36

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Katie_UPS (Post 974085)
I always wanted to see a big-wheel robot. :P

How big of wheels? we had 12" this year and i think 107(maybe a different team I'm going off memory) had the same ones too.

theprgramerdude 13-09-2010 20:37

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 967935)
With 130+lbs on the screws good luck not damaging the carpet from driving or getting pushed around.

Pushed on a screw drive? Bahahahahahahahahahahaha

davidthefat 13-09-2010 21:57

Re: Crazy Drive Train Ideas
 
Legs with legs


Nuff said

Here is a picture of it:


Mageofdancingdr 14-09-2010 02:55

Re: Crazy Drive Train Ideas
 
Train drive, with pneumatics.

hook up pneumatic pistons to crankshafts and as the pistons go in and out they create torque on the axel. most powerful drive system ever.

DinerKid 14-09-2010 06:45

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Mageofdancingdr (Post 974108)
Train drive, with pneumatics.

hook up pneumatic pistons to crankshafts and as the pistons go in and out they create torque on the axel. most powerful drive system ever.

It has been done with Vex a few times. The issue is that the system eats air like crazy.

http://www.vexforum.com/showthread.p...eumatic+engine

~DK

JamesCH95 14-09-2010 08:35

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Mageofdancingdr (Post 974108)
Train drive, with pneumatics.

hook up pneumatic pistons to crankshafts and as the pistons go in and out they create torque on the axel. most powerful drive system ever.

The compressor is just about the least powerful motor in the KOP, so that drivetrain will be about the least powerful. It could have high pushing force though.

Jared Russell 14-09-2010 19:52

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Bjenks548 (Post 974089)
How big of wheels? we had 12" this year and i think 107(maybe a different team I'm going off memory) had the same ones too.

You should see 522 :)

Aren_Hill 14-09-2010 20:11

Re: Crazy Drive Train Ideas
 


One of Mr Pat Fairbanks pictures from 08

Trent B 14-09-2010 21:51

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 974124)
The compressor is just about the least powerful motor in the KOP, so that drivetrain will be about the least powerful. It could have high pushing force though.

Gotta love semantics.

It would probably have the most pushing force, most powerful over the time period where there is enough air in tanks. Over the whole match probably the weakest.

Jared Russell 15-09-2010 07:14

Re: Crazy Drive Train Ideas
 
FRC rules have traditionally allowed energy to come from 4 sources:

-Battery
-Stored air
-Stored gravitational potential energy
-Deformation of robot parts

The fourth one could make for an interesting drive system (a "wind up toy"). Albeit one that would take a lot of engineering to make safe enough - yet powerful enough - to be useful.

JamesCH95 15-09-2010 09:47

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Trent B (Post 974180)
Gotta love semantics.

It would probably have the most pushing force, most powerful over the time period where there is enough air in tanks. Over the whole match probably the weakest.

Hehe, I suppose it is a little semantic, but there is a lot to be said for using precise and correct language, especially in the field of engineering.

AdamHeard 15-09-2010 15:09

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Trent B (Post 974180)
Gotta love semantics.

It would probably have the most pushing force, most powerful over the time period where there is enough air in tanks. Over the whole match probably the weakest.

I'd argue pushing force is completely independent and unrelated to the power source.

EricH 15-09-2010 15:24

Re: Crazy Drive Train Ideas
 
Possible pushing force might be unrelated, as there is only so much traction available from a given set of wheels.

Given a non-traction-limited drivetrain, however, where you get the power from can make a big difference. For a pneumatic drivetrain, if you can't keep the tanks full, you'll lose pressure quickly. The compressor would probably have a hard time keeping up with pressure loss in that case. But a motor-driven drivetrain does not have that problem, at least until the battery dies.

JamesCH95 15-09-2010 15:38

Re: Crazy Drive Train Ideas
 
^ exactly like that EricH said, the total integral work possible (not including mechanical inefficiencies) using the compressor for a whole match is 10.1kJ, whereas running 1 cim motor at full power for the whole match is 47.3kJ. So one CIM motor is nearly 5 times as powerful, and with proper gearing can deliver the same pushing force as pneumatics would.

What this says is that you need a compressor powered by several CIM motors :p

kgzak 15-09-2010 16:48

Re: Crazy Drive Train Ideas
 
Mecanum swerve :yikes:

buildmaster5000 15-09-2010 17:40

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by kgzak (Post 974244)
Mecanum swerve :yikes:

That would defeat the purpose of swerve: low traction omni drive is simply mecanum. The whole point of swerve is to have high traction omni drive

kgzak 15-09-2010 22:51

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by buildmaster5000 (Post 974255)
That would defeat the purpose of swerve: low traction omni drive is simply mecanum. The whole point of swerve is to have high traction omni drive

we were talking about it for a test platform. that way programers have a robot that you can run a few different drivetrains without having to change anything. It kinda became a joke throughout the season because we didn't know whether we wanted swerve or mecanum. I realize that it is on of the most pointless designs.

Mountain Man 16-09-2010 00:27

Re: Crazy Drive Train Ideas
 
See below.

http://www.chiefdelphi.com/forums/sh...threadid=86862

Mageofdancingdr 16-09-2010 02:22

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 974240)
^ exactly like that EricH said, the total integral work possible (not including mechanical inefficiencies) using the compressor for a whole match is 10.1kJ, whereas running 1 cim motor at full power for the whole match is 47.3kJ. So one CIM motor is nearly 5 times as powerful, and with proper gearing can deliver the same pushing force as pneumatics would.

What this says is that you need a compressor powered by several CIM motors :p

what if you create a shifting mechanism between pneumatics and CINs, so you can push with pneumatics engaged and drive with the CIM motors?

also, when I was thinking of power, I was thinking of the power during the time before the tanks ran out, which I think would be more powerful than the CIMs during the same time period (how would I do the math to find out though, where is the power rating for a cylinder?)

Ether 16-09-2010 08:17

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Mageofdancingdr (Post 974290)
I was thinking of the power during the time before the tanks ran out, which I think would be more powerful than the CIMs during the same time period (how would I do the math to find out though, where is the power rating for a cylinder?)

The power you can get from pneumatics on FRC is limited not by the cylinder, but by the solenoid ⅛” NPT port diameter and maximum Cv of 0.32

You can use solenoids in parallel to mitigate this somewhat, but other fittings and line losses limit what you can achieve.

A CIM has a maximum power of 337 watts, but this can be sustained only briefly, not the entire match.



JamesCH95 16-09-2010 09:19

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by Mageofdancingdr (Post 974290)
what if you create a shifting mechanism between pneumatics and CINs, so you can push with pneumatics engaged and drive with the CIM motors?

also, when I was thinking of power, I was thinking of the power during the time before the tanks ran out, which I think would be more powerful than the CIMs during the same time period (how would I do the math to find out though, where is the power rating for a cylinder?)

It is possible to do what you've described, but it is probably more cost and weight effective to use a shifter transmission because you will be traction limited.

And... what is this? A student who wants to know how to the math?! I'm confused and terrified right now :D more on this later...

Quote:

Originally Posted by Ether (Post 974294)
The power you can get from pneumatics on FRC is limited not by the cylinder, but by the solenoid ⅛” NPT port diameter and maximum Cv of 0.32

You can use solenoids in parallel to mitigate this somewhat, but other fittings and line losses limit what you can achieve.

A CIM has a maximum power of 337 watts, but this can be sustained only briefly, not the entire match.


What Ether said, though IIRC it's the internal valve diameter that severely limits flow through a solenoid, and I can't remember the dimensions off-hand. And yes, a CIM cannot be run full-power for an entire match (probably not more than once, anyway), though 4 Cims could likely be run at an average of 1/4 power (maybe more?) for a whole match. This would be an interesting experiment.

Back to the math...

I assume you are referring to using pneumatics in a reciprocating-piston setup, in which case you can calculate a theoretical power output using ideal Otto cycle calculations, where your volume values are computed by geometry, and your pressure values are determined from approximate flow rates through the supplying solenoid(s).

Edit: it won't be exactly like an Otto-cycle calculation, but it will be close, you'll be integrating work done in a PV chart.

JesseK 16-09-2010 10:53

Re: Crazy Drive Train Ideas
 
The pneumatic cyllinder feasibility problem appeared simpler to me when I thought about it a few months ago. Simply add it in as a "turbo boost" to an existing drive train via a 1-way clutch or paulet system. Linking the two rear drive train axles together with 1 shaft (or 2 shafts + differential) would easily allow for this functionality.

Once implemented, we can analyze the weight: it's about ~15lbs extra, just for a brief turbo boost once or twice in a match. YMMV, but it wasn't worth it for me to investigate further.

Jared Russell 16-09-2010 11:15

Re: Crazy Drive Train Ideas
 
If you're hung up on the idea of a pneumatic drive (store energy, then expel it all in one forceful lunge forward), you could accomplish the same thing by using a far more efficient motor, like a CIM, to compress a spring or gas spring (like many kickers did this year).

Trent B 16-09-2010 11:23

Re: Crazy Drive Train Ideas
 
Quote:

Originally Posted by JamesCH95 (Post 974216)
Hehe, I suppose it is a little semantic, but there is a lot to be said for using precise and correct language, especially in the field of engineering.

I know the correct usage of power, the problem is so many people don't so for the average person it seems to have a tendency to have qualities of semantics. Gotta love common english language and its distortion of terms to mean other things.


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