02-07-2011 11:30

Re: pic: Pigmice Northwest Drive

Looks good! Only question I have is you called it "Northwest Drive". Is this any different from West Coast Drive? If so, what are the differences and advantages/disadvantages? I'm assuming the duel omnis on the corners are for ease of turning, and that there is no drop on the center wheel because of that.

02-07-2011 15:11

Akash Rastogi

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by SuperNerd256 Looks good! Only question I have is you called it "Northwest Drive". Is this any different from West Coast Drive? If so, what are the differences and advantages/disadvantages? I'm assuming the duel omnis on the corners are for ease of turning, and that there is no drop on the center wheel because of that.

02-07-2011 23:43

Molten

Re: pic: Pigmice Northwest Drive

Just curious, why the 4 inch wheels? The smallest I've heard of in the past are 6 inches. Also, don't be nervous about posting stuff on here. It looks really good and you should be proud of your work. We may ask questions, but we try not to be too scary.

Jason

02-07-2011 23:59

NickE

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Molten Just curious, why the 4 inch wheels? The smallest I've heard of in the past are 6 inches.

03-07-2011 00:04

R1ffSurf3r

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by NickE 254 used 3.5" this year and 233's wheels were smaller.

03-07-2011 00:06

PAR_WIG1350

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Akash Rastogi This chain-path is on the outside of the frame rails. Traditional WCD has an inside chain-path. This also doesn't look like it has the characteristic bearing blocks of a real WCD.

03-07-2011 03:23

Molten

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by NickE 254 used 3.5" this year and 233's wheels were smaller. In recent years, small wheels have been one of the defining features of "west coast drive" robots such as this. Just look at the robots of two of the current world champions.

03-07-2011 03:43

R.C.

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Molten Why though? What is the functional advantage? Jason

03-07-2011 18:01

PAR_WIG1350

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Molten Why though? What is the functional advantage? Jason

03-07-2011 18:36

lemiant

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by PAR_WIG1350 Less, and thus lighter, gearing results in the same effective ratio, also the wheels are smaller. the weight savings might be enough of a reason, but smaller wheels and the associated gearing allow the motors to operate at a different, possibly more efficient part of the performance curves.

03-07-2011 18:41

MattC9

Re: pic: Pigmice Northwest Drive

I like it, but how are you attach your SS? and why did you make a "V" in front instead of adding a front rail because the rules for the bumpers this year would not allow that. How exactly are you planning to mount the bumpers to the 1' alum. tubing on the sides? and do I spy a custom center wheel? last question I promise, hex axle or keyed axle?

But looks great keep up the good work

03-07-2011 18:51

Akash Rastogi

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by PAR_WIG1350 I do believe that there have been WCD robots with the chain in both locations and even a few wit it inside of the frame rail. The real distigushing feature here is that this robot has omni-corners and no drop on the center wheel. ALL true west coast drives have droped center wheels and none use omniwheels.

03-07-2011 20:53

Molten

Re: pic: Pigmice Northwest Drive

Thanks for the responses. I knew there was a good reason just couldn't figure it out. I still have my reservations about such small wheels, but that is probably just because they are new to me.

Jason

03-07-2011 20:57

Colin P

Re: pic: Pigmice Northwest Drive

I've been thinking of a similar design, but I was planning on using 4 plaction wheels in the center with the 4 omnis in the corners. I believed this would help increase stability from being spun by other robots.
8 wheel - 4 plaction center, 4 omni corners for stability and forward pushing. No drop.

Anybody think the 4 wheel center would actually do anything to fight being spun from other robots pushing your corners?

03-07-2011 21:14

R.C.

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Colin P I've been thinking of a similar design, but I was planning on using 4 plaction wheels in the center with the 4 omnis in the corners. I believed this would help increase stability from being spun by other robots. 8 wheel - 4 plaction center, 4 omni corners for stability and forward pushing. No drop. Anybody think the 4 wheel center would actually do anything to fight being spun from other robots pushing your corners?

04-07-2011 13:54

Jeffy

Re: pic: Pigmice Northwest Drive

Many times it has been said that you shouldn't bother shifting if you are gonna have omni wheels. It's fairly accurate. You can do the math if you like, but it will be easier to spin the wheels and you won't win many pushing contests.

One other note: Low gear is defintely too slow. This past year we ran a similar speed w/ 13fps and 3.5fps. In low gear we could push without issues, but it took a very long time to get anywhere. It really wasn't worth it. Try gearing your low gear closer to the traction break point. Which will probably comeout to be 7-8fps.

04-07-2011 14:45

AdamHeard

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Jeffy Many times it has been said that you shouldn't bother shifting if you are gonna have omni wheels. It's fairly accurate. You can do the math if you like, but it will be easier to spin the wheels and you won't win many pushing contests. One other note: Low gear is defintely too slow. This past year we ran a similar speed w/ 13fps and 3.5fps. In low gear we could push without issues, but it took a very long time to get anywhere. It really wasn't worth it. Try gearing your low gear closer to the traction break point. Which will probably comeout to be 7-8fps.

04-07-2011 14:53

AdamHeard

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by Molten Thanks for the responses. I knew there was a good reason just couldn't figure it out. I still have my reservations about such small wheels, but that is probably just because they are new to me. Jason

04-07-2011 15:01

NickE

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by AdamHeard When you're driving around trying to get to places, shouldn't you always be in high gear? I know our driver stayed in our 17fps high gear 90% of the match, if not more.

04-07-2011 15:17

AdamHeard

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by NickE Agreed. I could probably count the number of times we used low gear in 2011 on one hand. Low gear is one of those things that is rarely needed in everyday match play. However, when we need it, we really need it. You can probably make low gear faster than 3.6 ft/sec, just make sure it's traction limited.

05-07-2011 09:08

Brandon Holley

Re: pic: Pigmice Northwest Drive

Quote:

Originally Posted by AdamHeard I know our driver stayed in our 17fps high gear 90% of the match, if not more.