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-   -   What do you think of the jaguars? (http://www.chiefdelphi.com/forums/showthread.php?t=76364)

mtaman02 03-04-2009 12:16

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by squirrel (Post 845354)
That is a great answer for those teams that have knowlegable mentors, coaches, and alumni. There are many young teams who don't have anyone who knows this stuff well, why not make things a bit easier for them?

I agree but someone still should have a basic knowledge of what M+ and M- and + - means. If I'm not mistaken the 883's and 884's were marked as such and I with no problems and no background got it right. I'm not trying to be tough even though it is coming off like that just saying there's documentation on it and if not or it's hard to find then YOU CAN ALWAYS ASK SOMEONE ON HERE @ CD!!!!! There are thousands of us here, hundreds of us on at a time so it's not like there's no ones around. There's nothing wrong with saying I need help like so many have said in the past... There is plenty of Alumni Mentors Coaches (Like Al S, Mark M and various others) that are constantly on here coaching teams through tech. specs.

So rookie teams if you need help PLEASE ASK!!! Yes it's cool to do it on your own, but it's even cooler to say I don't know please help... CDs open 24/7

MrForbes 03-04-2009 12:23

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by mtaman02 (Post 845356)
I agree but someone still should have a basic knowledge of what M+ and M- and + - means.

First you have to actually notice that there is an M on one end of the device...then you have to realize that it's important...then you might realize it means Motor. I've been in the pits on Thursday at rookie heavy regionals....

It can't hurt to mark the connections in an obvious way. How about it LM and IFI?

mtaman02 03-04-2009 12:27

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by squirrel (Post 845360)
First you have to actually notice that there is an M on one end of the device...then you have to realize that it's important...then you might realize it means Motor. I've been in the pits on Thursday at rookie heavy regionals....

It can't hurt to mark the connections in an obvious way. How about it LM and IFI?

I wasn't sure if the Jags had the same type of labeling since I didn't really look at them when I had the chance *note to self* look at Jags.

They could color code it better Red/Black since MOST of the wiring in the robot should be standard I know it doesn't end up that way but color coding might be best and then do a burn in label or just label on the sides with a much larger + or - with M or B next to it either way I'm all for making it easier, it's just getting the respective comp. attention to do it. Maybe E-Mailing them would be best???

Al Skierkiewicz 03-04-2009 13:23

Re: What do you think of the jaguars?
 
Mike and Jim,
Although the Red Black color coding is OK for the US it is not in other parts of the world. The best suggestion, now that you own the device, it take a nice, big, colored sharpie and write "POS IN", "NEG IN", "MOT +" and "MOT -" right on the cover. While you are at it, mark the Black side of the PWM cable as well. Your inspector will give you extra Brownie points.
One thing we should all be teaching is that there are documents that exist for our benefit. They come from First in the form of Manuals, Team Updates, spec sheets and KOP list. Most of the KOP suppliers have great websites that contain operating manuals and sometime service manuals and schematics.

MrForbes 03-04-2009 13:28

Re: What do you think of the jaguars?
 
Ok, I give up....

MikeE 04-04-2009 16:09

Re: What do you think of the jaguars?
 
It would be nice if Luminary put better markings on the controllers, but I agree that the DIY Sharpie solution solves the problems faster.

Back to the Jaguars...
We use 6 Jaguars in our drive system and through development, 22 matches at two Regionals (and an obscene number of practice rounds at NASA/VCU), we haven't had a single problem with them. They are mounted horizontally but under covers large enough to allow air cooling.
Due to some early design decisions we've had to rely more than we intended on the low speed characteristics of the Jaguars, and I have been very impressed with how controllable they allow the drive system to be.

Matt Howard 06-04-2009 13:15

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by MikeE (Post 845794)
We use 6 Jaguars in our drive system and through development, 22 matches at two Regionals (and an obscene number of practice rounds at NASA/VCU), we haven't had a single problem with them.

That may be true, however on the flipside of that there are teams using the same amount of Victors and have not had any problems with those either. Since our rookie year in 05' out of the 22 victors we've used, we've had a failure with 1. Which was due to carelessness. (Metal Shavings)

As much as some people like to put faith into the Jaguars, there have been too many mishaps over such a short period for them to be trustworthy in my book.

The combination of the large footprint, and less than reliable track record is what will be keeping Jaguars off of our robots until the eventual phasing out of the IFI products.

MikeE 07-04-2009 12:58

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Matt Howard (Post 846560)
That may be true, however on the flipside of that there are teams using the same amount of Victors and have not had any problems with those either. Since our rookie year in 05' out of the 22 victors we've used, we've had a failure with 1. Which was due to carelessness. (Metal Shavings)

As much as some people like to put faith into the Jaguars, there have been too many mishaps over such a short period for them to be trustworthy in my book.

The combination of the large footprint, and less than reliable track record is what will be keeping Jaguars off of our robots until the eventual phasing out of the IFI products.

One anecdote isn't a statistically significant result in either direction. However there is an understandable tendency for problems to be reported at a far higher rate than good experiences, so I wanted to throw our positive experience into the mix.
Reading all of the threads, there do seem to be some very specific issues with the Jaguars, but I suspect that a large percentage of the problems reported are due to inexperience with the controllers, not system design or manufacturing problems.

Time and careful analysis of the returns should yield a more comprehensive understanding.

Matt Howard 07-04-2009 13:10

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by MikeE (Post 846998)
One anecdote isn't a statistically significant result in either direction. ....I suspect that a large percentage of the problems reported are due to inexperience with the controllers, not system design or manufacturing problems.

I don't recall saying that it was.

As for the controllers, if the majority of problems caused really are due to user error, wouldn't we see the same types of failures with the victors in rookie teams? I can think of at least 3 rookie teams off hand that have didn't have any problems with Victors this year, and none of the students or mentors had ever used one.


The Jaguars have some neat features, but for the scale of what we are working on (HS Competition Robots) why replace something that's tried and true?

Alan Anderson 07-04-2009 13:29

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Matt Howard (Post 847005)
The Jaguars have some neat features, but for the scale of what we are working on (HS Competition Robots) why replace something that's tried and true?

Budget: A Jaguar costs less for a team to buy than a Victor.
Technical: A Jaguar has additional capabilities over a Victor. Some are usable without additional cost (though the limit switch input was disallowed by the rules this year). Others the cRIO will be able to take advantage of with a simple communication module.
I won't speculate on other reasons.

MrForbes 07-04-2009 13:50

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Alan Anderson (Post 847018)
Budget: A Jaguar costs less for a team to buy than a Victor.

This year we did the "budget" thing....we got 4 new Jaguars and one new Victor in the kit, we had a few used Victors to swipe off old robots, so that's what we used--4 Jags, 3 Victors

Matt Howard 07-04-2009 14:23

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Alan Anderson (Post 847018)
Technical: A Jaguar has additional capabilities over a Victor. Some are usable without additional cost (though the limit switch input was disallowed by the rules this year). Others the cRIO will be able to take advantage of with a simple communication module.
I won't speculate on other reasons.

Additional capabilities that we are unable to use, combined with a larger footprint and a less than reliable track record is what turns me off.

Alan Anderson 07-04-2009 16:12

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Matt Howard (Post 847036)
Additional capabilities that we are unable to use,...

Don't ignore what you were able to use:
  • built-in overcurrent protection
  • integrated pwm cable retension hook
  • status/diagnostic indicator (telling more than a Victor does)
  • high-temperature detection and shutdown

Whether any of that is beneficial (or indeed if it was detrimental to a team's intended design) is another issue.

Matt Howard 07-04-2009 22:55

Re: What do you think of the jaguars?
 
Quote:

Originally Posted by Alan Anderson (Post 847100)

Whether any of that is beneficial (or indeed if it was detrimental to a team's intended design) is another issue.

Which is exactly the issue at hand. Nobody is saying that the added features are a bad thing. However the product simply has a dubious track record at this point.

I'm sure all the problems people have been reporting will be cleared up between now and next season.

chessking132 07-04-2009 23:18

Re: What do you think of the jaguars?
 
Team 75 is using all jaguars this year and we have had only one problem. Knock on wood. In the Quarter finials of New Jersey it stooped working in the forward direction but it would go in reverse. We sent it back to Luminary Micro but they never go back to us on the cause of the problem. Other then that my only complaint is their size.

Matthew Simpson

Team 75 Driver


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