[DFTF] Jags v. Vics...

[Andrew Schreiber]

Originally Posted by Ether

http://www.chiefdelphi.com/forums/sh...92&postcount=4

http://www.chiefdelphi.com/forums/sh...2&postcount=43

Context? What is this in response to?

[Ether]

Originally Posted by Andrew Schreiber

Context? What is this in response to?

Jags vs Vics. Joe's original post.

[Andrew Schreiber]

Originally Posted by Ether

Jags vs Vics. Joe's original post.

Ok, sorry I was just confused.

[Joe Ross]

We've been using Jaguars since 2009. Since then, we've used approximately twice as many Jaguars as Victors. We've had 1 jaguar failure (in the regional finals) and one victor failure (in the championship division semi-finals). I think that just shows that things fail at the worst possible times. When choosing between them, the main thing we look at is whether we need control, and if we do, we use a jaguar.

I think that poor protection of the electronics while working is a major failure contribution. The Jaguars are not conformal coated, while the Victors are. NI has also said that a significant number of cRIO failures are due to swarf.

Every time we've had the jaguar over-current protection kick in, we were able to trace it to a loose wire somewhere in the current path or a very low robot battery. In that respect, it's been helpful because it caused us to look for the root cause.

[Billfred]

2815 has never been known for its advanced sensor usage; we use Victors for the reliability after going through a metric ton of issues during 2010's collaboration effort with 1398 with the Jaguars. Your mileage, of course, may vary...but I'd need to be sold on my team actually using all of the Jaguar's features before I blessed making the switch again.

[Peter Johnson]

We used 7 black jags on CAN in 2010 and were very happy with the results. Only two issues: died in one match because we had a piece of hardware fall onto the CAN connector and disconnect it (random failure, similar thing could have happened to the cRIO or any other single-point failure on the robot), and in one other match (in division quarterfinals, scarily!) we had a cRIO bootup sequencing issue (I believe since fixed in the image) that caused the CAN driver to not start. The Jaguars were mounted vertically along the edges of the robot, and we never had one die. We used current sensing (via CAN) on our ball magnet motor to detect possession, worked great.

We used 7 black jags on CAN in 2011, and 2 victors. We had a lot of electrical issues, we believe mostly due to our control board placement (belly pan style) which led to lots of metal debris falling onto the control board. We did switch our drive motors to PWM control halfway through championships because of a couple of control issues (we believe traceable to CAN synchronous updates).

In future years we're still planning on using jags and CAN, but being more careful with our electrical board placement to avoid the debris issues we saw in 2011.

[Phalanx]

We used 4 Black Jaguars and CAN for the first time this year. We used them for our drive train. We had no issues with them in voltage control mode.

While we didn't exploit any advanced functions in the Jaguar last year, but we do plan on trying to use some this year. (we must learn to crawl before we can run).

As with all things electronic, metal shavings will be the death of it.

A few points of note:

1) We used the 2CAN device instead of serial. 10MB of bandwidth versus 128KB as well as using the 2CAN dashboard wirelessly to analyze, monitor and debug.

2) Correct cabling and proper termination are critical. There were numerous teams that I assisted with all kinds of CAN issues and 98% were solved by correct cabling and proper termination.

3) This is my personal viewpoint only. Having no basis in fact, I personally believe that the days of the Victor are numbered in FIRST and Jaguars will be the only speed controller allowed in the future. So you might as well start using them now.