What do you think of the jaguars?

[utlinebacker]

Originally Posted by Tom Line

I'm not sure how willing IFI or Micro-Luminary would be to share comparable failure rates, but that's the only way you're going to get a real answer to that question.

It has been a few weeks since I have checked in on CD. We have been busy visiting various regional events and ensuring that teams have a great experience with their Jaguars. I figured this was as good a place as any to post this - since it is precisely where someone asked for it! We have provided this document to FIRST - and we will soon distribute it to each and every team that returned a Jaguar to us for failure analysis.

If you are going to Atlanta - and you happen to have a failure, let me know. We'll be there in force to keep you in the competition! Good luck!

Luminary Micro people to look for in Atlanta (wearing Luminary Micro apparel):
Jonathan Guy - Director of Systems and Software
Brian Kircher - Sr. Software Engineer
Scott McMahon - Sr. Systems Engineer
Kyle Norman - Applications Engineer
Jean Anne Booth - Founder, Chief Marketing Officer
Scott Emley - Product Marketing Manager

Regards,
Scott

[Vikesrock]

Thank you for posting this detailed report Scott. LM has done an excellent job throughout the season of answering our questions on this forum and provided the requested transparency and in many cases seems to have gone well above and beyond the call of duty.

I have seen numerous mentions to the possibility of swarf creation through the use of ring terminals. Is there any plan to fix this in future revisions. I know that at least for my team, we much prefer ring terminals to spade terminals for increased security of the connection. In a competition environment I just don't trust spade terminals even with proper strain relief.

[s1900ahon]

Originally Posted by Vikesrock

I know that at least for my team, we much prefer ring terminals to spade terminals for increased security of the connection. In a competition environment I just don't trust spade terminals even with proper strain relief.

Is the security you seek is to avoid the situation where a screw terminal loosens due to vibration and you think that a spade terminal might then become detached, because of gravity and the mounting orientation or spring force in the wire?

If so, you might consider starting with a ring terminal and cutting a small slot in the ring in a direction that isn't in line with the disconnecting force. For example, if I were to mount a motor controller on a vertical surface with the terminals up and down (up=M+/M-, down=V+/V-) I would cut the down rings at the 5 or 7 o'clock position so that I could slide the ring on knowing that if the V+/V- screw terminal loosened somewhat the wire won't disconnect due to the wire being pulled down.

Just a thought in an attempt to avoid removing the terminal screw while also avoiding the effects of vibration on a terminal screw.

[XXShadowXX]

I here bad thing after bad thing about jags, and every meeting and event i waited for them to fail, screw up, or release the magical smoke that makes them run. It never happened, so I am happy to report that we have had no issue with the jagaurs this year.

[Mrpresident1776]

They worked okay for 1507 (the Warlocks) at both Finger Lakes and Philadelphia. However, we fried our first Jaguar today in our last practice match. It took out our right drive train and rendered us a sitting duck for the match.
When I saw we weren't moving, my first though was a fried drive motor gearbox (happened once at FLR and once at PHL). Luckily, the Jaguar was a quicker fix (5m vs 15m) and we got a replacement from Luminary Micro.
I guess it's an okay piece of equipment although the PWM slot should be improved.

[pyr0b0y]

Our team had the same problem as mrpresident, half way through competition one of our jaguars totally stopped responding in one direction....plus they are a lot bigger that the victors. Although the jaguars are pretty straightforward to install, it doesnt mean they are as good as the victors. I used victors for 4 years in high school and never had one problem with them!

[,4lex S.]

Despite the supposed better reliability of the Vic's, we couldn't drag our programmers off of the Jaguars once they realized they had more linear output.

We only lost one, and it was promptly replaced by a Luminary Micro rep. I think the static problems of the regolith may have amplified the related failure rate this year. As long as you read the instructions, and it isn't a defective unit, they seem to work quite well.

[coalhot]

This year 304 only had one Jag fail, and that was because I put the voltage in in the motor out . (happens)...

One upside i will mention is that after blowing up the jag, it was very easy to get the technical data, and get the replacement parts. One night at the soldering iron, and the Jag was fixed. Especially after researching Victors(never had to service one, always had enough spares), the tech data came in so usefull.

--Philip

[artdutra04]

Maybe to counter some of the bias that appears in these threads (people with negative experiences tend to speak up more often), that apart from the increased real estate the Jaguars eat up, we've had absolutely no operational issues with them on both our competition and practice robots. Since we still have a bunch of Victor 884s around, we only used the four Jaguars that came in the KoP, two on the drive train of each robot.

Once our supply of Victors runs out (or as soon as they allow us to use the CAN bus and the advanced features of the Jaguars), we'll be using Jaguars for most functions on our robots except in locations where space is an issue. *cough* smaller Jaguars would be awesome *cough*

[lynca]

Originally Posted by artdutra04

we've had absolutely no operational issues with them on both our competition and practice robots.

Same here, we have driven the Jags for hours of Regional and Championship play without any issue the entire season.

[shgshgshgshg]

As far as speed control they are much better than the victors, but My team had some problems with them too. One of them came to us broken, and it took a while to get back to us with a good one. I think that it has a lot of potential, but if the manufacture can increase the durability of the controller a little bit it could be a great replacement for the victor...

[Steigerwald]

We managed to kill 4 the same way on out test bot. Basically, you need to make sure that it is not getting power from the motor when there is no power from the battery. We had our gearboxes set up with 2 cims each. When we wanted to test with only one cim per side, we just removed the power from the jaguar and not the motor. The unpowered motor acted like a generator and put a current back into the speed controller. It killed a tiny resistor at R5.

[Barak Shelef]

We had no problems during our build season or regional but at the second to last game in the championship we blew 2 jags at the same time... but there's a solution!

From what I understood from the guys from micro-whatever's booth in the pits, the driver gate was destroyed most likely due to static electricity backlash from the driving motors to the speed controller. caused probably because of the playing field (plastic wheels and plastic flooring) - because the robots weren't grounded to the floor, during a collision between a statically charged robot and an uncharged robot, the current might have gone back to the jaguar melting the drive gate.

If that really is the problem (supported by the statistics from utlinebacker's posted report), it can be easily fixed by adding a grounding rework from the robot. i.e. get a small wire, exposed on both ends, attach a connector to one side, bolt the connector to your chassis and let the exposed end be dragged on the field - similar to most cars. (even a small gauge wire would do the trick) And all the static charge will be immediately grounded.

However, for this to work, ALL teams must use that, otherwise even a grounded robot could be shocked by an ungrounded, charged robot. And although I find it hard to believe regolith is gonna be used next year as well, it's a good idea to do that anyways. just as a safe measure.

[galewind]

Wait, let me get this straight...does this effectively mean that you can't roll around the robot on the floor when you don't have the bot turned on? Turning wheels = turning motors, turning motors = generating power through the motor... generating power = fried jaguars?

[Hazmatt]

We used the jaguars for the main drive. Every jaguar we used failed.