pic: Daisy Bell Going Over The Bump

[Greg McKaskle]

The official shock rating of the cRIO and its modules is 50G's. Again, not that difficult to attain when the robot has no suspension. As a pretty predictable indication, the clip on the modules releases at over 50. Clearly the cRIO will often take more, but has not been validated or rated over 50g.

Commenting on team 704's experiences in Dallas, I visited their pits a number of times as their robot was amazingly robust, was catching lots of air, and disabling as a result. Early indications were that the zero-config button on the front of the black bridge was being pressed as the bridge hit the bottom or side of their lexan sleeve they made for it. After modifications so that wouldn't happen, the problem persisted. Apparently the PCB within the bridge was able to move and internally press the button. A replacement bridge had not issues with this, and the original may have been due to internal damage due to previous hits.

Greg Mckaskle

[apalrd]

Originally Posted by Greg McKaskle

....As a pretty predictable indication, the clip on the modules releases at over 50. Clearly the cRIO will often take more...

Wow. We had to glue our modules in to prevent this, as during testing our robot almost killed itself since it lost the analog module (it had no way of knowing it had lost its analog inputs, as they were within normal ranges). (And we don't go over violently). Maybe it had something to do with mounting the cRio sideways, so the modules face to the back of the robot instead of up?

As for the bridge, we had issues at Kettering, so we duct-taped the connections A LOT, and found that mounting it so the button is on the side instead of the top helped too.

[jspatz1]

This photo brings back memories of the Curie semifinals. Daisy Bell was all over the place, impossible to keep up with, a very athletic bot.

Our bump crossing method often gave us some very extreme impacts on our rear swerve modules, which mounted with verticle shafts. We softened the impact by stacking a few of these wave springs to gain some suspension - http://www.mcmaster.com/#catalog/116/1216/=94oqg3

[Jon Jack]

Originally Posted by jason701802

Did you guys ever figure out what was causing the random shutdowns in the finals in Salt Lake?

No we have not figured out what exactly is causing these issues. We thought we had fixed them at Championships, but they reappeared again at IRI. It's currently at the top of our off-season engineering to-do list.

As for shock absorbing...
When the robot was initially designed we kept this in the back of our mind. The first time the practice robot went over the bump was quite an interesting experience. The cRIO nearly ripped itself off the electronics board, the analog breakout flew off the robot, the router reset itself...

Afterwards, while making repairs to the electronics board, we put a layer of rubber over over the cross members where the electronics board mounted to. I don't know how big of a difference it really made.

We tried mounting the gateway on rubber as well, but during our 3rd match in San Diego the gateway reset itself. We decided to take a piece of polycarb, break it and mount the radio vertically. This worked much better and we had no issues with the gateway resetting itself for the rest of the season.

Another thing I will finally say is that during San Diego QF2-2 we sheered a 7075AL output shaft in one of our transmissions (Picture can be found here). It just so happened that a transmission output shaft was one of the shafts we did not have spares for in San Diego. So we removed the broken shaft, took a spare shaft from a different part of the robot and "MacGyvered" it in place. The whole operation took about 15 minutes - we didn't even have to use a timeout...

The robot ran through the next two semi-final matches without a glitch - still able to go over the bumps as though nothing was wrong. Thursday morning in Utah (our next regional) we completely rebuilt both sides of the drivetrain with new (redesigned) shafts and sideplates.

[jason701802]

Originally Posted by Jon Jack

No we have not figured out what exactly is causing these issues. We thought we had fixed them at Championships, but they reappeared again at IRI. It's currently at the top of our off-season engineering to-do list.

It is my understanding that the main breaker was tripping, is that right? I am just having trouble understanding how any soft of communication of controller error could cause the main breaker to trip.

[jspatz1]

Originally Posted by jason701802

It is my understanding that the main breaker was tripping, is that right? I am just having trouble understanding how any soft of communication of controller error could cause the main breaker to trip.

There were many reports of some faulty KOP main breakers that were overly sensitive to tripping, and could trip with a physical bump. Never had that trouble ourselves but our inspector at champs said he had seen several.

[jason701802]

Originally Posted by jspatz1

There were many reports of some faulty KOP main breakers that were overly sensitive to tripping, and could trip with a physical bump. Never had that trouble ourselves but our inspector at champs said he had seen several.

If their robot didn't turn off, repeatably, with almost exactly 45 seconds left in the match, I would agree with you.

[robodude03]

Originally Posted by Jon Jack

Another thing I will finally say is that during San Diego QF2-2 we sheered a 7075AL output shaft in one of our transmissions (I will post a picture on CD-Media after I make this post). It just so happened that a transmission output shaft was one of the shafts we did not have spares for in San Diego. So we removed the broken shaft, took a spare shaft from a different part of the robot and "MacGyvered" it in place. The whole operation took about 15 minutes - we didn't even have to use a timeout...

The robot ran through the next two semi-final matches without a glitch - still able to go over the bumps as though nothing was wrong. Thursday morning in Utah (our next regional) we completely rebuilt both sides of the drivetrain with new (redesigned) shafts and sideplates.

I remember this, it was an intense 15 minutes for sure! To make it without even using a timeout, there were some sweaty people at the end of those 15 minutes.