possible solution to the static problem

[Doctorwho]

I don't know how much it would affect traction, or if it would at all as the spray's viscosity is almost the same as water and it dries without leaving any sort of residue or film on the rover wheel plastic.

As I said in my first post you could also spray it on the more sensitive parts of your electronics and control board to reduce the likelihood of releasing the magic smoke.

The issue is is that the regolith sheets are over carpet and when you drive a robot over it the floor works like a capacitor, storing the charge until it builds up to the point of catastrophic discharge. At the Manchester Regional the field crew's solution was to spray water on the field to dampen the static, but I think that having water and electronics that close is asking for trouble plus it makes the field dangerous for people to walk on.

[EricH]

Originally Posted by nuggetsyl

Your first though scares me that you are more worried about a team getting traction then a team frying their driver station.

There are spares (or were) at the event.

Quite honestly, I don't really like the control system this year. There have been reports on top of reports of things breaking, frying at the slightest provocation, releasing magic smoke, etc. You'd think that with over a year to design for that, they'd be better. On the flip side, customer service has been excellent for the teams that do break system elements. I'm sure that there will be improvements for next year.

[dlavery]

Originally Posted by EricH

Quite honestly, I don't really like the control system this year. There have been reports on top of reports of things breaking, frying at the slightest provocation, releasing magic smoke, etc. You'd think that with over a year to design for that, they'd be better. On the flip side, customer service has been excellent for the teams that do break system elements. I'm sure that there will be improvements for next year.

Just out of curiosity, have you actually used the control system at all this year? Are your comments based on actual experience and personal practical knowledge? Or just second-hand information provided by others that you have not personally verified or validated?

I am just trying to understand how to calibrate credibility levels of the comments.



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[EricH]

Originally Posted by dlavery

Just out of curiosity, have you actually used the control system at all this year? Are your comments based on actual experience and personal practical knowledge? Or just second-hand information provided by others that you have not personally verified or validated?

I am just trying to understand how to calibrate credibility levels of the comments.



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Just on what I've seen on CD. This may be a small portion of teams that each fry multiple components, or not. I am not involved with a team this year due to location (no team within about 100-200 miles, and no car). However, my old team reports that if you set up the control system as spec'd, you should be fine (other than the risk of frying that has been reported).

[Matt C]

Hey Dave,
Just admit it, the GDC made a plastic wheel on plastic surface game so they could do accellerated ESD testing on the new control components.

[Team 135]

I would get a piece of braided copper ground wire, about 1 in, and drag that. We had a problem with static in our shop when we were testing crab drive ad that is what we did to fix the problem. With our new drive system we have not had any problems with static, knock on wood.

[MrForbes]

Originally Posted by EricH

Just on what I've seen on CD. This may be a small portion of teams that each fry multiple components, or not.

Eric--do you think we hear about problems more than we hear about things working well?

We haven't had any hardware trouble with the system, aside from some "no comm" during testing/practice, which might be due to the WGA location on the robot. And we used it almost continously from late December till ship.

[David Brinza]

Can the moderators merge this thread with this one: Field Static Solutions?

[Alan Anderson]

Originally Posted by Doctorwho

As seen in last weekend's regional competitions the electro-static discharge caused by the rover wheels and the floor can fry speed controllers, driver stations, and even knock the field systems out of whack.

I'm aware of many Driver Station issues, ESD sensitivity among them, and I hope appropriate corrective measures can be determined before too many weeks of competition go on.

Where have you seen reports of ESD frying speed controllers?

The data logs from the field electronics don't seem to show anything specifically ESD-related, with the understandable exception of a missing ground connection causing issues until reconnected.

Originally Posted by EricH

How about grounding the airlocks? Teams can't do that, but if FIRST figures out how to do it, then the issue won't exist anymore. At least, not as much.

Grounding them wouldn't seem to be as useful as insulating them. Simply taping over the airlock metal to attenuate the spark when a robot bumps into it ought to be a good solution.

Originally Posted by Doctorwho

I don't know how much it would affect traction, or if it would at all as the spray's viscosity is almost the same as water and it dries without leaving any sort of residue or film on the rover wheel plastic.

If it leaves no residue, it can't really affect anything, including static electricity. Obviously it must be leaving something behind.

As I said in my first post you could also spray it on the more sensitive parts of your electronics and control board to reduce the likelihood of releasing the magic smoke.

That's not how it works. You can't just apply a magic static-insensitivity solution to electronic components. What the spray does is reduce the ability of exposed surfaces to accumulate electrons and charge the system up to voltage levels where ESD is a problem. It doesn't work in many situations, though.[/quote]

[Wayne C.]

I have to jump in here-

during build season our team had horrible issues with static frying the ethernet ports on our driver stations. We had hooked up the cRIO on an old drive base and used it for programming while the competition robot was in the shop. We have ALWAYS had static charge accumulation on our chassis from our large rubber wheels running on carpet to the point where we would drag a grounding strip below most of our machines (with a sign that says "if you can read this we are screwed")
What we found was that even if we grounded the driver station to the nth degree if we tethered the robot to the station to dump code it would wipe out the ethernet port. We did this twice in the build season and Andymark graciously did a quick resupply of components for us.

Our solution to programming once we determined the problem was to dump our code remotely and we simply had no more problems with the driver station.

That is until NJ....

Obviously you cannot program remotely in the pits at the event. Therefore we were required to tether the robot. Almost immediately driver station issues began and we solved them by adding a switch in the line between the driver station and the robot. Doing that prevents the driver station destruction but we already have blasted one of the ports in the 5 port switch.

During calibration of the camera on the field we also had a driver station power supply blow out for no apparent reason and only a trip to Radio Shack and $30 was able to fix it. (there aren't resupplies in the pit area or on the Andymark page!)

Those at NJ may have noticed that our pit is fanatical about static charge now. We wear Static Guard like cologne. Nobody touches the robot or controls without a ground discharge procedure. But there are times when connection between the robot and the driver station is necessary and at those times we keep our fingers crossed and a new driver station ready.


But perhaps what is the most frustrating of all is the response we keep getting from FIRST - " OH we haven't heard of any problems" . I'm sorry but I hear a roar of problems when I talk to teams and I am not making this all up.

All we want is a control system with the reliability we have had in the past. I like the cRIO unit well enough. It is the peripheral parts that seem to be "less than satisfactory". And it would have been nice to have as greater degree of testing and ready support for this system before were received it in the AS WAS state it went out in.

WC

[Doctorwho]

At Manchester people were having issues with driver's stations frying themselves when running in tethered mode on the practice field. At the end of the first day they had teams searching for spares. It just seems to me that while the new system is fancier and more advanced it's not as durable as the old IFI system.

[David Brinza]

There are some of us in FIRST who do understand the importance of ESD control.

If you work on or near sensitive electronics hardware ESD controls are generally the rule. In my experience involving spacecraft hardware at NASA/JPL, there are very tight restrictions and mandatory training to avoid ESD issues. Dave's "other cars on Mars" (Spirit and Opportunity) were built with great care to avoid ESD.

We have requirements for use of grounded equipment, wrist straps, conductive garments and work surfaces (including floors), ESD-safe chairs with chains that drag on the floor, minimum relative humidity (>30%), air ionizers, avoidance of static-producing materials (i.e. no paper, styrofoam, teflon, adhesive tape or other non-conducting items) within one-meter of critical hardware. We use bleed resistors (10-100 MOhm) between electronics chassis and power/return line to avoid static charge build-up.

One of the tricky issues with ESD is that it can cause "latent" damage. A piece of equipment might continue to work after a "zap", but in reality some internal damage may have occurred. The next zap - even a tiny one, can cause a permanent failure.

I think we're learning lessons this year in the importance of ESD control. Basically, we've got six van de Graaff generators running around on a good insulator with equipment that is likely more susceptible to ESD than what was used in the past. The fact that we're seeing DS and robot resets attributed to ESD is frankly frightening to me. The guidelines from FIRST to deal with this threat needs some beefing up.

There's another thread dealing with this matter as well: Field Static Solutions

That thread should be merged with this one. Those out there with real-world experience in ESD control should post recommendations for teams. FIRST needs to take the appropriate measures with the field (some of which are already in place, like the earth ground at the alliance stations).

[Jared Russell]

Originally Posted by EricH

Just on what I've seen on CD. This may be a small portion of teams that each fry multiple components, or not. I am not involved with a team this year due to location (no team within about 100-200 miles, and no car). However, my old team reports that if you set up the control system as spec'd, you should be fine (other than the risk of frying that has been reported).

I think we all have seen the 100+ reply thread about failing Jaguars, but outside of that my experience with the new system has been largely positive (though I still maintain that it is 5x bigger and heavier than it needs to be).

[Bharat Nain]

Originally Posted by dlavery

Just out of curiosity, have you actually used the control system at all this year? Are your comments based on actual experience and personal practical knowledge? Or just second-hand information provided by others that you have not personally verified or validated?

I am just trying to understand how to calibrate credibility levels of the comments.



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Just out of curiosity, are you still questioning the fact that teams have had problems with the control system?

[dlavery]

Originally Posted by Bharat Nain

Just out of curiosity, are you still questioning the fact that teams have had problems with the control system?

To the best of my knowledge, I have never questioned that. If you can point to a specific statement where I have done so, please let me know and I will correct it. If you cannot, I trust you will correct your statement and your insinuation.

To the contrary, I am particularly concerned about making sure FIRST and the control system designers are able to gather accurate, factual, and correct information about the performance of (and where appropriate, lack thereof) the new control system. We are all intently interested in hearing first-hand, direct experiences from those that have had issues with the system, in as much specific detail as possible. Gathering as much of this sort of information as is available is the only way that the problems can be tracked down, diagnosed, and corrected. Posts like the one above from Steve Compton are full of great information and particularly useful. **

Conversely, unverified third-hand stories about how "I think my friend's uncle's cousin's Little League coach's team might have had a problem with a garstuckle that was ever so slightly out of plumb" are not particularly helpful. Frequently, they are actually detrimental to the process of getting the problem solved, as they cause a lot of energy to be expended chasing down false leads. So, it is important to identify and understand the difference.

-dave

** and toward that end, I would urge everyone with real, first-hand experiences with problems with the control system to please, please, please let the appropriate people know. Simply posting a story here on CD is not good enough. FIRST (in particular, Chris Jennings and Matt Pilotte) and the folks at National Instruments, Luminary Micro and KwikByte, have to know what is going on. They have to get real data on the performance, experiences, and problem reports associated with the control system. Please make sure you get your information and direct observations to them. One of the best ways to do this is to use the 2009 FRC Control Systems Forums.


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