Radio cuts out, student's foot run over
 

We had a somewhat scary incident with our robot yesterday.

Here's what we did:

1. Downloaded v14 firmware to the RC.
2. Drove the robot around for a while and experienced a few intermittent radio cutouts.
3. Disabled the robot at the OI via a "kill-switch"
4. Noticed that the Speed Controller LEDs were still solid orange (i.e. enabled)
5. Powered off the robot and changed the battery (we were about to do this anyway).
6. Powered on the robot and again noticed that the Speed Controller LEDs were solid orange.
7. After about 4 seconds (with 3 people standing around the robot) it took off at about full-speed without user input :ahh:
8. The robot ran over one of my student's foot before I could get ahold of it and lift it off of it's wheels.

For the record:

• The RC radio was mounted high on the robot and perdendicular to the ground
• The OI radio was mounted high on a wall about 15 feet away from the robot, also perpendicular to the floor.
• The kill-switch on the OI was in the disabled position from step 3 above and was NEVER moved back to enabled.
• The "disable" LED on the OI was solid orange and the RC mode LED was yellow/orange.
• The kill-switch has worked for many weeks now, disabling/enabling without issue.

Has anyone else seen anything like this?
BTW, the student is fine.

Re: Radio cuts out, student's foot run over
 

On your competition port however you wired it. There should be two switches for testing autonomous and disabled, at least that is the way we have it. Now if you flipped the autonomous that is probably why it did that. I know that when we first wired our we got confused as to which was autonomous and which was disable and had our robot take off once and almost take my had off in the process while I was working on the drive train.

Re: Radio cuts out, student's foot run over
 

Yes.

Our fancy dongle developed a loose connection last fall. If it had failed in a slightly different way, it could easily have thrown the robot into autonomous instead of disabling it. We of course repaired it.

Re: Radio cuts out, student's foot run over
 

we had the same problem more from bad wiring than anything else but ive seen it happen and i have been run over myself! but to be serious check the wiring on your dongle and make sure it is all good.also make sure the port is pluged in properly(also something weve done)

Re: Radio cuts out, student's foot run over
 

Suppose for a second that the wiring on the dongle is faulty and that the robot ran an autonomous program.
Here is our autonomous code that is called from the Autonomous() function in the competition template of EasyC - Pro:

Also, in the Initialization() method in the same competition template, we set all PWM outputs to 127. The Initialization() code gets run before both the Autonomous() and OperatorControl() functions have a chance to run.

I will check the wiring again... but I fail to see how the robot would take off in either of these cases.

Also, the student that had been driving the robot was asked multiple times what the state of the kill-switch was... He told me "disabled" every time I asked... I asked 3 times because I saw the LEDs on the speed controller were solid orange, enabled.

Re: Radio cuts out, student's foot run over
 

Grant,

I strongly suggest that you report this to IFI.

Mike

Re: Radio cuts out, student's foot run over
 

Which pwm outputs control your drive motors? I don't know whether EasyC fixes the "glitchiness" of pwm13-16. The default code regularly extends the pulse width on those outputs when interrupts happen. That's "forward" to a Victor.

Re: Radio cuts out, student's foot run over
 

If you're certain that the disable LED on the OI was solid orange (and not blinking rapidly), then the control system was indeed disabled and your dongle was working. All the PWM outputs should have been tri-stated, including 13-16. Are you 100% sure that the disable LED on the OI was solid orange? If so then this is a pretty serious problem.

Re: Radio cuts out, student's foot run over
 

If you feel certain that the robot was disabled at the Operator Interface, for the safety of all of us, please contact IFI immediately.

Re: Radio cuts out, student's foot run over
 

We had to robot take off with no user input before with my laptop attached through the programming cable. My fault though. Laptops okay. :)

Re: Radio cuts out, student's foot run over
 

Problems with the robot not correctly disabling motors when the radio signal is corrupted have (hopefully) been addressed with new beta test versions of the master code. If you are running the latest master code, and still have these problems, make sure you report it to IFI. They are looking for these reports. It is a good idea to pay careful attention to your radio setup, even without these problems, in that radio glitches would normally cause intermittent robot disablement. Keep track of any posted updates to this master code and install them as they are available.

To minimize radio connection problems (hiding any remaining disablement glitches), make sure that:
1) Your radio is placed as high as you can.
2) Your radio is mounted on plastic about a half wavelength away (5 to 6 inches) from any metal structure on your robot.
3) Your radio will not be shadowed by any large metal panels or closely spaced wire grids. If it is shadowed, the reliability might suffer when the robot is oriented so that the metal panel is interposed between the OI and the RC radio modems.

On the OI end, if you mount the radio on a wall, make sure that this wall is not a conducting surface such as metal. The best place for this antenna is in "free space," well clear of metal surfaces (except for a table that it might be sitting on).

If you continue to have problems while on the radio, make sure that you report these problems to IFI and use the tether while testing your robot until the problems are resolved.

All of the interference effects involved when a metal surface is near the antenna is one of the wonders of nature, but you don't want to be exploring these with your robot.

Eugene

Re: Radio cuts out, student's foot run over
 

He stated the radios were mounted correctly. The radios this year for many teams are defective. The radios need to get an RMA'ed and replaced chances are. You are not alone, the majority of the teams in my area are having the same radio cutting out problem.

Re: Radio cuts out, student's foot run over
 

Also, from our experience, this problem will only get worse in competition mode, not better! Apparently, at lower channel numbers, the radios are worst. (Our team ran through a testing procedure on almost all 40 channels; we have the results if anyone is interested.)

Re: Radio cuts out, student's foot run over
 

Very interested Please post

Re: Radio cuts out, student's foot run over
 

I will get the information from the students that ran the test and report back. :)

Re: Radio cuts out, student's foot run over
 

I am quite curious how you did this? By default, the OI will only allow the use of 6 channels.

From the OI Reference Guide (from ifirobotics.com)
The rest of the channels, to my understanding, are only available through the competition port, which is an undocumented protocol.

-Nate

Re: Radio cuts out, student's foot run over
 

A previously undocumented protocol. I figured it out over the summer last year. :D
So I now have a homebrew field controller!

Re: Radio cuts out, student's foot run over
 

Interesting. Does this involve talking to the OI through its competition port to set the channel number, or configuring the modems themselves?

I know there has been lots of discussion in years' past concerning the information going between the OI and the Arena Controller (through the Competition Port), but that conversation always led to discussions of how 'GP' it would be to reverse engineer that information.

-Nate

Re: Radio cuts out, student's foot run over
 

Yes, I talk to the OI through the competition port (I emulate an Arena Controller). As I am not releasing any info on the protocols or pinouts, I think it is acceptable as far as GP goes.

Re: Radio cuts out, student's foot run over
 

I guess they only tested 4 channels; sorry about that! :o

Here's the info anyway:
Channel 1 tested for 10 minutes, cut out 14 times.
Channel 14 tested for 5 minutes, cut out 6 times.
Channel 20 tested for 5 minutes, cut out 6 times.
Channel 38 tested for 5 minutes, cut out 4 times.

Re: Radio cuts out, student's foot run over
 

We have found a problem also that causes the robot to take off, when the dongle is switched from Autonomous/Kill, to Operator Control mode.

It seems the first value read from the joystick was 0 (which, when the value was copied to the Victor, made the motor go suddenly full-speed). After that the joystick values were read correctly. This was with Master Code V12, we have since upgraded to V13.

At first we put in a 1/2 second delay in Operator Control mode, before reading the joystick the first time. It seemed to work, but as code was being developed we had other accidents where motors were set to full-speed.

So we put the Victor output for left-side and right-side into two C procedures. The procedures check for legitimate PWM values 1-253. Joystick input procedures were similarly modified, to avoid the extreme values 0 or 254.

In this way, a 'glitch' or coding accident cannot send 0 or 254 to the Victors.

This has solved our problem.

Re: Radio cuts out, student's foot run over
 

our team had a similar incident which was mentioned in another post but yeah scary stuff because it came at me, one of our mentors had to dive infront of it.

Re: Radio cuts out, student's foot run over
 

Can you confirm that the radio was mounted per IFI's recommendations? http://www.ifirobotics.com/forum/vie....php?p=833#833. Specifically, team 179 found that the radios had to be 6-8" away from metal.

Re: Radio cuts out, student's foot run over
 

we too have had many problems with the V14 firmware, and some with the V13. We've had the robot continue for a full second after disabling with V13, and more than that with V14

Re: Radio cuts out, student's foot run over
 

The following is our compliance with the IFI radio recommendations.

We were running the v14 Master code when the robot took off.
We are using the 2007 OI and RC only.

We are using quick connects (spade connectors) for all 20 amp lines.
These connectors are from this year's kit and fit very tightly.
All connections were checked.
A charged backup battery was in use.
A fresh main battery was installed only seconds before the incident.

There were times when we only saw the Valid TX light on the OI go on.
Other times the No Data/Radio light was solid red.

Didn't really see this because we were busy chasing the robot.

1. Check
2. Check
3. Check
4. Check
5. Check, I think... the RC Radio Modem is mounted vertically, about 2 feet off the floor, very near 2 aluminum support colums (1 inch square AL tubing, about 3.5 feet long). However, the RC modem is not "sheilded" in a Faraday-Cage sense... most (90% or more) of the antenna's field of view is unobstructed.
6. Check
7. Check, but we haven't tried another channel yet.

I contacted IFI just the other day and reported this issue (robot taking off while apparently disabled).
They said that in 5000+ systems shipped, they have never once come across this issue.
IFI is waiting for us to reproduce the problem.
It would be great if other teams who are experiencing radio issues could try to produce this problem as well.

Thanks for all the feedback,
Grant

Re: Radio cuts out, student's foot run over
 

This happened to me at our team sponsored dinner/fundraiser. Our battery got so low we went to turn it around and wheel it back to the front of the hall and it spazzed and ran me over!

Re: Radio cuts out, student's foot run over
 

Did they really say that? That seems a bit like "You're making it up" to me..

..anyways, would it be possible to test this with older radios/firmwares from last season? Sorry if you already tried that and I missed it, I'm kind of in a rush here.

Re: Radio cuts out, student's foot run over
 

We are having a similar problem. I started a thread including a poll (not many people saw it, but still...). It is here: http://www.chiefdelphi.com/forums/sh...ad.php?t=54106

I am getting SO frustrated with IFI. The very least they could do would be to acknowledge that there is a problem.

Anyway, hopefully we can find an easy fix for this (though that doesn't seem likely).

Paul

Re: Radio cuts out, student's foot run over
 

We are using the 2006 radios on the 2007 RC with FW 13 with no problems.

Re: Radio cuts out, student's foot run over
 

Yeah... We have a set of 2006 radios that work beautifully. The 2007 radios crap out all the time. And how do they expect you to mount your radio so it is '6-8"' completely away from metal? Do they want a foot long piece of plywood sticking out from the middle of your bot in a direction away from any other part of the bot that doesn't violate the height limit and in a place where the cord can't get caught in moving parts / get run over by robots climbing up your ramp?

Why do the old 06 radios which are RS-232 have no problem, while these new larger RS-422 radios have all sorts of problems.

Also, they wont let us use the old ones. WHY???

Jacob

Re: Radio cuts out, student's foot run over
 

Actually, the '06 radios are also RS-422 (none of these radios were ever RS-232). The reason that IFI is not re-using the old radios is that they cannot get any more, as Electrowave (the suppliers of the radios) cannot get parts to build any more--this was in another thread on CD somewhere (I forget where :o ).

I am not happy about this either. I have also had critical parts discontinued for a product that I designed--not a good place to be. :mad: