[Tom Line]

At the Troy regional, we experienced our first bout with the 'lag monster'. For two painful matches, we were seeing the robot lag significantly - the driver and gunner both said they would try to make a motion and the robot would wait a few moments, then (sometimes) make the motion, then it would sometimes continue that motion well after they had stopped. As we neared the end of one match, we completely lost control of the robot.

The first thing we checked was CPU usage of the Crio. Rock solid at 70%. During tethered operation, we didn't see the same problems. Only on FMS.

Then, while tethered in the pits troubleshooting the issue, I clicked over to the charts tab our our driver station (09 Classmate model). We were seeing significant packet loss and round-trip-times off the chart.

This is with the standard driver station and dashboard. No modifications.

Initially I thought it was a bad tether cable, so we swapped it with no effect. Then, I hooked up our backup driver station (our top end programming laptop) and the lag and round trip issues completely went away.

Plugged back into to our classmate, and the problems came back instantly. Keep in mind however, while tethered, the problems were still not exhibiting themselves as lag. I suspect the added delay of traveling through the FMS system is what pushed it over the edge into creating a problem.

The classmate is 100% stock, completely clean and reimaged with nothing extra on it.

We won't be using the classmate anymore. The lag was gone using our higher end laptop in the next match.