paper: New Control Functions - Drive System Testing

[Arpan]

Originally Posted by Mark McLeod

That slide posted earlier from Behind The Lines was inadvertently incorrect as it was taken from an early sketch of the notes we were developing for the show.

Here are the latest notes:

Staged Brown Out when the battery voltage drops too low proceeds through the following stages:

Stage 1: 6.5-7.3v -PWM/CAN motor controllers/Relay outputs are cutoff, 6v power rail drops out
- Driver Station displays “Voltage Brownout”
- Servo power lost
- Disable pulse sent to PWM and CAN motor controllers, turning them off.
- Can result in robot stutter as motors pull the voltage low, get cut off, voltage rebounds, motors immediately pull voltage low again

Stage 2: 4.5-6.4v - , GPI outputs go High, 5v/3.3v power rails drop out
- Sensor brownout occurs, e.g., encoders!
- Stage 2 persists until battery voltage recovers to 7.5v

Stage 3:<4.5v - roboRIO drops out
- <3.5v the VRM/DLink drops out

I'm really not certain why this was done; we regularly pull our batteries below 7 volts in normal operation. Why is there no regulated supply to the roborio? Is there a technical hurdle to accomplish this?