I just uploaded the 2.0 distribution code and it seems like bittle is error'ing out (is that what the beeps are?) frequently.
It's not a resetting sound, but a low voltage alert. The current threshold LOW_VOLTAGE is set to trigger right before the battery's auto shutdown voltage.
However, when the robot is running fast, it will draw a lot of currents, temporarily reducing the battery's voltage.
You may comment out this line in OpenCat.ino:
//while (lowBattery()); //block the loop if battery is low