The above is a plot of distance travelled in the x axis, (edx, cyan) – positive is forwards – and the pitch angle Phoebe is tilted by (c pitch, green) – positive is nose-up providing reverse acceleration.
It does show drift control in action: as distances change (i.e. there is a non-zero velocity), the pitch angle changes to produce acceleration in the opposite direction to kill the velocity and stop the drift.
OK, it’s a bit wavey, but at least the idea’s right. That’s enough motivation to keep tuning.