Automatic Emergency Braking

This is actually a more important problem and hard problem than it seems.

If you draw your confusion matrix, you have two bad scenarios:

  • Too loose threshold: You don’t need to break, but AEB is toggled anyways False Positives
  • Too strict threshold: REALLY BAD. You have to break, but your AEB doesn’t toggle (you kill a pedestrian) False Negatives

Good AEB systems are really tuned well to find the perfect balance.

Nowadays, AEB systems in cars are mandatory to promote safety.

Simple AEB using TTC

The simplest way to do AEB is calculating TTC (Time-to-Collision), where

where is the instantaneous range measurements and is the current range rates. The operator is defined as .

We obtain:

  • by using the current measurements from the LaserScan message
  • by mapping the vehicle’s current longitudinal velocity onto each scan beam’s angle by using , where is the forward speed in the vehicle’s frame of reference (obtained from Odometry message), and is the beam angle obtained from LaserScan messages