Linear Backtracker

The Linear Backtracker is used whenever a collision of the car has been detected.
On receiving a collision message, this node publishes a negative torque input_torque and zero steering input in order to recover from a crash.

The car then drives backward for a predefined distance backtrack_distance. After that the backtracker stops publishing inputs until another crash message is received.

If this backtracker is not able to recover during a predefined max_backtrack_time interval, it will terminate without driving the desired distance.

  backtrack_distance: 0.1 # How far to drive back [m]
  input_torque: 0.3 # What torque (absolute value) to apply in backtrack state
  max_backtrack_time: 2 # How long to publish backtrack commands before giving up [s]