Backtrackers

When tuning parameters in real world experiments, the car might drive into the car boundary and is not able to recover from this accident.

In order to overcome this issue, a collision detection and backtracking setup is integrated into the framework which allows to recover from an accident.

Each of the depicted nodes come with a variety of tunable parameters:

Crash Detector Node

  distance_tolerance: 0.0 # How much slack we give on the track. A crash is only detected if the car is away from track boundary by this much
  time_tolerance: 10 # How long (s) the car has to not be moving to trigger the crash detector
  min_move_distance: 0.05 # How much the car must have moved during 'time_tolerance' to not trigger the crash detector [m]
  check_rate: 5 # How often we check for collisision [Hz]
  collision_msg_rate: 2 # send collision messages at x [Hz]

Input Filter Node

  block_time: 0.1 #How long to wait after the last emergency input to switch back to the main controller input

Linear Backtracker Node

  publish_freq: 20 # how often to publish input commands [Hz]
  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]

Example Configuration File

crash_detector_node:
  distance_tolerance: 0.0 # How much slack we give on the track. A crash is only detected if the car is away from track boundary by this much
  time_tolerance: 10 # How long (s) the car has to not be moving to trigger the crash detector
  min_move_distance: 0.05 # How much the car must have moved during 'time_tolerance' to not trigger the crash detector [m]
  check_rate: 5 # How often we check for collisision [Hz]
  collision_msg_rate: 2 # send collision messages at x [Hz]

input_filter_node:
  block_time: 0.1 #How long to wait after the last emergency input to switch back to the main controller input

linear_backtracker_node:
  publish_freq: 20 # how often to publish input commands [Hz]
  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]