Lane Departure Checker

The Lane Departure Checker checks if vehicle follows a trajectory. If it does not follow the trajectory, it reports its status via diagnostic_updater.

Features

This package includes the following features:

• Lane Departure: Check if ego vehicle is going to be out of lane boundaries based on output from control module (predicted trajectory).
• Trajectory Deviation: Check if ego vehicle's pose does not deviate from the trajectory. Checking lateral, longitudinal and yaw deviation.
• Road Border Departure: Check if ego vehicle's footprint, generated from the control's output, extends beyond the road border.

Inner-workings / Algorithms

How to extend footprint by covariance

1. Calculate the standard deviation of error ellipse(covariance) in vehicle coordinate.

   1.Transform covariance into vehicle coordinate.

   $$\begin{align} \left( \begin{array}{cc} x_{vehicle}\\ y_{vehicle}\\ \end{array} \right) = R_{map2vehicle} \left( \begin{array}{cc} x_{map}\\ y_{map}\\ \end{array} \right) \end{align}$$

   Calculate covariance in vehicle coordinate.

   $$\begin{align} Cov_{vehicle} &= E \left[ \left( \begin{array}{cc} x_{vehicle}\\ y_{vehicle}\\ \end{array} \right) (x_{vehicle}, y_{vehicle}) \right] \\ &= E \left[ R\left( \begin{array}{cc} x_{map}\\ y_{map}\\ \end{array} \right) (x_{map}, y_{map})R^t \right] \\ &= R E\left[ \left( \begin{array}{cc} x_{map}\\ y_{map}\\ \end{array} \right) (x_{map}, y_{map}) \right] R^t \\ &= R Cov_{map} R^t \end{align}$$

   2.The longitudinal length we want to expand is correspond to marginal distribution of \(x_{vehicle}\), which is represented in \(Cov_{vehicle}(0,0)\). In the same way, the lateral length is represented in \(Cov_{vehicle}(1,1)\). Wikipedia reference here.

2. Expand footprint based on the standard deviation multiplied with footprint_margin_scale.

Interface

Input

• /localization/kinematic_state [nav_msgs::msg::Odometry]
• /map/vector_map [autoware_map_msgs::msg::LaneletMapBin]
• /planning/mission_planning/route [autoware_planning_msgs::msg::LaneletRoute]
• /planning/scenario_planning/trajectory [autoware_planning_msgs::msg::Trajectory]
• /control/trajectory_follower/predicted_trajectory [autoware_planning_msgs::msg::Trajectory]

Output

• [diagnostic_updater] lane_departure : Update diagnostic level when ego vehicle is out of lane.
• [diagnostic_updater] trajectory_deviation : Update diagnostic level when ego vehicle deviates from trajectory.

Parameters

Node Parameters

General Parameters

Name	Type	Description	Default value
will_out_of_lane_checker	bool	Enable checker whether ego vehicle footprint will depart from lane	True
out_of_lane_checker	bool	Enable checker whether ego vehicle footprint is out of lane	True
boundary_departure_checker	bool	Enable checker whether ego vehicle footprint wil depart from boundary specified by boundary_types_to_detect	False
update_rate	double	Frequency for publishing [Hz]	10.0
visualize_lanelet	bool	Flag for visualizing lanelet	False

Parameters For Lane Departure

Name	Type	Description	Default value
include_right_lanes	bool	Flag for including right lanelet in borders	False
include_left_lanes	bool	Flag for including left lanelet in borders	False
include_opposite_lanes	bool	Flag for including opposite lanelet in borders	False
include_conflicting_lanes	bool	Flag for including conflicting lanelet in borders	False

Parameters For Road Border Departure

Name	Type	Description	Default value
boundary_types_to_detect	std::vector\<std::string>	line_string types to detect with boundary_departure_checker	[road_border]

Core Parameters

Name	Type	Description	Default value
footprint_margin_scale	double	Coefficient for expanding footprint margin. Multiplied by 1 standard deviation.	1.0
footprint_extra_margin	double	Coefficient for expanding footprint margin. When checking for lane departure	0.0
resample_interval	double	Minimum Euclidean distance between points when resample trajectory.[m]	0.3
max_deceleration	double	Maximum deceleration when calculating braking distance.	2.8
delay_time	double	Delay time which took to actuate brake when calculating braking distance. [second]	1.3
max_lateral_deviation	double	Maximum lateral deviation in vehicle coordinate. [m]	2.0
max_longitudinal_deviation	double	Maximum longitudinal deviation in vehicle coordinate. [m]	2.0
max_yaw_deviation_deg	double	Maximum ego yaw deviation from trajectory. [deg]	60.0