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Avoidance by lane change design#

This is a sub-module to avoid obstacles by lane change maneuver.

Purpose / Role#

This module is designed as one of the obstacle avoidance features and generates a lane change path if the following conditions are satisfied.

  • Exist lane changeable lanelet.
  • Exist avoidance target objects on ego driving lane.

avoidance_by_lane_change

Inner-workings / Algorithms#

Basically, this module is implemented by reusing the avoidance target filtering logic of the existing Normal Avoidance Module and the path generation logic of the Normal Lane Change Module. On the other hand, the conditions under which the module is activated differ from those of a normal avoidance module.

Check that the following conditions are satisfied after the filtering process for the avoidance target.

Number of the avoidance target objects#

This module is launched when the number of avoidance target objects on EGO DRIVING LANE is greater than execute_object_num. If there are no avoidance targets in the ego driving lane or their number is less than the parameter, the obstacle is avoided by normal avoidance behavior (if the normal avoidance module is registered).

trigger_1

Lane change end point condition#

Unlike the normal avoidance module, which specifies the shift line end point, this module does not specify its end point when generating a lane change path. On the other hand, setting execute_only_when_lane_change_finish_before_object to true will activate this module only if the lane change can be completed before the avoidance target object.

Although setting the parameter to false would increase the scene of avoidance by lane change, it is assumed that sufficient lateral margin may not be ensured in some cases because the vehicle passes by the side of obstacles during the lane change.

trigger_2

Parameters#

Name Unit Type Description Default value
execute_object_num [-] int Number of avoidance target objects on ego driving lane is greater than this value, this module will be launched. 1
execute_object_longitudinal_margin [m] double [maybe unused] Only when distance between the ego and avoidance target object is longer than this value, this module will be launched. 0.0
execute_only_when_lane_change_finish_before_object [-] bool If this flag set true, this module will be launched only when the lane change end point is NOT behind the avoidance target object. true