From 125faecbffabd38b5c6a935e42acbaf0cda2cce4 Mon Sep 17 00:00:00 2001 From: Takayuki Murooka Date: Thu, 13 Jun 2024 23:39:34 +0900 Subject: [PATCH] update README Signed-off-by: Takayuki Murooka --- .../docs/lanelet2_format_extension.md | 20 +++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tmp/lanelet2_extension/docs/lanelet2_format_extension.md b/tmp/lanelet2_extension/docs/lanelet2_format_extension.md index 744fd128..88394b45 100644 --- a/tmp/lanelet2_extension/docs/lanelet2_format_extension.md +++ b/tmp/lanelet2_extension/docs/lanelet2_format_extension.md @@ -479,3 +479,23 @@ _An example:_ ... ``` + +### Centerline + +Note that the following explanation is not related to the Lanelet2 map format but how the Autoware handles the centerline in the Lanelet2 map. + +Centerline is defined in Lanelet2 to guide the vehicle. By explicitly setting the centerline in the Lanelet2 map, the ego's planned path follows the centerline. +However, based on the current Autoware's usage of the centerline, there are several limitations. + +- The object's predicted path also follows the centerline. + - This may adversely affect the decision making of planning modules since the centerline is supposed to be used only by the ego's path planning. +- The coordinate transformation on the lane's frenet frame cannot be calculated correctly. + - For example, when the lateral distance between the actual road's centerline and a parked vehicle is calculated, actually the result will be the lateral distance between the (explicit) centerline and the vehicle. + +To solve above limitations, the `overwriteLaneletsCenterline` has a `use_waypoints` flag where the centerline in all the lanes is calculated. + +- `use_waypoints` is True + - The (explicit) centerline in the Lanelet2 map is converted to the new `waypoints` tag. This `waypoints` is only applied to the ego's path planning. + - Therefore, the above limitations can be solved, but the Autoware's usage of the centerline may be hard to understand. +- `use_waypoints` is False + - The (explicit) centerline in the Lanelet2 map is used as it is. Easy to understand the Autoware's usage of the centerline, but we still have above limitations.