steer_offset_estimator

Purpose

The role of this node is to automatically calibrate steer_offset used in the vehicle_interface node.

The base steer offset value is 0 by default, which is standard, is updated iteratively with the loaded driving data. This module is supposed to be used in below straight driving situation.

Inner-workings / Algorithms

Estimates sequential steering offsets from kinematic model and state observations. Calculate yaw rate error and then calculate steering error recursively by least squared method, for more details see updateSteeringOffset() function.

Inputs / Outputs

Input

Name	Type	Description
~/input/twist	geometry_msgs::msg::TwistStamped	vehicle twist
~/input/steer	autoware_vehicle_msgs::msg::SteeringReport	steering

Output

Name	Type	Description
~/output/steering_offset	tier4_debug_msgs::msg::Float32Stamped	steering offset
~/output/steering_offset_covariance	tier4_debug_msgs::msg::Float32Stamped	covariance of steering offset

Launch Calibrator

After launching Autoware, run the steer_offset_estimator by the following command and then perform autonomous driving. Note: You can collect data with manual driving if it is possible to use the same vehicle interface as during autonomous driving (e.g. using a joystick).

ros2 launch steer_offset_estimator steer_offset_estimator.launch.xml

Or if you want to use rosbag files, run the following commands.

ros2 param set /use_sim_time true
ros2 bag play <rosbag_file> --clock

Parameters

Name	Type	Description	Default	Range
initial_covariance	float	steer offset is larger than tolerance	1000	N/A
steer_update_hz	float	update hz of steer data	10	≥0.0
forgetting_factor	float	weight of using previous value	0.999	≥0.0
valid_min_velocity	float	velocity below this value is not used	5	≥0.0
valid_max_steer	float	steer above this value is not used	0.05	N/A
warn_steer_offset_deg	float	Warn if offset is above this value. ex. if absolute estimated offset is larger than 2.5[deg] => warning	2.5	N/A

Diagnostics

The steer_offset_estimator publishes diagnostics message depending on the calibration status. Diagnostic type WARN indicates that the current steer_offset is estimated to be inaccurate. In this situation, it is strongly recommended to perform a re-calibration of the steer_offset.

Status	Diagnostics Type	Diagnostics message
No calibration required	OK	"Preparation"
Calibration Required	WARN	"Steer offset is larger than tolerance"

This diagnostics status can be also checked on the following ROS topic.

ros2 topic echo /vehicle/status/steering_offset