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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. image

Inner-workings / Algorithms#

Estimates sequential steering offsets from kinematic model and state observations. image2 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