What does it really mean for param "steering_tire_rotation_rate"？

[Leslie-Jane]

Is it the steering rate of steering wheel？or the steering rate of front vehicle wheel ?

[Leslie-Jane]

Is it the steering rate of steering wheel？or the steering rate of front vehicle wheel ?

What's the different between the message param of twist.angular.z(geometry_msgs::msg::Twist) and "steering_tire_rotation_rate"?

[Leslie-Jane]

Thank for your explanation,sir,I get it.

[Leslie-Jane]

Steering tire rotation rate refers to the front tires.

The vehicle does not rotate with the tires (e.g., we can be stopped and the tires can rotate but the vehicle itself does not rotate), so the angular twist is for the rotation of the vehicle itself, not its tires.

And I think it(steering_tire_rotation_rate) reletes to the steering rate of steering wheel as well.Things gonna be change if I use Ackerman model？For example,how can I propel an ackerman model to turn left or turn right(in geometry_msgs::msg::Twist---angular.z) by autoware lateral message(autoware_control_msgs::msg::Lateral)? When I passed the value of steering_tire_rotation_rate to Angular. z, it was incorrect。

[maxime-clem]

Please let me make sure I understand your problem:

• your vehicle is controller by rotating the steering wheel.
• the message used is a Twist message and the angular.z controls the speed of rotation of the steering wheel.
• doing a one-to-one mapping of the steering_tire_rotation_rate to the twist.angular.z to control your vehicle does not work.

What you need is a conversion which is usually done using the https://autowarefoundation.github.io/autoware_universe/main/vehicle/autoware_raw_vehicle_cmd_converter/index.html
You can see an example of how the steering angle is converted for the simple_planning_simulator (https://github.com/autowarefoundation/autoware_universe/blob/main/simulator/autoware_simple_planning_simulator/data/actuation_cmd_map/steer_map.csv).
In your case you will need to prepare a map for the steering rate instead of the angle.

[Leslie-Jane]

Thanks a lot，I will make a feedback after reading your article.

Please let me make sure I understand your problem:

• your vehicle is controller by rotating the steering wheel.
• the message used is a Twist message and the angular.z controls the speed of rotation of the steering wheel.
• doing a one-to-one mapping of the steering_tire_rotation_rate to the twist.angular.z to control your vehicle does not work.

What you need is a conversion which is usually done using the https://autowarefoundation.github.io/autoware_universe/main/vehicle/autoware_raw_vehicle_cmd_converter/index.html You can see an example of how the steering angle is converted for the simple_planning_simulator (https://github.com/autowarefoundation/autoware_universe/blob/main/simulator/autoware_simple_planning_simulator/data/actuation_cmd_map/steer_map.csv). In your case you will need to prepare a map for the steering rate instead of the angle.

Thanks a lot，I will make a feedback after reading your article.

[Leslie-Jane]

Please let me make sure I understand your problem:

• your vehicle is controller by rotating the steering wheel.
• the message used is a Twist message and the angular.z controls the speed of rotation of the steering wheel.
• doing a one-to-one mapping of the steering_tire_rotation_rate to the twist.angular.z to control your vehicle does not work.

What you need is a conversion which is usually done using the https://autowarefoundation.github.io/autoware_universe/main/vehicle/autoware_raw_vehicle_cmd_converter/index.html You can see an example of how the steering angle is converted for the simple_planning_simulator (https://github.com/autowarefoundation/autoware_universe/blob/main/simulator/autoware_simple_planning_simulator/data/actuation_cmd_map/steer_map.csv). In your case you will need to prepare a map for the steering rate instead of the angle.

Thanks for answer my question, sir. My vehicle model is ackermann type,which means it drive without a steer wheel and receives message from autoware.(e.g., steering_tire_rotation_rate or steering_angle). One of the problems that is the steering angle or steering_tire_rotation_rate conversion.I will modify my chassis driver program to adapt it.