Hello. I'm trying to study vehicle kinematics with autoware simulation package.
I don't understand the code well.

On the code (in void VehicleGazeboInputSubscriber::twistCallback()). There are some lines for calculating steering position.

   output_steering_right_front.data = std::atan(std::tan(delta_ref) / (1.0 + (wheel_tread_ / (2.0 * wheel_base_)) * std::tan(delta_ref)));
    output_steering_left_front.data = std::atan(std::tan(delta_ref) / (1.0 - (wheel_tread_ / (2.0 * wheel_base_)) * std::tan(delta_ref)));  

Below are what I understood.

output_steering_right_front is a variable for steeringrightfrontpositioncontroller.
If it increases or decreases, it will push or pull the wheel which attached on the joint of it.
So, it should be calculated how much handle the steering to turn our robot body.
Given max_delta_ref (deltha) variable and vref_rear (linear velocity) variable, how to calculate the position of steering link?

Could you explain the formula represented by "std::atan(std::tan(deltaref) / (1.0 + (wheeltread_ / (2.0 * wheelbase)) * std::tan(delta_ref)))" ?