Planning do not depend the steering angle rate

[brkay54]

Hello everyone,
I realized that planning module in Autoware do not depend the steering angle rate. In lateral controller, we can set steering_rate_limit (here). When I set lower steering_rate_limit, the states that are calculated by lateral_controller are seem good. But longitudinal controller can not handle, It should slow down the vehicle because of low steering_angle_rate but it is not. vehicle could not turn over the high curvature paths. I investigated the planner maybe there is a parameter to handle this but I couldn't find anything. I guess MPT Optimizer should handle this but optimizer do not get the steering_rate_limit, It takes only max_steer_rad.

Do you know that planner can handle this or not in current implementation? If not, which module should handle this situation? Control or planning? In my opinion, MPT optimizer should handle this but it is open for discussion. Please feel free to share your opinion here.

[brkay54]

cc @maxime-clem @mehmetdogru @TakaHoribe

[takayuki5168]

@brkay54 Thank you for your question.
Currently, path shape (related to steering) and path velocity are planned almost independently.
When planning the path shape, we do not know the exact path velocity since the velocity is finally calculated in motion_velocity_smoother which is the last module of path velocity planners. So it's hard to consider steering_rate_limit in path shape planning.

With this assumption, to solve your issue, motion_velocity_smoother should consider steering_rate_limit in my opinion.
This package has a function to decelerate the velocity according to the path curvature so that the lateral acceleration is less than the parameter max_lateral_accel. Like this, we can add a function to decelerate the path velocity according to steering_rate_limit.

[takayuki5168]

@TakaHoribe Let me know if you disagree with something.

[brkay54]

Thank you for your answer, I agree with you. If both velocity and steering planning are independent, we should add a function that fills the velocity wrt steering_rate_limit. I will work on it.

[TakaHoribe]

Thank you for the nice discussion! The motion_velocity_smoother sounds good to me. It should consider the steering_rate_limit when it calculates the velocity.