Tuning Accel / Decel Push Ratios

[osholsonel20]

How would you go about finding the right Acceleration push ratio and brake push ratio for your system?

Is there a "calibration" procedure to get the right values?

[takayuki5168]

@osholsonel20 We have a calibration package here.
https://github.com/autowarefoundation/autoware.universe/tree/main/vehicle/accel_brake_map_calibrator/accel_brake_map_calibrator

But, it's kind of updating accel brake map rathar than initializing the map. So, if we use this calibration for initialization, the accuracy of the map is not so good.
We'are now developing a map initialization package.

[osholsonel20]

So this is great when we switch over to ROS2 and Autoware.Universe.

Currently we are using ROS1 and Autoware.AI. I wasn't sure if on the openplanner side in op_common_params.launch. If there was a clean way of finding the value for accel push ratio and brake push ratio vs. giving it arbitrary values and seeing what works.

[hatem-darweesh]

@osholsonel20
if you mean the push values in op_common_params. They are similar to a "P" value in the PID controller.
They are useful when you don't have reliable or delayed feedback from the vehicle.
Or when you don't have small movement of the vehicle (robot) then the PID error is very small, and It doesn't work as expected. specially when starting from zero.

So the push value is added to the error value to push the PID one step towards the target signal.

Finally: tuning this value depends on how fast do you want the system to respond to acceleration and braking.
Start with small value such as max_speed / 10.0 then move up.

[osholsonel20]

Awesome thank you! We are continuing to have this issue where the vehicle is stuck in a "loop" of breaking and accelerating at a very low speed, and I think adjusting these params are what we need to give it the "jumpstart" it needs