customized PID on top of pybrick PID controller

[familynygood]

I posted my question here a month ago: https://github.com/orgs/pybricks/discussions/2470 and no one answers.
Let me ask another question: what do you think of the idea of creating a customized PID on top of pybrick PID controller? Will the robot be confused with what PID to use? Please share what thoughts of pros and cons.
Thank you,

[laurensvalk]

What is the underlying goal here? Adjust performance? What about adjusting the Kp, Ki, Kd of the existing controller instead of building another on top?

You can separately adjust the PID values for forward/reverse (distance_control) and the one for steering (heading_control):

from pybricks.parameters import Direction, Port
from pybricks.pupdevices import Motor
from pybricks.robotics import DriveBase

# Set up all devices.
left = Motor(Port.A, Direction.COUNTERCLOCKWISE)
right = Motor(Port.B, Direction.CLOCKWISE)
robot = DriveBase(left, right, 56, 128)

# Get and display the original values
head_kp, head_ki, head_kd, *_ = robot.heading_control.pid()
print(f"Original heading  control: kp={head_kp}, ki={head_ki}, kd={head_kd}")

dist_kp, dist_ki, dist_kd, *_ = robot.distance_control.pid()
print(f"Original distance control: kp={dist_kp}, ki={dist_ki}, kd={dist_kd}")

# Do a test drive with the original for comparison.
robot.straight(250)

# Use double the original kp and half the original kd.
robot.distance_control.pid(dist_kp * 2, dist_ki, dist_kd * 0.5)

# Test again
robot.straight(250)

[familynygood]

Can you please provide one example how to adjust kp, ki and kd of the pybrick PID controller?

[laurensvalk]

Sure! I've updated the post above. Let me know how it goes :)

For a bigger robot, you may want to increase the values. The default values are quite low, or else it gets too jittery for the small example robot.