Additional motor with Pybricks - 4X4 X-treme Off-roader

[LegoMan228]

Hello to all! I have a model #42099 4X4 X-treme Off-roader. It's hub has 3 ports occupied, 1 is empty. I replaced the default firmware with the Pybricks one for this model. This let me use Lego remote (88010) to control my off-roader.
Then I decided to add another 1 L-motor, connected it to the 4th port of the hub (port D). Red buttons of the RC were assigned to operate the 4th motor. It works, but one direction is much slower, than another. I tried to replace the motor, changed the circuit direction, switched hub ports - no success to make it rotate with the same speed in both directions!
Is smth is wrong with my code?
Or the default Pybricks FW doesn't let me to add +1 motor to port D of the hub?
Please, could anyone help me?

Here is my code:

from pybricks.pupdevices import *
from pybricks.parameters import *
from pybricks.tools import wait

front = Motor(Port.A)
rear = Motor(Port.B)
steering = Motor(Port.C)
hook = Motor(Port.D)
remoteControl = Remote()

#steering calibration sequence
steering.run_until_stalled(500)
steering.reset_angle(0)
steering.run_until_stalled(-500)
maxAngle = steering.angle()
steering.run_target(500, (maxAngle/2)+10)
steering.reset_angle(0)

#main loop
while True:
    #update pressed buttons information
    pressed = remoteControl.buttons.pressed()

    #commands to drive forwards or backwards
    if Button.LEFT_PLUS in pressed:
        rear.dc(100)
        front.dc(100)
    elif Button.LEFT_MINUS in pressed:
        rear.dc(-100)
        front.dc(-100)
    else: 
        rear.brake()
        front.brake()

    #commands to steer
    if Button.RIGHT_PLUS in pressed:
        steering.run_target(1200, (maxAngle/2)-5, Stop.HOLD,False)
    elif Button.RIGHT_MINUS in pressed:
        steering.run_target(1200, -((maxAngle/2)-5), Stop.HOLD,False)
    else:
        steering.run_target(1200, 0, Stop.HOLD, False)

    #4th motor for hook, red buttons
    if Button.LEFT in pressed:
        hook.dc(-100)   
    else:
        hook.brake()

    if Button.RIGHT in pressed:
        hook.dc(100)   
    else:
        hook.brake()
        
wait(100)

[laurensvalk]

That is a nice extension 😄

no success to make it rotate with the same speed in both directions!

Have a look at this piece of your code.

    #4th motor for hook, red buttons
    if Button.LEFT in pressed:
        hook.dc(-100)   
    else:
        hook.brake()

    if Button.RIGHT in pressed:
        hook.dc(100)   
    else:
        hook.brake()

What will it do if one button is pressed, or when both are pressed?

By contrast, what will the following adaptation do?

    #4th motor for hook, red buttons
    if Button.LEFT in pressed:
        hook.dc(-100)   
    elif Button.RIGHT in pressed:
        hook.dc(100)   
    else:
        hook.brake()

[LegoMan228]

Oh, such a simple solution, thanks a lot!
I'm just making first steps in coding, that's why I haven't checked such a logical situation.
Hope, you will excuse a 10-years old boy))

[laurensvalk]

You are way ahead of where I was back then 😄

Have fun on your journey to learn coding!