Motors only work in certain parts of code

Programming Support VEXcode V5 Tech Support
1

I have a bot with mecanum wheels and I have a move_distance function that moves the bot a certain distance left, right, forward or reverse. The issue is that if I run the function after another function, move_sideways which starts motors and sets them to move at a certain speed and direction, it doesn’t do anything. Running the move_distance function in the beginning of my code, before move_sideways, works as intended. Why would that be the case?

def move_sideways(speed, direction):
    # Move straight in different directions
    if direction == RIGHT:
        front_left.set_velocity(speed, PERCENT)
        front_right.set_velocity(-speed, PERCENT)
        back_left.set_velocity(-speed, PERCENT)
        back_right.set_velocity(speed, PERCENT)
    elif direction == LEFT:
        front_left.set_velocity(-speed, PERCENT)
        front_right.set_velocity(speed, PERCENT)
        back_left.set_velocity(speed, PERCENT)
        back_right.set_velocity(-speed, PERCENT)
    elif direction == FORWARD:
        front_left.set_velocity(speed, PERCENT)
        front_right.set_velocity(speed, PERCENT)
        back_left.set_velocity(speed, PERCENT)
        back_right.set_velocity(speed, PERCENT)
    elif direction == REVERSE:
        front_left.set_velocity(-speed, PERCENT)
        front_right.set_velocity(-speed, PERCENT)
        back_left.set_velocity(-speed, PERCENT)
        back_right.set_velocity(-speed, PERCENT)

    front_left.spin(FORWARD)
    front_right.spin(FORWARD)
    back_left.spin(FORWARD)
    back_right.spin(FORWARD)

def move_distance(speed, direction, distance):
    # Move straight in different directions for a specific distance
    wheel_diameter_mm = 4 * 25.4  # 4-inch wheels converted to mm
    wheel_circumference_mm = math.pi * wheel_diameter_mm
    degrees_to_move = (distance / wheel_circumference_mm) * 360

    if direction == RIGHT:
        front_left.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        front_right.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        back_left.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        back_right.spin_for(REVERSE, degrees_to_move, DEGREES)
    elif direction == LEFT:
        front_left.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        front_right.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        back_left.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        back_right.spin_for(FORWARD, degrees_to_move, DEGREES)
    elif direction == FORWARD:
        front_left.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        front_right.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        back_left.spin_for(FORWARD, degrees_to_move, DEGREES, wait=False)
        back_right.spin_for(FORWARD, degrees_to_move, DEGREES)
    elif direction == REVERSE:
        front_left.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        front_right.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        back_left.spin_for(REVERSE, degrees_to_move, DEGREES, wait=False)
        back_right.spin_for(REVERSE, degrees_to_move, DEGREES)

def when_started1():
    black_threshold = 2000  # Based on line tracker values

    # Define motor speeds
    forward_speed = 25   # Based on percent of motor speed

    black_line = 0 # Number of black lines crossed

    # Move arm up
    grab_arm.set_velocity(60,PERCENT)
    grab_arm.spin_for(FORWARD, 300, DEGREES)

    while black_line < 2:
        # Read line sensor values
        right_sensor = line_tracker_c.value()
        center_sensor = line_tracker_d.value()
        left_sensor = line_tracker_b.value()
        # Move to the right
        move_sideways(forward_speed, RIGHT)
        if center_sensor > black_threshold:
            black_line += 1
            if black_line != 2:
                wait(1, SECONDS)
    move_sideways(0, RIGHT)

    while True:
        Kp = 0.01  # Proportional control constant, higher = more sensitive
        stop_distance_mm = 190  # Based on ultrasonic values

        # Read line sensor values
        right_sensor = line_tracker_c.value()
        center_sensor = line_tracker_d.value()
        left_sensor = line_tracker_b.value()
        distance_mm = Range.distance(MM)

        # Calculate the errors
        error_left = left_sensor - black_threshold
        error_right = right_sensor - black_threshold

        # Calculate the control actions
        # turn_speed_left = Kp * error_left
        # turn_speed_right = Kp * error_right

        if distance_mm < stop_distance_mm:
            turn_in_direction(0, 0)  # Stop all wheels
            grab_claw.spin_for(REVERSE, 270, DEGREES, wait=False)
            wait(2, SECONDS)
            break
        elif center_sensor > black_threshold:  # Center sensor sees black (on the line)
            # Move forward 
            move_sideways(forward_speed, FORWARD)
        elif left_sensor > black_threshold or right_sensor > black_threshold:
            # Calculate the control actions for turning while moving forward
            turn_speed = Kp * (error_left if left_sensor > black_threshold else error_right)
            # Move forward while turning
            front_left.set_velocity(forward_speed - turn_speed, PERCENT)
            front_right.set_velocity(forward_speed + turn_speed, PERCENT)
            back_left.set_velocity(forward_speed - turn_speed, PERCENT)
            back_right.set_velocity(forward_speed + turn_speed, PERCENT)
            # Start the motors
            front_left.spin(FORWARD)
            front_right.spin(FORWARD)
            back_left.spin(FORWARD)
            back_right.spin(FORWARD)

    move_distance(30, FORWARD, 500)

when_started1()
2

The expected behavior of

move_sideways;
move_forward;

is that the robot will only move forward. To make the robot move sideways first, you need a delay between the two lines.

3

I’m a bit confused, since there is already a delay due to the while loop taking some time to execute, also my issue isn’t move_sideways not executing, but the latter one, move_distance.

4

I was able to fix this error, I forgot to initialize the speed of the motors but once I did that, the move_distance function worked as intended