Calibrating motor speed

In this light green setting mode (when you press the right and left buttons simultaneously), you can calibrate the speed of the motors. Indeed, because no two motors are exactly the same, the same power level may result in different speeds. This page provides a procedure to calibrate the motors on your robot so that it will travel straight.

The calibration is supported starting from firmware V.9 in the setting mode. If you have an earlier version, upgrade the firmware of your robot.

Print this pdf file and tape it to a table or to the ground. (print the file on two A4 pages at 100 % and tape them together; alternatively, print on a single A3 page.) Place the robot between the lines and run the pre-programmed obedient (purple) behaviour, which enables you to control the forward speed of the robot. If the robot remains between the lines for 40 cm, calibration is not needed; otherwise, carry out the following procedure:

  • Choose the light green mode in the setting mode menu.
  • The "front" and "back" buttons make the robot move forward and backward. Press them once or twice to modify its speed, so that you can check if the robot travels straight at different speeds.
  • The "left" and "right" buttons increase or decrease the correction in the direction of travel: If the robot turns right, touch the left button to correct the direction until it goes straight, and conversely if it turns left, touch the right button.
  • When the robot goes straight, touch the central button. This will stop the motors and record the correction value into the robot.
  • Power off the robot.
  • Power on the robot again and check the results of the calibration by running the pre-programmed obedient (purple) behaviour.

Here is a video showing a calibration example:

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