Calibrate your joystick with the following steps.
Install the joystick calibration program with the following command:
sudo apt-get install joystick
Pair the joystick as a Bluetooth peripheral.
Run the calibration program with the following command:
Find your joystick and note the device ID for later.
Select your joystick and click Properties..
Click Calibration and follow the instructions.
Store the calibration with the following command:
sudo jscal-store /dev/input/js0