Joy stick Implementation on PID controlled balancing robot I am developing a self balancing robot which uses DC motor as actuator, IMU as input sensor and PID as controller. I want to use Dual axis joystick to control the forward and backward motion as well as to turn the robot left and right. Regarding forward and backward motion, I have come up with the idea however, I am stuck with the direction(left and right). I would be grateful if someone could share their idea on this.
I'm not 100% sure what your expect problem is … I assume you can read left and right on the joystick (very similar to up and down).

To make a left movement, you have to either stop the left wheel and rotate the right wheel forward (so you make a left turn), or if you want an even faster movement, move the left wheel backwards and the right wheel forward. 

For a right movement, do the opposite.

(actually having a different speed for the left and right wheel already causes a turning movement).