Two wheeled balancing robot is a inverted pendulum type problem. To keep the robot in balance it needs to measure the tilt angle and control the wheels to adjust the robot back in the upright position. In our case we are using accelerometer to measure the tilt angle and gyroscope to complement the readings from the accelerometer. Motors we are using are basic DC motors without any encoders.
The height of the robot affects robot controlling. In our case having center of mass higher helps the balancing because it slows down the angular acceleration.