“…Alternative, lower-bandwidth actuators, such as those based on pneumatic or hydraulic motors, were not considered. Typically, the deflection angle and speed of the inverted pendulum, and the speed and position of the pendulum platform were measured by means of absolute or incremental encoders [1,3,9,12,13,[20][21][22]. Additional sensors (such as gyroscopes) have been added in the special case of the two-wheeled mobile robot in order to improve its disturbance rejection [1].…”