In the simplified schematic picture from Fig. 1(a) the inverted pendulum is displaced from the upright position with a given a, 8 denotes the angle of the pivot arm, a dot and 8 dot are the angular velocities of the inverted pendulum and pivot arm. The parameters a and 0 are the generalized coordinates that describe the inverted The dynamic model of the inverted pendulum results from the decomposition of the plant into two planes: XY horizontal plane of the pivot arm and XZ vertical plane where the pendulum is rotating. From the Newton’s laws in the X and Z directions and Euler’s equations of the rotational motion around the points P and O results the equations of motion of the mechanical system [3,ll].The kinetic energy of the mechanical system arises from the rotating arm, which is driven by the dc motor. The final equations of the dynamics of the model are quite non-linear and a linear approximation of the non-linear system (l) can be obtained using the small angle formula.