In Fig. 6(a) the samples recorded shows that the inverted pendulum is maintained at the unstable upright position, the angle error is near the zero value with small oscillations and the duty cycle of the PWM signal is preserved in most of the time in a range of [-150;150].
To study the performances of the fuzzy control in presence of disturbance we added some short impulses with maximum 10 degrees amplitude to the angular position of the inverted pendulum by hitting its tip with hand. The evolutions of the same functional signals from Fig. 6 (b) highlight that the balance controller is good enough to maintain the pendulum in the upright position and keep it there stably even in presence of disturbance.