Bibliografie

(eng): This paper provides the comparison of nonlinear observers for underactuated mechanical systems with aplication to Acrobot walking. Namely, it aims to compare a reduced observer for the Acrobot angular velocities based on the respective angles measurements with a observer for the Acrobot angular velocity and angle based on the other angular velocity and angle measurement and then to combine this observers with the earlier developed full state feedback controllers. For the Acrobot it is not possible to measure the angle between its stance leg and the surface directly because this angle is underactuated. One possibility of measuring this angle is using laser beam sensor and then computation the stance angle from that distance. Main disadvantage of this approach is the high price of the laser beam sensor. The other observer is based on angular velocity of stance leg measurement using the digital gyroscope.