Fuzzy control strategy for Acrobots combining model-free and model-based control

A fuzzy control strategy for the control of an Acrobot is described. The strategy combines model-free and model-based fuzzy control. The model-free fuzzy controller designed for the up-swing ensures that the energy of the Acrobot increases with each swing. The control law for the torque is derived directly from the energy of the Acrobot. The model-based fuzzy controller, which is based on a Takagi-Sugeno fuzzy model for balancing, employs the concept of parallel distributed compensation. The stability of the fuzzy-control system for balance control is guaranteed by a common symmetric positive matrix, which satisfies linear matrix inequalities and is found by a convex optimisation technique