Fuzzy Gain Scheduling Control for a Special Case of 2nd Order Non-linear Systems

In this paper, a new control methodology is proposed for a class of nonlinear control systems. The proposed methodology combines the advantages of both gain scheduling technique and fuzzy control technique to obtain an advanced tracking control structure. This methodology is applicable for tracking a special case of second order nonlinear systems that represented in a general form similar to many electromechanical systems model representations, such as the magnetic ball levitation and the inverted pendulum. A continuous gain scheduled tracking controller is designed based on the use of state feedback. The state feedback controller is transformed into its equivalent PI+D controller with a pre-filter added on the reference input. At the first stage of employing fuzzy logic approach, a discrete model of the designed gain scheduled PI+D controller is obtained and then Fuzzy PI+D controller is implemented by using simple analytical equations with preserving the same linear structure of the discretized controller. Fuzzy logic is employed only for the design; the resulting controller does not need to execute any fuzzy rule base. Finally, a simulation is performed by applying the programmed fuzzy control approach to the simulation model of the magnetic ball levitation CE152. Simulation results showed that the proposed technique has achieved better performance compared to the PI +D controller without employing fuzzy logic control.