Experimental Validation of a Fractional Order Autotuner for a Two Rotor Aerodynamical System

Multivariable poorly damped processes can be easily destabilized using poorly designed controllers. In this case, controllers with increased robustness and flexibility are generally preferred. At the same time, model-based controllers are prone to modeling errors. Occasionally, autotuning methods can be used instead. A solution that meets all these requirements consists in the generalization of the PID, the fractional order controller. Autotuning methods for fractional order controllers are scarce, even so for multivariable poorly damped ones. No experimental validation of such methods has been reported. In this manuscript, an autotuning method is used to design fractional order controllers for a two rotor aerodynamical system. A novel approach using a sequential relay test and fractional order PIDs is used to extract required process information. Comparative closed loop results with standard PID controllers are included to demonstrate the advantages and disadvantages of the approach.