Near to optimal design of PIλDμ fractional-order speed controller (FOPID) for multirotor motor-rotor simplified model

In this paper a fractional-order (or alternatively known as a non-integer) FOPID type controller (that gives better performance than classical, integer-order PID type) was proposed for tracking of the rotational speed reference signal of propeller in electric propulsion system used in multirotor flying robots and platforms. For propulsion system (electronic speed controller, brushless direct current motor, three-bladed propeller) and measurement data from the test bench simplified models of motor-rotor (linear, analyzed within the range of useful forces and rotational speeds) were assumed. For selected one, a synthesis of the FOPID type controller was conducted. Tuning of controller parameters has been based on the procedure named as Best from the best, using aim function proposed by author for optimizing of tracking quality. It was shown that even so far reaching simplification in the model of the motor-rotor system allows to obtain a high quality as a result of tracking of the set rotational speed value, i.e. in a short time, at efficient damping of disturbances and high robustness to model parametric uncertainty. Providing of such a FOPID type controller properties is a key aspect from the perspective of the use of solutions in the context of stabilization, as well as control of the position and orientation of multirotor flying robots.