Sensorless Active Disturbance Rejection Hybrid Control With Adaptive Sliding Mode Observer for BLDC Motor Drives

The deployment of Unmanned Aerial Vehicles (UAVs) to perform complex maneuvers requires precise control of sensorless motors. However, chattering in UAV brushless direct current (BLDC) motor propeller systems, reaching steady-state in a short time, and physical sensors pose challenges. Field-oriented backstepping control (FOBSC) offers a superior dynamic response, and field-oriented input-output feedback linearizing control (FOIOFL) minimizes torque ripple and power consumption at steady-state. This paper proposes a hybrid controller that combines FOBSC and FOIOFL control approaches with a novel rule-based switching algorithm to optimize dynamic and steady-state control performance, such as fast convergence, improved tracking accuracy, and reduced chatter in the speed and torque of the BLDC motor drive. Besides, a model reference adaptive system (MRAS) disturbance observer is integrated with the proposed hybrid controller to enhance overall performance and actively reject disturbances. Furthermore, instead of using complicated physical sensors for UAV applications, an enhanced adaptive sliding mode observer (EASMO) is developed to estimate real-time rotor positions and speed and adapt variation in stator resistance, improving stability and performance. The stability of the proposed control strategy is validated using Lyapunov approach in all operational conditions. Various numerical and experimental test scenarios are conducted to find the effectiveness and superiority of the proposed sensorless active-disturbance rejection hybrid control approach compared to the individual FOBSC, FOIOFL control, and standard controllers.