Synthesis of Kalman filter in quadcopter roll control loop based on PD-PI controller

Quadcopter attitude control using synchronous motors poses challenges for stateestimation due to periodic disturbances caused by three-phase winding switching, whichviolate the standard Kalman filter's assumption of Gaussian noise. To address this, wepropose a Kalman filter design that incorporates control signals and explicitly modelsthese periodic disturbances. The filter is integrated into a roll and pitch angle controlsystem using a modified PD-PI controller structure, which ensures compatibility betweenthe control and estimation processes. Experimental validation on a real flightmicrocontroller, with implementation in C++, shows that the proposed filter reduces thevariance of the estimated signals by a factor of four compared to standard approac hes.Additionally, the system reveals that angle fluctuations at low speeds result frominteractions between switching frequencies and controller discretization. These resultsdemonstrate that the method enhances estimation accuracy and can be effectivelyapplied to quadcopter platforms using both synchronous and asynchronous motors.