A Comparative Study of PD, LQR and MPC on Quadrotor Using Quaternion Approach

This study addresses the performances of three different controllers Proportional-Derivative (PD), Linear Quadratic Regulator (LQR) and Model Predictive Control (MPC) on a quaternion orientation based quadrotor and determines their suitability for different applications. As these controllers are widely being used in quadrotor platform with Euler-angle orientation, alternatively they are evaluated with quaternion orientation because this orientation can ensure singularity-free flight. In order to compare the performances of the controllers, performance indices like tracking error, considering RMSE method and control effort, using norm of control inputs have been considered. Based on the comparison, it is found that MPC is suitable for outdoor applications while PD and LQR can be best-fitted for indoor applications. MATLAB and Simulink environment has been considered in order to evaluate their performances.