An Optimized Fuzzy-Padé Controller Applied to Attitude Stabilization of a Quadrotor

In this research, an Optimized Fuzzy-Padé Controller (OFPC) for attitude stabilization of a quadrotor is proposed by using Padé approximants and fuzzy singleton rules. To determine unknown coefficients of the Padé approximant, a PD-type Fuzzy Logic Controller (FLC) is first designed. As the number of the fuzzy singleton rules extracted from the FLC is less than the number of the unknown coefficients, some of them cannot be determined using the rules. The coefficients not specified are determined applying particle swarm optimization algorithm to increase convergence speed and decrease energy consumption. The simulation results for the OFPC demonstrate faster convergence speed, lower power consumption, larger convergence region, better robustness, and faster computational time in comparison to the FLC. Unlike the FLC, the OFPC is fast enough to be implemented on the microcontroller of the quadrotor. The experimental results indicate that the proposed controller quickly stabilizes the quadrotor, even with externally applied disturbances. The proposed approach possesses certain advantages over FLCs, and it can be employed wherever FLCs are not applicable due to the high computational burden.