Gain Scheduling of Backstepping Sliding Mode Controller Using Interval Type-2 Fuzzy Logic Approach for Quadcopter

The quadcopter, with its coupled dynamics and underactuated system, makes it a great platform for designing control schemes since it is highly nonlinear system. This paper aims to address these issues by proposing a control algorithm to operate quadcopter in the face of disturbances. This paper proposes an interval type-2 fuzzy logic backstepping sliding mode controller (IT2-FL-BSMC) to efficiently control altitude and rotational parameters of a quadcopter. Conventionally, gains of backstepping sliding mode controller (BSMC) are obtained by the trial-and-error method, which is time-consuming as well as may not be a reliable choice. To address this issue, an interval type-2 fuzzy gain schedule technique is proposed to modify all BSMC gains to be time-varying which results in the improvement of performance of the proposed nonlinear controller against external disturbances. To verify validity of the proposed controller, obtained results are compared with conventional BSMC and type-1 fuzzy logic backstepping sliding mode controller (T1-FL-BSMC) in terms of critical performance index like settling time, rise time and steady-state error. Furthermore, the effectiveness and robustness of the proposed controller is also observed in the disturbed environment. MATLAB® is used to simulate the modelling and control of quadcopter.