Hybrid Controller for Soft Landing of a Quadcopter

Mitigating the ground effect has become a big challenge for autonomous aerial vehicles. This paper proposes a sliding mode based on the Proportional Integral Derivative sliding surface control with backstepping (hybrid control) to improve quadcopter flight tracking performance during take-off and soft landing on the ground in a disrupted and windy environment. The proposed controller provided a quick adaptation and high robustness of the vehicle's fight control in the face of disturbances. Using the Lyapunov stability criterion condition has been derived to ensure that the Quadcopter system with a proposed hybrid controller is stable even when the upper bound for disturbance is unknown. The simulation results show that the total thrust generated by rotors increases linearly as the vehicle gets closer to the ground. Proposed controller during landing state reduces 4.77% settling time as compared to PIDSMC and 10% to SMC of the system with no load and with load it reduced 2.70% compared to PIDSMC and 7.35% to SMC. In terms of chattering effect and control effort, proposed controller PIDSMCBS outperformances the PIDSMC and SMC.