In this article. a fault tolerant controller (FTC) based on back-stepping sliding mode is proposed for a quadrotor unmanned aerial vehicle (UAV) with single-rotor failure. According to the working mechanism of the quadrotor. the control system of UAV is divided into position subsystem and attitude subsystem. https://www.roneverhart.com/Fit-Shaced-Shit-Faced-St-Patricks-Day-Shamrock-Drinking-Thermal-Shirt/