Reversible Thrust-based Fault Tolerant Control for Quadrotor UAVs against Motor Failure

Most of the existing approaches to fault tolerant control (FTC) of UAVs utilize the gyroscopic effect to stabilize a small and light weight quadrotor UAV with complete loss of motor(s), which are not suitable for large and heavy quadrotor UAVs as the quadrotors are required to spin at very high speed after one or more motor failures to maintain stability. This paper studies a reversible thrust-based active fault tolerant control approach for large and heavy quadrotor UAVs against any single-motor failure where the spin rate is low and the center of gravity (CG) may not be at the geometric center of quadrotor structure. This approach is based on nonlinear dynamic inversion and incremental control allocation using the negative thrust from reversed motor-propeller rotation. The flight experiment verifies the effectiveness of the proposed method. The demonstration video can be accessed via https://www.youtube.com/watch?v=Tcfe0o1SBr8.