Prescribed performance control using an adaptive super-twisting sliding mode method for quad-rotor UAV under the disturbance from variable-length gimbal

Recently, bridge detection by QUAVs(Quad-rotor Unmanned Aerial Vehicles) is more and more prevalent, however, there is a problem that QUAVs cannot fly close enough to get clear shots for some complex bridge structures. To solve it, an invention of variable-length gimbal mounted on QUAV is proposed in this study, at the same time, the control method of QUAVs with the gimbal is put forward. In detail, dynamic model of system is given considering the disturbance from gimbal and model uncertainty. Then, assuming the upper bound of the disturbance and uncertainty is unknown, an adaptive super-twisting fast terminal sliding mode control method meets prescribed performance is planned, which can achieve accurate estimation of the upper bounds. As a result, the validity of the method and its superior system performance is proved by simulation outcomes.