An Exclusive Landing Control System Fusing Vision of Multirotor UAV

The aim of this investigation is to clarify how the multirotor Unmanned Aerial Vehicle (UAV) can accurately and safely touchdown the parking apron of distributed airport autonomously. This paper proposed an exclusive landing control system fusing vision of multirotor UAV, which is only effective during touchdown period. First, the block diagram of exclusive control system fusing vision is designed. In the exclusive landing system, the pose control from existing control system is the inner control loop, the speed control system is the middle control loop and the position control fusing vision is the outer control loop. Second, the algorithm to acquire the position error from image of landing region is designed. Third, the control laws of position and speed controller are determined respectively. The simulation and field experiments show that: (1) It spends about 77ms by the airborne embedded system to process the image of landing region in order to acquire the target on the apron of distributed airport, which is basically satisfy the real time control requirement. (2) The control system with PI position controller and PD speed controller has obvious less overshoot and transition time than other control system during the simulation of landing period. (3) The average landing position error is about 0.14m while the PI position controller and PD speed controller are employed during the field experiments. Therefore, the exclusive landing control system fusing vision proposed in this paper can significantly improve the autonomously landing accuracy and safety of the multirotor UAV.