Terrain following and autonomous landing using optical flow

An optical flow sensor, which is fabricated by our laboratory, was mounted on a unmanned aerial vehicle (UAV) to implement terrain following and autonomous landing tasks by using optical flow as feedback. The performance of the optical flow sensor was tested and the UAV model was built. Control algorithm for terrain following based on optical flow was developed and landing strategies using optical flow as feedback was proposed. Mathematical simulations and hardware-in-loop tests show optical flow information can be used in a relatively simple form to control both the flying speed and altitude at the same time to ensure the safety of flying missions for the UAV. The optical flow sensor is proved available for flight control by the hardware tests.