Design of Image-Based Autonomous Landing Instrumentation and Control System for Unmanned Quadrotor Vehicles

The study designs an instrumentation and control system for autonomous quadrotor landing using a visual marker as the landing target. For landing process, the marker used as a landing target is an embedded ArUco marker, capable for detection for both long range and close-range detection. Position of the quadrotor relative from the ArUco marker is estimated using Perspective-N-Point pose estimation. The estimation errors compared to actual measurements are under 20 cm, which is less than the distance between ArUco border and its center. To keep camera for facing downward during the flight, the 2 axis inertially stabilization platform (ISP). The designed ISP can maintain the camera orientation even when quadrotor angle has changed. The landing control system is made for two different scenarios. First scenario is for landing with Global Positioning System (GPS) support, and the second scenario is without GPS support. The landing control system in GPS support scenario uses velocity setpoint to control the quadrotor while in without GPS support scenario, control system uses angle-thrust setpoint to control quadrotor. Quadrotor landing control system can attempt landing on top of the ArUco marker in both scenarios. The trajectory Mean Average Error (MAE) of x and y coordinates and radius of the landing process is (0.108, 0.326, 0.359) m for GPS support scenario and (0.301, 0.251, 0.436) m for without GPS support scenario.