LAUSR

Digital image processing serves as a multifunctional tool for measurement and positioning tasks in robotics. The present paper deals with the development of a camera-based positioning system for quadrocopters in order to automate their landing process. In this regard, a quadrocopter equipped with classical radio-control components is upgraded with applicable hardware, such as a Raspberry Pi 3B+ and a wide-angle camera. Hereupon, black-box system identifications are executed to attain the relevant plants of the attitude control performed by the flight controller. Thereby, a PID-controller for the altitude control including a back-calculation anti-windup as well as two PD-controllers for the horizontal plane are designed using a pole placement method. Effective tests of the controller gains are conducted by simulating the closed loops respectively. Since the camera functions as a position sensor, an image processing algorithm is then implemented to detect a distinctive landing symbol in real time while converting its image position into compliant feedback errors (pixel-to-physical distance-conversion). Ultimately, the developed system allows for the robust detection and successful landing on the landing spot by a position control operating at 20 hertz.