Obstacle Avoidance Algorithm for Circular Objects During Multiple Target Waypoints Navigation Mission of a Fixed-Wing UAV Using Polar Coordinates.

Abstract

This paper presents an obstacle avoidance algorithm that avoids 2D circular objects during an autonomous waypoint navigation flight of a fixed-wing UAV. We named the obstacle avoidance algorithm the Pre-Determined Virtual Circular Obstacle Avoidance Algorithm (PDVCOAA). If a circular obstacle is situated in between two consecutive target waypoints, the PDVCOAA generates an updated trajectory with new target waypoints to avoid the obstacle(s). The new target waypoint navigation plan is uploaded from a ground station to the flight controller on the UAV. The ground station software used in this work is QGroundControl and the flight controller is the Pixhawk 4 Mini, with PX4-Autopilot as its firmware. The performance of the PDVCOAA obstacle avoidance algorithm is assessed using a sample flight plan shared by the organizers of the 2022-23 SUAS competition through Software In The Loop (SITL) testing with a simulated fixed-wing vehicle as well as several custom flight plans in the Gazebo simulator. Once the obstacle avoidance algorithm was validated in the simulation environment, it was flight tested on a custom designed fixed-wing UAV. From the flight tests, we’ve validated that our UAV can avoid obstacles with a radius of 150 ft. and an acceptance target waypoint radius 33.2 ft (default setting in PX4 firmware) and 25 ft (acceptance radius specified in 2022-23 SUAS competition rules).