The Obstacle Avoidance System in A Fixed-Wing UAV When Flying Low Using LQR Method

A fixed-wing Unmanned Aerial Vehicle (UAV) is widely used for military and civilian needs to carry out monitoring missions at low altitudes. In the monitoring mission, many obstacles are in front of the UAV flight path so that it can interfere with the UAV flights. Therefore, the UAV requires a control system to avoid these obstacles without causing excessive overshoot. The obstacle avoidance system in this research uses the Linear Quadratic Regulator (LQR) method. LQR plays a role in producing full state feedback gain K. The deflection angle of all control surfaces and Pulse Width Modulation (PWM) signals as brushless motor rotational speed regulators are set to produce a force and torque according to the result of the full-state feedback controller. Control phase of avoiding obstacles is divided into three, namely cruise, climb, and descent. This research shows that LQR-based controls play a role in stabilizing UAV motion when avoiding obstacles. The obstacle avoidance process follows a pattern generated by the flight pattern generator.