| Title |
Modified Three-Loop Autopilot for Acceleration Control Performance Improvement of a Canard-Controlled Aircraft |
| Authors |
한광희(Kwang-Hee Han) ; 한지은(Jieun Han) ; 황익호(Ick-Ho Whang) ; 나원상(Won-Sang Ra) |
| DOI |
https://doi.org/10.5370/KIEE.2024.73.7.1220 |
| Keywords |
Autopilot topology; longitudinal flight dynamics; linear quadratic control; output feedback; canard-controlled unmanned aerial vehicle |
| Abstract |
This paper proposes a new autopilot topology with its optimal design methodology for canard-controlled unmanned aerial vehicles(UAVs). While the traditional three-loop autopilot has been considered as a rule of thumb to control a tail-controlled UAV, it is questionable whether this topology also becomes one of the best choices for UAVs with other wing configurations. To identify a probable improvement of the existing approach, the topological property of the conventional three-loop autopilot is investigated. As a result, it is shown that the three-loop autopilot consists of a full-state feedback controller with an angle-of-attack estimator as well as an integral compensator in its feedforward path. Based on this observation, a modified three-loop autopilot is suggested by replacing the integral compensator with the proportional-integral one to improve the acceleration tracking performance. The control gains of our autopilot are designed by solving the optimal output feedback control problem. To cope with the lack of stability margin due to un-modeled actuator dynamics, the weighting matrix associated with the cost function of the problem is systematically chosen to guarantee the desired phase margin and the gain cross-over frequency. Simulation results confirm that the proposed method shows better performance for canard-controlled UAVs than the existing topology. |