Flight Controller Design and Autonomous Flight Tests of 60cm-sized UAV

Abstract

This paper describes the design of flight controller for a fixed-wing small-sized UAV and the autonomous flight tests. The UAV which has been developed by the authors has 0.6m span and its weight is 0.27kg. It cruises at 6-12m/s. The flight controller is composed of attitude stability augment systems, feedforward filters, and guidance systems. The flight controller is designed for longitudinal and lateral-directional motions, separately. The UAV has advantages in safety and portability due to its light weight and low cruising speed. In order to ensure robust stability, the attitude stability augment systems are designed for these motions with µ-synthesis. The feedforward filters are designed in order to shape the command from guidance system to the inner closed-loop appropriately. The longitudinal guidance system, which is designed with PID-control manner, keeps the UAV at a desired altitude. The lateral-directional guidance system guides the UAV to the pre-defined waypoints with avoiding known obstacles. It is designed using the Artificial Potential Field Method. These flight controllers are implemented on the small on-board computer we have also developed. Autonomous flight experiments show that the developed UAV is able to fly autonomously, passing over pre-defined waypoints, and that the UAV has the ability of avoiding the known obstacle