Development of a Quad-Rotor Biplane MAV with Enhanced Roll Control Authority in Fixed Wing Mode

In order to ensure mission versatility, multi-role vehicles must be capable of vertical take-off and landings as well as rapid forward flights. In all flight modes, these vehicles must also have robust control systems in place. In this study, one such hybrid air vehicle, called the quad-rotor biplane is considered. It consists of four proprotors with two wings oriented in a biplane configuration. It was observed during forward flight that the baseline vehicle configuration suffers from a lack of sufficient roll control authority. This paper explores the deficiencies of the installed roll control method and investigates several other suitable control systems. These include a pair of pivoting wing tips, thrust vectoring via angled proprotors, and a variable collective pitch proprotor method. Roll moments were measured in a 6.25 m/s wind via a torque gauge and measured as much as 97% above baseline system roll magnitudes. It was found that by combining the angled proprotor and variable collective control, a 186% improvement in control authority could be achieved with an added benefit of improving the forward flight envelope from an advance ratio of 0.4 to an advance ratio of 1. This investigation will supply information to be utilized in the construction of a high-speed, high-endurance quad-rotor biplane micro air vehicle.