PhD Thesis Proposal

By

Emily A. Leylek

(Advisor: Dr. Mark Costello)

2:30 PM, Friday, September 18th, 2015

Clough Commons Room 127

Full Flight Control of Unmanned Aircraft Using Articulated Bleed Air Lifting Surfaces

ABSTRACT:

The demand for small unmanned aircraft is increasing, as applications for their use proliferate in both the civilian and military sectors. These vehicles serve in diverse roles ranging from military reconnaissance to journalism, environmental science studies, and rescue mission support in the civilian realm. This large variation in missions re                quires small unmanned aircraft to safely operate in a wide range of environments and conditions, from high altitudes to urban environments. Regulations aside, small unmanned aircraft are currently very restricted on where and when they can fly due to wind gust and turbulence sensitivity. Power limitations pose another challenge that also reduces mission effectiveness.

Innovative control mechanisms are sought that provide some combination of improving control authority, increasing efficiency, and reducing power requirements to address the challenges facing widespread use of small unmanned aircraft. One such device is a flow control mechanism called passive porosity, or bleed air. Bleed air control uses arrays of ports on the upper and lower surface of the wing connected through a plenum in the wing. Typically, the lower surface of the wing is the high pressure source, and upper surface is the low pressure area. When opened, air flows between the lower and upper surfaces, passively driven by the external pressure difference. This spoils the lift force on the wing, creating a change in force that can be used as a control effector. Lightweight, low-power actuators, such as piezoelectric louvers and MEMs-based microvalves, can be used to modulate the port openings. This control system also benefits from being hingeless, internally housed, and of lower mechanical complexity than conventional controls, leading to improvements in reliability and endurance of the air vehicle. Additionally, the bleed air can be coupled with wing articulation to tailor and improve the vehicle response. Wing articulation is allowed by a discrete compliant hinge, consisting of flexible material embedded in the wing, constructed by novel multi-material manufacturing techniques.

Parametric trade studies are conducted using standard rigid body 6 degrees of freedom and multibody simulations, which incorporate experimental aerodynamic data from wind tunnel tests. This  thesis will explore three areas: i) control strategies for full flight control with bleed air, ii) how compliant hinges alter the flight dynamics of unmanned aircraft, and iii) synergistic combinations of compliant hinges and bleed air actuators.

COMMITTEE:
Dr. Mark Costello, Advisor (AE/ME)

Dr. Eric Johnson (AE)

Dr. John-Paul Clarke (AE)

Dr. Ari Glezer (ME/AE)

Dr. Al Ferri (ME)