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A Stagnation Point Actuator is used to control the lateral dynamics of vortices generated over a sharp-pointed forebody, at high angles of attack, and the resulting rolling moment is studied. Effective roll control is demonstrated, including the ability to suppress the wing rock phenomenon. Piecewise-linear transfer functions are developed from experimental data for the changes in roll moment and pressure difference with actuator frequency content. These transfer functions are reduced to compact form in the frequency domain, and then to a time-domain model using 2 gains and 2 time scales. The roll response is classified according to angle of attack range. Some long time scales are observed in the surface pressure, velocity field and rolling moment, making the response relatively insensitive to speed. Thus over substantial speed ranges, linear transfer functions are shown to effectively describe the roll response to motion of the Stagnation Point Actuator.

The wind-driven dynamic manipulator is a device which uses the wind tunnel freestream energy to drive multi-axis maneuvers of test models. This paper summarizes work performed using the device in several applications and discusses current work on characterizing the aerodynamics of an X-38 vehicle model in pitch-yaw maneuvers. Previous applications in flow visualization, adaptive control and linear-domain parameter identification are now extended to multi-axis inverse force and moment measurement over large ranges of attitude. A pitch-yaw-roll version is operated with active roll to measure forces and moments during maneuvers. A 3-D look-up table generated from direct force calibration allows operation of the manipulator through nonlinear regimes where control wing stall and boom wake-wing interactions are allowed to occur. Hybrid designs combining conventional and wind-driven degrees of freedom are discussed.

Neural network augmented model inversion control is used to provide a civilian tilt-rotor aircraft with consistent response characteristics throughout its operating envelope, including conversion flight. The implemented response types are Attitude Command Attitude Hold in the longitudinal channel, and Rate Command Attitude Hold about the roll and yaw axes. This article describes the augmentation in the roll channel and the augmentation for the yaw motion including Heading Hold at low airspeeds and automatic Turn Coordination at cruise flight. Conventional methods require extensive gain scheduling with tilt-rotor nacelle angle and airspeed. A control architecture is developed that can alleviate this requirement and thus has the potential to reduce development time. It also facilitates the implementation of desired handling qualities, and permits compensation for partial failures.

Hybrid-electric powertrains for passenger vehicles and light trucks are generally being designed with two different configurations described as follows: The Toyota Hybrid System, THS-II, implemented in the 2004 Prius, the Lexus 400-H, and the Ford Hybrid Escape, is a power-split approach involving two electric machines and an internal combustion engine (ICE) mechanically coupled by a three-shaft planetary gear train. The second leading approach is a parallel hybrid-electric powertrain that generally includes a single electric machine and an ICE with a mating multi-ratio transmission. These parallel configurations are further divided as weak parallel and strong parallel. Honda uses a weak parallel powertrain in their Insight and Hybrid Civic. At Georgia Tech a strong (full), split-parallel hybrid powertrain has been implemented in a Ford Explorer. The vehicle is referred to as the Model GT.

In order to ensure the safety of a structure, adequate strength for structural elements must be provided. In addition, the catastrophic deformations such as buckling must be prevented. In most buckling analyses, structural properties and applied loads are considered certain. Using the linear finite element method, the deterministic buckling analysis is done in two main steps. First, a static analysis is performed using an arbitrary ordinate of applied load. Using the obtained element axial forces, the geometric stiffness of the structure is assembled. Second, performing an eigenvalue problem between the structure's elastic and geometric stiffness matrices yields the structure's critical buckling loads. However, these deterministic approaches disregard uncertainty in the structure's material and geometric properties. In this work, an interval formulation is used to represent the uncertainty in the structure's parameters such as material characteristics.

The interest in flying cars comes with the question of characterizing aerodynamic loads on shapes that go beyond traditional aircraft shapes. When carried as slung loads under aircraft, vehicles can encounter severe aerodynamic loads, which may also cause them to go into divergent oscillations that can threaten the vehicle and aircraft. Slung loads can encounter the wind at arbitrary attitudes. Flight test certification for every vehicle-aircraft combination is prohibitive. Characterizing the aerodynamic loads with sufficient resolution for use in dynamic simulation, has in the past been extremely arduous. Sharp changes that drive instabilities arise over small ranges of yaw and pitch. With the Continuous Rotation technique developed by our group, aerodynamic load characterization is viable and efficient. With two well-chosen attitude sweeps and appropriate transformations, the entire 6-DOF load map can be obtained, for several rates.

Loads slung under aircraft can go into divergent oscillations coupling multiple degrees of freedom. Predicting the highest safe flight speed for a vehicle-load combination is a critical challenge, both for military missions over hostile areas, and for evacuation/rescue operations. The primary difficulty was that of obtaining well-resolved airload maps covering the arbitrary attitudes that a slung load may take. High speed rotorcraft using tilting rotors and co-axial rotors can fly at speeds that imply high dynamic pressure, making aerodynamic loads significant even on very dense loads such as armored vehicles, artillery weapons, and ammunition. The Continuous Rotation method demonstrated in our prior work enables routine prediction of divergence speeds. We build on prior work to explore the prediction of divergence speed for practical configurations such as military vehicles, which often have complex bluff body shapes.