The Investigators propose to design the outer-mold-line (OML) geometry and evaluate the aerodynamics, flight stability and control characteristics of a novel blended wing-body aircraft configuration with electric propulsion, the Kitty Hawk 2 (KH2). The OML design will be based on flight performance analysis of two or more candidate configurations (one of which may be supplied by the sponsor, if desired). The aerodynamic and stability and control evaluations will be conducted via a sequence of increasing-fidelity modeling tools as well as steady wind tunnel force and moment measurements of a scaled vehicle model. The objectives of this Phase I effort are to quantify the aircraft lift and drag performance in steady flight, static stability, control surface effectiveness, trimability, and perform preliminary assessment of dynamic stability of the selected OML design. In the process of characterizing the baseline vehicle geometry in Phase I, an important aim is to develop the necessary analytical/numerical toolsets, experimental setups, and workflows for improving the overall aerodynamic design and performing parametric and tradeoff studies of various geometry parameters (body-wing geometry, control surface placement, etc) in potential future development.

The purpose of the proposed research is to design and prototype an amphibious multi-terrain robot with capabilities to navigate the Arctic regions autonomously using a helical drives-based propulsion system. This will be achieved through developing and validating dynamic models of helical drives on surface conditions found in the Arctic and Antarctic regions such as land covered in snow, ice, mud, gravel, and loose soil as well as small water bodies, followed by developing a fully-functional rover prototype and testing its locomotion capabilities in the field, and, finally, demonstrating the deployment readiness of the rover by simulating a survey mission in the Arctic. The research aims to address the fundamental gap in the field of robotics involving the lack of robust amphibious and multi-terrain functionalities within the class of rovers used to explore the polar regions. To solve this problem, we will address the robotics challenge of understanding how variable surface and terrain conditions couple to the dynamics, energetics, optimal design, and control strategy of a single, multi-functional locomotion system. Through this project the PI(s) will also provide a methodology to derive the dynamics, design, and control architecture of a highly adaptable amphibious multi-terrain rover thereby laying the foundation of the next generation of terrestrial and extraterrestrial exploratory robots.

The primary innovations of the proposed project will be: (1) a novel method of exercising control over the response of aeroelastic structures through prescribing upstream vortical flow disturbances; (2) an understanding of the mechanisms and governing parameters of unsteady wing force generation in response to impinging vortices; and (3) knowledge of the relationships between desired aeroelastic wing behavior and the appropriate spatial and temporal features of impinging flow disturbances. The current knowledge and understanding of the motion of elastic structures in response to impinging flow disturbances like vortices remains rudimentary and ad-hoc. Both natural and engineered systems offer numerous examples of vortical wakes and flow disturbances interacting with elastic structures. These examples range from fish adopting specialized swimming gaits to improve efficiency when in vortical wakes, to marine mammals sensing and following wake vortices of upstream prey via flexible whisker sensors, to oscillating fluid-elastic energy harvesters passively synchronizing and enhancing power extraction via constructive wake-coupled interactions. While these examples serve as motivating proofs of concept, engineering systems to exploit such interactions and use them as control mechanisms requires understanding of the nonlinear governing relationships between the flow disturbances and the structural dynamics. Our proposed aims will expand knowledge of the fundamental physics that facilitates these fluid-structure interactions such that we can tailor and control vortical disturbances to affect desired dynamic response from fluid-elastic structures. Our proposed work will create the required analytical framework, reveal the fundamental relationships between vortical flow feature parameters and wing forces, formulate control algorithms that produce desired aeroelastic wing responses on demand, and generate reproducible experimental validations that will enable engineers and scientists to understand, exploit, and control the interactions of elastic structures and vortical wake flows.

This CAREER project aims to create fundamental innovation in the dynamics and control of robots that physically interact with humans by modeling, optimizing, and validating a new paradigm for muscle-inspired soft actuators. Human muscle tissues employ a massively over-actuated architecture in which many internal degrees of freedom (motor units) are used in parallel to produce a single output degree of freedom (muscle tissue contraction), through a hierarchical, load-adaptive control process called motor unit recruitment. This architecture allows natural muscle to achieve fast response and a wide gamut of force and compliance levels on demand, all while minimizing metabolic energy consumption. Understanding how this adaptive actuation and control structure can be leveraged in robotics will allow unprecedented improvements in energy efficiency, bandwidth, stiffness control, and failure tolerance. Implementation in a soft, muscle-inspired, selective-recruitment actuator will make this new approach uniquely suited for human-assistive wearable devices, prosthetics, or other robotic systems that physically interact with humans.

In this research, we propose to study the effects of upstream vortical and viscous flow disturbances on the unsteady aerodynamics of airfoils undergoing prescribed motions and on the aeroelastic characteristics of flexible airfoils.

Providing reconnaissance and situational awareness in large and complex subterranean facilities will require multiple distributed sensing platforms (e.g. small multi-rotor UAVs) that can distribute themselves and navigate autonomously throughout the space. Implementing such a system poses several design challenges. How can multiple vehicles be inserted into the area with minimal human intervention? How can the swarm intelligently manage power levels across vehicles to provide both rapid initial mapping as well as continuous sensor coverage and endurance? These questions highlight UAS mobility, system power management, and decentralized exploration as key challenges in the development of a rapid subterranean mapping and monitoring system. One potential solution is a man-portable ����������������mothership���������������: an autonomous ground robot that can serve to launch, recover, and re-energize a swarm of small aerial vehicles. The mothership can be designed for rapid deployment through a small doorway or window. If needed it can then traverse to an initial launch point for the UAVs, and can continue to move forward to new locations as needed. When the power level of an individual UAV becomes low, it can return to the mothership for automatic battery recharge or replacement. Other vehicles in the swarm can be reallocated to continue exploration forward or maintain sensing and communication coverage throughout an area to be monitored. The ground robot itself can also provide additional heterogeneous capabilities to the system, including carrying larger sensor packages that exceed the payload capabilities of the UAVs, and perhaps featuring manipulator arms or sample collection equipment to investigate objects of interest. The proposed project will investigate this mobile UAS mothership concept through a combination of trade-off studies, analysis, conceptual design, and prototyping and testing of key subsystem technologies.

The purpose of this project is to investigate the magnitude of lift and pitching moment variation during an unsteady vs. the quasi-steady translation of a slender body from a cavity through a vortex-shear layer into supersonic flow. Mean- and time-varying, as well as frequency content of the normal force and pitching moment will be recorded. To correlate the forces on the store, simultaneous flowfield information, as well as surface pressure data will be obtained. The future application is to investigate whether timed-release of stores from cavities offer a benefit in a more accurate prediction of safe trajectory from the air vehicle.

The proposed work seeks to enable low-head hydropower systems based on densely packed arrays of oscillating hydrofoil generator devices. Harvesting energy from surface water flows such as river and tidal flows offers a vast source of clean energy, but traditional technologies such as hydroelectric dams and spinning hydrokinetic turbines pose inherent limitations on suitable sites, suffer from high costs, and have undesirable environmental effects. Oscillating hydrofoil generators (OHGs), with their rectangular swept areas, use space more efficiently than the circular swept areas of rotary hydrokinetic turbines. They can operate in shallow rivers and estuaries where depths would preclude rotary systems. This work will investigate the recently discovered synergistic multi-body wake-structure interaction effect and how it might be exploited to further the capabilities and power output of OHG arrays. Intellectual merit: The complex mechanics of fluid-structure interaction phenomena and unsteady flows offer intellectually rich, technically challenging, and broadly applicable problems with implications ranging from aerospace and transportation, to civil infrastructure, energy, and medicine. The novel wake-structure interaction effects to be studied under this program remain poorly understood. In addition to enabling new types of low-head hydropower installations, this work may offer insight into topics like fish schooling and formation flight. Broader impacts: The proposed project will directly benefit society in several ways. First, this work has the potential to enable efficient and power-dense, dam-less hydropower in rivers and tidal regions throughout the world. The approach of using oscillating hydrofoil devices that can interact synergistically when closely arranged together will open new markets for hydropower in locations previously considered too shallow or cluttered to be feasible. With many large population centers located on coastlines and on rivers, this new source of clean energy would have minimal transmission costs and losses. In addition to its technical objectives, this project will provide mentored summer research experiences for underrepresented undergraduate students through a multi-university program among North Carolina������������������s public colleges.

Providing reconnaissance and situational awareness in large and complex subterranean facilities will require multiple distributed sensing platforms (e.g. small multi-rotor UAVs) that can distribute themselves and navigate autonomously throughout the space. Implementing such a system poses several design challenges. How can multiple vehicles be inserted into the area with minimal human intervention? How can the swarm intelligently manage power levels across vehicles to provide both rapid initial mapping as well as continuous sensor coverage and endurance? These questions highlight UAS mobility, system power management, and decentralized exploration as key challenges in the development of a rapid subterranean mapping and monitoring system. One potential solution is a man-portable ����������������mothership���������������: an autonomous ground robot that can serve to launch, recover, and re-energize a swarm of small aerial vehicles. The mothership can be designed for rapid deployment through a small doorway or window. If needed it can then traverse to an initial launch point for the UAVs, and can continue to move forward to new locations as needed. When the power level of an individual UAV becomes low, it can return to the mothership for automatic battery recharge or replacement. Other vehicles in the swarm can be reallocated to continue exploration forward or maintain sensing and communication coverage throughout an area to be monitored. The ground robot itself can also provide additional heterogeneous capabilities to the system, including carrying larger sensor packages that exceed the payload capabilities of the UAVs, and perhaps featuring manipulator arms or sample collection equipment to investigate objects of interest. The proposed project will investigate this mobile UAS mothership concept through a combination of trade-off studies, analysis, conceptual design, and prototyping and testing of key subsystem technologies.

Three-dimensional in vitro cell cultures are finding increased application in the study of solid tissues. Both "simple spheriod" cultures derived from single cell types and "organoid" cultures derived from multiple cell types can be readily established using 96-well plates molded from ultra-low attachment substrates. Because these 3D cultures more closely resemble in vivo tissues than their 2D counterparts, they may provide more accurate modeling of in vivo tissues and prediction of patient outcomes. A limiting factor is the histologic analysis of 3D cultures using existing tools and techniques: the manual process is time-consuming and inefficient and cannot compete with the throughput of robotic systems used in the screening in microwell plate formats. This research seeks to overcome these limitations through the development of Smart Material Carrier Basket Arrays (smCBAs) that will enable simultaneous and direct transfer of the spheroids/organoids contained in a 96-well plate into a histology cassette for routine processing and paraffin embedding of the 8 x 12 array as a single specimen. Our proposed smCBAs will be fabricated from laser-cut sheet nitinol, which will be thermally activated to facilitate this transfer.