Education

Research Description

Dr. Bryant's research seeks novel solutions and new devices that contribute to the advancement of emerging technologies in areas including ambient energy harvesting, fluid-structure interaction, and robot actuation and mobility. His work emphasizes a multi-disciplinary approach and encompasses both experimental and theoretical investigations. Of particular interest are applications that incorporate smart or adaptive materials and structures, as well as be bio-inspired designs. He is currently working on (1) energy harvesting from piezoelectric structures that driven by fluid-induced vibration or flutter instabilities, (2) aerodynamics of flapping and oscillating wings, (3) development of self-powered sensing/actuation systems, and (4) bio-inspired artificial muscles for robotics and prostheses. At the graduate level, Dr. Bryant plans to teach a course in smart materials systems. This course will introduce students to modeling, analysis, design, and applications of smart materials systems with applications to piezoelectrics, shape memory alloys, and electroactive polymers.

Publications

Finite wing lift during water-to-air transition

Weisler, W. A., Waghela, R., Granlund, K., & Bryant, M. (2021), PHYSICAL REVIEW FLUIDS. https://doi.org/10.1103/PhysRevFluids.6.054002

Modeling of Resistive Forces and Buckling Behavior in Variable Recruitment Fluidic Artificial Muscle Bundles

Kim, J. Y., Mazzoleni, N., & Bryant, M. (2021), ACTUATORS, 10(3). https://doi.org/10.3390/act10030042

Theoretical and experimental investigation of an unsteady airfoil in the presence of external flow disturbances

SureshBabu, A. V., Medina, A., Rockwood, M., Bryant, M., & Gopalarathnam, A. (2021), JOURNAL OF FLUID MECHANICS. https://doi.org/10.1017/jfm.2021.484

Aeroelastic inverse: Estimation of aerodynamic loads during large amplitude limit cycle oscillations

Kirschmeier, B., Pash, G., Gianikos, Z., Medina, A., Gopalarathnam, A., & Bryant, M. (2020), JOURNAL OF FLUIDS AND STRUCTURES, 98. https://doi.org/10.1016/j.jfluidstructs.2020.103131

Amplitude Annihilation in Wake-Influenced Aeroelastic Limit-Cycle Oscillations

Kirschmeier, B. A., Gianikos, Z., Gopalarathnam, A., & Bryant, M. (2020), AIAA JOURNAL, 58(9), 4117–4127. https://doi.org/10.2514/1.J058942

Design and testing of a centrifugal fluidic device for populating microarrays of spheroid cancer cell cultures

Weisler, W., Miller, S., Jernigan, S., Buckner, G., & Bryant, M. (2020), JOURNAL OF BIOLOGICAL ENGINEERING, 14(1). https://doi.org/10.1186/s13036-020-0228-6

Dynamic Modeling for Bi-Modal, Rotary Wing, Rolling-Flying Vehicles

Atay, S., Buckner, G., & Bryant, M. (2020), JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME, 142(11). https://doi.org/10.1115/1.4047693

Dynamic Modeling of Passively Draining Structures for Aerial-Aquatic Unmanned Vehicles

Stewart, W., Weisler, W., Anderson, M., Bryant, M., & Peters, K. (2020), IEEE JOURNAL OF OCEANIC ENGINEERING, 45(3), 840–850. https://doi.org/10.1109/JOE.2019.2898069

Energetic analysis and optimization of a bi-modal rolling-flying vehicle

Atay, S., Jenkins, T., Buckner, G., & Bryant, M. (2020), INTERNATIONAL JOURNAL OF INTELLIGENT ROBOTICS AND APPLICATIONS, 4(1), 3–20. https://doi.org/10.1007/s41315-020-00119-2

Limit cycle characterization of an aeroelastic wing in a bluff body wake

Gianikos, Z. N., Kirschmeier, B. A., Gopalarathnam, A., & Bryant, M. (2020), JOURNAL OF FLUIDS AND STRUCTURES, 95(0). https://doi.org/10.1016/j.jfluidstructs.2020.102986

View all publications via NC State Libraries

Grants

Control of Aeroelastic Structures via Prescribed Aerodynamic Disturbances

(7/01/20 - 6/30/23)

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Control of Aeroelastic Structures via Prescribed Aerodynamic Disturbances

Sponsor:

Start Date: 7/01/20

End Date: 6/30/23

Abstract

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.

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Mobile UAS Mothership for Subterranean Mapping and Monitoring

(1/14/19 - 2/14/21)

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Mobile UAS Mothership for Subterranean Mapping and Monitoring

Sponsor:

Start Date: 1/14/19

End Date: 2/14/21

Abstract

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.

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CAREER: Muscle-Inspired Load-Adaptive Actuation for Compliant Robotics

(5/01/19 - 4/30/24)

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CAREER: Muscle-Inspired Load-Adaptive Actuation for Compliant Robotics

Sponsor:

Start Date: 5/01/19

End Date: 4/30/24

Abstract

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.

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Autonomous Sensing Platforms for Subterranean Mapping and Monitoring

(4/01/18 - 2/28/19)

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Autonomous Sensing Platforms for Subterranean Mapping and Monitoring

Sponsor:

Start Date: 4/01/18

End Date: 2/28/19

Abstract

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.

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Design, Fabrication and Testing of Smart Material Carrier Basket Arrays (smCBAs) for Automated Analysis of 3D Cell Cultures

(5/04/18 - 10/31/18)

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Design, Fabrication and Testing of Smart Material Carrier Basket Arrays (smCBAs) for Automated Analysis of 3D Cell Cultures

Sponsor:

Start Date: 5/04/18

End Date: 10/31/18

Abstract

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.

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Aerodynamic and Aeroelastic Behavior of Wings in the Presence of Upstream Vortical and Viscous Disturbances

(7/01/17 - 6/30/21)

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Aerodynamic and Aeroelastic Behavior of Wings in the Presence of Upstream Vortical and Viscous Disturbances

Sponsor:

Start Date: 7/01/17

End Date: 6/30/21

Abstract

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.

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Aerodynamic Forces on Slender Body in Supersonic Cavity

(7/09/16 - 9/30/19)

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Aerodynamic Forces on Slender Body in Supersonic Cavity

Sponsor:

Start Date: 7/09/16

End Date: 9/30/19

Abstract

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.

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Vortex-Enhanced Flow Energy Extraction through Wake Interactions

(7/01/15 - 6/30/16)

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Vortex-Enhanced Flow Energy Extraction through Wake Interactions

Sponsor:

Start Date: 7/01/15

End Date: 6/30/16

Abstract

The wake of the upstream bluff body represents an oscillatory flow with significant energy content at the specific vortex shedding frequency of the body. Common wind energy harvesting devices such as horizontal axis wind turbines (HAWTs) are only able to harvest energy from the constant component of the flow kinetic energy, and thus perform poorly in such an unsteady, vortex-dominated flow. Proposed here is the initial development and testing of wind energy harvesting devices capable of directly accessing both oscillatory and steady flow kinetic energy. This will create a flow energy harvesting device that will not only out-perform a traditional turbine in an unsteady flow, but is unrestricted by the Betz efficiency limit, and thus has the potential to achieve higher overall efficiency than a turbine even under ideal conditions. While others have attempted flow energy harvesters such as “eels” and “flags” (Figure 1) induced to flap or wave by bluff body vortex wakes, these pervious devices extract energy only from the oscillatory component of the flow, and are in fact unable to extract energy or produce motion in a steady flow. In addition, because they rely primarily on the oscillatory wake flow, these devices must be placed very close downstream of the bluff body, where the total flow momentum is decreased and less total energy is available. Our approach will utilize an oscillating lifting surface device that is capable of both operating in a steady free stream flow as well as synchronizing with the dominant frequency of the incident vortex wake for enhanced performance. Thus it will not only take advantage of the additional incident vortex energy through constructive interference with the energy harvester motion, but also tap into the constant component of the flow. Such a wind power device will therefore combine the benefits a steady flow energy harvester and vortex-induced vibration harvesters in a single mechanism to achieve higher performance and versatility.

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Control Approach Development for Variable Recruitment Artificial Muscles

(1/01/15 - 8/31/15)

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Control Approach Development for Variable Recruitment Artificial Muscles

Sponsor:

Start Date: 1/01/15

End Date: 8/31/15

Abstract

Appropriate control methodologies need to be developed to enable the variable recruitment muscle actuators to be implemented as antagonistic bundle-pairs capable of double acting actuation and control of a robot joint. Control of a variable recruitment artificial muscle bundle will require both discrete and continuous input variables. Previous work has shown that variable recruitment McKibben muscle bundles can use discrete changes in recruitment state to operate in widely different force regimes while applied pressure is held constant. Variation in applied pressure is an additional, continuously variable, input to achieve force-deflection combinations along the desired trajectory that lie between the discrete points achievable by switching the recruitment states alone. For energy efficiency purposes, it is desirable to operate the bundle in the lowest volume recruitment state possible to reduce the required fluid flow rate and volume and to minimize pressure reduction and throttling losses that must be created by the control valve. Thus control of the variable recruitment actuator necessitates an approach that is optimized for minimum energy consumption at the system level.

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WAKE MEDIATED COUPLING IN OSCILLATING HYDROFOIL TURBINE ARRAYS

(8/01/15 - 7/31/19)

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WAKE MEDIATED COUPLING IN OSCILLATING HYDROFOIL TURBINE ARRAYS

Sponsor:

Start Date: 8/01/15

End Date: 7/31/19

Abstract

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.

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