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

Structured identification of reduced-order models of power systems in a differential-algebraic form

Nabavi, S., & Chakrabortty, A. (2017), IEEE Transactions on Power Systems, 32(1), 198-207.

Bio-inspired online variable recruitment control of fluidic artificial muscles

Jenkins, T. E., Chapman, E. M., & Bryant, M. (2016), Smart Materials & Structures, 25(12).

Improving actuation efficiency through variable recruitment hydraulic McKibben muscles: Modeling, orderly recruitment control, and experiments

Meller, M., Chipka, J., Volkov, A., Bryant, M., & Garcia, E. (2016), Bioinspiration & Biomimetics, 11(6).

Aeroelastic modeling of a Piezo-Solar tensioned energy harvesting ribbon

Chatterjee, P., & Bryant, M. (2016), In Active and passive smart structures and integrated systems 2016. (Proceedings of SPIE-the International Society for Optical Engineering, 9799).

Control approach development for variable recruitment artificial muscles

Jenkins, T. E., Chapman, E. M., & Bryant, M. (2016), In Active and passive smart structures and integrated systems 2016. (Proceedings of SPIE-the International Society for Optical Engineering, 9799).

Toward efficient aeroelastic energy harvesting through limit cycle shaping

Kirschmeier, B., & Bryant, M. (2016), In Active and passive smart structures and integrated systems 2016. (Proceedings of SPIE-the International Society for Optical Engineering, 9799).

Variable buoyancy system for unmanned multi-domain vehicles

MacLeod, M., & Bryant, M. (2016), In Active and passive smart structures and integrated systems 2016. (Proceedings of SPIE-the International Society for Optical Engineering, 9799).

Electrohydraulic modeling of a fluidic artificial muscle actuation system for robot locomotion

Chapman, E., Macleod, M., & Bryant, M. (2016), (ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems, 2015, vol 1, ).

Low-order modeling of the unsteady aerodynamics in flapping wings

Gomez, J. C., Bryant, M., & Garcia, E. (2015), Journal of Aircraft, 52(5), 1586-1595.

Structural modelling of a compliant flexure flow energy harvester

Chatterjee, P., & Bryant, M. (2015), Smart Materials & Structures, 24(9).

View all publications via NC State Libraries

Grants

Vortex-Enhanced Flow Energy Extraction through Wake Interactions

NCSU Faculty Research & Professional Development Fund(7/01/15 - 6/30/16)

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Vortex-Enhanced Flow Energy Extraction through Wake Interactions

Sponsor: NCSU Faculty Research & Professional Development Fund

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

Defense Advanced Research Projects Agency (DARPA)(1/01/15 - 8/31/15)

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Control Approach Development for Variable Recruitment Artificial Muscles

Sponsor: Defense Advanced Research Projects Agency (DARPA)

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

National Science Foundation (NSF)(8/01/15 - 7/31/18)

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WAKE MEDIATED COUPLING IN OSCILLATING HYDROFOIL TURBINE ARRAYS

Sponsor: National Science Foundation (NSF)

Start Date: 8/01/15

End Date: 7/31/18

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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Angelfish: Initial Planning and Project Management

Defense Advanced Research Projects Agency (DARPA)(6/19/14 - 1/31/16)

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Angelfish: Initial Planning and Project Management

Sponsor: Defense Advanced Research Projects Agency (DARPA)

Start Date: 6/19/14

End Date: 1/31/16

Abstract

The objective of Project Angelfish is to develop a dual-purpose (air and water) unmanned system, referred to as Angelfish. The system to be developed will be capable of locomotion and controlled maneuvering in both the aerial and subsurface domains. The air-purpose performance (flight distance, duration, etc.) is to be minimally compromised by the water-purpose requirements, and the transition between air and water are to be as reliable as possible, again with minimal performance penalty (power). The goal of the effort is to develop alternative designs that lie throughout the trade space and to focus the further development on the most promising design or set of designs.

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Shape-Shifting Robots for Safety and Versatility

NCSU Faculty Research & Professional Development Fund(7/01/14 - 12/31/14)

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Shape-Shifting Robots for Safety and Versatility

Sponsor: NCSU Faculty Research & Professional Development Fund

Start Date: 7/01/14

End Date: 12/31/14

Abstract

Proposed here is the initial development of a new concept for lightweight robot limbs and manipulators with dynamically adjustable rigidity and compliance in both structure and actuation. Previous attempts at “soft” robots have resulted in rubbery devices that move slowly and support little load, while efforts to implement compliant actuators with a rigid, jointed frame address only one aspect of the problem. Our approach will create a robot arm that exhibits controllable rigidity, reconfigurable geometry, and high force actuation by using applied air pressure (positive gauge pressure) and vacuum (negative gauge pressure) to selectively rigidize, deform, and actuate using soft, adaptive structures. This approach will utilize fluidic artificial muscles for generating the actuation forces and motions, while a novel device concept that uses differential pressure applied to a membrane enclosing compressible or granular media will be used to create an adaptive, variable stiffness skeleton. The resulting robot will bridge the gap between rigid, high-force capacity robots that offer strength and speed but are inherently incompatible with close human interaction, and soft robots that are safe but slow, weak, and difficult to control precisely.

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INTEGRATED STRUCTURES FOR MULTIMODE AMBIENT ENERGY HARVESTING

National Science Foundation (NSF)(8/01/14 - 7/31/17)

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INTEGRATED STRUCTURES FOR MULTIMODE AMBIENT ENERGY HARVESTING

Sponsor: National Science Foundation (NSF)

Start Date: 8/01/14

End Date: 7/31/17

Abstract

Proposed here is the development of a multifunctional compliant structure that can generate electrical power from both incident solar radiation and ambient wind flow. Such a device could be an ideal power source for wireless sensor nodes or autonomous mobile sensing platforms in areas where hardwired power is unavailable and battery replacement is impractical. Combining wind and solar power takes advantage of the two major sources of ambient energy and would allow the energy harvesting system to operate both day and night. Such a device would be particularly attractive in the Polar Regions where sunlight is seasonally limited. The proposed work will create an integrated, solar and wind hybrid energy harvester that offers unparalleled simplicity and robustness, low mass, and a negligible increase in geometric footprint compared to a solar array alone. The envisioned device will consist of an array of slender, ribbon-like, flexible thin film solar cells that are laminated with piezoelectric patches. These piezo-solar ribbons will be mounted in longitudinal tension and exposed to a transverse wind flow, creating a fluid-elastic system that will experience aeroelastic limit cycle oscillations (LCO) over a broad range of wind speeds, causing them to vibrate in the flow like plucked guitar strings. These vibrations will produce cyclic strains in the piezoelectric layers, generating an alternating current that can be rectified and used to charge batteries or power electrical loads. The solar cells, on the other hand will directly transduce incident sunlight into direct current. 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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MULTIFUNCTIONAL COMPLIANT STRUCTURES FOR HYBRID WIND AND SOLAR ENERGY HARVESTING ON MARS

NCSU NC Space Grant Consortium(4/01/14 - 2/01/15)

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MULTIFUNCTIONAL COMPLIANT STRUCTURES FOR HYBRID WIND AND SOLAR ENERGY HARVESTING ON MARS

Sponsor: NCSU NC Space Grant Consortium

Start Date: 4/01/14

End Date: 2/01/15

Abstract

Proposed here is the development of a multifunctional compliant structure that can generate electrical power from both incident solar radiation and ambient wind flow. Such a device could be an ideal power source for small rovers, data collection stations, and, one day, even human settlements on Mars. While photovoltaics are generally a viable power source on Mars, sunlight becomes intermittently unavailable due to massive dust storms that may block the sun and shutdown solar energy harvesters for months at a time. These dust storms, however, are created by strong winds that provide a secondary opportunity for power generation through harvesting the wind kinetic energy. Thus creating a single device that has the capacity to generate power from both of these disparate energy sources could provide a reliable, year-round power source on Mars. While the concept of using a hybrid wind and solar energy system on Mars has been proposed by NASA for this reason current technologies and devices for both solar and wind power have made this option unattractive due to complexity and mass budget issues. Such a device could also find many applications on Earth, such as in the polar regions where sunlight is seasonally limited. The proposed work will create an integrated, solar and wind hybrid energy harvester that offers unparalleled simplicity and robustness, low mass, and a negligible increase in geometric footprint compared to a solar array alone. The envisioned device will consist of an array of slender, ribbon-like, flexible thin film solar cells that are laminated with piezoelectric patches. These piezo-solar ribbons will be mounted in tension and exposed to a transverse wind flow, creating a fluid-elastic system that will experience aeroelastic limit cycle oscillations (LCO) over a broad range of wind speeds, causing them to vibrate in the flow like plucked guitar strings. These vibrations will produce cyclic strains in the piezoelectric layers, generating an alternating current that can be rectified and used to charge batteries or power electrical loads. The solar cells, on the other hand will directly transduce incident sunlight into direct current. This concept will build on Dr. Bryant’s experience in modeling and developing aeroelastic devices for energy harvesting, but in an entirely new device concept, and for the first time, in combination with solar power.

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