The development of an effective system for extracting dissolved oxygen from water would enable hu... more The development of an effective system for extracting dissolved oxygen from water would enable humans to work underwater for extended periods. This would have applications to science, industry, exploration, military, and recreation. Human sustenance would require a very sophisticated and high capacity gill system, one that has not been developed to date. The overall aim of this research was to develop an artificial gill that would operate with a realistic and useful load. The load chosen for this research was a microbial fuel cell operating underwater. Countercurrent gill plates were constructed to evaluate several different candidates for use as the oxygen transfer membrane. The oxygen gain of each membrane was measured by comparing dissolved oxygen readings before and after the gill. Celgard 2500 (Celgard, Inc. Charlotte NC), a microporous polypropylene membrane, was chosen as the most suitable candidate; it sustained an oxygen gain greater than 2 mmol/sec. This was a much higher gain than necessary to sustain the fuel cell, which is on the order of 10 nmol/sec. The original fuel cell (NCBE, University of Reading, UK) was then redesigned. The new system was more modular, allowing for a multitude of different experimental configurations. Two of the configurations included an integrated gill, with no moving parts and therefore no power consumption. The cathode of the fuel cell was modified to respond more quickly to changes in oxygen supply. Experiments were conducted measuring the power output of the modified fuel cell and the oxygen uptake of the gill. The MFC ran for multiple days for each test cycle, and data was recorded on a Tattletale Model 8 microcontroller (Onset, Pocasset, MA). It was demonstrated that providing the cathode of the cell with oxygen enabled the cell to sustain much higher voltages than without a continuous oxygen supply. Typical experiments yielded a few microwatts of power between 100 and 200 mV
Studies of model humpback whale fins have shown that leading edge protuberances, or tubercles, ca... more Studies of model humpback whale fins have shown that leading edge protuberances, or tubercles, can lead to delayed stall and increased lift at higher angles of attack, compared to foils with geometrically smooth leading edges. Such enhanced performance characteristics could prove highly useful in underwater vehicles such as gliders or long range AUVs (autonomous underwater vehicles). In this work, Particle Imaging Velocimetry (PIV) is performed on two static wings in a water tunnel over a range of angles of attack. These three- dimensional, finite-aspect ratio wings are modeled after a humpback whale flipper and are identical in shape, tapered from root to tip, except for the leading edge. In one of the foils the leading edge is smooth, whereas in the other, regularly spaced leading edge bumps are machined to simulate the whale’s fin tubercles. Results from these PIV tests reveal distinct cells where coherent flow structures are destroyed as a result of the leading edge perturbations. Tests are performed at Reynolds numbers Re ˜ O(10^5), based on chordlength, in a recirculating water tunnel. An inline six-axis load cell is mounted to measure the forces on the foil over a range of static pitch angles. It is hypothesized that this spanwise breakup of coherent vortical structures is responsible for the delayed angle of stall. These quantitative experiments complement exiting qualitative studies with two dimensional foils.
Measurement delays are inherent in position feedback methods used for underwater navigation. Even... more Measurement delays are inherent in position feedback methods used for underwater navigation. Even for small delays, proper treatment of these measurements will provide more robust performance and reduce uncertainties, improving overall precision. The Kalman filter (KF) can be adapted to treat delayed measurements in an efficient and mathematically rigorous way. We present a delayed state sigma point Kalman filter (SPKF) implementation for underwater navigation using delayed position measurements. The implementation includes a novel model-based approach to fusing the delayed measurements, with the ability to handle varying delays. We provide an example mission scenario where a surface tender with an ultra-short baseline (USBL) system tracks a submerged vehicle. We use this example to renavigate field data from recent deployments of the National Deep Submergence Facility (NDSF) autonomous underwater vehicle (AUV) Sentry, and compare estimates from a delay-compensated filter to those from a filter that ignores the delay.
This paper uses rotors in Geometric Algebra to formulate a stable adaptive identifier on the grou... more This paper uses rotors in Geometric Algebra to formulate a stable adaptive identifier on the group of rigid body rotations. This identifier is intended to estimate the alignment offsets between independent sensors. The approach provides a straightforward geometric interpretation based on first-order rotor kinematics. Lyapunov theory is used to prove the stability of the identifier, and numerical simulations illustrate its behavior with and without measurement noise.
A novel navigation method is introduced using water current profiles measured by an Acoustic Dopp... more A novel navigation method is introduced using water current profiles measured by an Acoustic Doppler Current Profiler (ADCP) mounted on a moving vehicle. These current profiles are combined with measurements of vehicle attitude and depth to simultaneously estimate the local current and the vehicle velocity. This velocity estimate can be integrated directly to give a position estimate, or it can be fused with measurements from other navigation sensors, such as an Inertial Navigation System (INS), Long Baseline (LBL) or Ultra-Short Baseline (USBL) acoustic tracking system. The method allows an underwater vehicle to maintain an estimate of its global position throughout all phases of its mission, including descent and ascent.
Many marine robots, including industry and institution-grade systems, rely on substandard propell... more Many marine robots, including industry and institution-grade systems, rely on substandard propellers for thrust. This is especially true in small systems. Many of these systems are moving toward onboard power, which is often restricted. Inefficient propulsion becomes a major design problem in these vehicles. Using computational tools, we design, test, and evaluate a small-diameter ducted contrarotating propulsor with a high thrust coefficient.
... studies on a biologically-inspired design: leading edge tubercles. Tubercles are perturbation... more ... studies on a biologically-inspired design: leading edge tubercles. Tubercles are perturbations, or bumps, on the leading edge of the pectoral flippers ... Note the prominenttubercles on the leading edge. 1.1 Megaptera novæangilæ ...
The development of an effective system for extracting dissolved oxygen from water would enable hu... more The development of an effective system for extracting dissolved oxygen from water would enable humans to work underwater for extended periods. This would have applications to science, industry, exploration, military, and recreation. Human sustenance would require a very sophisticated and high capacity gill system, one that has not been developed to date. The overall aim of this research was to develop an artificial gill that would operate with a realistic and useful load. The load chosen for this research was a microbial fuel cell operating underwater. Countercurrent gill plates were constructed to evaluate several different candidates for use as the oxygen transfer membrane. The oxygen gain of each membrane was measured by comparing dissolved oxygen readings before and after the gill. Celgard 2500 (Celgard, Inc. Charlotte NC), a microporous polypropylene membrane, was chosen as the most suitable candidate; it sustained an oxygen gain greater than 2 mmol/sec. This was a much higher gain than necessary to sustain the fuel cell, which is on the order of 10 nmol/sec. The original fuel cell (NCBE, University of Reading, UK) was then redesigned. The new system was more modular, allowing for a multitude of different experimental configurations. Two of the configurations included an integrated gill, with no moving parts and therefore no power consumption. The cathode of the fuel cell was modified to respond more quickly to changes in oxygen supply. Experiments were conducted measuring the power output of the modified fuel cell and the oxygen uptake of the gill. The MFC ran for multiple days for each test cycle, and data was recorded on a Tattletale Model 8 microcontroller (Onset, Pocasset, MA). It was demonstrated that providing the cathode of the cell with oxygen enabled the cell to sustain much higher voltages than without a continuous oxygen supply. Typical experiments yielded a few microwatts of power between 100 and 200 mV
Studies of model humpback whale fins have shown that leading edge protuberances, or tubercles, ca... more Studies of model humpback whale fins have shown that leading edge protuberances, or tubercles, can lead to delayed stall and increased lift at higher angles of attack, compared to foils with geometrically smooth leading edges. Such enhanced performance characteristics could prove highly useful in underwater vehicles such as gliders or long range AUVs (autonomous underwater vehicles). In this work, Particle Imaging Velocimetry (PIV) is performed on two static wings in a water tunnel over a range of angles of attack. These three- dimensional, finite-aspect ratio wings are modeled after a humpback whale flipper and are identical in shape, tapered from root to tip, except for the leading edge. In one of the foils the leading edge is smooth, whereas in the other, regularly spaced leading edge bumps are machined to simulate the whale’s fin tubercles. Results from these PIV tests reveal distinct cells where coherent flow structures are destroyed as a result of the leading edge perturbations. Tests are performed at Reynolds numbers Re ˜ O(10^5), based on chordlength, in a recirculating water tunnel. An inline six-axis load cell is mounted to measure the forces on the foil over a range of static pitch angles. It is hypothesized that this spanwise breakup of coherent vortical structures is responsible for the delayed angle of stall. These quantitative experiments complement exiting qualitative studies with two dimensional foils.
Measurement delays are inherent in position feedback methods used for underwater navigation. Even... more Measurement delays are inherent in position feedback methods used for underwater navigation. Even for small delays, proper treatment of these measurements will provide more robust performance and reduce uncertainties, improving overall precision. The Kalman filter (KF) can be adapted to treat delayed measurements in an efficient and mathematically rigorous way. We present a delayed state sigma point Kalman filter (SPKF) implementation for underwater navigation using delayed position measurements. The implementation includes a novel model-based approach to fusing the delayed measurements, with the ability to handle varying delays. We provide an example mission scenario where a surface tender with an ultra-short baseline (USBL) system tracks a submerged vehicle. We use this example to renavigate field data from recent deployments of the National Deep Submergence Facility (NDSF) autonomous underwater vehicle (AUV) Sentry, and compare estimates from a delay-compensated filter to those from a filter that ignores the delay.
This paper uses rotors in Geometric Algebra to formulate a stable adaptive identifier on the grou... more This paper uses rotors in Geometric Algebra to formulate a stable adaptive identifier on the group of rigid body rotations. This identifier is intended to estimate the alignment offsets between independent sensors. The approach provides a straightforward geometric interpretation based on first-order rotor kinematics. Lyapunov theory is used to prove the stability of the identifier, and numerical simulations illustrate its behavior with and without measurement noise.
A novel navigation method is introduced using water current profiles measured by an Acoustic Dopp... more A novel navigation method is introduced using water current profiles measured by an Acoustic Doppler Current Profiler (ADCP) mounted on a moving vehicle. These current profiles are combined with measurements of vehicle attitude and depth to simultaneously estimate the local current and the vehicle velocity. This velocity estimate can be integrated directly to give a position estimate, or it can be fused with measurements from other navigation sensors, such as an Inertial Navigation System (INS), Long Baseline (LBL) or Ultra-Short Baseline (USBL) acoustic tracking system. The method allows an underwater vehicle to maintain an estimate of its global position throughout all phases of its mission, including descent and ascent.
Many marine robots, including industry and institution-grade systems, rely on substandard propell... more Many marine robots, including industry and institution-grade systems, rely on substandard propellers for thrust. This is especially true in small systems. Many of these systems are moving toward onboard power, which is often restricted. Inefficient propulsion becomes a major design problem in these vehicles. Using computational tools, we design, test, and evaluate a small-diameter ducted contrarotating propulsor with a high thrust coefficient.
... studies on a biologically-inspired design: leading edge tubercles. Tubercles are perturbation... more ... studies on a biologically-inspired design: leading edge tubercles. Tubercles are perturbations, or bumps, on the leading edge of the pectoral flippers ... Note the prominenttubercles on the leading edge. 1.1 Megaptera novæangilæ ...
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Papers by Jordan Stanway