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Scripps Autonomous Underwater Explorer
Spring 2017 MAE 156B Senior Design Project
University of California, San Diego
Sponsored by:
Background
Background
Scripps Institution of Oceanography (SIO) is a leading research and education center for ocean, earth, and atmospheric science. To study the ocean internal waves and to simulate the drift behavior of plankton, SIO deploys miniature Autonomous Underwater Explorers (AUE) to specific depth profiles to collect ocean data. These AUEs are capable of active vertical movements using a buoyancy control that changes the overall volume of the system to sink or float to the desired depth. However, the current AUE model used takes longer than desired to adjust buoyancy, causing the system response to be highly unstable even with the presence of small perturbations. The mechanical noise of the system generated by the motor also hinders hydrophone function for geographical location purposes. In addition, the AUE is constructed with mostly custom machined parts that significantly increases its cost.
Scripps Institution of Oceanography (SIO) is a leading research and education center for ocean, earth, and atmospheric science. To study the ocean internal waves and to simulate the drift behavior of plankton, SIO deploys miniature Autonomous Underwater Explorers (AUE) to specific depth profiles to collect ocean data. These AUEs are capable of active vertical movements using a buoyancy control that changes the overall volume of the system to sink or float to the desired depth. However, the current AUE model used takes longer than desired to adjust buoyancy, causing the system response to be highly unstable even with the presence of small perturbations. The mechanical noise of the system generated by the motor also hinders hydrophone function for geographical location purposes. In addition, the AUE is constructed with mostly custom machined parts that significantly increases its cost.
Objectives
The primary objective of this project is to design a new AUE with a volume of 3 to 6 liters to simulate the drift behavior of plankton while being able to record ocean data. The new AUE must have a depth rating of at least 30 meters under water, a buoyancy control time of less than 30 seconds, and the noise level of the system must be low enough for an onboard hydrophone to detect pings for location purposes. A desired dive time of 72 hours per deployment requires a low power system that will be able to use minimal power over long periods of time.
The primary objective of this project is to design a new AUE with a volume of 3 to 6 liters to simulate the drift behavior of plankton while being able to record ocean data. The new AUE must have a depth rating of at least 30 meters under water, a buoyancy control time of less than 30 seconds, and the noise level of the system must be low enough for an onboard hydrophone to detect pings for location purposes. A desired dive time of 72 hours per deployment requires a low power system that will be able to use minimal power over long periods of time.
Final Design
The final design includes an acrylic housing with an linear actuator connected to a piston which protrudes from the bottom of the system to adjust volume, as well as 2 T100 Thrusters on the sides to provide extra force. A pressure sensor sends feedback data to an MKR1000 Arduino MCU, which controls the previously mentioned actuators. 11 amp-hours of batteries supply power to the system. A dual thruster and buoyancy-control system was designed. While the buoyancy control would keep the system close to neutrally buoyant, the thrust provided by the propeller would provide immediate response to deviation from the target depth.
The final design includes an acrylic housing with an linear actuator connected to a piston which protrudes from the bottom of the system to adjust volume, as well as 2 T100 Thrusters on the sides to provide extra force. A pressure sensor sends feedback data to an MKR1000 Arduino MCU, which controls the previously mentioned actuators. 11 amp-hours of batteries supply power to the system. A dual thruster and buoyancy-control system was designed. While the buoyancy control would keep the system close to neutrally buoyant, the thrust provided by the propeller would provide immediate response to deviation from the target depth.
Jaffe Laboratory for Underwater Imaging
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