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A.U.V. Emeric Rochford Dale Williams Bryan Douse Ryan Gray
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Background Autonomous underwater vehicles are becoming popular in many applications, including oil exploration, and marine studies. Autonomous underwater vehicles are becoming popular in many applications, including oil exploration, and marine studies. Underwater vehicles are also used to check the hulls of large ships for homeland security, and maintenance. Ryan
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Mission Statement Original design specifications were derived from an AUV competition in San Diego, California. Design an Autonomous Underwater Vehicle that can operate at depths up to 38 feet. The Vehicle must descend to a predetermined depth and remain at this depth during its mission. While underwater the AUV must remain stable on both vertical and horizontal planes. Ryan
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Solution Hull constructed from PVC tubing Hull constructed from PVC tubing Four electric motor driven propellers for propulsion and steering Four electric motor driven propellers for propulsion and steering Linear leveling system for stability control Linear leveling system for stability control Water pressure used for depth sensing Water pressure used for depth sensing Use HC08 microcontrollers for subsystem control Use HC08 microcontrollers for subsystem control Ryan
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Internal System Overview Side View Emeric
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External System Overview Emeric
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Hull
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Hull Testing Torque = 20 ft lbsTorque = 20 ft lbs Depth = 3.5 ftDepth = 3.5 ft Time Submerged = 15 minTime Submerged = 15 min No Leaks! Emeric
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Propulsion Minimum Requirements: Torque 1.012 ft lbs Torque 1.012 ft lbs Power 0.114 hp Power 0.114 hp Thrust 1.3 lbsThrust 1.3 lbs Motor Selected: CerMag RS 540S 12 Volts 12 Volts Thrust x2 with a 3” prop Thrust x2 with a 3” prop = 3.1lbs = 3.1lbs Emeric Total Hydrodynamic Drag Force of Hull = 84.9 N or 19.08 lbf Motor Assembly
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Depth Sensing There is a linear relationship between pressure and depth. There is a linear relationship between pressure and depth. The following is the mathematical representation of the relationship: The following is the mathematical representation of the relationship: ΔP = γh ΔP = γh –ΔP Pressure Difference –γ Specific Weight of Liquid Bryan
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Freescale MPX4250AP Ported Pressure Sensor Bryan
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Pressure Sensor Tests The data collected from the pool test shows that the sensor has a linear output of about 62mV per foot. The data collected from the pool test shows that the sensor has a linear output of about 62mV per foot. This gives us a full scale voltage of about 4.25 V which provides an excellent resolution to feed into the A2D converter on the HC08. This gives us a full scale voltage of about 4.25 V which provides an excellent resolution to feed into the A2D converter on the HC08. Bryan
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Leveling System Design The leveling system operates by redistributing weight in the hull of the vehicle. The mechanical design consist of a motor coupled to a lead screw with a weigh threaded onto it. The motor can be commanded to turn clockwise or counter clockwise to move the mass up and down the hull as needed. This is the only leveling system that is needed because the hull is designed in a way that most of the weight is at the bottom of the vehicle to stabilize it in the other direction. Dale
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Leveling System Control Circuit The electrical design consists of a potentiometer with a pendulum on it to sense the angle of tilt the AUV is at. This signal is than input into two comparators to determine if the weight should be moved, and if so what direction. Dale
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Electrical Overview `` HC08 Motor Controller Motor Controller 12 volt battery Opto- Isolator Opto- Isolator 9 volt battery Leveling Motor Depth Control Subsystem Propulsion Subsystem Leveling Subsystem Ryan HC08 Opto- Isolator Opto- Isolator Motor Controller Motor Controller Sensors Control Circuit
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Depth Control System Pressure Sensor Depth Motor Driver HC08 Motor Water Sensor Opto- Isolator Ryan
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Software Overview Depth Control depth equal to 30? Ascend Start Surface Water Present in hull? No Yes No depth Greater than 30? descend Yes No Yes // initialize variables CMD = 200; //Value we set for our depth A2D = 0; PWM = 0; COUNT = 0; ConfigurePorts(); ConfigureTimebase(); ConfigureSCI(); ConfigureIRQ(); StartA2D(); Void Controller (void) { Call controller = 0; //summing junction Xn = CMD – A2D; //controller Yn = 255 * Xn; //check and limit saturation If ( Yn > 255.0 ) { Yn = 255.0; } Else if ( Yn < - 255.0 ) { Yn = - 255.0; } // load Pulse Width Modulator if ( Yn < 0 ) { Yn =0; } PWM = ( char ) Yn LoadPWM (); startA2D(); return; Ryan
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Sonar Overview For the design competition our AUV is required to follow a sonar ping. For the design competition our AUV is required to follow a sonar ping. The sonar receiver operates by containing an array of three sonar sensors spaced 60 degrees apart. Each of the detectors will output independent signals into a microcontroller that will than decide what direction to steer the vehicle to point it towards the sonar transmitter. The sonar receiver operates by containing an array of three sonar sensors spaced 60 degrees apart. Each of the detectors will output independent signals into a microcontroller that will than decide what direction to steer the vehicle to point it towards the sonar transmitter. Dale
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Budget SectionItemPrice Hull PVC$100.00 Threaded Rod$30.00 Misc. Hardware$10.00 Gasket material$8.00 Power Systems Batteries$260 Motors$90.00 Motor Drivers$85 Microcontrollers$10 Sensors Pressure sensor circuit$10.00 Optical sensor circuit$10.00 Sonar reciver circuit$8.00 SectionItemPrice Leveling System Threaded rod$8.00 Motor$12.00 Misc. Hardware$10.00 Controll Circuit$15.00 Sealed Drive Shafts X3$60 Glue & Silicon$5.00 Total$721.00 Dale
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Schedule Bryan
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Summary Currently our hull design is complete and we have assembled a sealed prototype. Currently our hull design is complete and we have assembled a sealed prototype. Our depth control system is operational as well as our leveling system. Our depth control system is operational as well as our leveling system. What remains to be accomplished is the completion and installation of our navigation system. What remains to be accomplished is the completion and installation of our navigation system. Questions? Bryan
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