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Boat. Magnetohydrodynamic. GROUP 6 : Alex Mavrommatis David Hobbs Jeffrey Schaffer Jared Kelley. Motivation. To design a boat that can operate on the MHD technology Take something that has mostly been realized in science fiction and make it a reality
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Boat Magnetohydrodynamic GROUP 6: Alex Mavrommatis David Hobbs Jeffrey Schaffer Jared Kelley Group 6 Senior Design 2 Summer 2011
Motivation • To design a boat that can operate on the MHD technology • Take something that has mostly been realized in science fiction and make it a reality • Design a wireless system that can control the boat from a distance Group 6 Senior Design 2 Summer 2011
Overview of the Project Group 6 Senior Design 2 Summer 2011
Magnetohydrodynamic JeffereySchaffer Group 6 Senior Design 2 Summer 2011
MHD Overview • Magnetohydrodynamics • Made popular by “The Hunt for Red October” • No moving parts. • Silent • Can be used as a generator or motor. • Can be scaled up using a superconducting magnet. Group 6 Senior Design 2 Summer 2011
MHD Objectives • The propulsion system must be able to withstand corrosion from the electrolysis generated from operation. • The metal contact must not interfere with the magnetic field lines so they must be made of a diamagnetic material. • The propulsion system must be insulated such that the losses are kept to a minimum. Group 6 Senior Design 2 Summer 2011
MHD Specifications • The MHD drive must provide 5lbs of thrust. • The MHD drive must be lightweight in order to keep with the 10lb boat requirement. • The MHD power supply must provide 24V and capable of discharging 10A for 15 minutes. • The MHD power supply must be under 8lbs. • The MHD drive must provide enough thrust to achieve a 5 MPH top speed. Group 6 Senior Design 2 Summer 2011
MHD Magnets • Block magnets allowed for an isolated channel design. • 2 magnets - 0.2 Tesla each. neodymium rare earth magnets. • Total weight of 245.8 grams. Group 6 Senior Design 2 Summer 2011
MHD Power Source Group 6 Senior Design 2 Summer 2011
Calculations Group 6 Senior Design 2 Summer 2011
MHD Prototyping Prototype 1.0 (2/2011) Prototype 2.0 (6/2011) Group 6 Senior Design 2 Summer 2011
Final Prototype • Magnets stacked and contained inside hull. • Isolated Channel • Insulated • Aluminum Contacts • 4” x 1” x 1” • High Current Clips instead of soldered leads. Group 6 Senior Design 2 Summer 2011
Current Sensor • Utilizes a Hall Effect Current Sensor • Electrically disconnected from the line being measured • Outputs a value linearly proportional to the current being detected. • Capable of measuring up to 57 Amps. Group 6 Senior Design 2 Summer 2011
Group 6 Senior Design 2 Summer 2011
Current Sensor Calculations N=number of loops I = current carried in MHD line ± is dependent upon current direction Corresponding maximum : Group 6 Senior Design 2 Summer 2011
Current Sensor Testing Percent accuracy (9/9.06)*100 = 99.34% Group 6 Senior Design 2 Summer 2011
The Current Controller Jared Kelley Group 6 Senior Design 2 Summer 2011
Variable Current Source Wirelessly controlled switches allow the current to be drawn directly from the battery, or from the voltage regulators We Utilize two LM138 voltage regulators in the Precision Current Limiter configuration obtained from the datasheet Provides On-Chip thermal overload protection for the power transistor Provides a constant regulated current output. Group 6 Senior Design 2 Summer 2011
Variable Current Source Design The LM138 develops a reference voltage of 1.25V between the Vreg and Common pins of the device, a 0.25Ω resistor then sets the output at 5 Amps. We use this configuration twice to provide 10 Amps for the low speed setting. Group 6 Senior Design 2 Summer 2011
High Current Switching • The Texas Instruments relay driver (ULN2803) is used to provide the current through the coils of each switch. • A logic high output from the microcontroller provides the necessary 1 mA to the base of the transistor causing it to conduct the needed 75 mA to close the corresponding switch. Group 6 Senior Design 2 Summer 2011
LOW SPEED : HIGH SPEED : Group 6 Senior Design 2 Summer 2011
The Microcontroller David Hobbs Group 6 Senior Design 2 Summer 2011
NXP LPC2388 • USBizi144 Chipset • Runs the Microsoft .Net Micro Framework • USB host • PWM outputs Group 6 Senior Design 2 Summer 2011
PC Board Schematic Group 6 Senior Design 2 Summer 2011
Microcontroller PCB Group 6 Senior Design 2 Summer 2011
MCU and Current Control • Will send digital signals to control the high current switches • There will be three different states that send three different levels to the MHD. • The MCU will be programmed using logic to output the different combinations and states for current control Group 6 Senior Design 2 Summer 2011
MCU and Servo Motor • Pulse width 1 ms: 0° • Pulse width 1.5 ms: 45° • Pulse width 2 ms: 90° Group 6 Senior Design 2 Summer 2011
The Wireless Design Group 6 Senior Design 2 Summer 2011
Requirements for the Wireless control • The range of the wireless must reach at least a minimum of 50 feet. • Must display the accelerometer data that is controlling the on board servo. • Must be easy to learn and interface with. Group 6 Senior Design 2 Summer 2011
The Wireless options Group 6 Senior Design 2 Summer 2011
Receiver/ Transmitter • Transmitter is located in the watch • 433 Mhz Receiver interfacing with the MCU Group 6 Senior Design 2 Summer 2011
Directional control display • Enables the user to visually see the value of the accelerometer. • Left 90° • Down 90° Group 6 Senior Design 2 Summer 2011
Current Control • Located on the “*“ button • High- 15 Amps • Low - 7.5 Amps • Push button selection • High and Low Group 6 Senior Design 2 Summer 2011
Current Control • Off Located on the “#” button. • Off – 0 Amps Group 6 Senior Design 2 Summer 2011
Budget Group 6 Senior Design 2 Summer 2011
Conclusion • MHD • Wireless • Current Control Group 6 Senior Design 2 Summer 2011
Questions? Group 6 Senior Design 2 Summer 2011
