Magnetohydrodynamic Boat GROUP 6 Alex Mavrommatis David Hobbs

Magnetohydrodynamic Boat GROUP 6: Alex Mavrommatis David Hobbs Jeffrey Schaffer Jared Kelley 9/18/2020 Group 6 Senior Design 2 Summer 2011 1

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 9/18/2020 Group 6 Senior Design 2 Summer 2011 2

Overview of the Project 9/18/2020 Group 6 Senior Design 2 Summer 2011 3

Magnetohydrodynamic Jefferey Schaffer 9/18/2020 Group 6 Senior Design 2 Summer 2011 4

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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 5

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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 6

MHD Specifications • The MHD drive must provide 5 lbs of thrust. • The MHD drive must be lightweight in order to keep with the 10 lb boat requirement. • The MHD power supply must provide 24 V and capable of discharging 10 A for 15 minutes. • The MHD power supply must be under 8 lbs. • The MHD drive must provide enough thrust to achieve a 5 MPH top speed. 9/18/2020 Group 6 Senior Design 2 Summer 2011 7

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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 8

MHD Power Source 9/18/2020 Group 6 Senior Design 2 Summer 2011 9

Calculations 9/18/2020 Group 6 Senior Design 2 Summer 2011 10

MHD Prototyping Prototype 1. 0 (2/2011) 9/18/2020 Prototype 2. 0 (6/2011) Group 6 Senior Design 2 Summer 2011 11

Final Prototype • Magnets stacked and contained inside hull. • Isolated Channel • Insulated • Aluminum Contacts • 4” x 1” • High Current Clips instead of soldered leads. 9/18/2020 Group 6 Senior Design 2 Summer 2011 12

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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 13

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Current Sensor Calculations 9/18/2020 Group 6 Senior Design 2 Summer 2011 15

Current Sensor Testing Percent accuracy (9/9. 06)*100 = 99. 34% 9/18/2020 Group 6 Senior Design 2 Summer 2011 16

The Current Controller Jared Kelley 9/18/2020 Group 6 Senior Design 2 Summer 2011 17

Variable Current Source • Wirelessly controlled switches allow the current to be drawn directly from the battery, or from the voltage regulators • We Utilize two LM 138 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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 18

Variable Current Source Design The LM 138 develops a reference voltage of 1. 25 V 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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 19

High Current Switching • The Texas Instruments relay driver (ULN 2803) is used to provide the current through the coils of each switch. • A logic high output from the microcontroller provides the necessary 1 m. A to the base of the transistor causing it to conduct the needed 75 m. A to close the corresponding switch. 9/18/2020 Group 6 Senior Design 2 Summer 2011 20

LOW SPEED : HIGH SPEED : 9/18/2020 Group 6 Senior Design 2 Summer 2011 21

The Microcontroller David Hobbs 9/18/2020 Group 6 Senior Design 2 Summer 2011 22

NXP LPC 2388 • • USBizi 144 Chipset Runs the Microsoft. Net Micro Framework USB host PWM outputs 9/18/2020 Group 6 Senior Design 2 Summer 2011 23

PC Board Schematic 9/18/2020 Group 6 Senior Design 2 Summer 2011 24

Microcontroller PCB 9/18/2020 Group 6 Senior Design 2 Summer 2011 25

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 9/18/2020 Group 6 Senior Design 2 Summer 2011 26

MCU and Servo Motor • Pulse width 1 ms: 0° • Pulse width 1. 5 ms: 45° • Pulse width 2 ms: 90° 9/18/2020 Group 6 Senior Design 2 Summer 2011 27

The Wireless Design 9/18/2020 Group 6 Senior Design 2 Summer 2011 28

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. 9/18/2020 Group 6 Senior Design 2 Summer 2011 29

The Wireless options Type Frequency Range Cost TX Cost RX Controller Cost Chronos 433 -Mhz ~100 ft $50 $0 Included with TX Wi-Fi 2. 4 -Ghz 50 -100 ft i. Phone $55 $15 app RC Car controller 27 -Mhz ~30 ft $5. 00 Included 9/18/2020 Group 6 Senior Design 2 Summer 2011 30

Receiver/ Transmitter • Transmitter is located in the watch • 433 Mhz Receiver interfacing with the MCU 9/18/2020 Group 6 Senior Design 2 Summer 2011 31

Directional control display • Enables the user to visually see the value of the accelerometer. • Left 90° • Down 90° 9/18/2020 Group 6 Senior Design 2 Summer 2011 32

Current Control • Located on the “*“ button • High- 15 Amps • Low - 7. 5 Amps • Push button selection • High and Low 9/18/2020 Group 6 Senior Design 2 Summer 2011 33

Current Control • Off Located on the “#” button. • Off – 0 Amps 9/18/2020 Group 6 Senior Design 2 Summer 2011 34

Budget Component Estimated Cost Actual Cost Magnets $100 $50 Boat Hull $60 $30 Wireless Receiver $50 $0 Handheld Transmitter $50 MCU $15 $30 Power Sources $40 $46 Propulsion Control $20 $50 Directional Control Motors $40 $20 Current Sensor System $50 $45 PCB $75 $70 Shipping $0 $120 Misc. $50 $29 Total $500 $540 9/18/2020 Group 6 Senior Design 2 Summer 2011 35

Conclusion • MHD • Wireless • Current Control 9/18/2020 Group 6 Senior Design 2 Summer 2011 36

Questions? 9/18/2020 Group 6 Senior Design 2 Summer 2011 37