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P08456: Lighting System for an Underwater Robot Concept Design Review. Jeremy Schiele Jonathan Lent Ryan Seeber Justin VanSlyke Benoit Hennekinee. Project Background. The design of an underwater LED lighting system that is multi-platform capable
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P08456: Lighting System for an Underwater RobotConcept Design Review Jeremy Schiele Jonathan Lent Ryan Seeber Justin VanSlyke Benoit Hennekinee
Project Background • The design of an underwater LED lighting system that is multi-platform capable • Focus on modular, scalable & open source design • Housing design is in conjunction with Thruster design • Funding provided by the Dresser-Rand Corporation
Multi-Spectral Lighting Considerations • Chosen wavelength dependent on absorption and scattering of light by water and materials contained within • Best overall wavelength ~550-600nm Absorption curve courtesy of Dr. Ientilucci
LED Bulb System LEDs Design Concepts: Concept #1 - Single LED advantages: simple, only 1 LED to control disadvantages: less powerful because only 1 LED per fixture, requires 4 lights, 2 per color Concept #2- 6 small LEDs advantages: tiny LED, multiple designs, adaptability, powerful disadvantages: more complicated to control Concept #3 – 2 layers advantages: intermediate solution, multiple LEDs in a larger housing disadvantages: large housing design, difficult to design
LED Bulb System Choice of the LED: For each concept, the Pugh’s Matrix has been established in order to choose the best LED. For the concept chosen, the LEDs are tiny and are able to be surface mounted on an circuit board.
LED Driver The choice of the LED driver has been made with the following specifications: • 1A output at least, • VOUT ≥ 12V, • VIN = 24V, • Allow PWM Dimming (dedicated input), • Step-down (buck) regulator with efficiency as high as possible, • Switching regulator control, • Bulk as tiny as possible. LED Drivers that fit the criteria
LED bulb and Driver schematic Schematic of implementation of LEDs & Driver.
Control System The lighting system will be controlled over an RS-485 communication line. Inside the enclosure a microcontroller will accept the commands and execute them using the LED circuitry.
RS-485 Communication Any computer with a serial port can be used as the master system for testing or in actual applications using this circuit to convert RS-232 to the RS-485 signals. Circuit design provided by Dr. Reddy
Micro-controller Selection The Atmega168 was chosen for the microcontroller. This is an example circuit connecting the microcontroller to RS-485 and the LED circuitry. Scoring Matrix of micro-controller options
Mounting Hardware • Dual or Single Ball Joint LED Mount • Pros • Maximum adjustability • Quick one/two screw adjustment • Extension away from ROV chassis • Cons • Less secure in holding a position
Mounting Hardware • Hinge Style LED Mount • Pros • Two axes of adjustability • Quick and secure method of adjustment • Simple, effective design • Cons • Close to ROV chassis- shares line of sight to object with video
Mounting Hardware • Thruster Hard Mount Extension • Pros • Most secure with rigid attachment • Extension away from ROV chassis • Feasible for use with light units too • Cons • No adjustability
Mounting Hardware • Commonalities of all designs: • Two hole bolt pattern for housing attachment • Allows any mounting system to be used with either housing • Allows for quick attachment and detachment • Corrosion resistant material • 316L S.S. or anodized Aluminum • Prevents seizing of adjustment points • Preserves aesthetic look of product
Scalable • This option allows the housing to be the same design, yet sized appropriately for application • Theory: assume current is RP-10 • Used on RP-1, 10, 100… • RP-1 motor housing is RP-10 LED housing • RP-10 LED housing is RP-1 motor housing
Interchangeable • This option allows for the same base housing for both thruster and light • End cap is interchangeable for swapping between thruster and light
Housing Design • Scalable • Best option if motor diameter is significantly larger then LED diameter • Interchangeable • Best option if motor diameter and LED diameter are similar • Accounts for difference in length • Simplified machining: one program, one size stock material • Identical sub-parts: o-rings, clamps, etc. • Hot swappable