P 08456 Lighting System for an Underwater Robot

P 08456: Lighting System for an Underwater Robot Concept Design Review Jeremy Schiele Jonathan Lent Ryan Seeber Justin Van. Slyke Benoit Hennekinee

Project Background l l 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 l l Chosen wavelength dependent on absorption and scattering of light by water and materials contained within Best overall wavelength ~550 -600 nm 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. Concept 2 LUXEON REBEL Selection Criteria CREE XLAMP XR-E Edison Opto EP 5 W-2 E 00 Weight Rating Weighted Score Brightness 35% 3 1, 05 1 0, 35 3 1, 05 Low Power 10% 5 0, 5 3 0, 3 Luminous Efficiency 30% 5 1, 5 4 1, 2 2 0, 6 Size 20% 5 1 4 0, 8 Angle 5% 4 0, 2 2 0, 1 3 0, 15 100% 4, 25 2, 9

LED Driver The choice of the LED driver has been made with the following specifications: l l l l 1 A output at least, VOUT ≥ 12 V, VIN = 24 V, Allow PWM Dimming (dedicated input), Step-down (buck) regulator with efficiency as high as possible, Switching regulator control, Bulk as tiny as possible. Linear Technology: - LT 3474 - LT 3496 - LTC 3783 MAXIM: ü National Semiconductor: - LM 3405 - LM 3404 - MAX 5053 - MAX 5035 - MAX 5024 - MAX 16819 - MAX 16821 - MAX 16831 TI: - TPS 63000 LED Drivers that fit the criteria

LED bulb and Driver schematic Schematic of implementation of LEDs & Driver.

Power Supply Schematic

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 Atmega 168 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 l Dual or Single Ball Joint LED Mount l l Pros l Maximum adjustability l Quick one/two screw adjustment l Extension away from ROV chassis Cons l Less secure in holding a position

Mounting Hardware l Hinge Style LED Mount l l Pros l Two axes of adjustability l Quick and secure method of adjustment l Simple, effective design Cons l Close to ROV chassis- shares line of sight to object with video

Mounting Hardware l Thruster Hard Mount Extension l l Pros l Most secure with rigid attachment l Extension away from ROV chassis l Feasible for use with light units too Cons l No adjustability

Mounting Hardware l Commonalities of all designs: l Two hole bolt pattern for housing attachment l Allows any mounting system to be used with either housing l Allows for quick attachment and detachment l Corrosion resistant material l 316 L S. S. or anodized Aluminum l Prevents seizing of adjustment points l Preserves aesthetic look of product

Scalable l l This option allows the housing to be the same design, yet sized appropriately for application Theory: assume current is RP-10 l Used on RP-1, 100… l RP-1 motor housing is RP-10 LED housing l RP-10 LED housing is RP-1 motor housing

Interchangeable l l 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 l l Scalable l Best option if motor diameter is significantly larger then LED diameter Interchangeable l Best option if motor diameter and LED diameter are similar l Accounts for difference in length l Simplified machining: one program, one size stock material l Identical sub-parts: o-rings, clamps, etc. l Hot swappable