MSD Project Team P 08454 Underwater Thruster Design

MSD Project Team P 08454 Underwater Thruster Design Anthony Squaire – Team Leader - Industrial and Systems Engineering Alan Mattice – Lead Engineer - Mechanical Engineer Cody Ture - Mechanical Engineer Brian Bullen – Mechanical Engineer Charles Trumble – Mechanical Engineer Aron Khan – Electrical Engineer Jeff Cowan – Electrical Engineer Andre Mc. Rucker – Computer Engineer

Project Background • Derived from one of the most successful projects in RIT’s history: P 06606 • Project mission is to design an open source thruster that can be used and/or improved for future RIT MSD projects • Customers: • Dresser Rand • Dr. Hensel and the RIT Mechanical Engineering Department • Hydroacoustics • The design needs to be competitive with the current thruster designs in use: • Seabotix • Tecnadyne Figure 1: ROV Design from MSD project P 06606

High Level Customer Needs • Thrust must be improved over the current Seabotix Thruster • Power consumption must be better than the Seabotix Thruster • Mounts as easy as the Tecnadyne Thruster • Operational in 400 ft. (173 psi) of water • Needs to work in temperatures from 38 -75 F • Modular, open source design • Comply with federal, state, and local laws, including the policies and procedures of RIT

Current State of Design • Completed two design reviews and met with the customers so that they could voice their concerns • Machine drawings are complete for specialty parts and overall thruster design • Have ordered the high priority/long lead time parts: • Motor, magnetic coupling, shaft bearings, o-rings, motor controller, development board for microcontroller and feasible impeller prototypes • Have two test plans completed and started to put together additional test plans to confirm the design specifications • A test rig is built that will test the final thruster design

Current State of Design cont… • Continue to meet with the lighting team to discuss the project interface for the light and the thruster bodies • The major concerns of the design have been identified through the two design reviews and additional meetings with the customers and changes (if needed) will be implemented to mitigate the concerns: • Heat dissipation, condensation forming, sealing the enclosure, and containing and balancing the magnetic coupling/shaft assembly

Assembly Drawing Figure 3: Front View of thruster Figure 2: Rear View of thruster Figure 4: Section view of P 08454 thruster design (Note: Does not include rear section that will house the electronics)

Exploded Assembly Animation

Anaheim Automation: BLWRPG 17 Brushless DC Motor • Planetary Gear Ratio: 4. 9 to 1 • Torque: • 117. 943 oz-in @857 rpm (Geared) • Power: 25 W • Feedback using Hall Sensors • Weight: 1. 37 lbs Figure 5: Motor Picture from Anaheim Automation • Dimensions: 2. 36 in (Motor), 1. 39 in (Gearbox), 1. 654 in (Diameter) • Cost: $90. 00 per motor Figure 6: Motor dimensions from Anaheim Automation

Magnetic Coupling Max Continuous Torque: 71 oz-in Max Continuous Speed: 26000 rpm Effective Gap: 0. 23 in Containment Barrier: Made in house, using PAEK (Polyaryletherkeytone) or PEEK (Polyetherkeytone) • High temperature and pressure resistance Inner Hub Diameter: 0. 87 in (Outer) Outer Hub Diameter: 1. 73 in (Outer) Length/ Diameter: 1. 73 in/ 1. 73 in • Relatively cheap as compared to metals like titanium Total Cost (Coupling): $140. 00 per unit Figure 7: Proposed magnetic coupling exploded view

Sealing and Condensation Sealing: • Standard Viton O-rings • Resistant to hydraulic and natural oils • Weather resistant: can handle environment changes • Medium Hard on the Durometer Shore Figure 8: Viton O-ring A scale Condensation: • Silica Gel Insert • Condensation may occur at depth due to being sealed in a moist air environment • Hydrophilic substance that will collect any moisture from the inner air and any Figure 9: Silica Gel beads moisture that may condense out

Impeller Geometry Computer Fans • Thousands of different sizes and shapes • Lightweight plastic is easy to modify and resistant to corrosion or deformation • “Low Noise” fans more hydrodynamic Figure 10: Solidworks Model Used for CFD Analysis Final Selection • Effective propeller comparison requires measurement of shaft speed (Hall Sensor) • To be evaluated on final thruster housing in MSD II. Figure 11: 120 mm ”Low Noise” Silverstone Fan

Impeller Geometry Testing for MSD II • Similar single axis test rig • Each of 6 designs at varying gear ratios • USE BLEACH Kort Nozzle • Use of an accelerating nozzle can increase thrust by as much as 40% • Wide blades with little clearance

Microcontroller: ATmega 168 Benefits of using a Microcontroller: • Easy to program • Easily modifiable design for future designs • Source code remains stored in the memory Top View Benefits of the ATmega 168 • Low power consumption • Sufficient PWM channels Bottom View • Numerous communication protocols Figure 12: Top and Bottom Views of the ATmega 168

Software Function Flowchart

3 -Phase Brushless DC Motor Driver Figure 13: ST Microelectronics L 6235 motor driver

3 -Phase Brushless DC Motor Driver cont… • Integrated Hall Effect sensor for the accurate feedback of ωr, direction of rotation, and position • Rated Current: 5. 6 A, Rated Voltage: 52 V • Over Current Detection Circuitry reads the current in each high side • Tachometer for easy implementation of closed loop control • PWM input for speed control

Comparing to Current Designs Figure 15: P 08454’s Thruster Figure 14: Seabotix Thruster Figure 16: Tecnadyne Thruster Cost (Dollars) Thrust (lbf) Power Consumption (watts) 750. 00 Comparable to Both* 39 Yes Seabotix 1, 000. 00 4. 8 (Forward), 4. 4 (Reverse) 80 No No Tecnadyne 4, 000. 00 12 (Forward), 4 (Reverse) 50. 4 No Yes P 08454's Design Open Source Design Feedback from the Motor * Numbers not yet known but design intends to be comparable to both thrusters using different impeller designs • Listed above are the most important metrics when comparing the three thruster designs.

Risks/Concerns • Membrane Integrity • The membrane will have to be very thin • Build small rig to test pressure effects on membrane • Bearing Configuration/Life Figure 17: P 06606 ROV Prototype • Will use a plain bearing to support the output shaft • If assembly is unbalanced then bearing can wear prematurely • O-ring Effectiveness • Most critical piece of the housing sealing • Need to use hydraulic o-rings to combat depth pressure • Current Spikes at Start-up • If start-up current peaks over 4. 5 A, then potential damage can occur to the power supply • If fuses are placed on the power supply, then the risk should be mitigated • Heat Dissipation • An analysis has shown that the amount of heat that can be dissipated from the thruster far exceeds the heat that will be produced by it’s components

Concept Design Review: 19 October 2007 Questions/Concerns: • Concerns with magnetic coupling? • Sealing around the electrical cords, feeding power and control through same tether? • What is the worst failure mode that could happen? • Oil vs. Air filled? • Power is at a premium • How will the thruster interact with the computer interface? • Considered using a heat sink to help dissipate heat?

Detailed Design Review: 2 November 2007 Questions/Concerns: • What compromises are made in choosing a motor? • Are the electronics purchasable or do they need to be bread boarded? • Do you need to worry about heat dissipation from or warping of the magnetic couple membrane? • Plan on running the life test rig continuously? • Do you have a method of choosing the best impeller design?

Where to Next? • Purchase remaining parts and place orders in the machine shop for custom parts • Write verification test plan to confirm that the design meets all specifications • Build prototype models • Verify that the design meets all of the specifications using the verification test plan • Optimize the design based on data collected during testing and adjust Figure 18: Current Hydroacoustics ROV final design according to optimizations • Place thrusters on Hydroacoustics ROV for testing

Figure Sources n n n n Figure 1: Concept Model of P 06606’s ROV: https: //edge. rit. edu/content/P 08454/public/Home Figure 5: Anaheim Automation: http: //anaheimautomation. com/blwrpg 17_brushless_dc_planetary_gearmotors. aspx Figure 6: Anaheim Automation: http: //anaheimautomation. com/blwrpg 17_brushless_dc_planetary_gearmotors. aspx Figure 7: Magnetic Technologies Ltd: http: //www. magnetictech. com/prod_magcoup_coax_sae. htm Figure 8: Mc. Master-Carr: http: //www. mcmaster. com/ Figure 9: Silica Gel Beads: http: //en. wikipedia. org/wiki/Image: Silica. Gel. jpg Figure 10: Silverstone Tek: http: //www. silverstonetek. com Figure 12: ATmega 168 Microcontroller: http: //www. atmel. com/dyn/resources/prod_documents/2545 S. pdf Figure 13: ST Microelectronics: http: //www. st. com/stonline/products/literature/an/9214. pdf Figure 14: Seabotix: http: //www. seabotix. com/products/btd 150. htm Figure 16: Tecnadyne: http: //www. tecnadyne. com/images/Model-260 -2. jpg Figure 17: P 06606: http: //designserver. rit. edu/Archives/P 06606/webcontent/Images/large_photos/Sponsor. ROV 2. jpg Figure 18: Hydroacoustics: http: //hydroacousticsinc. com/marine_technology. php Information Sources n n n n n Anaheim Automation: http: //www. anaheimautomation. com Seabotix Inc. : http: //www. seabotix. com/products/btd 150. htm Tecnadyne: http: //www. tecnadyne. com/Brochure/Model%20260%20 Brochure. pdf Danaher Motion: http: //kmtg. kollmorgen. com/products/motors/ Huco Dynatork: http: //www. huco. com ST Microelectronics: http: //www. st. com Microchip: http: //www. microchip. com Atmel Corporation: http: //www. atmel. com Mc. Master-Carr: http: //www. mcmaster. com/