MSD Project Team P08454 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 McRucker – Computer Engineer

Project Background Derived from one of the most successful projects in RIT’s history: P06606 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 P06606

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 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

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 Current State of Design cont…

Assembly Drawing Figure 4: Section view of P08454 thruster design (Note: Does not include rear section that will house the electronics) Figure 3: Front View of thruster Figure 2: Rear View of thruster

Exploded Assembly Animation

Anaheim Automation: BLWRPG17 Brushless DC Motor Planetary Gear Ratio: 4.9 to 1 Torque: rpm (Geared) Power: 25W Feedback using Hall Sensors Weight: 1.37 lbs Dimensions: 2.36 in (Motor), 1.39 in (Gearbox), in (Diameter) Cost: $90.00 per motor Figure 5: Motor Picture from Anaheim Automation Figure 6: Motor dimensions from Anaheim Automation

Magnetic Coupling Max Continuous Torque: 71 oz-in Max Continuous Speed: rpm Effective Gap: 0.23 in Inner Hub Diameter: 0.87 in (Outer) Outer Hub Diameter: 1.73 in (Outer) Length/ Diameter: 1.73 in/ 1.73 in Figure 7: Proposed magnetic coupling exploded view Containment Barrier: Made in house, using PAEK (Polyaryletherkeytone) or PEEK (Polyetheretherkeytone ) High temperature and pressure resistance Relatively cheap as compared to metals like titanium Total Cost (Coupling): $ per unit

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 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 moisture that may condense out Figure 8: Viton O-ring Figure 9: Silica Gel beads

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 Final Selection Effective propeller comparison requires measurement of shaft speed (Hall Sensor) To be evaluated on final thruster housing in MSD II. Figure 10: Solidworks Model Used for CFD Analysis Figure 11: 120mm ”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: ATmega168 Benefits of using a Microcontroller: Easy to program Easily modifiable design for future designs Source code remains stored in the memory Benefits of the ATmega168 Low power consumption Sufficient PWM channels Numerous communication protocols Top View Bottom View Figure 12: Top and Bottom Views of the ATmega168

Software Function Flowchart

3-Phase Brushless DC Motor Driver Figure 13: ST Microelectronics L6235 motor driver

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 3-Phase Brushless DC Motor Driver cont…

Comparing to Current Designs Listed above are the most important metrics when comparing the three thruster designs. Cost (Dollars)Thrust (lbf) Power Consumption (watts) Open Source Design Feedback from the Motor P08454's Design750.00Comparable to Both*39Yes Seabotix1, (Forward), 4.4 (Reverse)80No Tecnadyne4, (Forward), 4 (Reverse)50.4NoYes * Numbers not yet known but design intends to be comparable to both thrusters using different impeller designs Figure 14: Seabotix Thruster Figure 16: Tecnadyne Thruster Figure 15: P08454’s Thruster

Risks/Concerns Membrane Integrity The membrane will have to be very thin Build small rig to test pressure effects on membrane Bearing Configuration/Life 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 4.5A, 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 Figure 17: P06606 ROV Prototype

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 final design according to optimizations Place thrusters on Hydroacoustics ROV for testing Figure 18: Current Hydroacoustics ROV

Figure Sources Figure 1: Concept Model of P06606’s ROV: Figure 5: Anaheim Automation: Figure 6: Anaheim Automation: Figure 7: Magnetic Technologies Ltd: Figure 8: McMaster-Carr: Figure 9: Silica Gel Beads: Figure 10: Silverstone Tek: Figure 12: ATmega168 Microcontroller: Figure 13: ST Microelectronics: Figure 14: Seabotix: Figure 16: Tecnadyne: Figure 17: P06606: content/Images/large_photos/SponsorROV2.jpghttp://designserver.rit.edu/Archives/P06606/web- content/Images/large_photos/SponsorROV2.jpg Figure 18: Hydroacoustics: Information Sources Anaheim Automation: Seabotix Inc.: Tecnadyne: Danaher Motion: Huco Dynatork: ST Microelectronics: Microchip: Atmel Corporation: McMaster-Carr: