University of Houston

Senior Design I

MECT 4275

Fall, 2016

Team Nautilus Report

Matthew Byrne

Douglas Seagraves

Roland Rodriguez

Wendell Briggs

ContentsAbstract4Executive Summary5Objective6Deliverables6Marine Advanced Technologies Education7MATE Competition History82015 MATE Competition82016 MATE Competition92017 MATE Competition10Research12History of ROV12Industry13Market Research14Team Structure15Mentors16Faculty Advisor16Alumni Advisor17Industry Advisor17Underclassman17Design Concepts17Materials18Frame Design20Prototyping21Manipulators22Electronics and Programming23Electronics Enclosure25Project management26Member Contribution27Cost & Man hours Estimate27Risk Matrix29Risk Mitigation29Risk Progression30Risk over time31Milestones & extras31Appendix A Risk Matrix33Risk Matrix created 10/2/1633Risk Matrix created 11/8/1633Risk Matrix created 12/06/1634Risk through time35Appendix B Timeline and Gantt chart36Appendix C - Manipulator Design37Appendix D Frame Design38Appendix E Thruster Design38Appendix F Electronics Enclosure Design39Appendix G Layout Drawings39Appendix I Electronics Enclosure Calculations55Works Cited56

Figure 1 - Sample material cost18

Figure 2- Initial Cost Time estimate27

Abstract

Team Nautilus is a highly motivated senior design team, composed of four mechanical engineering technology students from the University of Houston. The objective for the team is to design and build a fully functional underwater remotely operated vehicle (ROV) to compete in the 2017 Marine Advanced Technology and Education (MATE) competition. The ROV will have several unique features that are beyond the 2017 MATE competition requirements; the first will be the use of two manipulating arms (one power arm and a dexterous articulating arm). The power arm will be used to stabilize the ROV and will be operated through the use of hydraulics. The articulating arm will have 3 degrees of freedom and be operated by servomotors. The second unique feature is a vortex hydro cannon to clear sand and silt disturbed by the thrusters in order to have unobstructed video feed. The third unique feature is the ability to lift a payload of 30 pounds underwater by utilizing rotating thrusters.

Team Nautilus will utilize their engineering and design skills to make these complex systems work as one. These tools will allow the ROV to successfully manipulate underwater objects and complete the multiple tasks for the 2017 MATE competition. The team will use the 2016 fall semester for planning and design, then will utilize the 2017 spring semester to execute the plan and manufacture a fully functioning ROV. Team Nautilus will team up with industry and faculty advisors for advice, guidance, and complex problem solving. The initial ROV has an estimated overall budget of $15,400. The team will acquire the capital needed to finance the project by aggressive fundraising techniques and by establishing a large network of industry professionals and mentors.

Executive Summary

Team Nautilus has an intrinsic passion to prove their skills within a real-world setting. Students in the University of Houston Mechanical Engineering Technology department will leverage their senior design project to showcase the engineering skills they have gained throughout their academic career. Team Nautilus will test their engineering knowledge through design, fabrication, and testing of a first article underwater remotely operated vehicle (ROV). Team Nautilus will incorporate design challenges into the ROV such as a vortex hydro cannon, alter thruster orientation remotely, and an articulating arm with a minimum of three degrees of freedom. Additionally, Team Nautilus will take upon them the requirements to manage all facets of the project.

Utilizing project management principles such as Gantt charts, risk matrices, and work breakdown structures, Team Nautilus will complete this project within two semesters. The project has been divided into multiple phases: planning, design, execution. Each of these phases have multiple subcategories as well as milestones. A major milestone is the conclusion of semester one in which the team is required to have much of the planning and design accomplished.

With the conclusion of the semester, Team Nautilus has accomplished many tasks which range in size and complexity. The final design for both the frame and manipulators is what they are most proud of. In addition, the team has prototyped an approximate 1:1 scale model of the ROV with cardboard, made several prototypes of vortex ring cannons and 3-D Printed a model of the ROV. Through more trials and tribulations, they will continue to make progress as they strive to reach their goal of proving to themselves that they have simple, effective, and innovative engineering capabilities.

Objective

The objective is to design and build a Remotely Operated Underwater Vehicle, (ROV) for entry into the MATE 2017 Explorer class ROV competition. The ROV will be able to navigate unassisted (driven by remote) under water and complete the various missions as prescribed in the competition rules. The ROV will consist of a durable frame to encase all of the peripherals, a camera to aid in navigation and identification of mission objectives, a drive thruster system to maneuver and steady the ROV under water, a logic system to analyze and interpret sensors (as required by MATE competition missions), a power arm to provide stability and an articulating arm for the retrieval and manipulation of objects under water.

Deliverables

Design and construct an ROV within the design constraints of the MATE competition

Operate the ROV through LabVIEW

Incorporate a fluid powered arm

Incorporate three degrees of freedom in the articulating arm/gripper

Lift a 30 pound payload under water

Increase a thrusters baseline velocity by 5%

Build the ROV to fit in a 24 circle footprint on the largest dimension

Incorporate a camera that will rotate to see 270 around the ROV

Incorporate a self-correcting gyroscope

Incorporate a remote system to change the thruster orientation

Build and incorporate a vortex hydro cannon

Marine Advanced Technologies Education

The Marine Advanced Technologies Education (MATE) Center is an organization and education center that has partnered with industry and educators to advance marine technologies and showcase career opportunities for students. This education center offers professional development workshops for students and educators to better prepare themselves for the workplace, as well as teach about current marine technologies in the workplace. Also, MATE prides itself with promoting and introducing students to the STEM field. The organization was established in 1997 and has been holding an ROV competition for K12, community colleges, and university students since 2001. The annual MATE ROV competition is internationally recognized and teams from around the world participate.

The annual competition challenges teams to design, fabricate, and then compete in unique, real-world scenarios. The scenario for each competition changes each year. Due to the complexity of the tasks and the range of participants, MATE divides all ROVs into three classes: Explorer, Ranger, and Scout. Depending on the ROV class, there are minor differences within the competition guidelines. All teams competing must accomplish several tasks in front of a live audience. One of the aspects that makes this competition unique is that not only are the teams graded on preforming several underwater tasks with their robot, but also on product presentation, technical documentation, marketing display, and a safety inspection. The teams are graded by educators and industry professionals.

MATE Competition History2015 MATE Competition

The theme for the 2015 MATE competition was Arctic Ocean drilling and took place in St. Johns Newfoundland and Labrador Canada. There were three different missions in which each mission had several tasks to be completed. The teams were given 5 minutes to get the ROV into the water and ready to start the mission. Next the teams had 15 minutes to complete as many missions as possible. Then the teams were given 5 minutes to remove the ROV from the water. If a team takes extra time to remove the ROV, points are deducted from the overall score. The first mission was named Science Under the Ice. This mission consisted of deploying the ROV through a hole in the ice to collect samples, place a sensor in a designated location, survey an iceberg, and identify several species in the area. The second mission was dubbed Subsea Pipeline Inspection & Repair. The first task was to find a corroded section of a pipe during an inspection, remove the corroded section and bring it to the surface, repair the section that was removed, and prepare a wellhead for installment of a subsea Christmas tree. The final mission was named Offshore Oilfield Production & Maintenance. To complete this mission teams had to check the ground on an oil platform leg, find the angle the wellhead makes with the seafloor, and measure water flow through a pipeline.

For the 2015 competition, Jesuit Robotics from Jesuit High School won the Explorer class competition with a total of 569.83 points followed by Eastern Edge from Memorial University with a final score of 525.50 points. The winning teams ROV had an estimated cost of $12,800 and used three specialized frames for extreme conditions. The final cost including re-used items was $33,921.36.

2016 MATE Competition

The 2016 competition was designed to simulate a trip to one of Jupiters moons, a coral reef identification and study, and a rig shutdown process. As in the 2015 competition, the teams were given 5 minutes to get the ROV into the water and ready to start the mission, 15 minutes to complete as many missions as possible, and 5 minutes to remove the ROV from the water. If the teams take extra time to remove the ROV points are deducted from the overall score.

This competition consisted of five missions. The first set of missions were named Outer Space: Mission to Europa, and consisted of connecting an environmental sensor to a power hub, measure the temperature of a vent, and take pressure readings. The second mission Inner Space: Mission-Critical Equipment Recovery required the teams to identify specific equipment by serial numbers, and transport the specified equipment to a recovery basket. The third mission, Forensic Fingerprinting, required the teams to collect oil samples, return the samples to the surface, and analyze the samples gas chromatographs. The forth mission, Deepwater Coral Study, challenged teams to collect two coral samples, bring the samples to the surface, and then photograph a coral colony. Rigs to Reefs was the final mission, which required teams to plant a flag in a designated location, attach a wellhead cap to a flange, and lock down the well head with bolts.

The 2016 MATE competition was held at the NASA Johnson Space Center in Houston, Texas. The first-place team was Memorial University of Newfoundland with a total cost of $6,731.00 and a total of 9750 man hours on it. The second-place team Jesuit High school with a total budget of $27,416.56 and spent 3800 hours constructing it. The third-place team AMNO&CO spent $9,560.82 and a total of 4000 hours constructing it. There were 33 teams that competed in the competition, and the average money spent on ROV construction was $9,473.00 with an average 3100 man hours. The median amount spent was $8,348.00 and the median hours spent was 2038 man hours. Purdue University was the team that spent the most money in the competition at a total of $27,100.00 and 6500 hours building the ROV. Purdue University took 13th place in the competition. At a reported $2530.00, Hong Kong Polytechnic was the lowest spending team with a man hour investment of only 495 hours. Copia Lincoln Community College was the lowest man hours spent on the project. It should be noted that the lowest reported hours and money spent only accounted for changes made to an ROV from previous years and not the total project.

2017 MATE Competition

The 2017 Mate mission manuals were released at the time of writing, detailing the missions and requirements. There will again be four missions to be completed in one demonstration run. This year, to qualify for the MATE competition the teams will be required to submit an audition video by May 10, 2016. The video must show the ROV is conformant to the regulations of the Competition. Additionally, the ROV must complete a specified mission in a 15 min in a raw unedited video to shoe the ROV can function and maneuver unassisted under water. This introduces a new challenge as this was not required in previous years.

The first mission will be called Commerce: Hyperloop Construction and will be composed of five tasks. The first task is to insert two rebar reinforcement rods into position in a steel baseplate. Then the ROV must install a frame onto the baseplate, remove a pin to release the chains holding the frame, and transport and position a hose for pouring concrete into the frame. Finally, the ROV must retrieve the three positioning beacons and return them to the surface.

The second mission will be named Entertainment: Light and Water Show Maintenance. The first task in the mission will be to disconnect the power cable from the platform, and turn the valve to stop the flow of water to the platform. Next the ROV will disengage the locking mechanism at the base of the fountain, remove the old fountain, and install a new one. Last the ROV will re-engage the locking mechanism at the base of the fountain, turn the valve to restore the flow of water to the platform, reconnect the power cable to the platform, and return the old fountain to the surface, side of the pool.

The third mission will be Health: Environmental Cleanup. The ROV will use a simulated Raman laser to determine if contaminants are present in two sediment samples. It must then collect a 100-mL sediment sample from the contaminated area and return it to the surface. The sediments will be simulated by agar. Next, the ROV will collect two clams from the contaminated area and return them to the surface. Lastly a cap will be placed over the contaminated sediments.

The final mission will be Safety: Risk Mitigation. The ROV will need to locate four cargo containers, activate each containers Radio Frequency Identification (RFID) (This will be simulated by shining a light into a port on the side of the container to activate the sensor), and obtain RFID data via Bluetooth. The data will be used to determine the containers identification number, contents, and if the contents are high risk. (MATE will provide a container manifest.) A buoy marker will need to be attached to the eye-bolt on the container with high-risk cargo. The distance from the high-risk container to the other three containers will need to be determined, as well as the direction from the high-risk container to the other three containers. The distance and direction will be used to make a survey map of the incident site. (MATE will provide a blank map with 0.25 meter squares.)

ResearchHistory of ROV

The history of the underwater ROV is brief due to the relatively recent conception of the technology. The first tethered remotely operated vehicle was made by Dimitri Rebikoff in 1953. In the early 1960s the United States Navy saw the value of utilizing this new technology and funded most the development and testing of ROVs with the primary purpose of recovering and salvaging lost ordinance and wreckage. This lead to the development of Cable-Controlled Underwater Recovery Vehicle (CURV). The next major advancements came during the 1970-1980s when the offshore oil and gas industry starting using ROVs. This lead to the development of different ROVs to accomplish different tasks. Since then ROV development has been strongly correlated with the offshore oil industry. Now ROVs are used to survey underwater structure, environmental monitoring, and pipeline surveying to name a few.

ROV Types in order of increasing functionality:

Small electric vehicles- Primarily used for observation and inspection typically only have a camera and go to depths of 300m

High Capacity Electric ROV- larger versions of SMV can dive to 6000m. Still only equipped with cameras. Small electric power supplies limit the use of other peripherals or tools.

Work Class Vehicles- Powered electrically and hydraulically so they can perform more tasks. Typically, limited payload and lift capacities. This class of ROV will have a manipulator and a grabber

Heavy work class ROV- Most advanced version capable of working up to 3000m of water and lift capacities of up to 11,000lbs. Most have multiple manipulators and grabbers as well as specialized tool attachments.

Autonomous Underwater Vehicles- The next step in ROV technology. Only military testing is known to exist in AUVs. Hybrid AUVs may be seen in the near future to reduce the umbilical size from the ROV to the ROV Types in order of increasing functionality

Industry

The ROV industry is vast and has become well diversified. Most ROVs now are built for a specific tack or can attach and detaching several different instruments to accomplish the current task at hand. The industry offers ROVs for hobbyists, large industrial applications, and underwater exploration. Industrial ROVs are generally governed by API 17H and ISO 13628. The two standards are nearly identical and are considered interchangeable. The standard gives recommended practices for the development and design of ROVs, the interfaces on subsea production systems, as well as ROV Classifications.

Per API 17H, ROVs are defined as Free swimming or tethered submersible craft used to perform tasks such as inspection, valve operations, hydraulic functions, and other general tasks. [1] The ROVs are generally grouped in the following main categories:

OBSROV (observation class ROV; MCA Class I and Class II) small vehicles fitted with cameras/lights and may carry sensors or inspection equipment. They may also have a basic manipulative capability. They are mainly used for inspection and monitoring.

WROV (work class ROV; IMCA Class III) ROVs normally equipped with a five-function grabber and a seven-function manipulator. These commonly have multiplexing controls capability that allows additional sensors and tools to be operated without the need for a dedicated umbilical system. WROV are split into two classes: medium WROV and large WROV depending on their defined work scope. WROVs can carry tooling packages to undertake specific tasks such as tie-in and connection function for flowlines, umbilicals, rigid pipeline spools, and component replacement.

For an industry use, the company OCEANEERING is considered a world leader. OCEANEERING designs, manufactures, and operates their fleet of ROVs and as of January 2015, OCEANEERING was operating 336 work class ROV systems. Due to the high demand and extensive work necessary, OCEANEERING employs over 2000 people to run their offshore ROVs.

Market Research

The ROV market has been set up so that it can cater to recreational and industrial applications. One of the larger markets for the ROV is for the hobbyist. Most of these models are used for underwater viewing and recreation. Several companies produce different sized models from small to medium ROVs. These ROVs are usually under forty-five pounds and can range from 99 dollars DIY kits to 30,000 dollar professional models. Most of these come with a tether that connects the control module with the ROV. The control module allows steering of the bot, and allows real time viewing of the ROVs on board camera system. Some of the smaller models also come with a manipulating arm. Several examples of this class of ROV are the DTG2 Worker with a base model cost of approximately 9,500.00 dollars, the HydroView Pro 7M which retails for approximately 16,000.00 dollars, and the ROVEEE priced at 33,000.00 dollars with a five-thruster set up and extended tether.

ROVs created for industrial application also make up a large portion of the market. These ROVs are usually designed for underwater pipeline survey and special oil rig applications. Some of these applications would be installing a manifold on an oil well, monitoring a well-head, or assisting in sealing oil wells in the Gulf of Mexico where the water depth can reach up 9,000 feet. These machines are usually designed to accept several different types of manipulating arms, which are attached or detached depending on the task at hand. These arms are used to lift, screw, and rotate object into a more desirable fashion. These ROVs are usually operated by a small team working in remote locations. Most of these ROVs are large and bulky and weigh from 50 to 14,000 pounds. They are also usually very expensive with prices ranging from 50,000 to 2,000,000+ dollars.

Team Structure

The team is structured in a way to optimize the teams production. Matthew Byrne was chosen to be the team lead by group decision. This decision was based on his management experience and overall leadership qualities. Once this decision was made the team then broke down the ROVs components and operating systems into several major and sub-categories. Then based on our current knowledge of ROVs, the team grouped all the major and sub-categories of the ROV into four master groups. These master groups were then discussed and debated amongst the team, and finally assigned to team members. The final designation of responsibilities is as follows: Wendell Briggs as the frame and materials lead, Roland Rodriguez as power and articulating arm lead, Douglas Seagraves as electronics lead, and Matthew Byrne as team lead and thruster design lead. These positions were assigned to maximize the teams potential and to fully utilize each team of the members unique set of abilities. In addition to having leads on each aspect of the ROV design and construction, the team appointed a second for each aspect. The second is there as the first resource to the lead if they become overwhelmed in their assignments. This concept was also utilized to reduce the risk of a single contributor missing an aspect of the design.

Mentors

One of the biggest factors for success are mentors. This was a particular aspect of the project that the team wanted to take advantage of the most. Mentors play a key role due to their ability to leverage their life long experience and industry expertise, offer advice for problems encountered, and shine light on some possible future problems. The selection process began with a team meeting. During this meeting team members voiced potential problems with the project and possible teachers, associates, and industry professionals that might offer help to engineering students. Once a list of names was compiled, the team then listed their qualifications and pros and cons.

Faculty Advisor

The team assigned some of the members recruiting tasks based on personal relationships and opportunity. The first target was Professor David V. Rypien for faculty advisor because of his motivation to teach and active outreach to students. He has also been a licensed PE in the state of Texas since 1991. Having a licensed professional engineer to advise the group was a major goal since the team members all aspire to obtain a PE license in the future.

Dr. Rypiens knowledge was utilized heavily through the frame design. A meeting with all members present was held in which the topic of pros and cons concerning aspects of the frame. The learning to all members was invaluable.

Alumni Advisor

The next acquisition was of Ryan Payne to fill the alumni spot. One of the major reasons for selecting Ryan was because of his prior experience with Professor Raresh Pascali, and was also on an infamous senior design team that built an ROV for the MATE compotation which flipped the breakers at NASA. Ryan will be a critical tool in advising the team of potential issues when following the MATE guidelines, and offer guidance when the team hits a wall.

Industry Advisor

The next slot the team filled was an industry advisor. Billy Snider, who works for FMC Technologies, was asked. Billy is a University of Houston graduate and recently has been appointed to the Engineering Alumni Association.

Underclassman

The last position that needed to be filled was the underclassman. This was a tough decision and the group used the assistance of a graduate student who made a few suggestions of students. This decision is still underway but will be resolved soon.

Design Concepts

The ROV Design concepts will culminate into an ROV that is both functional and efficient in the water. The ROV will need to be Robust to withstand loading, lightweight to pass MATE requirements, and lastly compact as to conform to the deliverable requirements. The ROV will be an integration of several subsystems starting with a sturdy frame, manipulators, thrusters, and the electronics system. The systems will need to be manufactured from common materials, integrated by the electronics system and controlled through LabVIEW

Materials

The materials that will be utilized to construct the teams ROV will have to withstand large amounts of pressure. Another consideration is that the team wants to keep the weight of the ROV low, so the unit can be lifted and moved by two or three people. Also, the different thruster orientations and two arms will increase the forces acting on ROV. The ROV will be in compression from the hydrostatic pressure and will also be subjected to torques. This will cause axial and shear stresses on the ROV, which the materials used for the frame must be able to withstand. Some of the materials that the group are considering are polymers, metals, and composites.

Some of the metals that are being considered are carbon steels, alloy steels and aluminum. Carbon steels generally have a density of 7850 kg/m3, an elastic modulus from 190-200GPa, and a Poissons ratio from .27-.3. Alloy steels generally have about the same density, elastic modulus, and Poissons ratio, but have a greater hardness and are more brittle than carbon steel. Alloy steels do not have as much ductility as carbon steels and is much more likely to have critical failures. Carbon steels are more likely to corrode than some alloy steels, and since the materials will be in contact with corrosive agents. Also, machining carbon steel will be much cheaper than machining the alloy steels. Aluminum on the other hand offers light weight and strength.

Aluminum has a density of about 2800 kg/m3. This is much lighter than any types of steel. The 7000 series of aluminum alloy has a modulus of elasticity of 71.7 GPa, Poissons ratio of .33, and with a ultimate tensile strength of 552 MPa. The 7000 series has good machinability and for the aluminum alloys as the series goes down to 6000 and down the machinability decreases and the modulus of elasticity deceases some as well. Below figures are a representation of our decision matrix for materials and sample costs.

Figure 1 - Sample material cost

Some of the different types of flotation material that are currently being considered are polyisocyanurate and syntactic foam. Both foams have high compressive strength and good insulation properties. These two types of foams are currently being used in the ROV industry. Polyisocyanurate foams are relatively cheap and are easily formed into desirable shapes. Syntactic foam is used mainly for deep water application, costs more, and is encased in resin, so it is harder to manipulate into desirable shapes.

Frame Design

The Frame of the ROV must be Robust enough to withstand the loading of the appendages of the ROV as well as the payload. The Payload will include the 30 lbs. the ROV will be able to pick up for the deliverables as well as any other load resulting from carrying and manipulating objects in the mate mission objectives.

One of the main concepts that will be applied during the design and construction of the ROV Frame will be Archimedes principle, static fluid principles and the relationship between the center of gravity and the center of buoyancy. The use of the Archimedes principle will be to determine the buoyant force that is acting on the ROV. This force will be equal to the weight of the liquid that is displaced by the ROV. This force will act on the ROV, so if the weight of the liquid displaced is less than the weight of the ROV, the vehicle will sink. If it is the opposite way around, then the object will float.

Another important concept that will be taken into consideration when finding the hydrostatic pressure acting on the vehicle will be the static fluid principle. This principal states that the static pressure acting on and object is only dependent upon the depth of the object, the shape of the object, the density of the fluid, and the acceleration due to gravity. Using this principal, the team will be able to approximate the static pressure that will be applied to the ROV as it descends into various depths. This information will be critical for selecting the different materials that will be used to manufacture the remotely operated vehicle.

Another important aspect of the ROV that will be considered will be the location of the center of buoyancy and the center of gravity. The stability of the vessel is directly related to the relation of these two points. The easiest way for the vessel to be stable is to have the center of gravity and the center of buoyancy aligned with one another. This includes considering the distance between these two points. The distance between these two points corresponds with the righting force that the ROV will experience when the center of gravity and center of buoyancy become unaligned due to different forces applied to the ROV in different locations. Examples of this could be forces due to the arm lifting an object underwater or currents in the water pushing the ROV.

Prototyping

Once the frame design was selected the next step was to decide the dimensions that will minimize the overall footprint of the ROV, while allowing the team to accomplish the goals set at the start of the project. One of the deliverables that played a large role in the sizing of the frame was the rotating thrusters. With this deliverable in mind, the team decided to place the thrusters on the outside of the ROV. To maintain the desired footprint, the original frames width was reduced by twice the diameter of the thrusters. After this the rest of the frame was resized to fit with the new width. Once the second iteration of the frame was complete, team Nautilus decided to come together as a group and build an approximate 1:1 scale model.

During this process the team worked together, and manufactured the frame out of cardboard. The team also made the thruster mounts, and idealized thrusters for the ROV. Once the frame was assembled several possible issues because apparent. First it became apparent that there would be several potential issues with mounting the thrusters that would control the vertical movement of the ROV, the thrusters on the top of the vehicle. Several options were discussed and it became apparent that by adding two additional angle braces to the top of the ROV would provide ample mounting for the vertical thrusters.

Second with the reduction of space enclosed by the frame due to thruster location, the electronic housing now has a fixed maximum size. This housing must be large enough to fit all the electronics needed to complete the tasks for the 2017 MATE competition. The team was initially considering circular electronic housing, but due to the geometry and limited space now a square or rectangular geometry is being considered to utilized the space with maximum efficiently. The fixed maximum size will add some complications, but this will just give team Nautilus another opportunity to display complex problem solving skills.

Another realization was that the team would encounter several complex assembly issues that were not accounted for. This would cost the team extra time during assembly and lead to possible frame squaring issues. This problem also tied into the mounting of the vertical thruster. The team discussed using brackets to address this issue, but it was determined that by using angle on the top portion of the frame would allow the team to use the angle as a bracket. This also gives the ROV the ability to have extra mounting capabilities that will allow as discussed earlier better mounting options for thrusters.

Manipulators

The ROV will employ two separate manipulators, each with a specific purpose. First there will be a Power Arm. The power arm will be used to steady the ROV underwater while working at a workstation underwater. The second arm will be an articulating arm that will be used to manipulate objects underwater.

The power arm on our ROV will be pneumatically fluid powered to give strength. The power arm will be a simple appendage that only has one moving part and operates using one cylinder. The simplicity of the power arm is such that we can spend more time designing a more complex articulating manipulator. The design concept for the power arm is in Appendix C.

The Articulating Arm will allow the ROV to complete more complex tasks by incorporating three degrees of freedom in the ROV. The choice to incorporate as many degrees of freedom into the arm was determined by the complexity of the missions in the MATE competition. Though it is not a requirement of the competition, some missions would be difficult to complete without a dexterous manipulator. The most complex degree of freedom is the ability of the gripper to rotate about the axis of the arm. The ability to perform this task is all but necessary in the competition as we must grip a gate valve and rotate it 1080 to open and close the flow to a fountain. The design concepts for the articulating arm are in Appendix C.

Two preliminary designs were evaluated for the articulating arm. The main differences in the design are the joint orientation and the linkage concept. The first difference is the orientation of the joints. The joint orientation defines the range of the manipulator. In using three degrees of freedom we are tasked with getting the most maneuverability we can while at the same time designing something that can easily be manufactured and repeated. The other difference is the design of the linkages. Robot arm members can be found in an array of shapes and two different shapes were chosen to represent the type of linkage. The first was a solid pivot and beam assembly and the other was a plate and spacer assembly. The solid pivot and beam assembly was chosen because of the simplicity of manufacturing and low time to develop. In addition, the joint orientation in the solid pivot model was chosen as it gives us the most range for the use of the three degrees of freedom. A copy of the decision matrix for the manipulators is given in Appendix C.

Electronics and Programming

One of the most important components of the ROV will be the electronic system. The electronic system will be used to power the logic system, which will control the thrusters, manipulating arms, and any sensors to be used. Currently, the team is still deciding whether to integrate the camera system into the overall logic system in order to mediate any unnecessary complexity. The decision to utilize a National Instruments NI myRIO was finalized due to the understanding of the level of difficulty of programming necessary coupled with limited time. An additional reason why the myRIO was chosen is because of the availability of a spare myRIO that was offered to the electronics lead to begin practicing on.

The myRIO is a reprogrammable input/output used for controls, robotics, mechatronics, automotive, and aerospace applications. It is a FPGA (Field-Programmable Gate Array) based technology that allow the user to graphically program their system. The software to be used to program the myRIO is LabVIEW from National Instruments. This was chosen due to LabVIEW having myRIO templates for important components, as well as the large number of support articles online produced by National Instruments, university students, and industry professionals.

The myRIO will be utilized for data acquisition, or DAQ, and controls for the ROV. A major benefit of using the myRIO and LabVIEW is the ability to perform DAQ tasks, which can be simplified into the following process: a sensor converts a physical phenomenon to an analog electrical signal (voltage, current, resistance, or another electrical attribute that varies over time). Then, a data acquisition device (the myRIO) converts the analog signal to a digital signal (either a 1 or 0) for a computer to interpret. During the initial reception of the analog signal the DAQ device will condition the signal (amplify, excitation, etc.), convert the signal to digital, and send the digital signal to the computer bus (system that transfers the data). The same process, but in reverse can be used for controlling certain components of the ROV. For example, accelerometer data is sent to the computer bus where, using LabVIEW, is programmed to be shown as a specific yaw, pitch, and roll. Using a joystick or other method the pilot then tells the ROV to move, which is done by sending a specific voltage (which correlates a specific thruster speed) to an individual thruster.

The electronic circuitry has not yet been designed since all necessary electrical components to be used in the electrical system (such as resistors, capacitors, circuit boards, etc.) have not been quantified. Certain constraints have been given by MATE in regards to the amount of power allowed and how that power must be converted. MATE 2017 constrains each ROV to a maximum of 48 volts and 30 amps DC. It also dictates that all power conversion must be done onboard the ROV, and that no onboard electrical power (battery) is permitted. These constraints will force Team Nautilus to innovate their electrical system to satisfy all rules.

Electronics Enclosure

For the electronics to function under water, a water-tight pressure hull must be incorporated into the design. The hull will house all the electronics and circuitry, as well as the pneumatic components. The pressure hull (addressed as the electronics enclosure from here on) will not only provide a water-tight enclosure to protect the electrical and pneumatic components, but also provide buoyancy to the ROV.

There are several key factors that must be considered when designing the enclosure. One of which is the depth at which the ROV will be operating at. For the MATE 2017 competition the maximum depth encountered will be 3.7 meters. By utilizing Pascals Law the pressure at that depth can be calculated (Appendix I), which was determined to be approximately 5.26 psi. The second key factor that must be considered in the design is the shape of the enclosure, and surface area on which the fluid acts on. The shape of the enclosure strongly affects the ability to withstand the hydrostatic pressure without deforming. The two most common pressure resistant shapes are spheres and cylinders. The third key factor that should be considered is the material the enclosure is to be built with. The enclosure should be built with materials that have a high strength-to-weight ratio to minimize the mass of the ROV, but still provide enough strength to withstand the hydrostatic pressure.

Considering these key factors two preliminary designs were created (Appendix F). The first model is cylindrical with a spherical nose. This design utilizes pressure-resistant shapes, as well as a streamlined nose to assist in lowering the drag while maneuvering. The second design is a rectangular enclosure. Although the rectangular enclosure is an uncommon design, it was created because of the greater surface area that would assist in dissipating heat from the electrical components. A downfall of this design is the inability to compensate for deformations caused by the hydrostatic pressure. A way to mitigate this design flaw is to include a fluid diaphragm; the key property of the diaphragm is bulk modulus of the fluid inside of it. This allows the diaphragm to deform by displacing the fluid instead of deforming the enclosure itself.

Analyses have been conducted on both designs in order to determine their effectiveness at the pressure that the ROV will be operating at. The analyses have shown that the resulting stresses are far below the yield stress of aluminum, which was used as the material for analysis purposes. Currently, no final decisions have been made as to which design we will use, however, we plan to make this decision soon.

Project management

The project management aspect of this project is tracked my Microsoft Project. The Work Breakdown Structure (WBS) was initialized in Project with the high-level tasks involved in the project. The high-level tasks were than broken down into lower level task and continued until the lowest level work elements were identified. A preliminary timeline was created and the overall project Gantt Chart was formed. These items are used to guide us in our progress throughout the project. The critical path to compete in the MATE competition was found and the project timeline was modified to facilitate the completion of these items and have the other extra deliverables as peripheral tasks as we feel the most important aspect of this project is to represent the University of Houston College of Technology in the MATE competition.

Member Contribution

To keep all members involved we implemented a weekly meeting, usually held on Sunday afternoon. During our weekly meeting, the team takes care of the administrative tasks of the project. The accomplishments of the previous week are discussed as well as the shortcomings. The team works to mitigate obstacles that are preventing us from meeting our weekly goals. The goals for the upcoming week, the longer foreseen goals are identified and broken down into smaller portions so they can be completed in smaller tasks in a short time frames. The team believes if we can make and meet these small goals the larger objectives will be met.

Cost & Man hours Estimate

Through the first stages of the project, an initial cost and time estimate were created. Initially, it is estimated that the cost of the project to total $15,312.50 with a need of 2326 man hours. As the project, has continued, the budget has been updated as decisions have been made. The categories that have been updated include the frame, logic system, and drive system. The improvement in the budget for the frame arose from the decision to utilize common standard sizes in the design (Appendix D). The drive system budget was improved after the decision to use the Blue Robotics T200 thrusters was made (Appendix E). A summary of the overall improvement to the budget can be seen on the last column in the table below.

Activity

Approximate Time (hours)

Approximate Cost

Updated Approximate Cost

MATE documentation

120

$0

$0

Frame Design

120

$0

$0

Articulate Arm Design

160

$0

$0

Logic System Design

160

$0

$0

Drive Design System

240

$0

$0

Remote Interface Design

160

$0

$0

Waterproof Enclosure Design

160

$0

$0

Build Frame

180

$2,200

$1,000

Build Arm

200

$2,400

$2,500

Build Logic System

180

$2,700

$1,100

Build Drive System

240

$2,500

$1,300

Build Remote Interface

150

$1,500

$1,500

Assemble ROV

160

$500

$500

Test ROV

80

$200

$200

Register for MATE

16

$250

$250

Contingency

$3,062.50

$1,253

Totals

2326

$15,312.50

$9,603

Figure 2- Initial Cost Time estimate

The cost estimate is a living document, and will change as the semester progresses.

Risk Matrix

The first step in this process was to identify the potential problems that could hinder the completion of the ROV. This was accomplished during a team meeting and through group collaboration. The following list identifies the areas for concern: fundraising, materials and product selection, lab view programming, MATE completion, system integration, communication, system complexity, time management, sub systems, weight, registration, and team member contribution. The next step was to go down the list and as a group rate the probability that a problem will occur. Once this was accomplished the team went back down the list, and designated the severity or impact the problem would have on the overall project if it was to occur. Once this was accomplished the team made a list of solutions for the problems and list of ideas to reduce the probability of a problem occurring. The risk matrix created is shown in Appendix A.

Risk Mitigation

One of the problems the team has identified is fundraising. Some of the ideas to mitigate this issue would be attending the 2016 Marine Technology Society BBQ, networking, and budget cuts. The next risk identified was the Procurement and selection of materials. Some of the possible solutions for the problem are a group decision on dropping particular deliverables, and design modification. Another risk that the group will encounter is programming in LabVIEW, to reduce the risk of included early research and contact mentors for advisement. Another solution considered for this issue is contacting computer science majors within the University of Houston. Another possible risk is group communication. Some of the things the group currently does to decrease the likely hood of this occurring is the creation of a group text, Team email, and weekly meeting. Then other possible solutions the group has agreed on are to involve the professor and have an intervention, voting the member out of the group or put on probation. For this extreme action to take place there would have to be a unanimous vote between the three members. These are just a few examples of problem analysis that have been planned for by the group. These plans ensure that if a problem is to arise, the team is ready and has a plan of action or contingences to fall back on to reduce the overall effect of the problem.

Risk Progression

As the semester, has progressed, the risk matrix has been updated accordingly. These changes can be seen in Appendix A. Most these changes resulted in risk categories moving higher in the matrix. These changes include the material procurement, programming, MATE 2017 mission, communication, weight, registration, and member contribution. The increase in risk for the materials procurement resulted from the realization and understanding of the high reliability on fundraising. The programming risk increased due to the high complexity of the system. The MATE 2017 mission risk increased because of the unknown aspect of it since not all mission details have been released. The team came to an agreement that the communication risk needed to be increased because of the unsustainable momentum from the start of the project as other school-related obligations have arisen. A key difference that should be noted is the removal of the subsystems risk within the matrix. This was removed since system integration is already a major risk category, thus making subsystems redundant. The weight risk increased due to the materials selection balance that will be necessary to satisfy the MATE 2017 requirements. Similarly, the registration risk rose due to the increased MATE 2017 registration requirement. Finally, the last risk category that increased was member contribution. The justification for this increase being that a single team member could begin to lose scope on the overall project by focusing on one specific subject.

Risk over time

One of the unique pieces of our project management is our representation of the assumed risk as it changes through the progression of the project. As represented in Appendix A, the original assumed risk is shown as the black envelope in the polar graph, the risk as of the second presentation is shown in blue and the current is represented in red. As the risk value increases, the plotted point is moved further from the center and as the risk is reduced the point is moved closer to the center. The area inside the envelope created by these plots is the total assumed risk for the project. It can be noted that moving from the first Black envelope to the Blue the area of the envelope increases. This indicated an increase in project risk. This was a direct result of the feedback given to us by our advisors about the large scope of our project and not enough consideration for some of these risks were given. Moving from the Blue to the red envelope the area decreases as some of the risks have been effectively mitigated. Some of the risks remained at the same level as they are still critical points in the project that will continually need to be addressed.

Milestones & extras

The team has made several decisions on meeting location and team building events to benefit the group as a whole and encourage team bonding. The team quickly made the decision to have a weekly meeting at the team leaders house. This was an easy decision as he is centrally located to all other group members. A majority of the members live close to this location and it is easily accessed due to the freeway set up in Houston. These meetings have created unity amongst the team and helps to keep group members on task. A major accomplishment for the team was finding Ryan Payne as a mentor early in the project. The team could interview Ryan before the CTR was approved. The team again utilized car-pooling to maximize group bonding, reduce overall gas consumption, and minimize the overall environmental footprint of the group.

Teambuilding is viewed by the group as an essential requirement necessary for cohesion and ultimate success. Teambuilding events are an investment into the group. This time could otherwise be used to design, analyze or contribute to the project, however, the team agreed that a strong bond can prevent future frustrations which could lead to greater inefficiencies. Two teambuilding events that have been set up to go camping event and have a family BBQ. The team feels that it is important to build moral, and bring the groups family members together to strengthen the team.

Appendix A Risk Matrix

Risk Matrix created 10/2/16

Risk Matrix created 11/8/16

Risk Matrix created 12/06/16

Risk

1 Fundraising

2 Material procurement

3 Programming

4 MATE 2017 mission

5 System integration

6 Communication

7 System complexity

8 Forward progress

9 Weight

10 Registration

11 Member contribution

Mitigation

Team NautilusPage 56 of 57

1 MTS BBQ & local contacts

2 Fundraising & donations

3 Started programming & CIS tech students

4 Integrate into planning

5 Constant communication

6 Peer review

7 Mentor assistance

8 Milestone & benchmarking

9 Material selection

10 Register ASAP & social media connection

11 Backup member & peer review

Risk through time

Appendix B Timeline and Gantt chart

Appendix C - Manipulator Design

Appendix D Frame Design

Appendix E Thruster Design

Appendix F Electronics Enclosure Design

Model 1Model 2

Appendix G Layout Drawings

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

All dimensions in inches

Use standard tolerances unless specified

Appendix I Electronics Enclosure Calculations

Appendix J CAD Project Case Study

The following case study was conducted by Team Nautilus for a mid-term project within MECT 3365 Computer Aided Design I.

The following appendix is the entire study and is to be used for reference only.

PAGE NUMBERS FOR THIS CASE STUDY ARE NOT INCLUDED.

Works Cited

[1] American Peteroleum Institute, "Remotely Operated Tools and Interfaces on Subsea Production Systems 17H," API Publishing Institute, Washington, DC, 2014.[2] MATE Center, "MATE - Marine Advanced Technology Education :: ROV Competition Home," 29 August 2016. [Online]. Available: http://www.marinetech.org/files/marine/files/ROV%20Competition/2017%20competition/Missions/2017%20Competition_Product_Demo_Spec%20briefing_FINAL.pdf. [Accessed 6 September 2016].[3] Oceaneering International Inc., "ROV Services," OCEANEERING, 2016. [Online]. Available: http://www.oceaneering.com/rovs/. [Accessed 8 October 2016].

Presentation 1FundraisingMaterial procurementProgrammingMATE 2017 missionSystem integrationCommunicationSystem complexityForward progressWeightRegistrationMember contribution2061022010169626Presentation 2FundraisingMaterial procurementProgrammingMATE 2017 missionSystem integrationCommunicationSystem complexityForward progressWeightRegistrationMember contribution20202092015169121612Presentation 3FundraisingMaterial procurementProgrammingMATE 2017 missionSystem integrationCommunicationSystem complexityForward progressWeightRegistrationMember contribution202020910899883

FundraisingPresentation 1Presentation 2Presentation 3202020Material procurementPresentation 1Presentation 2Presentation 362020ProgrammingPresentation 1Presentation 2Presentation 3102020MATE 2017 missionPresentation 1Presentation 2Presentation 3299System integrationPresentation 1Presentation 2Presentation 3202010CommunicationPresentation 1Presentation 2Presentation 310158System complexityPresentation 1Presentation 2Presentation 316169Forward progressPresentation 1Presentation 2Presentation 3999WeightPresentation 1Presentation 2Presentation 36128RegistrationPresentation 1Presentation 2Presentation 32168Member contributionPresentation 1Presentation 2Presentation 36123Average Risk ScorePresentation 1Presentation 2Presentation 39.727272727272726615.36363636363636311.272727272727273

Probability (5) x Severity (5)

8.00

1.50

.25

1.00

3.00

ME

CT 4276-S

enoir Design

Team N

autilusS

ize: AD

rawing: F1-P

1S

heet: 1S

cale: 2:1

Sheet 1ViewsVIEW_TEMPLATE_1VIEW_TEMPLATE_3bottom_4

2.00

45.00

.50

1.50

2.00

2.50

ME

CT 4276-S

enoir Design

Team N

autilusS

ize: AD

rawing: F1-P

1S

heet: 1S

cale: 2:1

Sheet 1ViewsVIEW_TEMPLATE_1VIEW_TEMPLATE_2VIEW_TEMPLATE_3

1.00

10.00

.25

ME

CT 4276-S

enoir Design

Team N

autilusS

ize: AD

rawing: F1-P

5S

heet: 1S

cale: 2:1

Sheet 1ViewsVIEW_TEMPLATE_1VIEW_TEMPLATE_3

10.00

.251.00

1.00

ME

CT 4276-S

enoir Design

Team N

autilusS

ize: AD

rawing: F1-P

7S

heet: 1S

cale: 2:1

Sheet 1ViewsVIEW_TEMPLATE_1VIEW_TEMPLATE_3

decision matrix coststrengthdensitySGmachinability

6061 AL2.722

Acrylic1.194

Fiber Glass1.422

Steel ASTM1087.889

Carbon Fiber1.389

3D print0.000

Wood0.594

PVC1.111

Delrin1.500

nylon1.139

ksilbs/in^3

$5.228.000.041easy

$11.478.700.054difficult

0.0214

0.04

good

good

easy

0.098

0.043

0.0512

0.284

0.05

???

difficult

good

difficult

good

easy$0.35

$4.47

35.00

8.1-11.25

7.0-40.0

54.00

232.00

need baseline

8.60

4.50

$4.03

$5.82

$6.80

$14.59

$30.00

???