AA Testing Procedures

Introduction

The final solution of the ROV frame must be integrated with the other systems of the ROV such as the mechanical arm, cameras and electrical steering. The frame must be as close to neutrally buoyant as possible, able to properly mount electronic systems, provide smooth steering, enough steering power to accommodate the weight of the ROV and be able to survive underwater conditions such as depth and pressure. The ROV frame must be able to steer with all the equipment on board smoothly and efficiently and provide a stable neutrally buoyant platform for the mechanical arm. Each area of testing involves the ROV frame, propulsion system and ballast. Team member Andrew Ahn will both administer testing and record and judge the results of testing. Majority of the testing will take place underwater in tanks and pools to simulate slight depth pressure.

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Drawing

Condition of Testing Stage: Conceptual
Conditions of Testing Area: on paper

Tools and Equipment Required: Paper, pencil, ruler, eraser and research notebook

Testing Procedures:
1. Review research and brainstorming materials
2. Draw/sketch alternative solutions
3. Post onto blog, bring into class for teacher assessment
4. Assess functionality, usability, ease of production and cost effectiveness

Testing type: Exploratory

Testing Stage: Secondary

State of Solution: Design matrix

Condition of Testing Stage: Conceptual
Conditions of Testing Area: On paper

Tools and Equipment Required: data table

Testing Procedures:
1. Construct a grid
2. Determine grid size using specs and limits and design solutions
3. Determine a rating scale
4. Rate each solution using a specific criteria
5. Add points together
6. Determine highest scoring solutions
7. Combine or move forward with best solutions

Testing type: Exploratory

Testing Stage: tertiary

State of Solution: model

Condition of Testing Stage: to scale (half scale)
Conditions of Testing Area: On paper

Tools and Equipment Required: 0.5 inch PVC piping and joints, Lego pieces and Lego propellers, foam pool noodles and 8 inch zip ties

Testing Procedures:
1. Acquire design solution 3
2. Measure half scale of design solution 3
3. Begin cutting PVC piping to half scale of design solution 3
4. Assemble base of ROV frame
5. Set three way joints to forty five degrees
6. Slip three inches of pool noodle onto PVC pipe which will go on wing structure
7. Assemble all PVC piping and joints according to design solution 3
8. Zip tie pool noodles onto PVC piping
9. Zip tie Lego parts onto PVC piping according to drawing

     

Testing type: Assessment

Testing Stage: Preliminary

State of Solution: Final Construction 

Condition of Testing Stage: Stationary
Conditions of Testing Area: Wet

Tools and Equipment Required: Ballast tanks, container of water

Testing Procedures:
1. Fill tub completely with water
2. Place the ballast tanks inside the tub
3. Allow ballast tanks to float for at least five minutes
4. Remove ballast tanks and shake contents
5. Listen for sound of water and check water tightness
6. submerge ballast tanks for at least five minutes
7. Repeat steps 4 and 5

Testing type: Assessment

Testing Stage: Secondary

State of Solution: Final Construction

Condition of Testing Stage: Stationary
Conditions of Testing Area: Wet

Tools and Equipment Required: ROV frame (no ballast), swimming pool

Testing Procedures:
1. Ensure ROV frame is properly glued and aligned
2. Place ROV frame into pool
3. Submerge ROV frame to bottom of pool depth for five minutes
4. Remove ROV frame from pool and check for water tightness of glue

Testing type: Assessment

Testing Stage: Tertiary

State of Solution: Final Construction

Condition of Testing Stage: Stationary
Conditions of Testing Area: Wet
Tools and Equipment Required: Fully assembled ROV frame, swimming pool

Testing Procedures:

1. Ensure ROV frame is properly glued, aligned, assembled and secured (ballast tanks)
2. Place ROV frame into pool
3. Let ROV sit in pool to ensure positive buoyancy
4. Submerge ROV frame using swimmer to the bottom of the pool
5. Remove ROV frame from pool and check assembly and water tightness
 

Testing type: Assessment

Testing Stage: Primary

State of Solution: Final Construction

Condition of Testing Stage: Stationary, on
Conditions of Testing Area: Dry

Tools and Equipment Required: 5 volt motors, wiring, arduino, designated power source

Testing Procedures:
1. Wire motors to arduino
2. Wire all components together
3. Turn on power
4. Ensure that drive shaft of motor is spinning

Testing type: Assessment

Testing Stage: Secondary

State of Solution: Final Construction

Condition of Testing Stage: Stationary, on
Conditions of Testing Area:Dry

Tools and Equipment Required: assembled propulsion systems wiring, arduino, designated power source

Testing Procedures:
1. Wire motors to arduino
2. Wire all components together
3. Turn on power
4. Ensure that propellers and drive shaft are spinning
5. Reverse polarity of current from the arduino
6. Ensure that propellers and drive shaft are spinning in opposite direction

Testing type: Assessment

Testing Stage: Tertiary
State of Solution: Final Assembly

Condition of Testing Stage: Stationary, on
Conditions of Testing Area: Wet

Tools and Equipment Required: Propulsion systems, wiring, arduino, designated power source, swimming pool

Testing Procedures:
1. Wire motors to arduino
2. Wire all components together
3. Submerge assembled propulsion system units into pool
4. Turn on power
5. Ensure that propellers and drive shaft are spinning properly and smoothly
6. Reverse polarity of  the current from the arduino
7. Ensure that propellers are spinning in opposite direction and smoothly
8. Turn off motors
9. Remove motors from pool
10. Ensure that water tightness and electrical wiring are not compromised
 

Testing type: Assessment

Testing Stage: Quaternary

State of Solution: Final Assembly

Condition of Testing Stage: Mobile, on
Conditions of Testing Area: Wet

Tools and Equipment Required: Assembled ROV frame (with propulsion systems), Swimming pool

Testing Procedures:
1. Wire all propulsion system units to arduino
2. Wire all components together
3. Place assembled ROV frame into water
4. Observe ROV, determine if ROV is positive or negatively buoyant
5. Submerge ROV to bottom of pool
6. Turn on motors, begin maneuvering ROV
7. Ensure that motors are smoothly operating
8. Stop motors
9. Reverse polarity of electrical current from arduino
10. Ensure that motors are smoothly operating
11. Turn off motors
12. Retrieve ROV
13. Check for water leaks, ensure ROV frame's water tightness is intact

 

Testing type: Validation

Testing Stage: Primary

State of Solution: Final Assembly

Condition of Testing Stage: Mobile, on
Conditions of Testing Area: Wet

Tools and Equipment Required: ROV frame, ROV mechanical arm, ROV cameras and electrical face, swimming pool

Testing Procedures:
1. Mount arm onto ROV
2. Place assembled ROV onto water
3. Determine buoyancy of ROV
4. Submerge ROV
5. Turn on mechanical arm
6. MECHANICAL ARM TESTING IN PLACE
7. ELECTRICAL SYSTEMS TESTING IN PLACE
8. Turn on propulsion systems
9. Maneuver arm and propulsion systems simultaneously

Testing type: Validation

Testing Stage: Secondary

State of Solution: Final Assembly

Condition of Testing Stage: Assembled, mobile and functional
Conditions of Testing Area: Wet

Tools and Equipment Required: Fully assembled ROV, screens, controller, swimming pool, testing site and simulation

Testing Procedures:
1. Set up testing site and simulation
2. Place ROV in water to ensure water security
3. Test cameras, arm and propulsion systems
4. Begin simulation by picking up rings and dropping them into crates underwater
5. Record any observations, problems and times

sample ROV challenge

Neptune Aquatic Center

 

Model

The model depicted below is a close representation of design 3 alternative solution. The model is exactly half size of the actual solution and is constructed of PVC half inch diameter PVC piping. Rather than using pool noodles for a source of positive buoyancy, closed system PVC piping filled with air was used to provide buoyancy. Lego pieces represent locations for vertical and horizontal propulsion.

Figure 1: front view of model

Figure 2: side view of model

Figure 3: top view of model

 

AA Rationale

Introduction: ROV Frame and Propulsion

The ROV team must design and construct an ROV system that is capable of being submerged and remotely performing tasks like picking up underwater rings using a mechanical arm and placing them into crates in separately designated locations. Each team member is given a certain task and area of research and development. The rationale below is focused towards the area of frame and propulsion for the ROV. Summer work involving research and development and two months of joint team meetings have contributed to four separate designs for the ROV frame and propulsion systems. 

Alternate Solution 1

Introduction

Alternate solution one resembles a rectangular prism using PVC piping as the frame. The top front section is missing to reduce drag; it is also non-essential for structural support since PVC is used. The piping is jointed together using 90 degree and three way joints. A cross section is located in the middle of the frame. Two motors for horizontal propulsion and one for vertical propulsion are placed on the cross section. The top of the frame holds ballast for positive buoyancy.

Pros

Solution one is stable and relatively easy to maneuver due to the cube like shape. The geometric shape makes solution one easy to construct and design. Solution 1’s hydrodynamics through the water is also stabile due to the shape and location of vertical and horizontal propulsion. PVC construction also makes design one relatively cheap to build.

Cons

Solution is simple yet effective but does not specialize for any type of mission. The shape and location of propulsion is typical of most ROV’s and is not special for any one mission. The only adaptation for a mechanical arm is the absence of the top forward cross section. The prism like shape also makes the ROV look boring and gives the wrong mood for the mission.

Conclusion

All in all, solution one is a good, simple and sturdy design. Yet, it is too generic of a ROV for the specific mission and use of a mechanical arm. The prism like design also gives the incorrect mood of exploration and adventure. But the construction of PVC makes constructing and purchasing materials very easy.

Alternate Solution 2

Introduction

Alternate solution two is constructed of plastic pieces from common physics demo kits. The plastic pieces themselves are perforated with small holes through the entire length of the rods. The frame is in the shape of a cube with two support struts at the rear of the frame to provide stabile mounting for the propulsion systems. Empty film canisters serve as positive buoyancy ballast atop the frame.

Pros

The cube shape allows for easy handling and maneuverability through the water. The use of plastic physics kit pieces makes purchasing materials cheap or easy to look for. The plastic physics kit pieces also make the frame easy to build and manipulate wherever needed.

Cons

One drawback of design two is the cube shape. The cube shape prevents room for a mechanical arm to maneuver within the frame and allows for less room to mount equipment. The method to assemble the pieces also reduces the amount of weight it can carry since the plastic rods cannot stick together with too much stress.

Conclusion

In conclusion, design two provides a small cube like frame made of plastic physics kit rods. It allows for easy assembly and purchase but it means that it is weaker and has structural issues. The cube shape gives some more structural integrity but it also hinders the movement of a mechanical arm and room to mount potential equipment.

Alternate Solution 3

Introduction

Alternate solution three is slightly different from the other solutions. Design three also uses PVC piping and pool noodles for flotation, but the shape is what sets it apart. The bottom of the frame is a flat rectangular plane. The frame possesses wing like projections, which are flared out from the bottom of the frame at a forty-five degree angle. At the top of the “wings” are the foam ballast to provide some positive buoyancy to the craft. The horizontal propulsion motors are located at the rear of the “wings”; the vertical propulsion motors are located toward the left and right sides of the bottom of the frame.

Pros

The PVC construction of the frame makes purchasing materials cheap and construction simple. The wide and positively buoyant top of the craft make the entire frame very stabile. Since the base of the craft is heavier and narrower than the top of the craft, the frame remains steady during maneuvering due to basic physics. The wide top and narrow base also gives much more room for the mechanical arm to maneuver and to mount electrical equipment on the frame. Horizontal propulsion is located mostly toward the rear of the craft to account for the weight of the mechanical arm and the vertical propulsion is located in the middle of the craft. The locations for propulsion make handling smoother.

Cons

The wide top and narrow base of the frame may make maneuvering and steering stabile and smooth but speed is slower. The wider the frame the more drag is in the water. Although the horizontal propulsion compensates for the weight of the mechanical arm, it also means that left and right turning is not very accurate since steering is not located directly in the middle of the frame.

Conclusion

Overall, design three is the most stabile of all four alternative solutions. The splayed “wings” allow for greater control and stability of the craft during maneuvers and allows for more to mount the mechanical arm as well as electrical equipment. The PVC construction makes purchasing parts cheap and assembling them easy. But, the wide top frame makes turning slow and cumbersome. Horizontal steering located towards the rear also makes turning a bit of a hassle.

Alternate Solution 4

Introduction

Design four is also constructed of PVC piping for the frame. The entire frame is essentially a flat plane. The top of the frame uses empty bottles, which can be filled or emptied of water to control buoyancy on the craft. The bottom of the craft has small PVC pipes, which can be filled with weight to further help balance the weigh of the craft. The middle of the frame is empty and filled with either plastic or metal netting to allow equipment to be mounted in the middle of the rectangular frame.

Pros

The frame is very cheap and easy to manufacture. Parts are easily accessible and equipment can be easily mounted to the frame.

Cons

Since the frame has no vertical structures the frame is somewhat unstable. Balancing the craft is hard and the movement of the mechanical arm may cause the frame to list during maneuvers.

Conclusion

To conclude, the design is essentially too simple for the tasks the ROV must be able to perform. The flat plane design is too unstable and risky to use. But the PVC piping with weights is a great way to help bring the frame to neutral buoyancy.

Overall Conclusion
After using a rationale chart to determine the highest scoring designs, design three had the highest point score. Design three of all four designs was the most stabile because the ballast system was spread farther than the base of the ROV frame. Because the ballast is removed farther from the actual frame and there is no overhead support struts or structures, the ROV frame allows for more storage capability in terms of electronics and mechanical equipment such as a mechanical arm. However, the wide ballast structure also makes turning slightly more difficult. Lastly, an additional PVC pipe running down the center of the frame needs to be added due to mounting concerns for the mechanical arm.



AA Rationale Chart

Specifications	Design 1	Design 2	Design 3	Design 4
Stability	4- very stabile, little chance of listing	3- sufficiently stabile, provides a good base for maneuvering	5- extremely stabile frame, little to no chance of flipping or heavy listing	1- very unstable, high chance of listing or tipping
Manufacturability	3- average, easy to find parts but numerous pieces	3- average, easy to find parts but numerous pieces	4- easy to find parts and few pieces to put together	5- easy to manufacture and find parts, few pieces
Cost	3- PVC piping	4- plastic demo kits	3- PVC piping	3-PVC piping
Mood	3- average, somewhat scientific not very adventurous	2- below average, appears to playful	4- good, appears adventurous and scientific	4- good, appears adventurous and scientific
Maneuverability	4- maneuvers well	4- maneuvers well	2- maneuvers steadily but very slowly, lots of drag	1- difficult to turn and maneuver
Space	3- average amount of space, enough room for arm and equipment	2- not enough space for arm plus equipment	5- more than enough room for arm to maneuver and to fit equipment	5- more than enough room for arm to maneuver and to fit equipment
Total Score	20	18	23	19
Average Rating	3.333	3	3.8333	3.1666
Rank	2	4	1	3

AA Alternative Solutions

Design 1

       Design one's frame primarily consists of PVC piping and jointing. the entire hull resembles a rectangular prism except it is missing the front top cross section. The top cross section is absent to reduce drag through the water while also retaining as much rigidity and structural stability as possible. 

The absence of the cross section also slightly lowers the total weight of the frame and allows more room for mounting equipment. PVC piping was used because of its structural strength and because it is fairly cheap, easy to manipulate and easy to mount equipment to. PVC piping is significantly cheaper than aluminum kits or acrylic molding.

       Majority of the equipment such as the mechanical arm and cameras can be easily attached to the ROV by simply using zip ties or aluminum fasteners which are screwed into place. Before assembling the ROV, holes can easily be drilled into the piping to use as mounting points and can later be sealed.

       Design one also has a cross section running through the middle of the frame laterally. The cross section is meant as a mounting point for both vertical and horizontal propulsion systems. Since the design resembles that of a prism, the most stable point to mount any propulsion would be in the middle of the frame. When placed in the middle of the frame, the hydrodynamics across most surfaces become even throughout the entire craft. This allows for smoother turning and handling.

       This frame also uses foam pool noodle ballasts for positive buoyancy. Foam pool noodles are easy to find, are cheap and are very easy to cut and mount. If the positive buoyancy is too great, than some of the foam ballast can be jettisoned and adjusted to the overall weight of the craft. 

        Design one also incorporates small DC RC motors for propulsion through the water. All other designs share this because small RC motors are cheap, easy to find, easy to waterproof and provide ample propulsion for their small size. 

Figure 1: Design 1 side view

Figure 2: Design 1 Front View

Figure 3: Design 1 Top View

Figure 4: Design 1 Isometric View

Figure 5: Design 1 Front, Top and Side View

Design 2

       Design two's frame is not constructed of PVC plastic tubing, rather it uses plastic parts found in hobby shops and numerous physics build kits. these plastic pieces are strong, rigid and are extremely easy to use and put together. These rods come in numerous different sizes and lengths and are similar to how legos or k'nex fit together. These rods snap together because of the tips on the ends and the holes in the center of each rod. Since the plastic is also strong, put together the rods are able to handle a sizable load. Since the rods also have holes in them, they provide additional points for mounting equipment such as cameras or wires.

       The frame is almost literally a cube, since the rods are not exactly as strong as PVC piping, a stable shape or design is required. But, the cube shape also allows for smooth easy handling. Due to the fact that a cube is symmetrical anywhere, the water flow across the surfaces is even. This allows for controlled handling through the water. 

       Although this frame is expected to carry as much weight and equipment as other designs, not as much ballast is needed for positive buoyancy. The plastic is much lighter and less dense than PVC piping. So, empty film canisters glued shut act as positive buoyancy. The film canisters are located along the top rails to provide stability when ascending or descending depth.

       When mounting equipment, zip ties can be used again or plastic fencing/netting  can be placed at the bottom of the frame to create a stable platform in which equipment can be strapped to. The mechanical arm can be laid across the bottom of the frame where the netting is located or it can be strapped across the side of the ROV.

       Design two again takes advantage of the small DC motors to propel itself through the water. The back area of the frame has two bars running down from the top rear cross section down to the bottom of the frame. The purpose of these two bars is to provide a specific mounting point for the two RC motors. The two bars will sandwich the motor and give a snug stable area for the motors to mount on. 

Figure 6: Design 2 Front View

Figure 7: Design 2 Top View

Figure 8: Design 2 Side View

Figure 9: Design 2 Isometric View

Design 3

       Design three's frame takes on an interesting shape. The bottom of the frame is a simple rectangle; but, rather than have the sides of a cube the frame splays our wing like projections at a forty five degree angle. With positive buoyancy at the tops of these wings it allows the craft to be extremely stabile and allows much more room at the base of the frame for mounting any and all equipment. However, with the craft being stabile, turning will be difficult and slow.

       The wing like projections also have ballast at the top cross section. With the wings splayed at a forty five degree angle more room is allow for equipment. The ballast again will be foam pool noodles because of their cheap price, versatility and ease of use. Because the top of the frame is wider than the base, it offers a steady platform because the ballast is located so far from the base.

       The propulsion is also small RC motors. The horizontal propulsion motors are located behind the last vertical section of the wing. With a high and wide ballast, the horizontal propulsion no longer needs to be exactly centered. The vertical propulsion is on the PVC pipe in the middle of the frame. Although the ballast does make the craft more stabile, the vertical propulsion should stay in the middle. If the propulsion is off center than the whole craft may tip.

       Design three may be cumbersome in size and appearance both the wide upper frame allows for a steady platform to mount equipment and the mechanical arm. The wing like projections also allows ample room for cameras and such. But, the wide frame also causes more drag which in turn causes the ROV to move slower through the water. 

Figure 10: Design 3 Front View

Figure 11: Design 3 Side View

Figure 12: Design 3 Top View

Design 4

       Design four is a simple plane design. The entire frame is essentially a submerged barge under the water. The frame is made of PVC again since it it so easy to mount equipment on. However the ballast is completely different. The ballast consists of plastic bottles which can be filled with air and water to control the amount of positive buoyancy. These bottles are placed on the outside edges of the frame to provide stabile lift and to prevent the frame from wobbling or tipping.

       Additionally, weights are placed underneath the the craft right next to each other. These weights are PVC pipes that will be filled with BB or lead shots to accurately control the weight of the craft and to bring it as close as possible to neutral buoyancy. These weights are placed underneath the flat base centered and right next to each other. 

       Small RC motors again provide propulsion. Vertical propulsion is located on the outside of the frame next to the plastic bottles. Horizontal propulsion is located toward the rear of the craft behind everything including ballast. 

       The middle of the base contains either hard plastic non corrosive metal netting in which the mechanical arm and additional equipment can be laid across. 

Figure 13: Design 4 Side View

Figure 14: Design 4 Top view

Figure 15: Design 4 Front View