Construction: Final Design Solution

ROV Demonstration Video

This video shows the situation that our team will be facing. The challenge of picking up and placing the rings in designated areas are also shown in this video. (20 second mark demonstrates the best visual of the situation)

 

 

 

 

 

 

Plan of Procedures

 

Plan of Procedures for the SeaPerch ROV Mechanical Arm



 

       The mechanical arm will be produced from all of the materials listed below. The individual roles for the final solution are listed in the notes section of the materials list besides purposes that are self explanatory. The mechanical arm consists of two servo motors that perform the open and closing mechanism for the claw and the up and down motion for half of the arm. The hull will be the stationary platform holding the arm in place. The assembly work ranges in difficulty from easy to detailed and specific. The image below shows about what the final product should look like.

 

 

 

Supplies
Number	Material	Quantity	Size	Notes
S2	Electrical Tape	1	Roll	Securing wires
S3	PVC Primer	16 oz.	n/a	Connecting PVC
S4	PVC Glue	16 oz.	n/a	Connecting PVC



 

     Some of the parts are made using the following tools. The PVC, or outside housing (P2) for the mechanical arm must be cut to the proper length and attached using bolts (P1), gears (P3), and servos (P4). The wiring will all be handled by our electrical engineer. Electrical tape (S1) will be used to secure the wires inside the PVC housing.

 

Tools List
Number	Tool	Quantity	Use
T1	Ruler	1	Measuring length of PVC
T2	Saw	1	Cutting PVC to proper length
T3	Clamp	1	Holding PVC in place while being  cut
T4	Pencil	1	Draw lines where to cut
T5	Drill Press	1	Put holes in PVC
T6	Scissors	1	Cut electrical tape
T7	Wrench	1	Securing Bolts

 

Parts List
Number	Part	Quantity	Size	Notes
P1	Bolts	15	1" (TBD)	Secure objects to structure
P2	2" PVC (Outside Housing)	2	2 feet	Cases motors and makes up arm structure
P3	Gear	5	1 inch (TBD)	Attaches to claw and through gear
P4	Servo	2	1.65” x 0.83” x 1.57"	Moves claw and arm motion
P5	Curved Plastic	2	3 inches	Makes up claw
P6	Aluminum Axel	3	2 inches (TBD)	Attaches gear to claw

 

Step 1: Cut PVC to proper dimensions

 
1. Using a pencil (T4) and ruler (T1), mark out the 2" PVC (P2) into two 10" pieces from the end.
2. Using the saw (T2), cut on the lines made to make to 10" PVC pieces.
3. Using a pencil (T4) and a ruler (T1), mark out holes 2" from each other, lengthwise on the PVC pipe on both sides.
4. Use a drill press (T5) to cut out holes in the areas you marked.

Step 2: Create the claw

1. Take the curved plastic (P5), aluminum pole (P6), and gears (P3).
2. Place the aluminum pole (P6) into the hole in the gear (P3) and glue (S4) to seal the pieces in place.
3. Take the curved plastic (P5) and the aluminum pole (P6) and gear (P3) piece, attach the curved plastic (P5) to the piece using glue (S4).

Step 3: Put together the mechanical arm

1. Take one servo (P4) and two bolts (P1) and bolt the servo 2-1/2" into the front portion of the 10" PVC pipe. This will be where the claw attaches.
2. Place the claw created with gears (P3), aluminum poles (P6), and curved plastic (P5) into the front portion of the 10" PVC piece you just created, aligning the gears with that on the servo.
3. Take the second servo (P4) and two bolts (P1) and bolt the servo into the other 10" piece of PVC
4. Take the last aluminum pole (P6) and place it through the hole in one gear (P3).
5. Place the aluminum pole (P6) and gear (P3) 1/2" into the first 10" PVC on the opposite side of the servo. Using glue (S4), seal the piece in place.

Developmental Work

Design Solution Five:

 



The solution chosen beat out the other solutions on the design matrix. Design solution five provides ease of use, efficiency, and simplicity other solutions do not offer. Design solution five requires two motors for an up and down motion and a claw that opens and closes. The solution consists of a perforated PVC material with metal joints. After discussions with the team, changes to the original design were made. The original metal design of the entire arm proved too heavy and at fault for the overall instability ROV. Upon figuring out the problem, the material changed to a perforated PVC to increase the stability of the overall ROV.

 

 

 

 

 

 

 

 

 

 

 

 

 

Materials List:

1. S1 - Claw - Galvanized Metal - Open and closing mechanism to retrieve plastic rings
2. S2 - Motor - Concealed in a plastic box to prevent water damage - Rotates gears to open and close the claw.
3. S3 - Connecting Tube - Perforated PVC - Attaches arm together with casing for wires
4. S4 - Joint - Galvanized Metal - Up and down motion for mechanical arm
5. S5 - Connecting Tube - Perforated PVC - Attaches arm together with casing for wires

S3 + S5

 

S1

 

S2

 

 

 

S4

 

Rationale

The ROV construction must have the capabilities of a standard ROV that allow the overall system to pick-up, move, and place stationed rings on an underwater tower. In this case, the mechanical arm of the ROV must provide the proper capabilities to pick-up and move the plastic rings without dropping the rings or inaccurately placing the rings. To achieve this goal, the design of the ROV’s mechanical arm must be maneuverable, functional, and efficient.  Achievement of this includes the proper construction and attachment of the parts of the mechanical arm to each joint and the ROV itself.

The first alternate solution consists of a very compact design. This design has many advantages due to its ease of move and close joints. This design is made of PVC and metal joints. The material make-up of this design does not give this solution a good rating due to the fact that it affects the buoyancy of the ROV. The largest problem with the first alternate solution lies in the length of the mechanical arm design. The length of the mechanical arm in this design does not give a long reach to the plastic rings placed on the underwater tower causing the efficiency and effectiveness to decrease in rating.

The second alternate solution designed consists of a PVC make-up, a three pronged claw, and two main joints. However, using the second alternate solution reduces the capabilities of the ROV. Using this solution allows the ROV to have more range, better efficiency, and more effective and accurate attachments to the plastic rings. This alternate solution causes uneven buoyancy throughout the ROV due to the PVC make-up.

The third alternate solution gives more responsibility to the ROV driver. This design does not have a joint that allows the arm to move in the left and right motion. This reduces the functionality and efficiency of the ROV. The third alternate solution lacks in length which causes similar problems to the first alternate solution. This alternate solution is made up of a metal make-up. This causes an extremely uneven weight distribution throughout the ROV by placing more than half of the weight on the hull.

The fourth alternate solution takes a different approach on the third alternate solution. Material make-up remains consistent between the third and fourth alternate solutions. The extended length of the fourth alternate solutions in conjunction with the metal make-up of the mechanical arm causes an even larger uneven weight distribution which reduces the capabilities of the ROV. However, the length of the fourth alternate solution extends the reach of the ROV. The lack of a joint giving the mechanical arm a left and right motion decreases the ability of the mechanical arm to pick-up and place the plastic rings efficiently.

The fifth alternate solution consists of a PVC make-up with metal joints and a metal two-pronged claw. The PVC in this design incorporates holes in the design to allow water to flow through the mechanical arm. This allows the mechanical arm to keep more of a buoyant state due to the fact the PVC with holes allows water to enter and releases air. The fifth mechanical arm design includes only one joint that moves the mechanical arm in a left and right motion. The two-pronged claw at a ninety degree angle allows for the ROV to move up to the plastic ring tower and place the claw around one part of the ring without knocking the ring off of the ring stand. This design also has a two foot length which allows the mechanical arm to reach out at a distance and allows the mechanical arm to be functional and efficient.

 



The chart above rates five viable solutions for mechanical arm alternate solutions. The scale used for each category is on a scale from 1-5 where five is the highest and one is the lowest. Each solution was scored off of specification generated in the design process. Solution five fits the design the best due to the design’s rating in all specifications.

Testing Procedures

Introduction:

            The final solution of the SeaPerch ROV must be integrated with the combined components of the mechanical arm, cameras, electrical steering, and connection to the hull. The mechanical arm must be as easy to move as possible to increase the efficiency of the ROV while completing the task at hand. The mechanical arm must also account for buoyancy by keeping a reduced weight as to not throw off the total buoyancy of the ROV. Materials must be water proof and must be of an anti-rust material or have coating that decreases rusting. One major section of the task involves the mechanical arm on the ROV. Team member Glenn Beveridge will control the mechanical arm during testing and also keep track of any results. The majority of testing will take place underwater in tanks and pools to simulate the situation and slight depth pressure.

            Throughout the design process, each step is assessed by a number of people. The designer must create solutions that fit within the design specifications and to me the parameters of the task at hand. The designer assesses each solution personally to determine whether the solution fits within the parameters set in place. For expert support, the designer will contact any mentor with the solutions and receive mentor suggestions.

 

To Test Drawing:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Conceptual on paper

Tools and Equipment Required: Pencil, paper, eraser, ruler, and research

1.     Look over research and brainstorming

2.     Draw precise alternate solutions

3.     Post onto blog for teacher assessment

4.     Asses functionality and usability of each alternate solution

To Test Solution One:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Drawing

1.     Examine specifications and limitations

2.     Examine design

3.     Ensure design fits within specifications and limitations

 To Test Solution Two:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Drawing

1.     Examine specifications and limitations

2.     Examine design

3.     Ensure design fits within specifications and limitations

 

 

 

 

 

 

To Test Solution Three:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Drawing

1.     Examine specifications and limitations

2.     Examine design

3.     Ensure design fits within specifications and limitations

 

 

 

 

 

 

To Test Solution Four:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Drawing

1.     Examine specifications and limitations

2.     Examine design

3.     Ensure design fits within specifications and limitations

 

 

 

 

 

 

 

 

 

To Test Solution Five:

Testing Type: Exploratory

Testing Stage: Preliminary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Drawing

1.     Examine specifications and limitations

2.     Examine design

3.     Ensure design fits within specifications and limitations

 

 

 

 

 

 

 

 

 

 

 

 

To Test Chosen Solution Five (Above Surface):

Testing Type: Validation

Testing Stage: Secondary

State of Solution: Stationary

Condition of Testing Stage: Dry

Tools and Equipment: Mechanical Arm

1.     Connect controller to device

2.     Move joint one, up motion

3.     Move joint one, down motion

4.     Move joint two, open claw

5.     Move joint two, close claw

 

To Test Chosen Solution Five (Below Surface):

Testing Type: Validation

Testing Stage: Secondary

State of Solution: Mobile

Condition of Testing Stage: Preconstruction

Tools and Equipment: Mechanical arm attached to ROV

1.     Move joint one, up motion

2.     Move joint one, down motion

3.     Move joint two, open claw

4.     Move joint two, close claw

 

 

 

 

 

 

 

 

 

 

 

 

To Test Water Resistance of Mechanical Arm:

Testing Type: Validation

Testing Stage: Secondary

State of Solution: Stationary

Condition of Testing Stage: Preconstruction

Tools and Equipment: Mechanical arm

1.     Use mechanical arm to test functionality

2.     Submerge mechanical arm in water

3.     Remove mechanical arm from water

4.     Use mechanical arm to test functionality