Final Solution

Rationale

There are many different ways in which one can design the electrical system for an ROV. You can take the path of running wires to control boxes or having micro controllers connecting to PlayStation controllers doing all the work for you. An important specification my design required was that the user would have full control over the ROV, allowing them to pick up an object and move in every direction. The variations in my design come largely from the placement of the micro controllers. Certain solutions are more clutter free and organized but require more wires. Others require a waterproof box which will add a lot of buoyancy to the final solution.

Solution 1: Micro controller and power source on land

My first solution places both the micro controller and the power source on the surface and not on the ROV. The micro controller will be comprised of an Adafruit Motor Shield and an Arduino Uno. The set up will be powered with a 12 volt battery connecting to the VIN and GND terminals on the Arduino Uno. The Arduino Uno will be connected to 10 thermostat wires which will run from the output terminals on the Arduino Motor Shield to the positive and negative ends of the motors on board the ROV. There will be 4 DC motors and 2 servo motors. Waterproofing the wires is necessary to ensuring that nothing is damaged when the wires enter the water. The micro controller is connected to a PlayStation controller which sends signals to the motors to tell them when to turn on and off. Also, there is a camera connecting to the hull of the ROV which will run a live feed to a monitor via a USB cable. Figure 1 shows a diagram of solution 1.

Pros: By allowing the micro controllers and the power supply to be on land, there will not have to be a need to waterproof the set up of Arduinos. Only the wires will have to be waterproofed to ensure the ROV works. A waterproof box will add a lot of buoyancy to the ROV that will be most likely needing weight to keep it neutrally buoyant.

Cons: While this solution seems like a great idea, the wires travel over a very far distance individually. In certain situations, there will not be a strong signal going towards the ROV and it may lapse in its commands. Also, this tether is the heaviest possible solution considering the final solution will be running ten thermostat wires. This option presents a lot of drag for the ROV as it moves through the water.


Solution 2: Micro controller and power source on board
My second solution involves having the micro controller and power source on board the ROV. The set up will be powered with a 12 volt battery connecting to the VIN and GND terminals on the Arduino Uno. The Arduino Uno will be connected to 10 thermostat wires which will run from the output terminals on the Arduino Motor Shield to the positive and negative ends of the motors on board the ROV. There will be 4 DC motors and 2 servo motors. Waterproofing the wires is necessary to ensuring that nothing is damaged when the wires enter the water. In this solution, the Arduino and battery will need to be waterproofed as well. The micro controller is connected to a PlayStation controller which sends signals to the motors to tell them when to turn on and off. Also, there is a camera connecting to the hull of the ROV which will run a live feed to a monitor via a USB cable.

Pros: There is very little drag from this solution because there is only one wire running the Arduino Ethernet cable to the surface. This allows for much less weight in terms of wires. Also, the wires will be more organized and easier to work on and access.

Cons: By placing all the components on board, the ROV becomes much heavier and there are more calculations that need to be taken into place when figuring out buoyancy, This also creates the challenge of waterproofing the battery and the Arduino system. There is also a long cable running from the ROV to the surface and there is the possibility that it will miscommunicate.


Solution 3: Power supply on surface and Arduino set up on board
My third solution involves having the battery or external power supply on land where it will be free from the ROV except for wiring. The Arduino set up will stay on board the ship inside a waterproof container. There will be wiring connecting the Arduino to the four dc motors on board and the two servo motors as well as a wire to the PlayStation controller and power supply on land. This will allow there to be a small amount of weight on board the ROV and not as many things will have to be waterproofed.

Pros: There will be less weight on board the ROV and a smaller waterproof container will be needed when attempting to keep from water breaking our system, There will also be smaller wires running from the Arduino to the motors and they will be lighter and less of a drag than in solution 1.

Cons: There is still the issue of running a long wire from the PlayStation controller to the Arduino set up. In this case with the tether to the ROV it will be larger than in other solutions because the PlayStation controller and battery wires are on land and running to the ROV. This will create more drag through the water.


Solution 4: Arduino on surface and Arduino and power supply on board
The fourth solution I have is very different from the rest of them in that there will be a micro controller on the surface and on board the ROV. There will be a Dual Shock PlayStation shield connecting the micro controller to the actual controller. That will be connected to an Arduino Ethernet shield which will run numbers to the Ethernet shield on board telling it what to do. These both will be stacked on top of an Arduino Uno which will serve as power and memory for everything. These three systems will be on land. On board there will be another Arduino Uno and Ethernet Shield as well as an Adafruit motor shield. This motor shield will be where the motors can connect to, allowing them to move when told. It will also be where the power from the battery comes from.

Pros: This will be the most efficient system because of the additional shields helping the controller get to the motors in the most effective way possible. There is still a long cable running from the surface to the ROV but it will be in the form of a CAT-5 cable. There will be no failure between ports now with this addition. Also, using a PlayStation controller without it having to be hooked up to a computer is much more efficient and less bulky.

Cons: Of all the possible solutions, this one requires the most amount of parts. Therefore, it will be the most expensive. There is also a lot of weight that is added on the ROV because of the three shields and power supply. With this solution, a bigger waterproof box will be needed to compensate for the bulkiness of the design.

Executive Summary of Research

In recent years at MAST, many groups have attempted to build ROVs of their own. A previous years group used Arduino connected to PlayStation to control their ROV. This program works great for projects like this because you can control Arduino to do certain task. Another group also installed ballast tanks in the frame of the ROV so the PVC can fill with water and submerge. As well as the tanks, the group used a mechanical arm to operate the ROV’S tasks underwater.

Just as the previous year has done, we will be using PVC pipe for the main body of our ROV. Unlike their ballast system which mimics that of a traditional submarine, my group will be doing our best to make the submarine neutrally buoyant to the point where the ROV freely moves up and down in the water. Besides that, we will also be using typical propellers to move the ROV in all six ways. A mechanical claw will pick up the objects dispersed around the bottom the pool. Finally, a PlayStation controller will connect to all of the motors where a button on the controller will correspond to a certain motor, either rotating clockwise or counterclockwise. The main goal of our ROV challenge is to retrieve multiple blocks on the bottom of the pool while navigating small obstacles as well. This can all be easily accomplished with the right team and design.

Testing Procedures

Assembling the ROV
Testing Type: Assessment
Testing Stage: Preliminary
State of Solution: In construction
Condition of Testing: On dry land
Tools and Equipment: Claw, ROV hull, electrical components
1. Meat with team
2. Ensure each members' parts' locations meet the design requirements
3. Ensure each members' parts meet the parts' designs specifications and
limitations

To Test PlayStation Controller

Testing Type: Exploratory

Testing Stage: Preliminary
State of Solution: Stationary
Condition of Testing Stage: On dry land
Tools and Equipment: Completed controller, ROV, wire
1. Toggle all buttons interfaced with ROV
2. Ensure each button activates correct part of ROV
3. Identify and address all noted issues

To Test Camera Connection

Testing Type: Assessment

Testing Stage: Preliminary
State of Solution: Stationary
Condition of Testing Stage: On dry land
Tools and Equipment: Camera, LED screen, Ethernet cable
1. Turn camera on
2. Ensure camera image live feeds to LED screen
3. Identify and address all noted issues


To Test Claw

Testing Type: Assessment
Testing Stage: Preliminary
State of Solution: Stationary
Condition of Testing Stage: On dry land
Tools and Equipment: ROV claw, controller, ROV
1. Toggle button that activates claw
2. Ensure the button activates claw according to the claw's specifications and limitations
3. Identify and address all noted issues

To Test Waterproofed Tether
Testing Type: Validation
Testing Stage: Secondary
State of Solution: Submerged underwater
Condition of Testing Stage: Underwater
Tools and Equipment: Ohm meter, waterproofed tether cable, water
1. Use ohm meter to find initial resistance of cable
2. Submerge cable in water
3. Take cable out of water
4. Use ohm meter again to test new resistance of wet cable
5. Ensure that the second test results did not decrease from first test results

Specs and Limits

Specs and Limits

The solution must be able to operate all components requiring power
     Limitations:
     The solution is limited to a 12 Volt Power Source
     The solution is limited to 4 thrusters

The solution must be able to attach to the hull
     Limitations:
     The solution is limited to the size of the hull
The solution must be in an organized layout
The solution must be water proof
The solution must be able to be operated from the surface
     Limitations:
     The solution is limited to one controller

Design Briefs

Design Briefs

Group

To design and integrate a system of components to interface and operate propulsion or any such device to control the six degrees of movement for an underwater ROV to be used in the lab during testing and in a pool during a timed event. 

Individual

To design and create a system of components to power an electrical system for an underwater ROV in a lab or pool during a timed event.