September Log

9/29/10

Today I completed the descriptive abstract for my three alternative solutions. The only piece missing from my blog are pictures of each solution to go with the abstract. My background information needs two more pictures and my individual and team testing procedures need to be refined.

Alternative Solutions

The alternative solutions cover  how to power the mechanical claw and the shape of the claw to accomplish the tasks of the MATE ROV competition. Three power resources taken into consideration when creating the alternative solutions were hydraulics, an electric motor, and a servo. In addition, the shape of the claw was designed to the tasks provided by the competition, specifically the tasks involved with collecting samples of crustacean species, bacteria mats and resurrecting Hugo's frame.

Alternative Solution #1

The first alternative solution utilizes an electric motor to power the mechanical claw open and closed. The motor directly connects to the idler gears, which are located inside a cage measuring 6" in length by 4" in width. The idler gears will have 2 gears on one side of the 1" big gear and 1 gear on the other. In this solution, the speed ratio that the mechanical claw will open and close will be the same because the two gears on the same side will measure 1/2" each, while the single gear on the opposite side will measure 1/4". A 1/8" spindle gear will connect to the motor before the 1" big gear to lower the ratio. The claw will be constructed in a shape that has a pronged segment on the bottom to pick up objects and a rectangular shaped segment on the top to lock the objects in place.

Alternative Solution #2

The second alternative solution also utilizes an electric motor to power the mechanical claw as it does in the first solution. The cage containing the gears will be a square measuring 4" on each side. A 1/8” spindle gear will connect directly to the motor, so it will spin at the same speed as the motor. A 1” big gear behind that will be used to lower the ratio to one that is slow enough to operate the claw effectively. A 1/8” gear will be on one side of the big gear and two 1/2” gears will be on the other, separated by the pivot point. The claw will close much faster than it will open because the ratios on each side are not the same. The mechanical claw will be 8” long and consist of two half-circular shaped cups that will come together. The size of each cup will be 4” in length and 2” in depth. The fulcrum of the claw will be constructed distant enough from the cups so that the objects will not be forced out in the opposite direction when being picked up. In addition, rubber will be inserted on the lip of each circular cup to add traction. 

Alternative #3

  The third alternative solution requires a servo for a power source to make the mechanical claw function. A servo is a specific type of motor that consumes little energy because of its size. Servos have built in control circuitry. In this solution, a servo will power the claw to close, which remains open during all other parts of the competition until needed. The servo motor will be attached to the pivot point of the claw with a metal wire. The claw on this solution will be the same design as solution 2, but smaller in length. The two segments from the pivot points to the circular cups will be 3” as opposed to 5”. The location of the fulcrum on the claw will be constructed at a distance far away enough from the cups so that objects will not be forced out the front when the two claws converge.

The three alternative solutions consist of two different power sources, which are the electric motor and the servo motor. Solution 1 and solution 2 have variations of gear sizes. As a result, solution 1 operates on an even gear ratio, while solution 2 closes faster than it will open. Despite using less power, solution 3 is also a viable option. It utilizes a servo motor to close a mechanical claw that is a scaled down version of the claw implemented in solution 2. Both types of mechanical claws used in the three alternative solutions were designed based on the principle of shoveling the objects.  

Research and Brainstorming

The alternative solutions will reflect the aspects considered in the research and brainstorming stage. I will design and construct a mechanical arm to be placed on the design structure of the remotely operated vehicle that a team member can operate efficiently. One important aspect to consider is the type of material used to construct the mechanical claw. Some of the types of material used on current ROV mechanical claws include plastic and metal materials. In addition, another important aspect to consider is the function that will power the mechanical claw to operate effectively.

Type of Material-

PVC Plastic Material:

Pros:

-Cheap

-Lightweight

-Durable

Con:

-Difficult to find in shape to construct claw

Metal Aluminum Material:

Pros:

-Durable

-Commonly used to construct claw

Cons:

-Costly

-Heavy

Type of power-

Electric Motor:

Pros:

-Effectively maneuvers in all directions

-Powerful

-Easily found

Cons:

-Heavy

-Cage for gears consumes space

            Servo-

            Pros:

            -Lightweight

            -Consumes little area

            Cons:

            -Limited range of motion

            -Small power source

Testing Procedure

Testing Procedures

The final solution for both the mechanical claw and the ROV will function efficiently and be able to perform all tasks provided by the MATE ROV competition. The final solution will be able to collect samples of a crustacean species, collect samples of a bacteria mat, sample a vent site, and resurrect a PVC structure on the bottom of the testing pool. The hull will be able to fit all other components of ROV including the mechanical claw, propulsion, and camera. The hull will be constructed so it has the ability to maneuver efficiently allowing for all components to complete the tasks in the competition. The electrical system will power the ROV to maneuver effectively in the x, y, and z planes of the testing pool. The mechanical claw will be utilized in almost all tasks of the competition, specifically collecting samples of a crustacean species, bacteria mat, and resurrecting “Hugo”. The testing of the final solution will be administered by one team member who will control all functions of the ROV.

There are four types of tests to investigate the effectiveness of the final ROV solution. The first is an exploratory test, which is implemented prior to design solutions of the ROV. During this testing stage, the team designing the vehicle will understand the concepts related to the MATE competition, such as rules and regulations and tasks they must complete. The exploratory stage will iron out all kinks so the design solutions for the vehicle are within the confines of the competition and most importantly, will work if constructed properly.
Test that:
1. The idlers gears on the mechanical claw works properly
2. The power source for the mechanical claw is geared down to a usable speed
3. The mechanical claw is waterproof
4. The two claws come together when operated

The second type of testing is the assessment stage. The assessment tests will answer questions concerning the usability of the concepts applied to the design solutions. These tests will ensure the design solutions can complete the tasks provided by the competition. For example, assessment tests for the mechanical claw will ensure the designs will be able to collect samples of a crustacean species and bacteria mat, sample a vent site, and resurrect a structure.
Test that:
1. The mechanical claw opens to a size sufficient enough to grasp samples of a crustcean species and bacteria mat.
2. The claw design can resurrect a PVC structure

Validation testing will follow next in the testing stages, but will occur after the product has been created. This will be the first time all components of the final solution is all together. The purpose of this stage is to ensure the final ROV does not have any issues with the functioning parts. Also, it will test that the ROV meets all specifications for each part and that it achieves all goals previously set prior to the construction.
Test that:
1. The electric motor on the mechanical claw powers the idler gears properly
2. The mechanical claw graps the sample of a crustacean species
3. The claw succesfully samples a bacteria mat/vent site

Comparison testing will be performed at many stages during the testing process. It will be used to compare various ideas on how to build a specific part of the ROV, the type of material used to construct, and the method or power source utilized to make a part function. For example, a design matrix is implemented in the alternative solutions to decide what solution compared the most favorably to the specifications.

The mechanical arm testing process will focus around the effectiveness of the claw design and the power source to manipulate the arm. The preliminary stages for testing the claw design will be performed when the ROV is stationary and the other functions on the hull are not being powered. The preliminary stage will test that the claw is secure to the hull and does not hinder the movement of the hull or any other parts on the ROV.

The secondary stages will test the usability of the mechanical claw. It will ensure that the entire claw is sealed and the section containing the power source is waterproof. The secondary stages will be performed by placing the mechanical claw in a container of water. The tertiary stages will test the effectiveness of the claw. The mechanical claw should open and close efficiently. This stage will be tested by placing the mechanical claw on the hull and then hooking up all electrical systems to the claw. The ROV will be placed in the water and the mechanical claw will pick up samples and resurrect a structure.

1. Does the mechanical claw prohibit the other functions on the ROV?
2. Is the mechanical claw secure to the hull?
3. Is the section around the servo/electric motor waterproof?
4. Is the gear ratio low enough to operate the claw effectively?
5. Does the mechanical arm close and re-open?
6. Does it open to a size of at least 3 inches?
7. Does it pick up a sample?
8. Does it resurrect a PVC structure?
9. Does it collect and move objects to the targeted area?



ROV in testing pool



Specs and Limits

Specifications:
-The design must be operated remotely from a shack

-The design must be able to maneuver in any direction of the water column

-The design must have a mechanical arm to pick up objects

-The mechanical arm must open to a size of atleast 3 inches

-The mechanical arm must collect samples of a crustacean species
-The mechanical arm must collect samples of a bacteria mat
-The mechanical arm must sample a vent site
-The mechanical arm must resurrect a PVC structure also called "Hugo"

Limitations:

-The design must operate at a depth of 4 meters

-The design can only run on a 12 volt 25 amp battery

-The design must use nonpermeable water materials

Design Briefs

Team Design Brief

            Design and construct a submersible remotely operated vehicle to achieve the tasks provided by the MATE ROV Competition that a team operator can use to simulate a real life ROV exploration in a chlorinated testing pool.   Each team member will individually design a different operating component of the remotely operated vehicle, which will include: propulsion systems, design structure, and a mechanical arm.

Individual Design Brief

Design and construct a mechanical arm to be placed on the structure of the remotely operated vehicle that a team member can operate efficiently. The mechanical arm must collect samples of a crustacean species and bacteria mat, sample a vent site, and resurrect "Hugo".

Background Information

The MATE ROV competition gives teams a chance to simulate an underwater environment and exploit the problems that often occur in these settings. The multiple tasks provided by the compeition parallel the tasks a professional in remotely operated vehicles would have to perform in a real life situation. The MATE ROV competition requires each team to design and construct an ROV to complete the following tasks: collect samples of a crustacean species, resurrect "Hugo", sample a new vent site, and collect a sample of a bacteria mat. The team goal of this competition is to complete the tasks in the fastest time possible, while utilizing a mechanical claw, camera, hydrophone, and propulsion system to maneveur the ROV through the testing site. The team will be comprised of three members that each specialize in a different component of the vehicle, which include the propulsion, hull, and mechanical claw. My area of specialization is the mechanical claw, which will be used to collect the various samples and resurrect "Hugo". ROVs are useful tools because they allow humans to complete tasks environments that they normally could not on their own.




MATE ROV Competition

Hydrophone commonly found in all types of ROVS

 



Camera lenses are essential for vision underwater



Mechanical claw found in larger ROVS

 



  


ROV projecting lights to see the object

 

  The team designing and constructing the vehicle is made up of three members. Matt Gannon is specializing on the electrical system to operate all functions on the ROV. Ross Basri is specializing on the hull that fits all functions on the vehicle. I am specializing on the mechanical claw to collect samples and perform the other tasks in the competition. This team concept models a real life situation in which a team would also comprise of members specializing on a specific aspect of the remotely operated vehicle. One member of the team will control the ROV at the competition while in the control shack.


ROV design that includes a camera and claw



MATE ROV International team



ROV Operation Center

Man operating ROV in BP oil spill

IFE ROV Engineer working on electrical unit



 Humans are limited in underwater environments. They are limited to the depths they can reach and they are limited to the areas they can maneuver into. ROVs are extremely versatile and can do things humans simply cannot. ROVs are used to investigate shipwrecks, such as the Titanic. They are used to retrieve objects at depths that humans cannot reach. ROVs are utilized in oceanographic research situations, and have even discovered a handful of new species. Remotely operated vehicles are often found around oil drilling platforms working to repair damaged structure. The MATE competition gives each team member a chance to experience what an entry level mechanical engineering job entails.






ROV exploring sunken vessel



Photo taken by ROV during deep sea archaeology

ROV used to explore in the Arctic Ocean

ROVs can repair objects such as the pipe pictured above



The team will design and construct an ROV in an effort to simulate how an ROV would allow a team to complete a task in a real life situation. In many cases, remotely operated vehicles are used in predicaments such as oil spills or mine warfare. ROVs can allow a team to examine and fix an oil spill or clear mines that have been ready to deploy for decades; events that not only effect people in those fields, but also the general public. ROVs are used in significant situations and are used in a professional manner. They can be used for entertainment, but they are a very vital part of reducing the risks involved in dangerous occupations.

Professional ROV used for deep sea exploration



Mini ROV used for entertainment

Various types of ROVs found in research/exploration settings

 Mechanical claws are not only utilized on remotely operated vehicles. They are modified to be commonly placed in arcade games. One popular game that includes a 3 part mechanical claw is a claw crane (which is also called a variety of names). The player participating in this game uses a joy stick to manipluate the crane that controls a claw. The claw can move back and forth, as well as side to side. After the claw is positioned to win it's intended prize, the player clicks a button to descend the claw downward to grip onto the prize. Mechanical claws are also used in other industries, including film and production.



Three part claw





Crane claw arcade game



Claw toy produced by Fisher Price