Research Installment #1

Dear Kind Readers,

Today I will allow you to view my some what extensive research done over the summer. What you will fine below is mostly a compact list of the types of designs I had viewed last competition. This research is only preliminary and will expand.

From what I have gathered the claws obviously have to be reliable under all pressures and needs to be able to have a constant hold on the object designated for the competition. Last year the object that was target was a "crab" approximately 2 inches in diameter with decorative (and sometimes aiding) pipe cleaners as "legs of the crab". Besides the basic requirements, the arm/claw has to have to some added features that will put it over the top to win the competition. For example, a claw that can pick up multiple objects quickly during one trip down to the bottom of the pool will be more successful than one that is less efficient. With all this in mind many different designs were created.

Claws Using Activation Devices: This type of claw will automatically attach to the object once an activation button is pressed. In many cases this activation button is electronically connected. However there was one ROV that was very very creative in all ways including its arm design. This claw also used an activation device. On the bottom of the hull were five strategically placed rat traps. They would be used as the ROV slowly hovered over the object and carefully placed the rat trap over the object. As soon as the object was far enough in the rat trap the rat trap would snap closed. The group would stay at the bottom of the pool and methodically place the ROV over five different crabs. ++Advantages: Because the device used an activation device there was no problem in the timing of closing the claw. Also the grip that the rat traps had were very good. --Disadvantages: The ROV only had five one use rat traps, therefore only five could be picked up during one trip. Also the rat traps had to be perfectly place over the objects in order for them to be successful.

Grade: B-

Claws Using Gears: Many of the claws also used a set of gears. The gears were used in certain ratios so that some of the claws had greater torque or and increased speed to open and close the claw. Many of the gears that were used included spiral gears as well as round gears. ++Advantages: Because the gears could be easily tuned the torque as well as speed could be adjusted. Also the geared claws had great grip on the object. --Disadvantages: Because gears have to be finely tuned alot of the gears had problems. For example the gears constantly became misaligned or the torque over powered itself. Also if water got into the gears there were some issues.

Grade: C

Claws Using Water Pressure: One particular ROV included a design that I found very efficient and creative (I have modified it in my alternative solutions). This design used water pressure, specifically water syringes to control the claw. The way it worked was very unique. one syringe, which was controlled by a team member, was connected through a plastic tube, to a second water syringer that was then connected to the claw. Due to a constant water presence in the tube, an inverse effect occured. When one syringe handle was pulled out the opposite was pulled inward. Because the claw was connected to the syringe handle it was controlled to grab an object. ++Advantage: The method used here was not only creative but also reliable. Also the grip was probably the strongest of all the types. It was also a very cheap method. --Disadvantages: The syringe had a lot of pressure behind it so it could possible break.

Grade: A

Love,
T.ango F.oxtrot