S.E.A. 2 See :

Submerged Environment Analyst

Calvin College Senior Design Team 6

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Project Description

We are developing a small remotely controlled submersible to be used as a research vessel for fresh water lakes. The submersible will serve the educational and research purposes of the Annis Water Resources Institute, located in Muskegon Mich. The AWRI mission statement is "To integrate education, outreach, and research to enhance and preserve freshwater resources" [1].

Our initial passion for this project came from the apparent need for aquatic research tools, as well as the obvious "cool" factor. We felt that through this project, we could contribute to increasing the knowledge of human impact on the environment. There is a lot to be learned about underwater environments, especially with the dynamic state of bodies of water due to climate change. Present technology is limited, and improving the technology applicable to marine research is crucial to understanding these dynamic environments.

The sub will be remotely controlled via physical connection (tether). The sub will be equipped with a video camera for live video feedback to the host device. It will utilize a fully controllable ballast system to acheive neutral bouyancy and complete 3-Dimensional range of motion. Additionally, the sub will be designed for easy integration of commercially available sensor units. Sensors could include temp, pH, O2, CO2, and conductivity.


What's New:
11/22/08 Updated Website
2/18/09

PPFS update,
AWRI link update
Milestones added

2/27/09 Task Schedule added
3/02/09 Progress Updates added (check below for regular updates)
5/15/09 Video of final prototype here
 

 
 




 
 
 
 
 
 
Progress:

Feb 28, 2009:
We have spent the past three weeks thinking and re-thinking the design of the ROV's ballast system. After coming up with a solid plan for creating a waterproof chamber for the pump and solenoid valve, we began acquiring the appropriate parts last week. These parts were varied pieces of PVC (8", 4", 2", caps, and adapters). Last Friday we began cementing a temporary ballast tank for testing. Videos of our test sequence can be seen here: Part 1, Part2, Part3.

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Mar 2, 2009:
Today we had a couple disappointments. First, the servo leaked oil, which we had put inside the gear box to waterproof it. It leaked out of the motor shaft, which we knew was our weak point, since every other seam had been sealed with superglue. We had hoped that the surface tension of the oil would be enough to keep it inside, but now we will have to look into getting some sort of gasket to make the seal better.

Also, our clever idea for supporting the ballast pump inside the pump chamber failed. As you can see above, the pump is hanging off of the back of the end cap by two pieces of flex tube. This pump is going inside of an 8" tube of PVC, but we needed some way of bracing it so it wouldnt jostle around. We decided to make a mold by covering the pump with foil and putting it inside a scrap piece of 8" tube. We then filled the mold with foam sealant, hoping it would solidify and create a perfectly formed brace to hold our pump. Unfortunately the foam needed oxygen to solidify, and while the top and bottom sections hardened, the middle section fell apart. Oh well.

On to plan B...

 

Mar 11, 2009:
After an unfortunate scheduling setback, we are currently getting back on track and finishing things up. We had anticipated receiving props to test our motors a week ago, but they just came in yesterday. Now we have a lot of catch up work to do to reach our goal of a basic pool test by Spring Break (less than two weeks away). We want to have our ballast tank mounted on a frame with motors, put it in a pool and make it go down and come up, and hopefully scoot it around a little bit. This Saturday we will spend all day working, and we hope to get more stuff done before then. So, if all goes as planned, we will have a lot more information to put up here within the next couple of days.

 

Mar 16, 2009:
So we had a fairly productive weekend. We talked out a lot of big decisions and planned for this final week we have before spring break. Our goal of testing our completed ballast system on our frame still stands for Thursday and looks promising. In addition, we re-waterproofed the servo, adding an o-ring to seal it a little better, and so far the results seem very positive. We also did some experimenting with the props, and learned a lot, but not enough to reach any major milestones before spring break. We were able to go ahead and move forwared on a variable speed control system that Wyatt and I (Danny) are very excited to dig into.

Today (Monday) we started sealing up our pump chamber. This included resealing all of our PVC joints with either glue or epoxy, and putting a new port into our tank for the wires to pass through. The pictures below show the final, sealed solenoid system, and the new port on our 8 inch cap. Tonight we have to run a couple tests to decide which option is best for waterproofing our wire port, but once we get those results, we will seal up our pump chamber (Finally!) and move on to our ballast tank. We are getting both excited and nervous about putting the pump chamber in the pool, but were all expecting positive results.

 

Apr 06, 2009:
Its been awhile... Two weeks ago we had spring break, and resolved to not even think about this project. Last week we played catch up to make up for that fact. We unfortunately did not get our pool test in before the break, and when we came back we realized we had made a fairly significant mistake. We had calculated that we would need some additional weight in our pump chamber to make it sink, but we didn't really realize how heavy that was actually going to make things. So we spent the majority of last week redesigning and rebuilding our pump chamber. We took off about 4 inches of length in order to reduce its buoyancy and allow us to sink with less weight. We should finish putting it back together today or tomorrow, allowing us to test again by the end of the week.

We decided to hold off on the pool test until we get the motors on the sub, since we can test the ballast system completely in our small tank. We tested the bi-directional controllers we ordered over the weekend, and they work perfectly, even after we modified them for the joystick controller we want to actually use. Everything is looking good to go, pending the completion of our pump chamber. Pictures of the final assembly and videos of our tests will follow shortly.

 

Apr 20, 2009:
Finally, the pool test we have been trying to run for the past month or so was accomplished last Thursday! Our pump chamber is finally finished, and our motors were mounted (without the servo yet, though). We are getting into crunch time, putting the final pieces together and trying to make it look good. Wyatt and I can finally move ahead with building the controller; it will be fun to do some more electrically intensive work.

Here are some pictures of our pool tests. Everything worked just as we expected. If you see in the videos, it sat at an angle underwater, but we knew this was going to happen, since we hadn't done any stabilization work yet. We have already planned to correct this by switching to a two ballast system. We bought all the parts, and the final construction should be relatively simple, and in theory it should work fine. But, back to the pictures (links to the videos are below):

Videos: Diving, Resurfacing, Moving around

 

Apr 21, 2009:

Today we did a quick test of our camera in a completely dark room to see how well its 'nightvision' worked. We were shocked by the illumination of the video it took in the dark. That video can be seen here. This made us reconsider if we would need supplemental LEDs on our submersible. We sent the video to AWRI and we are waiting for feedback from them.


May 13, 2009:

Apparently it has been awhile since the website was updated... Unfortunately these last few weeks have been extremely busy trying to get this project done (try 18 hours of sleep over 5 days!) but we were successful! It did everything we wanted it to do perfectly. And now, rather then go back and try and remember everything that happened and on what day, I am instead going to give a quick overview of the past month. Also, check out our Final Report back at the top of the page, it will give details about the evolution of our final design.

It was very much a rollercoaster ride. We had huge successes followed by terrible failures. Everything from our camera breaking, to instability problems, to mechanical binding issues, and electrical shorting issues happened, but fortunately we were able to take them all in stride and produce a finished product. Basically, after April 21, we just started putting things together. We made our controller (below), our frame, changed the design for our motor shaft and made that, put together our final ballast system, made a mount for the camera, wrapped our tether (also below, this was an especially fun night for us), and more. We also had to angle our ballast tanks outwards, giving our sub a "V" shape, to make sure we were stable underwater. The four of us spent more time together then apart, but it was an experience that I wouldn't trade for anything, and I believe I have made life long friends. Hooray! :)

But now the pictures (the bottom one is our camera mount):