Red October- MATE Competition ROV


#1

Hey everyone. After being on the forum for a little bit of time, asking for help here and there. I’m happy to say that our ROV is mostly finished. It is going to be used in a regional MATE ROV Competition. We decided to go a little overkill for the “Navigator” class of the competition but we wanted a ROV that could be reused for the years to come. The ROV this year is named Red October.

With the MATE ROV Comp. in mind, we had to design an ROV that would for their guidelines. We probably would done some things differently but with the rules and guidelines of the competition, we could not. :frowning:

The ROV was built from ground up using the 2.8 Dev Kit. Our electronics housing is mounted on the two horizontal frame support aluminum tubes, held together with 3-D printed fittings. Mounting pieces for the housing were built on a milling machine. To maximize frame space we chose to keep the motors inboard. We use propeller shrouds to maximize the efficiency of our propellers. The accessories used to perform the tasks were designed with simplicity, functionality, and flexibility in mind. Two main accessories will complete the majority of all tasks, the claw and the “whiskers”. The claw can move 90 degrees down and the claw opens and closes a reasonable amount.

They are used for collecting multiple objects and completing multiple tasks. The claw is a simple tool allowing for precise collection of hard to reach or capture objects. The whiskers is made of a tube with 1/16in holes drilled through and in these holes, are rounded carbon fiber rods. Both of these tools retract into the frame maximizing the use of our size.

There are a couple things we did change around. The ROV is powered powered by a tether. The tether consists of a power line and ethernet cable. The power tether is 14 gauge and is about 50 ft long. If I remember correctly there is around a half volt drop from one end to the other. The ethernet cable is used for data and communication. Two of the strands inside are used for communicating with the ROV, the leftover six strands are used for video. The extra cameras that are used are FPV cameras designed for RC products. To waterproof them, we pot them in Epoxy. The plastic cover is removed after the potting and the camera turns out rather clean looking.

At the top end of the tether we made our little box for the topside adapter. The tether connects to the box and then splits off to various connections including video connections, our power source including the fuse and also the topside adaptor of course.

We also made some changes to 2.8 controller board. We added an extra ESC for the extra lift motor and a couple of other power connections to help reduce brownouts of the system. Overall, we are happy the ROV but more could be done to the system to improve it, we have just ran out of time. The competition is coming up and we need to practice. It would be nice to hear some feedback on what y’all think. Thanks all.

Also, here are some more photos. :smiley:







#2

Wow, looks great guys! Best of luck in the MATE competition! Thanks for all the great pictures too!

I’m unfamiliar with the competition requirements, but my only concern is how much it might roll. You may want to consider buoyancy as high as you can get it and ballast as low as you can get it. Both evenly distributed to keep the vehicle stable.

Let us know how it works out and please share any video you take.


#3

Yeah. Currently,we are way too buoyant. We will be weighing down the ROV some. The weights will at the bottom edges of the frame. Right now, the ROV is actually really stable. If I recall, we don’t get any roll really. We are heading to the pool for some more testing tonight. I will try and remember to take a video so you can see what it is like in the water.

Thanks for your input.


#4

Looking forward to the video! You all have made a very slick and clean ROV! Great job :smiley:


#5

Thanks for sharing the great photos! I can’t wait to see more picture and video, and see you in person at the competition! Best of luck! Practice, practice, practice!!


#6

Well done guys! It looks fantastic and I am very impressed by your creativity. Do you have any pictures/test with the gripper yet? I feel like it might add a lot of unstable buoyancy and control issues. (depended on the size and the relation which is hard to tell). Do you have a picture of the tether and the connection to the ROV? Good luck with the competition!


#7

@Kevin_K @Colin_Ho @Fe3C

Thanks for interest in the ROV. Your comments are very appreciated. :smiley: Unfortunately, I was unable to take a video of the ROV this weekend. Our ROV ended up having a couple of problems with the servos on the claw and we also suffered a leak into the electronics tube. Everything is alright though. The leak was through one of cable connectors. This two problems resulted in non stop work over the weekend, sorry for no video. I do though have an older video of our initial testing with ROV. That can be seen [here] (https://drive.google.com/file/d/0B3Oyv7j56qRsN2tLWFR6emRaZk0/view?usp=sharing).

The rebar attached to the front was to balance it out for our intial test because it was rather buoyant at the beginning.

Here is a requested photo of the claw attached to our ROV. The other photo also shows how are mechanism works somewhat. Due to size constraints in the competition, our claw extends and retracts.It slides on the tubes of the frame. You can see towards the middle of the sub, there is servo with a large arm that controls that function. The other two servos work to move the claws “wrist” up to 90 degrees down and open/close. With the testing of the claw currently, it does not add problems when driving the ROV.


About the tether, I do not think I have a picture of the actual tether, only the connectors it plugs into. You can see the style of connector that is used in the photo below. The one currently plugged in to the ROV in the picture is used to take the servo wires out and also our additional camera wires.

Once again, thanks for your interest the ROV guys!


#8

I’m designing one as a project, curious what camera you used, my ROV design is similar to you that the canister is vertical with the camera in the front opposed to the canister being horizontal.

I would love to pick your brain as I’m just starting out!

My email is kerfootjl@gmail.com


#9

We originally started off by using a Logitech C920 Webcam. The problem we ran into with this webcam was the BBB had a hard to to compress the frames and send it the cockpit. This would cause more latency and sometimes our ROV camera would freeze do to the BBB not being able to send the frames. I have seen other use the same camera on the forum so maybe we just need to work some things out.

We have now changed to a Logitech C525. It runs at a lower resolution and still looks good. It also still has auto focus and all that jazz. We have an occasional issue with it but it seems to work a lot better. In the future, it would be nice to take advantage of hardware based H.264 encoding to reduce the load on the Beaglebone .

I will send you an email and we can talk if you more questions. Welcome to the forum! :smiley:


#10

Could someone please tell me the manufacturer of those couplings that have the blue caps?


#11

Hi,

We simply used cheap connectors off eBay for the connectors. We epoxied the ends of them after installation but they are still removal.

Here is the link for once similar.