Building my own ROV

propulsion
sos
software

#1

Greetings!

First of all is very grateful to find this kind of forums where people can give ideas about the same projects, let me introduce my self before i jump into my design project. I am a 23 year old Mechatronics Engineer and have worked for 3 years offshore as ETO (Electro Technician Officer), and that is where my project begins.

One day around May 2013 I Joined a DSV (diving vessel) and for the first time I saw this ROV´s, for me it was amazing to meet this kind of deepsea operation.

Now I decided to build my own ROV and I know OPENROV is already a software developer and structure builder but please consider this is only a hobbie for me, is not going to be related to business.

I am starting from zero and I already programmed my own software using arduino UNO but I have some inquiries about ROV. first question, Why ROVs do not use Azimuth propellers? maybe some will say is not a need but somehow we can reduce te amount of Thrusters.

Well I am using a stepper motor for azimuth propultion using magnetic coupling, the command will be executed by a lever, depending of where you want to move it, my stepper motor will move 5 degrees for each step and will tell by a LCD how many degrees are the command given by the lever and how many degrees is the real possition of the stepper motor which i call feedback.

for propultion i am using DC motors with magneting coupling, I havent bought this ones but i will probably buy from some internet page i found called bluerobotics.com, I will use 3 Thrusters, ( 2 azimuth thrusters and 1 center tunnel thruster) all this propultion motors will be also controlled by levers which will give order for RPM controlled by PWM, I see some people talk about ESC, may somebody please tell me what is this?.

now i have some questions about my connections, how can i enclosure to watertight conections? we all know this is critical and i dont wnat any leakage of water going inside my ROV.

if i use 200 meters cable, will I lose data while sending from my microcontroller to the motors? pr there is no problem?

I only want this project to be a 100 meters ROV, so i am pretty sure i dont need to presurize anything with some oil or do i need?

many thanks to everybody who takes a second to read my post.


#2

Hi there!

Welcome to the community and hopefully you find some good ideas here for your own research and development. search through some of our old threads and you should come up with some good ideas that may not be complete due to time/money.

The OpenROV electronics and software are great to experiment from. Walt Holm and I have been experimenting with adding more functionality and a 6 thruster configuration. He and I are just reduced by time at the moment.

  1. “Why ROVs do not use Azimuth propellers?”

I can’t name a single professional or commercial ROV that uses azimuth thrusters. If you’re operating in salt water, the less moving parts you have the better. Also rotating thrusters is not a very rugged design and any hard knocks might move things out of alignment. You are welcome to try, but just know there aren’t any examples (that I know of) to work from. 3/4/5/6 Hard mounted thruster configurations are most common.

  1. ESC

Electronic Speed Control. It takes power from your power source, and a signal from a PWM output and can drive a motor at a desired speed. There are specific ones for brushed and brushless motors.

  1. “how can i enclosure to watertight conections?”

you’re going to have to pot the wires/connections like how OpenROV does it, use cable penetrators, like BlueRobotics or use expensive bulkhead connectors.

  1. “if i use 200 meters cable, will I lose data while sending from my microcontroller to the motors?”

You should be fine if you are using an Ethernet data connection.

  1. “i am pretty sure i dont need to presurize anything with some oil or do i need?”

Oil is messy and burns off with heated electronics. My recommendation is to not use it.


#3

Hello kevin_k!

is very nice to read a post from you because the first topic i Read was from you 2013 where you started developing ROV´s, so thank you so much for taking some time.

yes i know there arent any azimuth propellers for ROV´s that is the reason I will try to make one, as i said,with a stepper motor and magnetic coupling must be a good idea to do not have any kind of water leaking inside.

about ESC, i believe this is like a H bridge? this means in electronics using Transistors and diodes to separate your control device ( this is PWM) and your power device (this is motor).

let me ask you this question is going around in my head, i really do not know how to conect my arduino via RS232 with ethernet cable do you have any idea? or how to conect potentiometer wiper through 200 meters to reach my arduino analog input and do not lose data.

about enclosure watertight conections i saw the OpenRov potting like BlueRobotics and it seems nice also i saw SEA CON connectors which seems good!! i attach link http://www.amronintl.com/seacon.html.

thanks for reply again my friend!


#4

Hi Luis:

If you are new to ROVs and want to try designing your own, I highly recommend this textbook:

It’s expensive but well worth the money.

-W


#5

Thanks Luis, it’ll get done eventually!

Yes, ESC’s are a bit like H Bridges, although I don’t know of anyone who still uses those. Brushed ESC’s have mostly taken their spot.

I’m not really up with serial communications, but there are a few devices such as this that might work for your applications: http://yourduino.com/sunshop2/index.php?l=product_detail&p=323

I second Walt’s recommendation for the Underwater Robotics textbook. I also use the ROV Manual (Second Edition) for my reference. http://www.amazon.com/ROV-Manual-Second-Remotely-Operated/dp/0080982883/ref=sr_1_1?ie=UTF8&qid=1448423102&sr=8-1&keywords=rov+manual

Yes, those connectors from Amron are what I use. I use the Micro Wet-Con series and have had very good results. When I start upgrading enclosures, I’m starting to look at using bulkhead connectors (lower right). They are pretty expensive but worth it in the long run to me.


#6

do share your work with us… start a blog/page of your design & exploration.
:heart_eyes:


#7

Thanks to everybody for supporting me,

as soon as i start my project i will let you know, I will start by january because at the moment im working (offshore) as i said, the only possibility for me to start developing my project is only programming my software and at the moment i am guessing how to communicate through 200 meters with out losing data but i think i figured out how.

for those who are doing the same project as me the way to communicate is using RS485 commuicaating arduino masters to arduino slaves and this slave will execute what master says (for me, moving my motors).

will be kind of difficult but I am really interested on this.