Luna I is a small, cable operated, deep diving observation class ROV. It is designed to go to 300m and have an operation time of 3 hours.
First of all, I was surprised to find that Luna I was featured in the latest Hacklet edition for water borne projects!
It has been a while since my last blog posting because I have become very busy. I am currently working to complete the design and test some parts, The thrusters, through hull connectors and tether are the most difficult to figure out. As an aside, it is important to note the design of the Kort nozzles come from the SV Seeker website: http://svseeker.com/rov_thrurters.htm
In the coming weeks you should see the motor tests. This project is definitely long term because many of the parts are not cheap, many require custom fabrication and take much consideration before following through on a purchase. I also plan to update the design and the parts catalog to have real part links in the coming days.
I realized that I had no good way of mounting the thrusters to the t-slot. I decided I would engineer a bracket to snap fit into the bottom of the thruster pieces and then screw into the t-slot. On my second prototype I was happy with the result and decided to post it. The Stl file can be found here http://www.thingiverse.com/thing:1341956
Thruster isn't exactly level due to a print warp. A few screws should help with this
3D printing has made this build by far easier. I have now created the thruster pieces from the Ole herman Godø thruster plans and am ordering motors for them soon. For very deep dives, the hollow nature of 3D prints may cause a crush hazard. As I have no money to send one of these to somewhere like WHOI for high pressure testing, the crush depth is, and may always be unknown.
Shown here is the 2 blade design which will soon be updated to 3 blades for ease of printing. I am also designing a plate which will keep the bottom pieces aligned on the robot. I plan to test the thrust output in fresh water soon. It is expected to be about 12.5N of thrust at the top end. But tighter control of thrust in the lower end. These will be used when maneuverability outweighs the need for speed.
In 2015. I saw a video of a professional ROV doing work under water. At that moment, I thought "wouldn't it be great if this wasn't so expensive" one thing led to another and the ROV Luna I was created. The picture you see here is a concept drawing from Fusion360, this has many differences to the real thing which will be shown in the build logs. Luna I was created to explore deeper than the average scuba diver, safely and effectively observe and recover items from the bottom of lakes, and the ocean in the future. The ocean is a secondary goal for the moment due to the issues presented with salt water and currents. The great lakes look to be a good option for testing this system to full depth in the future.
The goal with this ROV is to learn about operating in deep water and understanding how large ROV systems work. I have built several land robots, written a ton of code and designed several PCBs. But nothing that I have done compares to the multi-disciplinary challenge of working in deep water. This is a learning experience for me and it is my hope that you will learn something from reading these logs too. Happy Hacking!