Final_Project:

Final Project: Hako USV (first sketch)

For my final project I will be designing and building a modular, solar powered, unmanned surface vehicle (USV).

How it will work:

Each hull will have minimum 3 basic sections containing different modules designed for different purposes both hydrodynamicly and functionally and the two hulls will be held together with by a solar panel that will house the electronics underneath it in a waterproof container:

I will add a depth sounder to gauge the depth of the body of water and possibly find fish as well as IoT and GPS capabilities to be able to operate the vehicle remotely

rctestflight autonomous box boat

Why a USV?

Having grown up near the ocean and spending my past few years in Thailand reignited my passion for the ocean and I wanted to combine my passion for the ocean and technology into this final project and I stumbled across a YouTube video of a guy making a basic USV from a box which inspired this project but I didn’t have the resources at that time. now I am living in Shanghai and there are these murky waterways all over the city and I would love to explore them and find out whats in them.

waterways where I live

Why modular?

I wanted to design a USV that will be able to be a robotics platform well into the future but having never done this before the likelihood of making an flawed boat on the first attempt is probably whats going to happen. maybe it will be too small or too big or not buoyant enough… So I didn’t want to go all in on a design just to find out its the wrong boat fro the job and I have wasted months of work and thousands of dollars. So the boat needed to have sections. The boat to be built easily by people who have never build a boat project before and have limited skills and possibly limited access to a workshop or a large space to build huge hulls in one peice. So I imagined a design where each hull module could be printed in as few sections as possible on a 3D printer with one roll of filament or less. I also wanted to simplify the building process. One of the difficulties I imagined for novices would be the building and fiberglassing bulkheads in the hulls of a catamaran so I decided to rather have sections stuck together so the outer walls will function as bulkheads and it would also stop leaks in the hull from sinking the entire boat. this would also make transporting and working on different sections of the boat more manageable. To keep the the weight low in the boat the hulls will house components and have small removable acrylic windows giving access to the components

catamaran bulkheads

modular hull design

Design Inspiration

I have been heavily inspired by the saildrone company and their USVs and a youtube channel called RCtestflight who has done many USV experiments.

saildrone:

rctestflight:

The boat will need to be be air powered using drone motors to avoid bio fouling and needs to be modular in the sense that I can add or take away hull sections according to my needs with the hull sections containing extra sensors or batteries etc. Airboats generally have a flat bottom and catamarans generally have a curved displacement hull. Having a flat bottom on a small catamaran like this could allow it to be blown around to easily by the wind and having the curved hull design would make it difficult to design the expandable modules. So I thought about the parametric laser cutter design section of the corse and the dodecahedron parametric kit that I made in 2022 and the self building machines from the MIT fab lab and was wondering if there was anything like this in nature and immediately box fish and pufferfish sprang to mind was thinking about how I could design an efficient hull with these two concepts with solar power in mind and boom sunfish. I remembered baby sunfish have a wild geometric shape to them and thought this is all starting to work so I started looking at geometric inspired designs for ships from the “warmind” expansion of destiny 2 that inspired my original parametric laser cut kit and then randomly cruising through google images I came across a modular boat design by a Danish triangle cult called “n55” that used tetrahedrons and octahedrons that seemed to solve all these problems. The shape can be combined infinitely to make a hull as needed and the V shape at the bottom will help the boat track straight as seen below.

Video game inspiration: Destiny 2 warmind expansion

Similarities between Voxels and warmind cells from destiny 2 and baby molomola:

N55 modular boat design:

2D and 3D Modeling

I started just converting my sketch to a 3D model to assess how realistic it is and what improvements need to be made.

Overall good hull shape, the biggest improvements needed to be made would be increased freeboard and a sturdier method to connect the hulls as using the solar panel might not be very structurally sound.

Design v2:

Changes:

increased freeboard to 50cm

changed from pentagonal sections to hexagonal for ease of use

added an acrylic bridge section to hold hulls and solar panels together

added a connecting mechanism to hold hulls and bridge together

added acrylic windows to access hull sections more easily

Prototyping:

first cycle:

1. Make a motor circuit that works and test some different components
2. 3D print a hull and check that the parts fit
3. Build the connecting mechanism and test for strength

Motor circuit:

I selected a list of components from am open source drone project to ensure compatibility

Tmotor p60

Lip battery

60A ESC

PDB

Additionally I ordered some battery connectors and a servo motor tester

3D printing:

Since these are just to test the size and fit I will be using PLA on my ender 5 on default settings

Connector mechanism:

I ordered two 16mm carbon fiber tubes and some 3D print screw threads

https://fabacademy.org/2019/labs/fct/students/antonio-gomes/projects/final-project/