Project Epsilon — Project Nebula
SONAR ACTIVE
AUV — Generation 5

Project Epsilon

Our fifth-generation autonomous underwater vehicle — purpose-built for RoboSub competition, engineered for precision at depth.

5thGeneration
8Thrusters
ROS2Framework
4KVision System
PELICAN CASE PRESSURE VESSEL T200 THRUSTER PVC FRAME
Vehicle Overview

Built to dive deeper — and think faster.

Epsilon is Project Nebula's fifth and most capable underwater vehicle, designed from the ground up for autonomous deep-water operation. Every system — from power distribution to the vision pipeline — was engineered in-house by our eight-member team.

The vehicle's modular architecture allows rapid reconfiguration between competition tasks. A new aluminum pressure vessel, tight cable management, and a centralized compute stack make Epsilon the most reliable machine we've ever put in the water.

At the core of Epsilon's intelligence is a ROS2-based autonomy stack fused with a real-time computer vision system capable of detecting, classifying, and tracking mission objects at depth — all without a tether.

Technical Specifications

By the numbers.

Hull Material
6061 Aluminum
Anodized, pressure-rated
Dimensions
610 × 330 mm
Length × diameter
Operating Depth
5 m rated
Competition pool max
Thruster Count
8× T200
Blue Robotics, 6-DOF
Battery
14.8 V LiPo
15 Ah, 4S pack
Compute
Jetson Orin
NVIDIA, onboard AI
IMU
VN-100
VectorNav, 9-axis
Vision
Stereo 4K
OAK-D, 30 fps
Software Stack
ROS2 Humble
Ubuntu 22.04 LTS
Subsystems

Under the hull.

Every major system — designed, built, and integrated by our team.

01
Mechanical Systems
Hull · Frame · Pressure Vessel · Manipulator
Mechanical

The vehicle frame is assembled from schedule-40 PVC pipe with custom 3D-printed T-joint connectors, housing a central circular aluminum pressure vessel. A modular endcap system allows fast payload swaps. The manipulator arm provides active gripping for object-handling tasks.

Pressure vessel — dual O-ring face seal, rated to 5 m with leak testing protocols
Vectored thrusters — 45° cant angle for full 6-DOF actuation without gimbal loss
Gripper manipulator — servo-driven, 80 mm jaw span, pneumatic-free design
FEA-validated frame — SolidWorks Simulation verified for pressure and impact loads
02
Electrical Systems
Power · PCB · Sensors · Wiring
Electrical

The power system is built around a custom power distribution board managing ESC feeds, 5V/12V regulation for compute, and fused protection for all rail outputs. All cables route through penetrator glands with secondary redundancy sealing.

Custom PDB — KiCad-designed, 4-layer PCB with overcurrent protection per rail
14.8 V, 4S LiPo — 15 Ah capacity, hot-swap capable endcap design
Fused ESC bus — individual fusing per Blue Robotics T200 thruster
Sensor integration — Bar30 depth/pressure, VN-100 IMU, DVL interface
03
Software & Autonomy
ROS2 · Mission Planning · State Machine
Software

Epsilon's software core is a ROS2 Humble architecture on Ubuntu 22.04 running on an NVIDIA Jetson Orin NX. A hierarchical state machine drives mission execution while a hardware abstraction layer decouples all driver code from business logic.

ROS2 HAL — clean interface between hardware drivers and mission logic
SMACH state machine — modular, testable mission sequencing for all tasks
Simulation pipeline — Gazebo Harmonic for HIL testing prior to pool runs
Data logging — ROS2 bag recording for post-dive diagnostics and replay
04
Computer Vision
Detection · Tracking · Stereo Depth · Localization
CV / AI

The vision system uses an OAK-D stereo camera feeding a custom-trained YOLOv8 model for real-time underwater object detection. Stereo depth maps provide 3D localization of targets, feeding directly into the navigation controller for closed-loop visual servoing.

YOLOv8 detector — fine-tuned on curated underwater dataset, >85% mAP
OAK-D stereo — on-device depth inference at 30 fps, hardware-accelerated
Visual servoing — closed-loop target alignment using centroid + depth feedback
Dataset curation — augmented pool footage with Roboflow annotation pipeline
05
Controls & Navigation
PID · Sensor Fusion · Thruster Allocation
Controls

Cascaded PID loops handle depth, heading, pitch, and roll stabilization. An extended Kalman filter fuses IMU, DVL, and pressure data for robust state estimation. A thruster allocation matrix translates 6-DOF commands to individual motor outputs.

Cascaded PID — independent loops for depth, yaw, pitch, roll, surge, sway
EKF sensor fusion — VN-100 IMU + Bar30 depth + DVL velocity integration
Thruster allocation — pseudoinverse TAM maps wrench to 8 motor commands
Dynamic tuning — in-pool parameter sweep with bag replay for iteration
Competition Tasks

What Epsilon has to do underwater.

RoboSub 2025 mission tasks — solved autonomously, no pilot, no tether.

01
Gate Passage
Navigate through a marked entry gate using heading hold and forward visual detection to align with the target frame and pass cleanly through.
02
Buoy Manipulation
Detect, approach, and physically interact with colored buoy markers using the gripper manipulator and visual servoing for precise positioning.
03
Path Marker Follow
Detect orange path markers on the pool floor via downward-facing camera and follow the sequence to the next task location autonomously.
04
Bin Drop
Identify target bins via overhead view, hover in position using depth hold, then release a marker payload into the correct bin using servo actuation.
05
Torpedo Target
Align with and fire pneumatic markers through small apertures in a target board using stereo depth-based targeting and precise lateral control.
06
Surface & Return
Complete the mission sequence and execute a controlled ascent to the octagon surface marker, demonstrating full autonomous mission completion.
Build Log

Epsilon's journey to the water.

August 2024
Design kickoff & requirements review
Team reviewed lessons from Delta, defined Epsilon's design goals: lighter frame, improved waterproofing, and a full autonomy stack.
October 2024
CAD finalized & parts ordered
Hull geometry locked in SolidWorks, FEA validation complete. PCB and thruster hardware on order.
December 2024
Mechanical assembly complete
Frame machined, pressure vessel assembled and leak-tested in dry dock. Thruster mounts verified.
February 2025
Electrical integration & first power-on
PDB installed, Jetson Orin booted, all ESCs enumerated. First full electronics test passed.
April 2025
First pool runs & controls tuning
Wet testing underway. PID loops being tuned per-axis. Vision pipeline validating in live pool conditions.
July 2025
RoboSub competition — San Diego
Target: complete full autonomous mission run and place competitively at AUVSI RoboSub.

Meet the team behind the machine.

Eight builders, one submarine. Learn about the people who designed, wired, coded, and dove Epsilon into existence.

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