Complex three-link tail system design1 amplifies tail motion whilst minimis-

ing fish body motion, required for stable video stream

Forward kinematics method applied to design motion amplifying linkage.

Single motor used to entirely mimic fish swimming motions

1: Sayyed Farededdin Masoomi: Design, Fabrication, and Swimming Performance of a Free-Swimming Tuna-Mimetic Robot a Free-Swimming Tuna-Mimetic Robot

Kinematics

Robotic Fish

A custom PCB was manufactured for the electrical requirements:

Atmel microcontroller Required for hardware interrupts

PWM2 driver Servo & LED control

IMU3 Live pitch and roll update

Pressure sensor Live depth data

Motor driver Driver for tail linkage and buoyancy system

PCB Raspberry Pi 3 Model B A raspberry pi micro-computer was used as the main processor. This was essential for encoding the live video stream.

2: Pulse width modulation 3: Inertial measurement unit

Team members: Ben Fortune Mark Rayne Ben Mitchell Winston Poh

Director of Final Year Projects:

Dr. Mark Jermy

Client: Dr. Sharyn Goldstien (School of Biological Sci-ences, University of Canterbury) Supervisor: Dr. Stefanie Gutschmidt

Technicians: Julian Murphy, Garry Cotton Other University staff: Dr. Mark Jermy, Dr. Don Clucas, Julian Phillips, David Read Technical help: Nils Jensen

Problem Statement

The University of Canterbury's Department of Biological Sciences requires

an underwater vehicle to traverse the coastal waters of Kaikoura, to obse-

rve marine life with minimal disturbance to them. Water sample collection

is also a required feature.

Specification

Operation to depths up to 20 m underwater

Minimum 30 minutes operation on full charge

High resolution live video stream for navigation in highly turbid environ-

ment

Problem Statement

Peripheral driver circuit board Tail linkage

driver motor

RaspberryPi single-board computer

for data and video processing

Water sampling valves

Tail linkages

Pectoral fin

servos Depth control

syringe and motor

Rib-reinforced

silicone tail

Biomimetic Robotic Fish

Tether for real-time video stream-ing and control.

Two sampling vials

Up to 20m depth control

Up to 30 minutes operation on full charge

Solution

Li-Po batteries (rechargeable)

Camera and stabilizer servo

Design

Caudal Fin Pectoral Fins

Fish Head

Window

Electronics