02.1 - Project Proposal
Introduction
In city tours like those in Venice, Italy, and Bangkok, Thailand, canoe or boat tours provide a unique way to see the sights of a city from its waterways. This traditional form of transportation adds to the history of the cities and allows visitors to have a unique experience. However, traditional methods of human-powered canoes take a lot of human effort and energy.
While boat engines such as the Sterndrive and Jet Drive Engine deliver sustained power, they are inherently noisy and tend to pollute the tranquil atmosphere of nature. To help solve this issue, our team’s project idea was inspired by Viking longships, which have multiple paddles to help propel the canoe to move forward. In this project, we plan to design a mechanism that can deliver efficient thrust to the canoe. Additionally, the team aims to allow the canoe to move forwards, backwards, and perform turns, adding to the travel possibilities of its passengers.
Problem Statement
In our proposal, each side of the canoe has multiple paddles moving in synchronous motion, like the paddles of a Viking longship. In addition to that, each side needs to be able to move independently for turning purposes. To provide enough thrust, we plan to develop a linkage system that pushes the paddles above the water surface and pulls them under the water.
This cannot be accomplished by a simple joint because the optimal path is a complex, non-circular path. This is due to the optimal path the paddle takes minimizing the distance traveled above water, to maximize the efficiency of the system.
Motion profile of rowing:
Simulation of rowing in an optimization context | Multibody System Dynamics
Mechanism
Our idea for the rowing mechanism combines four-bar or six-bar linkages with a gear train. This allows each paddle to follow the ideal rowing path while remaining synchronized for its side.
The linkages system directs the paddles to move in the desired shape, which is similar to that of a walking linkage. Each linkage receives power from the coupling rod for its side.
6 Bar Walking Linkage - DIY Walkers
The gear train mechanism receives power from a motor and powers the coupling rod to drive the paddle linkages. The coupling rod is attached to gears on opposite sides of the gear train at the same position on each gear. These end gears are the same size and have the same gear ratio to the drive motor. This will always keep the coupling rod horizontal, ensuring that all attached linkages will remain in phase. There is an independent motor linked to each side’s gear train to allow for turning and breaking by independently manipulating each side.
Scope of Work
Stage 1, motion analysis and rowing mechanism design:
Identify optimal path for paddling
Complete kinematic analysis to the output of the linkage systems
Design the 4-bar linkage mechanism to achieve motion and verify functionality
Order the necessary components that are needed for linkage and gear systems.
Stage 2, overall CAD design and Arduino programming:
Get one paddle fully functional
Design train of gears
Design all other necessary cad (body, etc)
Design wiring diagram and write arduino code
Stage 3, fabrication and refinement:
Testing single paddle
Testing multiple paddles together?
Scope of Work Summary:
Final goals:
Successful rowing motion, evaluated against ideal path
Need to perform motion analysis for ideal motion prior to fabrication.
Need to manufacture rowing mechanisms
50% power efficient mechanism
Compact mechanism
Synchronized rowing motion for each side
Incorporate multiple paddles
Need to manufacture gear train mechanism with coupling rod
Independently controlled rowing motion between each side
Need to write Arduino program to control motors
Need to design wiring for motor controller, Arduino, power, and user control.
Looks like a Viking longship
Stretch goals:
Tiago Goal: Floats and operates in water --> tiago takes swim class 🏊
Remote/wireless control
Preliminary Design Ideas
4-bar mechanism with planar input, ball-socket joint at oar connection for non-planar motion
Gruebler equation:
3(L-1) - 2J1 – J2
For a 4-bar:
3(4-1) - 2*4 = 1DOF