Human Electric Trike Thesis

Design of an electrically assisted human powered trike

Thesis Proposal

Problem

Current bicycles and recumbent tricycles are good forms of human powered transportation for most regions. However, for those that live in hilly or mountainous terrain, conventional human powered vehicles (HPV’s) are not well designed to traverse up and down the often severe grades in these regions. Unless the rider is in top physical shape, climbing hills will slow the vehicle to 3-4 MPH and require an extreme amount of physical exertion. In addition, some vehicles are not well designed to handle the descents, which can reach upwards of 35 MPH.

Several companies market motor assist kits to add electric power to existing bikes. Most kits include motors rated below 1 hp and have limited battery capacity which severely limits the range between charges. While these kits are good for level terrain they do not have the power or capacity required to climb steep hills at a reasonable speed. Another option, offered by some manufacturers, are power assisted recumbent tricycles. RunAbout Cycles (www.runaboutcycles.com) markets an electrically assisted recumbent trike that has a 40 mile range.

The recumbent design allows for a comfortable riding position and eliminates any balancing issues for those who may not be able to ride a conventional bike.

Objective

The objective of this project is to design, build, and test a lightweight human electric hybrid recumbent trike that will improve upon the capabilities offered by current vehicles. Analytical modeling, FEA, and CFD will be used to optimize the vehicle to meet the following preliminary requirements:

Maximum Assist Speed – 30 MPH on 0% grade, 20MPH up 10% grade

Range – 50 miles on 0% grade, 20 miles up 10% grade

Weight – less than 150#

Prototype Cost – less than $3000

Suspension – three wheel independent with damping

The preliminary requirements will be finalized after doing market research, and after evaluating analytical performance models. Before the design work is started, a Design Specification document outlining the requirements of the design will be written. In addition to the functional specifications, the vehicle will be designed with attention to manufacturability and industrial design.

Procedure

The following steps will be used to accomplish the goals of this project:

  1. Research existing human powered and power assisted vehicles – A comprehensive search for existing powered and un-powered HPV’s will be conducted to evaluate how other vehicles compare to the proposed specifications of this project. Vehicles will be evaluated by cost, range, weight, and power to see what is the current state of the art.
  2. Create Excel performance model
    Build an analytical model to predict performance of the vehicle. Model will include calculations for rolling resistance, aerodynamic drag, and motor and transmission losses. Model will allow for range and top speed predictions using different components to aid in selection of the correct motor and batteries to meet the specifications.
  3. Develop design specifications – Create a Design Specifications document outlining the vehicle’s design requirements. Document will define performance, weight, and cost requirements for the project. This document will also describe the analyses and tests required to meet the specifications.
  4. Design and create solid model of power assisted vehicle – A Sun EZ Tadpole donor tricycle (see attachments) will be used for many of the vehicle’s components such the as seat, wheels, controls, and drive train components. Solid models of the Sun trike’s existing components will be built in SolidWorks, and a new frame, suspension, and power train using will be designed.
  5. Perform weight study – Calculate weights for all components using the solid model and determine the mass distribution of vehicle using riders of different weights. Weight should be evenly distributed between the three wheels and within the weight target.
  6. Analyze vehicle components and structure using FEA – Analyze and optimize key structural components using CosmosWorks finite element software to determine part stresses. Design and analyze suspension movement using CosmosMotion motion analysis package. Build CFD model of trike and rider using Cosmos FloWorks software to determine drag and investigate drag reduction options.
  7. Produce drawings for fabricated components – Produce detailed drawings for all fabricated components. Create assembly drawing and parts list for all required components.
  8. Fabricate and procure components – Submit drawings for quotes, select vendors, and order all necessary components. Track all outsourced work to ensure schedule is maintained.
  9. Assemble prototype vehicle – Assemble all components and bench test sub-assemblies. Test motor – controller module before installing on vehicle, road test vehicle and adjust as required.
  10. Test vehicle – Instrument and test vehicle per tests specified in design requirements document. Make modifications if necessary and retest as needed, analyze, and document results.

Evaluation

This project will be evaluated by testing the final product against the goals set forth in the design specifications developed in the beginning of the project. A successful vehicle will be one that meets the performance and cost requirements and is a significant improvement over vehicles currently available in the marketplace.

Follow-Up

Upon completion of the project, a report will be written summarizing all activities and accomplishments of the project. An oral presentation of the project will be presented before the School of Engineering and any questions or concerns will be addressed.

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13 Responses to “Thesis Proposal”

  1. Gerfried said

    I’m flattened by this site- cool project. We are working one category below regarding power in our hyperbike.cc project.
    Would be nice to team if possible in some intercontinental RTD projects…

  2. Dave Moffitt said

    Dear Sir,
    I am a secondary school teacher and engineer working on a power assisted trike project of my own. Currently running a greenspeed tadpole trike with Bionx 250W assist. Looking to trial more powerful configurations. i would be very interested in following your project.

  3. Guillo said

    You work is amazing. My father and I began a proyect of Recumbent Bikes, just for fun. Now we have expand our limits becose your work.

    Continua inspirando, beneficia al mundo.

    Guillo.

  4. Odi said

    I like how you are using the Schwinn scooter motor. I think I might go to Sam’s Club and get one of those scooters and adapt the drive system to my mountain bike. Looks like a very cost effective way of doing it. Thanks for the idea!!!

  5. R Balaji said

    respected sir,
    i am a m.tech student.i am in need of a project based on design and analysis.i request you to kindly let me know about any available projects regarding design.i would like to get reply as soon as possible.

    thanking you

    yours faithfully

    R Balaji..

  6. Tim said

    Have there been any updates?

  7. Hey Bob, as you may know, when your done, you could get/make a shell for it. This would solve another problem: rain. Then you would have a velomobile: > http://en.wikipedia.org/wiki/Velomobile http://www.leiba.de (a 2 seater like this would be nice too) <. Keep up the good work, I’ll be back to check your progress.

  8. […] Not much activity on this site since he handed in his thesis, but some interesting material:- Thesis Proposal Human Electric Trike Thesis […]

  9. lenny said

    hi first up id like to say nice work. the thing is whilst its definately fun to go faster the troble is your speed and power are legally limited. surely the most productive area of research would be on extending the range of the trike with new energy storage technolagy and light weight materials, maby some solar assist. obviously you couldnt drive the bike exclusively off of solar but it would extend range and charge the bike, allbeit slowly, when parked. anyway best of luck with your project

  10. lem said

    its a nice work..
    is there any further ideas
    and complete information about this??

    Im very interested..may I ask
    permission for you to post
    all the detailed information about your work..
    plese…..^-^

  11. Hi, I happen to be writing a very similar dissertation to what you have done here. The only differences are my trike is more production orientated and the design is more focused on aerodynamics.

    The idea is to investigate the design of an electric three wheeled vehicle, to do this i am creating a hypothetical design (not to be constructed) and optimised this for a level of drag (Cd.A = 0.26 m^2). The website is in bits and pieces at the moment but i am constantly updating.

  12. Charles said

    Maybe look at this website. They are using lighter weight batteries and photonic solar film and items like hub motors to make lightweight solar electric vehicles. I supplose you could take their ideas and just make a reclinable seat and adjust the wheels and make a Reverse T Cycle. By removing the cycle components you might have better luck.

  13. Charles said

    http://www.solarvehicles.org/veepicturesvideos.html

    This is the web site it doesnt show up in the body. It is somewhat interesting. The newer light bike batteries and hub or wheel motors can make for some lighter designs.

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