Shenwei Zhu (A5) Sep-18-2006
Multiple-human Power Transmission System Feasibility Study Proposal
Purpose of study:
The multiple-human pedaling power transmission system here is very similar to a tandem bike
pedaling transmission system. The purpose of study is to optimize the energy transmission efficiency
from human pedaling energy to generator input energy. This feasibility study will also study the output
torque and RPM trade-offs to best suit the generator that will be used in the human-powered water still.
Design Variables: Material of the gear and chain, Type of lubricants, Distance between each gear.
Root diameter, Circular pitch, Tooth space, Tooth thickness, Addendum and dedendum of all gears.
State Variable: Efficiency of energy transmission, Gear ratio, Input to output torque ratio (it can be
calculated through gear ratio), length of the chains.
Constraints: Material life cycle (5000 hr), Cost (<$480), Maximum human-output power (150 W) and
RPM (100), Human output torque (can be calculated from power and RPM).
Analysis and Results:
MATLAB will be used to simulate and optimize the relationships between the design variables
(root diameter, circular pitch, tooth space, tooth thickness, addendum and dedendum) and the state
variables (gear ratio, input to output torque ratio). Before building prototypes, Pro E will be used to
simulate the motion of the transmission system under different human power input and RPM. Pro E will
also be used to study the possible negative effect of multiple human inputs working against each other.
The quantitative information that is developed will include the optimal root diameter, circular pitch,
tooth space, tooth thickness, addendum and dedendum of all gears; gear ratio and input to output torque
ratio can also be calculated to predict the behavior and performance of the transmission system given
reasonable human pedaling power input and RPM.
This feasibility study is in parallel with a differential transmission system study done by another
team member. Along with the differential transmission system trade study, team will choose either a
tandem bike transmission system or a differential transmission system to provide multiple-human power
input. The decision will be based on cost, efficiency of the energy transmission, as well as the availability
of purchasable parts. If the tandem bike transmission system is chosen, this study will also determine the
design variables listed above to optimize the performance of the overall system.
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Milestones 9/19 9/26 10/3 10/8 10/10 10/12
Indiv. Trade Study Proposal Due X
Matlab Model of DV vs. State Variable Built X
Parts' Specs Defined X
Feasiblity Decision Made by the Team X
If Feasible, Parts Will be Ordered X
CAD Model & Mechnica Simulation X
Indiv. Trade Study Due X