P13211: Colisionless Rimless Wheel (Wired)

Detailed Design

Table of Contents

Website should document your journey through MSD, so include work-in-progress as well as latest results. Use PDFs for display whenever possible so that information is easily viewable without the need to download files and open applications. (Your EDGE file repository should still contain original files).

Week 9 Design Revelation

We went through several versions of actuation before we finally settled on one type. However, running simulations of our proposed system proved that our method would not work. So, we came up with a solution that works in simulation. It can be found at:
Methods of Actuation

Detailed Block Diagram

Detailed Block Diagram

Energy Flow Chart

Energy Flow Chart

Engineering Specifications to Customer Needs with Test Plans

Engineering Specifications

Engineering Analysis - Equations and Calculations


Electronic Off-Board Storage

Storage Comparison
Between 2 Mb and 144 Mb needed (2Mb for 1 60-second long trial with 10 16-bit inputs at 500Hz and 144Mb for 30 trials of 60 seconds with 10 16-bit inputs at 300Hz)
The verdict: On-board storage of microcontroller and development combined not enough for even a worst case scenario. Off-board storage is needed.

Timing Diagrams

Single-step Analysis

Periodic motion from MATLAB simulation. All quantities are scaled by their maximum value.

A close up view of the periodic motion during one cycle. All quantities are again scaled by their maximum value, except for the total energy, which is plotted as a percent change from the initial energy.

A close up view of the actuation. All quantities are again scaled by their maximum value, except for the total energy, which is plotted as a percent change from the initial energy. The effect of actuation can be seen in the linear increase in the total energy of the system.

A close-up view of the collision. All quantities are again scaled by their maximum value, except for the total energy, which is plotted as a percent change from the initial energy. The discontinuities in all quantities are due to the collision.

System Delay

link to simulations/calcs


MATLAB parameter simulations

Current Prototype Parameter Values Proposed System Parameter Values Units of Parameter
Number of spokes 5 5 Quantity
Length of legs 0.4064 0.41656 m
Mass of frame 0.737 1.5 Kg
Inertia of frame 0.021 0.066 Kg m^2
Mass of inertia wheel 0.9108 1.25 Kg
Inertia of inertia wheel 0.00723 0.112 Kg m^2
k-value of spring 3 5 (10.88) N m / rad (lbs/in)

Drawings and Pictures

Mechanical 3D diagrams

Frame Design/Plate Selection

public/pic_week11_frame.PNG public/pic_week11_frame2.PNG


public/pic_week11_frame3.PNG public/pic_week11_frame4.PNG


public/pic_week11_frame5.PNG public/pic_week11_frame6.PNG


public/pic_week11_frame7.PNG public/pic_week11_frame8.PNG

Plate Fabrication Trial

Plate Fabrication Trial
In case the above link doesn't work:
/public/Senior Design 1/Plate Fabrication Trial 2012-11-16.pdf

Electrical Systems

TI LaunchPad

Microcontroller Development board:


public/nh-aa250x1.jpg public/battholder.jpg




Microcontroller setup

Motor Control Algorithm

Control Algorithm Block Diagram

Block Diagram of Algorithm

Bill of Materials (BOM)

Tentative Bill of Materials - Googledoc Spreadsheet

Risk Assessment

Probability & severity on 1 - 3 scale, where a "3" rating in both cases means very likely and we are totally screwed, respectively.
Description Probability Severity Risk Factor Mitigation/Prevention Strategy Watchdog
Illness/time consuming obligations 3 2 6 Do not rely upon having time in the future to accomplish task All
Materials unavailable & long lead times 2 3 6 Determine parts orders as far in advance as possible. Where applicable, have alternative vendors lined up. Owen
Lag time of system from data collection to movement 2 2 4 Compile very accurate system timing diagram by reviewing each parts' delay and minimize delays where possible. Maddy
Real life does not match up with simulations and theoretical data (includes if actuation will actually work or not & general theory -> physical) 3 3 9 Run as many simulations as possible, double-check work, get as many professional opinions as possible before diving into system realization. Hao
Cost v.s. quality 2 3 6 Determine minimum requirements for quality Owen
Proper distribution of weight 1 2 3 Wise placement of devices Dan
Ability to obtain motor at all/in time 3 3 9 Keep looking, ask for help if needed Becky
Complete structure breakage (mistake, breaks during tests) 1 3 3 Design system (choose materials) to be strong Owen

Detailed Design Review

DDR Presentation
Pre Read Package

Beginning of SDII

Shared Vision for week 3 of MSDII

Home | Terminology | Planning & Execution | Systems Design | Build, Test, Document | Photo Gallery