Group 11- ASME Design Competition

• Alicia Christie

• Desmond Bourgeois

• Toddrick Ruff

ASME Design CompetitionRule Update

•Rocks do need to touch receiving area

•1 rock in each circle

 ScoreS = Σ (R*t) +1000P - W - A - 1000T – 5sR = designated rock score t = target multiplier W = Weight of the vehicle in grams A = milliamp-hours available to the device according to the battery labels T = Times device touches border tape s = seconds to complete task, maximum 240 P = bonus for parking vehicle at end of task (1 = parked, 0 = not parked)

 

2 – 1700 pt rocks1 – 1600 pt 2 - 1500pt2 – 1000pt

Schematic of Test Course

Decision from Last Presentation3 – Wheel Design

Street Sweeper

Mechatronics, Ariel University Center

Design Conceptrotate

move

Must be in an equilateraltriange configuration forsymmetry

r

2*cos(30)[r+s/2]

s

L3.500

4.000

Wheel set distance D = 4r + s : if r = 1 in, s = 1.18 in, D = 5.18 in

D*2 + 4 in (box size with guides in back) = 14.36 in with wheels and box touching

Max length is 14.5 in

r + 2*cos(30)*[r+s/2] = 3.75 in

Design Concept

4.00

3.50

r

3.5-r

d

r

?

d 42

3.5 r( )2 in

Final Design

•Wheels are offset with front wheels on inside

barrier

barrier

Idea for body expansion

• Switch blades

Approximate

Extension Length

Interim Prototype

3 Wheel Operating Principle

Exploded View Assembled View

Assumptions•Const. load with uniform shock•Const. mesh with no backlash•Axial load is negligible•Qv < 5, low pinion velocity < 13m/s•99% reliability•Full-depth teeth with tip loading• Pressure angle 20º •Operating temps < 200º • Teeth form standard AGMA profile

Gear Force Analysis

RadialTangential

Axial

Gear Force Analysis

TPH

p 20 deg H .121hp

TP 3.447N m

TP 2.542ft lbf

wt

TP

dp

2

wr wt tan wresultant

wt

cos

wt 229.768N wr 83.629N wresultant 244.514N

wt 51.654lbf wr 18.8lbf wresultant 54.969lbf

Resulting Forces

Given

.p 250rpm

Rock Collector

Free Body Diagram

Position #1• Assumptions

– Weight of box = 2lbs– Weight of Front = 7lbs– Tipping will not occur

on back wheel

TdWdWTM FrontBox )cos()cos(; 21

3.5in

2lb

1lb

3lb 3lb

1.5in5.9in

10.225in

M = 34.04 lb-in, moment created by rock collector would have to exceed this limit to tip over giving a negative moment

∑M = ∑F*d

Cost Analysis

Cost Analysis

Current Total: $943.70

Future Plan

• FEM Analysis to determine ways to remove material

•Exact gear placement to minimize motor use

•Power input and velocity calculations

•Exact placement of wheels and expandable body to fit within size requirement

•Placement of batteries and motors

•Control configuration

•Amount of motors, gears, other control components

•Program control components