ROBOTIC TIGER
P13029
http://www.plasticpals.com/?p=30286
Agenda
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Project Goals
Legacy Projects
Air Muscle Info
Customer Needs
Specs
Functional Decomposition
System Flow Chart
Tiger Jump Dynamics
Jump Logic
Morphological Chart
Concept Selection (Pugh)
Tentative Parts List
Kinetics
Testing
Theoretical Muscle Force Calculations
3D Modeling
Feasibility
Risk Assessment
Schedule
Project Goals


The project goal is to create a robot that mimics a
jumping tiger both dynamically and to a lesser
extent, aesthetically
The jumping force is to be provided by air muscles
Legacy Projects





P08023/08024 - Artificial Limb I/II
P09023 - Artificial Limb III
P10029 - Process Development for Air Muscles
P11029 - Biomimetic Crab
P12029 – Biomimetic Robo Ant
Air Muscles



Rubber tube inside of a braided mesh sleeve
Pressurized tube inflates causing the mesh to
contract in length
Closely mimics biological muscles
Air Muscle Contraction
• 28% contraction at 49psi under 29lb load
Air Muscle Fill Speed
• .18s to reach 28% contraction
• Source: http://www.shadowrobot.com/downloads/datasheet_30mm_sam.pdf
Customer Needs
Customer
Need
Importance
(1 = high)
CN1
CN2
CN3
1
1
1
CN4
CN5
2
2
CN6
2
CN7
CN8
2
3
Description
Can jump forward a distance equal to at
least the length of its body (only 1 jump
required per tank fill)
Use air muscles to provide jumping force
Lands safely without damage
Is ready to jump again after landing,
without user adjustment of robot body or
legs
Self-contained (on board power sources)
Portable (small enough for one person to
carry)
Reasonable battery life; battery charging
takes hours
Resemble a tiger
Specifications
Spec
Source
Metric
Unit of
Measure
Marginal
Value
1*body
length
Ideal
Value
1.5*body
length
Yes
Preferred
Direction
S1
S2
CN1
CN1,2
Horizontal Jump Distance
Uses Air Muscles
Feet
Binary
S3
S4
S5
S6
S7
S8
CN3
CN4,5
CN3,6
CN3,5,6
CN3,5,6
CN3,5,6
Sliding Distance After Landing
Self-Contained
Overall Weight
Overall Length
Overall Height
Overall Width
Inches
Binary
Lbs
Feet
Feet
Feet
3
2
Yes
25
2
1
Down
50
4
2
1
S9
CN8
Resemble a Tiger
Percent
80
100
Up
S10
CN2
psi
<60
S12
S13
S14
CN9
CN2,9
CN2,9
Regulated Air Pressure
Total Response Time to Jump
Command
Solenoid Response Time
Muscle Fill Time
0.3
50
0.1
0.15
25
0.75
Down
Down
Down
S15
S16
CN2,7
CN2,8
50
100
Yes
Up
S17
CN4,5
Battery Life
Four Actuated Legs
Tank can be removed in 5 min,
without tools
s
ms
s
# of
Jumps
Binary
S18
CN1,2,3,4
Allowable error in leg
measurement/adjustment
Binary
Degrees
Up
Down
Down
Down
Down
Down
Yes
3
1
Down
Functional Decomposition
System Connections
Air Energy
from
compressor is
stored in tanks
Pressure
energy is
converted into
motion
Air Muscles
and Cables
Moves hind
legs for
jumping action
Leg Mechanism
function
simultaneously
for Jumping
motion
Control system
Designed for
system (Lab
View)
Sends a
Output through
Wireless
transmitter
Output
Changes the
state of the
Solenoid
Valves
Battery/Tether
Power Runs
Compressor
Tiger
Jumps
Forward
Tiger Locomotion
Using the average cat as a
model, the muscular and
skeletal systems were observed
to get a basic idea of what
muscles are involved in a feline
jump with special attention
given to the front and hind legs
Tiger Locomotion


Jumping force will come from
the hind legs and lower back
Front legs will be used as
shock absorbers for landing
as well as getting the robot
in position for each jump
Bracing for Impact
1st
2nd
3rd
Air Muscle Layout
Concept 1
Concept 2
Concept 3
Leg Design
Overhang for cable
attachment
Jump Logic
Power On
Contract muscle
Group 1
Reset Muscle
Positions to normal
Contract muscle
Group 2
Wait for Go
Input Command
Go?
Yes
No
Return
Wait for
landing Sensor
input
Yes
Release
Muscles
No
Hold
Morphological Chart
Concept Generation
Component
Cheap
Baseline
Light Weight
Sturdy
Group Opinion
single tank
single tank
carbon fiber tank multiple tanks
single tank
lithium ion
lithium ion
NiMH 2000 mAH
Air Supply
Electrical source
NiMH 2000 mAH NiMH 2000 mAH
Controller
push button w/
delay
push button w/
delay
tethered control
tethered control
push button w/
delay
no handles
no handles
no handles
handles
no handle
plate
frame and plate
frame
frame and plate
frame and plate
plastics
aluminum
carbon fiber
steel
plastics plate,
aluminum tube
plastics
aluminum
composit tubing
steel
aluminum
plastics
aluminum
plastics
steel
plastics
none
fiber glass
none
carbon fiber
rapid prototyping
Transport
Base
Base Material
Leg Material
Joint Material
Housing Cover
Pugh Chart
Selection Criteria
Weight
A
B
C
D
E
Cheap
Weighted
Rating
Score
Baseline
Weighted
Rating
Score
Light Weight
Weighted
Rating
Score
Sturdy
Weighted
Rating
Score
Group Opinion
Weighted
Rating
Score
cost
+/-
3
1
3
-1
-3
-1
-3
0
0
technical risk
+/-
3
0
0
0
0
-1
-3
0
0
portability
+/-
2
0
0
1
2
-1
-2
1
2
land safely
without
damage
+/-
1
-1
-1
1
1
1
1
1
1
air capacity
+/-
2
0
0
1
2
2
4
2
4
3
1
3
-1
-3
-1
-3
1
3
3
1
3
1
3
-1
-3
1
3
reuses available
yes/no
parts
weight
+/-
Total Score
Rank
8
2
DATUM
0
4
2
3
-9
5
13
1
Tentative Parts List


Legacy parts used to reduce cost
Clippard Pneumatic parts
Material/Item
Air Tank
Regulator
Solenoids
Manifolds
Air Muscles
Air Hose
Air Fittings
Batteries
Charger
Arduino
Wiring
Name
Paintball HPA Tank
Regulator for Paintball Tank
24V 2000 mAhr NiMH Battery
Tenergy Smart Charger 12-24 V
Arduino Mega 2560
QTY Description/Part Number
1 3000psi compressed air 48 cubic inches
1 High pressure air regulator
24V solenoids
1
1
1
Used to connect muscles to manifold
Tank to manifold connections
Existing battery pack from previous projects
Existing charger from previous projects
Mouser 782-A000047
Various electronic connections and wires
Kinetics


MATLAB simulation will yield required forces from
air muscles
Simulation consists of two portions
 Take
off
 Free flight
Preliminary Testing
A quick rough test rig was set up (see
video bellow) In order to see how
muscles behave under loading
(deflections, Inflation speeds, max force
to failure) and also get a rough idea of
what kind of forces and deflections we
can get out of an air muscle, Much
more testing to come
Blue air muscle specs:
Roughly .5” deflection
32 lbs till Failure (fitting pulled out)
Test Muscle Data
Tested Air Muscle Dimensions\Information
Tube and Mesh Constructed
Muscle Identity
Orange Mesh
Uncompressed
Length
Compressed
Length
Tube
Dia. at
Rest
Max Dia.
OD
Material
Type
ID
Mesh
Thickness
Rest Dia.
Contracted
Dia.
4.625
3.5
0.3
0.595
0.18
0.09 Silicone
0.036
0.3
0.73
RWB Mesh
4.5
3.25
0.28
0.745
0.18
0.09 Silicone
0.036
0.28
1
Red Mesh
4.5
3.5
0.257
0.59
0.18
0.09 Silicone
0.036
0.257
0.573
Tan Mesh
4
2.5
0.75
2.215
0.5
0.25 Silicone
0.125
0.75
2.5
Blue Mesh
3.4
2.9
0.5
1
0.5
1.3
Rubber
Theoretical Calculations
Calculations
Muscle Identity
Weave Angle
(degrees)
Weave Angle
(radians)
Pressure
(psi)
Dia. at
Rest
ε
F
Orange Mesh
20
0.34906585
60
0.3 0.243243 18.74689
RWB Mesh
20
0.34906585
60
0.28 0.277778 12.05734
Red Mesh
20
0.34906585
60
Tan Mesh
20
0.34906585
60
Blue Mesh
20
0.34906585
60
0.257 0.222222
0.75
16.0316
0.375 7.883798
0.5 0.147059 93.38133
Theoretical Air Muscle Calcs
• Source: http://lucy.vub.ac.be/publications/Daerden_Lefeber_EJMEE.pdf
Theoretical Air Muscle Calcs
Force vs. Rest Weave Angle
40
Tension Caused by Muscle (Pounds)
35
30
25
20
15
10
5
0
14
15
16
17
18
19
Rest Weave Angle (Degrees)
20
21
22
23
Theoretical Air Muscle Calcs
Force vs. Pressure
25
Tension Caused by Muscle (Pounds)
20
15
10
5
0
40
45
50
55
60
65
Pressure (psi)
70
75
80
85
Theoretical Air Muscle Calcs
Force vs. Rest Diameter
70
Tension Caused by Muscle (Pounds)
60
50
40
30
20
10
0
0.25 0.26 0.27 0.28 0.29 0.3 0.31 0.32 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.4 0.41 0.42 0.43 0.44 0.45 0.46 0.47 0.48 0.49 0.5
Rest Diameter (in)
3D Modeling
Rendering
2: Legs and
tiger design
in a ready to
jump
position.
Rendering
3: Concept
in a fully
extended
position, just
after jump
initiation.
3D Modeling
Rendering 1: Shows the right side view of the 3D modeled concept
leg design.
Design Sensitivity
D
R
F
Diagram: Shows dimensions used in design sensitivity analysis of
leg joints.
Design Sensitivity
Design Sensitivity
Design Sensitivity
Feasibility

Battery Life (continuous use, 2000mAh 24V NiMH)
 L=battery
life, I=current per solenoid
𝑡=

Force
 Simplified
𝐿
𝑁(𝐼𝑠𝑜𝑙𝑒𝑛𝑜𝑖𝑑 )
2000𝑚𝐴ℎ
𝑡=
3 (4)(27𝑚𝐴)
𝑡 = 6.2 ℎ𝑟𝑠
linear actuator model
 165lbs of force for 20lb robot to jump 1.6ft
Risk Assessment
Risk
Long Lead Time
Effect
Group
Dysfunction
Unable to complete
robot construction
due to lack of
certain ordered
parts.
Could result in
changes in
development.
Unable to complete
some aspects of
project.
Dissatisfied
customer. Follow up
projects would be
hindered
Divergent design
ideas.
Inadequate
Lack of or sub-par
Mismanaged
Budget
Mismanagement
of Time
Poor
Documentation
Cause
Natural for some
unique parts. Poor
group planning
Poor group planning
and limited funds.
Poor group planning.
Lack of time
management.
Poor documentation
throughout design
and testing process.
Poor communication
and decision
protocol.
Chance
of
Occurri
ng
3
2
Severity
4
4
Importan
ce
12
8
2
3
6
2
4
8
1
2
2
Action to Mitigate
Make sure to plan on
ordering specialized
parts promptly. Include
shipping times in planning.
Exercise budget
management properly.
Plan out all aspects of
development and testing
properly for allotted time.
Continually update logs
and keep track of data.
Make back-ups of data.
Build a decisions making
system.
Research muscle
Risk Assessment
Risk
On Board Power Supply
Dynamics Design
Dimension Related Muscle
Interference
Air Muscle Performance
Failure
Electrical Communication
Failure
Material Failure
Effect
Cause
Failure of electronics to
operate.
Not enough power supplied
from on board.
Proper jump motion is not
achieved.
Poor leg design
Muscles cannot expand
fully causing less than full
utilization of muscle
potential
Poor layout planning.
Inadequate attention paid to
design around muscles.
Muscle tears or expands Poor construction protocol.
in an unexpected manner Non-uniform construction
leading to poor dynamics quality of muscles.
and function
Failure of all solenoids to
release air to muscles.
Extreme movement of this
robot could loosen wires.
Landing may also cause strong
enough impulses to disconnect
electrical circuits.
Material yielding leading Poor material selection/design.
to failed operation.
Chance of
Occurring
Severity
Importance
Action to Mitigate
Test power supply.
3
3
12
5
4
20
Take care when in design
phase.
6
Take care when in design
phase. Account for muscle
expansion.
2
4
3
4
16
Take great care when
constructing each air muscle to
ensure quality and uniformity.
Make sure electrical
connections are secure.
2
3
1
2
2
6
Consider strains and stresses
induced in structures when
designing tiger.
Schedule
MSD1
Meet With Guide
Learn Edge
Code of Ethics
Customer Needs
Specs
Benchmarking
Functional
Decomp
System Flow Chart
Risk Assesment
Morph/Pough
Chart
Leg Concepts
Tiger Leg Modeling
Jump Logic
System Design
Prep
System Design
Review
Muscle Data
Collection
Peer Review
Create Test Plans
Prototyping
CAD Models
Bill of Materials
Arduino Code
Project Manag.
Review
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Week 10
Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S Su M T W R F S