This document presents research on developing perching mechanisms for robots. It discusses developing micro spines inspired by how birds perch on surfaces. Various micro spine designs are explored with different shapes at the tip and top. Mechanical tests are conducted to evaluate the designs. The document also discusses alternative perching mechanisms using ionic polymer metal composites (IPMCs) that change shape when stimulated by electric fields similar to Venus flytrap plants. IPMCs are fabricated and tests show they actuate under applied voltages. The goal is to develop effective perching abilities for small robots to climb structures like birds and insects.

1. 10/7/2012
By
Sakthivel.R (09MI08)
PSG College of Technology Coimbatore.
,
Under the guidance of
Dr. P. Radhakrishnan, Director, PSG IAS.
And Co – Guided by
Mrs. Bindu Salim, PSG IAS
Courtesy: [1]
• Ability to attach or get clanged to inclined
surfaces or elevated positions.
• To develop appropriate perching devices for
Robots to perch on rough and glazed surfaces
• Small aircraft model robot can perch on vertical
surfaces using simple mechanical and suction-
based gripping systems.
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• Direct contact
• Data on current condition
• Bring samples
• Accurate information
• Automatic inspection and repair
• Ride out bad weather
• Preserve their energy
• Interchangeability of technology
• Watch out for the target
[3]
[5]
[4]
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The basic sequence of action through which the robot shall perch the vertical
surface shall be inspired from the perching action of birds.
identifying the slowing down itself striking the surface with Perching on the
surface in the when on the path the help of spine surface
mode of flight of perch
(Courtesy : Lillian Stakes 2008; [2])
possible velocities and orientations
mecha nical properties of the s uspension
• action of impact over a sudden period of time
• for rough surfaces the mechanical strengths of
the spine and asperity become the factors
• for smoother surfaces friction is more
important and the ability to pull in toward the
surface is much reduced
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• Arrays of small spines.
• Supported by a nonlinear suspension
• No power for clinging
• Relatively unaffected by films of dirt
and moisture
• Support large loads
[4]
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• Spine tip radius
• Distribution of asperities
• Average asperity size
• Surface roughness properties
• Narrowness and slant of peaks and valleys
• Number of spines per foot
Normal Force
SMD1
Tangential Force
Spine
SMD2
Spine Loading Cycle SMD3
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kinematic study.wmv
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• Spring Steel High Carbon
of Indian Standard IS
4454 Part I Grade 3
• Cutting a spring steel
blank of 1mm diameter
• Grinding one edge
• Bent to the required
radius at the top and tip
• Bent at the bottom
•Extruded acrylic sheet
•Laser cutting process
•5mm thick sheets
•Central sheet sawed
and cut for the invert
shape of the spine
•Holes using manual
drilling machine
•Load limiting pin was
glued.
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Ty pe 1 Ty pe 2 Ty pe 3
•Type 1: the top was bent for 4 mm inclined to an angle of
45°and spine tip wasbent with a radiusof 1mm.
•Type 2: the top was bent for 4 mm inclined to an angle of
45°and spine tip wasnot bent.
•Type 3: the top was bent for 4 mm inclined to an angle of
50°and spine tip wasnot bent.
•Inference: Type 1 was more smooth due to the tip bent
and type 3 slipped off often due to steep top bent.
Part Amount (INR)
Micro Spine 10.00
Spring Unit (one compression and
15.00
two tensile springs)
Fastening Rods and Load Limiting Pin 10.00
Spine holder, Side plates, Revolving
250.00
joint and assembling
Total 285.00
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• Shape change when stimulated by electric field
• When voltage applied, they contract in width
due to electrostatic forces and become longer
• Perfluorinated ionic polymers sandwiched
between thin noble metal electrodes
• Selectively pass ions inside the polymer network
• Embedded distributed circulatory system
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BASE MATERIALS [6]
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• Si l ver Oxi de Formation
• Uni form Coat of Electrode
• Surfa ce Roughening and Stretching
• Annealing
• Dehydration
The chemical constituent solutions used in reference to the bottle numbers.
II – Sodium Hydroxide, III – Millipore Water, IV – Chromic Acid, V – Ammonia Solution,
VI – Silv er Nitrate Solution, VII – Sodium Borohydrate Solution
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• Pre-Treatment of Membrane
• Silver – Amine Complex Solution is prepared by using 30mg
of silver nitrate in 10ml water and 1 ml of NH4 OH (1ml
ammonia in 10ml of water).
• Rinsed Nafion® substrate was put into the prepared silver –
®
amine complex solution and kept immersed for 10 minutes.
No colour change was observed in the membrane.
• The Strip is then rinsed, wiped and then immersed in
Sodium Borohydrate solution (30mg of NaBH4 in 20ml of
water) for 10 minutes.
• The silver deposition was identified from the appearance of
bright silver colour on the substrate.
• Solution of Sodium Hydroxide (10 pellets of NaOH
in 20ml of water) for 30 min and rinsed with water
• Dipped and taken at once in dilute chromic acid
• A substrate of Nafion® is dipped in a beaker
®
containing water and kept in ultrasonic cleaner
for 10 minutes.
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• The Membrane was dipped in Chromic Acid
Solution for 20 minutes.
• The Membrane is then rinsed with water and
wiped.
• A substrate of Nafion® was cleaned in a solution of
water and wiped using tissue paper.
• The water used in the entire process of Silver
coating over Nafion Membrane is de-ionized
millipore water.
Method 1
Method 2
Method 3
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Method 4
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• Contact wire soldered to
nylon fixture.
• DC supply - 1 to 3 volts.
• AC supply - square wave
of 1.5Vpp of 0.1Hz
frequency.
• 5 mm of the 30mm length
IPMC was kept inside the
fixture.
• The IPMC was hydrated
for 50 minutes.
• Responsive in the range
of 1 to 3 volts
• Response time - 2 to 3
seconds
• Step response
• Slow initial response due
to threshold limit of
IPMC.DC.wmv energy
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• Responsive in 2.5 to 3.5 volts
• Responded for 5 to 6 cycle times
• Degrading response for every
cycle time
• No response change after
3.5 volts.
• Back relaxation
• IPMC remained in its actuated position
IPMC AC voltage.wmv
• There was significant actuation response from
the IPMC.
• There was actuation response for both AC and
DC voltages. Back relaxation was found clearly
on application of AC voltage.
• The IPMC was effectively responding only for
the first actuation after every hydration.
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Fig. 2. Bending Response of Venus Flytrap [12].
• The i ono-elastic tri gger hairs generates an action potential
• This move hydrogen ions into thei r cell walls, lowering the pH
a nd l oosening the extracellular components.
• Osmotic effect - K+ is released into the leaf tissues and makes
the cel ls on one surface of the leaves swell.
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NEED FOR EFFICIENT ENERGY CONVERSION
DEMAND FOR ENERGY
DEVICE
USE OF DIRECT ENERGY CONVERSION
DEVICES
• Limitations of Vacuum Pump
– Working area
– Weight
– Pressure drop
– Usage of a pump
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IPMC - proposed.avi
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Development of IPMC model
• from membrane theory [9]
The forces a cting on the displaced membrane, restoring
forces and the dynamic equation governing the vi brating
membrane a re given by
F r is f orce in r-η plane
F Ө is f orce in Ө-η plane
P is the tension f orce
σ is the mass per unit
area of the membrane
material
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Development of IPMC model
• from lipid bilayers [10]
The converse flexoelectric effect describes the generation of
curva tures induced by a pplied electric fields and the
equilibrium radius of the tether as
IPMC ANALYSIS CASE STUDY [11]
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Material Properties
orthotropic relativ e permittivity 0.031
density : 2975 kg/m 3
[12]
dielectric constant of 0.00032 and
corresponding ANEL Matrix
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DEVELOPMENT OF IPMC MODEL FOR
CIRCULAR CONFIGURATION
Diameter = 40mm
Thickness = 0.3mm
Results
Displacement = 14.436mm
• The maximal tip displacement can nearly reach radius
• create a cup shape.
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• No s i gnificant response.
• Li ttl e a ctuation response - bending force created not enough
to overcome the constrained provi ded by the hollow plate.
• Significant actuation
• Did not form cup shape
• Bend about an axis along the diameter determined by initial
curvature of the membrane
• The IPMC was effectively responding for three actuations MOV06819.AVI
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• Cup shape by using two cantilever IPMC kept
crossed to each other.
• Suction creation using the setup.
• Integration of micro spine and IPMC assembly
to the robot
• Gripping force to be generated to resist wind
• Ways to detect failing of the grip is failing and
recovery before the plane falls
1. Analysis And Development Of Technology For Perching Mechanism For Flying
Robots for “National Seminar On Recent Adv ances In PIE And Remote
Technologies For Nuclear Fuel Cycle (RAPT 2010)” on September 23-24, 2010
at SRI Conv ention Centre, Anupuram, Kalpakkam.
2. Develop ment Of Technology For Perching Robots Using Ionic Polymer Metal
Co mposite f or “The First National Conf erence On Energy Efficient Mechanical
System Design And Manuf acturing” on 11th-12th March, 2011 at Department Of
Mechanical Engineering, PSG College of Technology, Coimbatore
3. Develop ment Of Micro Spine Technology For Perching Robots, f or “The First
National Conf erence on emerging Trends in CAD, Cam, CIM”, Department Of
Mechanical Engineering” on 29th April 2011 at Department Of Mechanical
Engineering, PSG College Of Technology, Coimbatore.
4. Develop ment And Performance Of Circular Shaped Ionic Polymer Metal
Co mposite f or “National Conf erence on Design and Manuf acturing 2011” on
27th – 28th May 2011 at IIT Madras Campus, Chennai. Also published in
“International journal of Applied Engineering Research” Volume 6, No.5.
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Dextrous Manipulation Laboratory: October 2, 2008.
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.
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, .
Micro Aerial Vehicles.
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[5] Robert T Pack, Joe L. Christopher Jr and Kazuhiko Kawamura: A Rubbertuator-Based Structure-Climbing Inspection
. .
Robot.
[6] Mohsen Shahinpoor et al.: Artificial Muscles – Applications of Advanced Polymeric Nanocomposites: T aylor and
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[7] Keisuke Oguro: preparation procedure - ion-exchange polymer metal composites (IPMC) membranes.
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/IPMC_PrepProcedure.htm
[8]M. Shahinpoor et al.: Ionic Polymer-Metal Composites (IPMC) as Biomimetic Sensors and Actuators - Artificial
,
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[10]Ben Harland: Voltage-induced bending and electromechanical coupling in lipid bilayers: The American Physical
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[11] Hanmin PENG, Yao HUI, Qingjun DING, Huafeng LI, Chunsheng ZHAO : IPMC gripper static analysis based on finite
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[12] W.A.Lughmani: Modeling of bending behavior of IPMC beams using Concentrated Ion Boundary layer:
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