seminar presentation of robotic finger

8/14/2019 Seminar Presentation of Robotic Finger

1/15

SOME ISSUES ON DESIGNING ROBOTFINGERS FOR STABILITY OF GRASP WITH

ENHANCED FORCE

Soumya Das,Indranil Gupta, and Bibek Jyoti Das

Final Year, Dept. of Mechanical Engineering andProduction Engineering

Haldia Institute of Technology


2/15

OBJECTIVE & SCOPEObjective

primary objectives of the investigation is,

to develop one finger with a kinematic linkage systemwith the similar motion characteristics to human fingers.

Scope

The scope of the present project emphasizes ondevelopment of a robotic hand with newly developedfinger for dexterous manipulation with further integration

to sensory motor systems.


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EVOLUTION OF A DIRECT LINKED ROBOTICHAND

In the present investigation, a direct linked robotic finger

has been developed, that can replicate the human fingermotion characteristics. Synthesis has been done on thebasis of some pre defined criterion and the finger hasbeen analyzed through ADAMS as well as real life modelsimulation. It has been observed that as per as thegrasping forces are concerned this poses higher grasping

force.


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BASIC GRASPING ALGORITHM

Planning

&Interpreting

Command

Preshaping

Holding

SlipNoYes

Grasping force

Stable Grasp


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RANGE SYNTHESIS OF DIRECT LINK FINGERTo synthesis the finger two conditions are given,

a) the ratio of the fingers is given. If the length of the L5

is a

length of the link L7

is 1.6a and length of the link L8

is

2.58a.

b) the final positions between the links are known, i.e. anglebetween the link L

7and link L

8is 900 and after that the angle

between the link L7

and link L5

is 1200. The link L8

would be

fixed to the ground.

Then by trial and error method the links of the robot finger issynthesized.


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THE KINEMATIC LINKAGE FOR ACTUATIONOF THE FINGER

Input link Finger tip


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PT = Input force

Force at E (Along L2)

Force along L4

PL4 =3

0

3421

32

)sin()sin(

)sin(

L

LP

T

+

+

GRASPING FORCE ANALYSIS

)sin(12

2 +

=T

L

PP


8/15

FORCE AT FINGER TIP

6

5

3

0

3421

5432

)sin()sin(

)sin()sin(

L

L

L

LPF

T

+

+=

At a particular position, with measured angles andsynthesized lengths of links, the relation between F and PThas been developed as

TPF = 84.0


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FINGER ACTUATION MECHANISM (THROUGH

ADAMS)

Initial Position of The finger

Final Position of the Finger


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PHOTOGRAPHIC VIEW OF THE FINGER

Point of force application

Finger tip


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EXPERIMENTAL SETUP

Then an experiment has been performed by the robot fingerand load-cell apparatus. In the experiment, the fixed link hasbeen attached (of the finger) with a rigid body. A rope pulleyarrangement is to apply the loads. The tip of the finger is onthe load cell. Then the loads have been applied and get thereadings.

After synthesizingthe wholesomedesign of the robotfinger, the robot

finger has beenmanufactured byaluminum sheetand rivet.


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RESULTS

The theoretical value of the fingertip force is a bit higher thanthe actual grasping force, which was had from theexperimentation with the load cell.


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FUTURE SCOPE

A robotic hand may be developed employing thenewly developed fingers with proper sensory motorsystem. The object information may be grabbed by

camera. Hence, utilizing vision integrated Prehensiontechniques and stability criterion, the real time stablegrasp may be achieved.


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ACKNOWLEDGEMENTS

The author is highly indebted to his project guide and teacherMr. Bikash Bepari, Lecturer, Department of Mechanical andProduction Engineering for his guidance, perpetualinducement and constant encouragement which made thedaunting task much easier to bear.

The author is grateful to Mr. Subhadip Sarkar, Lecturer,Department of Mechanical and Production Engineeringfor hishelp and cooperation.

The author expresses his sincere thanks to Mr. SusantaBanerjee, TIC Department of Mechanical and ProductionEngineeringhis help to carry out to do this project.


15/15

Thank you!

seminar presentation of robotic finger

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