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A 3DOF Transtibial Robotic Prosthetic Limb
Presented by - D.G. Kanishka Madusanka
([email protected])
Department of Mechanical Engineering
University of Moratuwa
D.G.K. Madusanka, L.N.S. Wijayasingha, K. Sanjeevan, M.A.R.
Ahamed, J.C.W. Edirisooriya, R.A.R.C. Gopura
ICIAfS 2014 Colombo, Sri Lanka
12/23/2014
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2OUTLINE
o Motivation
o Introduction
o Biomechanics of lower limb
o State of the art
o Design of the prosthesis
o Experiments and results
o Conclusion
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3oAmputations caused by diseases, injuries and
accidents - affect negatively.
o Significant number of amputees are transtibial.
Prosthesis for transtibial amputees
o Human alike lower limb with,
o 3 DOF ankle joint
o Passive Regeneration
MOTIVATION
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Cosmetic
Body powered
Externally powered
INTRODUCTION
Prosthesis - Device that replaces a missing body part
Classification
amputation levels
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5BIOMECHANICS OF LOWER LIMB
Motion Moveable Range (Deg.)
Dorsiflexion/ Plantarflexion 20 / 50
Abduction/ Adduction 20 / 25
Inversion/ Eversion 35 / 25
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6STATE OF THE ART
All most all prosthetic ankles are 2DOF or less
Model Actuation method DOF
SPARKy Ball screw driven by motor 1
PROPRIO Ball screw driven by motor 1
MIT Prosthesis 1 Ball screw driven by motor 1
MIT Prosthesis 2 Ball screw driven by motor 1
PANTOE Ball screw driven by motor 2
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Design was carried out in 3 stages
1st Design 2nd Design
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DESIGN OF THE PROSTHESIS
less reliability
Low speed of worm & wheel
less maintainability
High power demand of LA
High weight due to gears and LA
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8DESIGN OF THE PROSTHESIS
o The weight is reducedbased on FEA results
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9DEVELOPED PROSTHETIC LIMB
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= cos . sin .
= 90
sin()
=
sin
tan =
2 = 2 + 2 + 2 . +
and can be found by gait data
and can be obtained.
KINEMATIC ANALYSIS
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= +
natural length of spring be d0,
= .
= 0 =
=
= . .
, and can found by gait data
PASSIVE REGENERATIVE SYSTEM (PRS)
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SIMULATION RESULTS OF PRS
= 30 kN/m
Less motor power requirement
Find power requirement with varying K
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EXPERIMENTS AND RESULTS
Two experimentso Verify the moveable ranges
o Evaluate possibility of using EMG based control
Experimental Setup
Verify the moveable ranges and
evaluate possibility of using
EMG based control
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RESULTS OF PD CONTROLLER
Motion Achieved Range (Deg.) Natural Range (Deg.)
Dorsiflexion/ Plantarflexion 12 / 32 20/50
Abduction/ Adduction 20 / 25 20/25
Inversion/ Eversion 30 / 25 35/25
Implemented a PD controller
= . + .
Dorsiflexion/plantarflexion Abduction/adduction
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RESULTS OF EMG CONTROLLER
Proportional EMG controller is implemented
- Sampled at 2000Hz and 100 samples per rms signal
- Tibialis anterior (ch:1) and gastrocnemius (ch:2)
= 1. 1 2. 2
EMG Signals Results of dorsiflexion/ plantarflexion
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CONCLUSION
o Developed a transtibial prosthetic limb with 3DOF
ankle and passive regenerative system.
o Experimental results verified the effectiveness of
motion generation and possibility of using EMG
Signals.
o Simulation results shows the effectiveness of
passive regenerative system.
Future Work Improve the EMG based controller
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THANK YOU !
