Calibration Techniques for Indigenously Developed GRF Measurement System in comparison to Standard Reference Tool

1
Calibration Techniques for Indigenously Developed
GRF Measurement System in comparison to Standard
Reference Tool

• Venkateswarlu Gaddam, Gautam Sharma, Neelesh
  Kumar, Amod Kumar, S.K . Mahna
• NIT Kurukshetra
• Central Scientific Instruments Organisation
  (CSIO)
• Council for Scientific and Industrial
  Research(CSIR)
• Chandigarh ,India

2
OVERVIEW

• Introduction
• Objective
• Materials and Methods
• Observations
• Results
• Conclusion
• References

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Introduction

• GRF- Ground Reaction Force
• It is equal in magnitude and opposite in
  direction to the force that the body exerts on
  the supporting surface through the foot .
• Vertical GRF (Fz) its importance-
• It is considered to be prominent amongst
  the three components of the GRF and has
  importance in the gait analysis, clinical
  assessment etc.
• Force Plate (FP)- To measure GRF in the human
  and animal locomotion.
• Available FPs- AMTI FP, Bertec FP, Kistler
  FP
• Kistler FP- Standard Reference Tool
• Developed FP
• Calibration Techniques
• Static calibration
• Dynamic Calibration

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Objective

• To measure static dynamic calibration of
  Developed FP
• Comparison of their (kistler FP Developed FP)
  results

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GRF MEASUREMENT WITH Kistler FP
Subject walking on force plate
Kistler Data Acquisition Unit
PC with Analysis Software
Vertical component of ground reaction force
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Kistler FP

• Type- 9286B (Switzerland)
• Sensing Devices- Piezoelectric sensors
• Cost-17 lacks
• Plates- aluminum

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Kistler Interfacing device

• DAQ system for Bioware software
• Type-5691A

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Bioware Software

• To measure analyze the acquired signal
• Force calculation
• Moment calculation
• Center of pressure (COP) calculation

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Materials Methods
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Force Plate Design
Plates (2)-Brass Sensors- Linear Pot Length- 60
cm Breadth- 36 cm Height- 7.4 cm Springs
arrangement
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Sensor Arrangement
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Experimental Setup
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NI-DAQ Interfacing Device

• NI USB-6259
• 32 inputs,16 bit,32Ms/s
• Multifunction I/O with correlated digital I/O for
  USB

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Software Tool

• LabVIEW Laboratory Virtual Instrument
  Engineering Workbench
• LabVIEW Signal Express-8.6
• Major Role
• Simulation
• Data Acquisition
• Instrument Control
• Testing Measurements
• Industrial automation
• Data Analysis

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Calibration Techniques

• Calibration- calibration is a comparison between
  measurements-one of known magnitude or set with
  one device and another measurement made in a
  similar way as possible with a second device.
• Purpose- to check if the developed FP gives the
  same measurement readings as the Kistler FP,
  thereby checking the repeatability, sensitivity,
  linearity of VGRF for the Developed FP.
• Static Calibration
• Input- Fixed Loads
• Output- Volts

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• Dynamic Calibration
• Subject- Human being
• Input- Applied Force from human feet during
  walking
• Output- M-Shape curve in Volts

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Results

• Static Calibration Dynamic Calibration

Load Vs Voltage
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Comparison of Both the Plates
539
646
735
(N)
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Observations
Developed FP
Kistler FP

Range of Weight ( Kg) Sensitivity of Kistler FP (mv/N) Sensitivity of Developed FP (mv/N)
55-66 12.22 41.11
66-75 6.667 28.88
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Uses Conclusions

• To evaluate Gait Parameters which are used for
  Prosthetic Knee quantification
• In clinical assessments to know data analysis of
  a patient
• Inexpensive

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References

• 1. Senanayake S.M.N.A .(2004) Walking, Running
  and Kicking using Body Mounted Sensors.
  Proceedings of the 2004 IEEE. Conference on
  Robotics, Automation and Mechatronics Singapore.
  Pg 1141-1146.
• 2. Hynd D.,Hughes S C.,Evins D J.( 2000) The
  development of a long, dual-platform triaxial
  walkway for the measurement of forces and
  temporal-spatial data in the clinical assessment
  of gait. Proc Instn Engrs vol 214 Part H pg
  193-201.
• 3. Liu T., Inoue Y., Shibata K.(2009) 3D Force
  Sensor Designed Using Pressure Sensitive Electric
  Conductive Rubber. Journal of system design and
  dynamics, VOL 3 No 3 pg 282-295.
• 4. Roland E.S., Hulla M.L., Stover S.M.,
  (2005) Design and demonstration
• of dynamometric horseshoe for measurinh
  ground reaction loads of horses during racing
  conditions. Journal of Biomechanics 38 pg
  2102-2112.
•  

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• THANK YOU!