Venkateswarlu Gaddam, Gautam Sharma, Neelesh Kumar, Amod Kumar, S.K . Mahna

NIT KurukshetraCentral Scientific Instruments Organisation (CSIO)

Council for Scientific and Industrial Research(CSIR) Chandigarh ,India

IntroductionObjectiveMaterials and MethodsObservationsResultsConclusionReferences

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

To measure static & dynamic calibration of Developed FP

Comparison of their (kistler FP & Developed FP) results

GRF MEASUREMENT WITH Kistler FP

Vertical component of ground reaction force

Subject walking on

force plate

Kistler Data Acquisition UnitPC with Analysis Software

Type- 9286B (Switzerland)Sensing Devices- Piezoelectric

sensorsCost-17 lacksPlates- aluminum

DAQ system for Bioware software

Type-5691A

To measure & analyze the acquired signal

Force calculationMoment calculationCenter of pressure (COP) calculation

Plates (2)-BrassSensors- Linear PotLength- 60 cmBreadth- 36 cmHeight- 7.4 cmSprings

arrangement

NI USB-625932 inputs,16

bit,32Ms/sMultifunction

I/O with correlated digital I/O for USB

LabVIEW –Laboratory Virtual Instrument Engineering Workbench

LabVIEW Signal Express-8.6

Major RoleSimulation Data AcquisitionInstrument ControlTesting & MeasurementsIndustrial automationData Analysis

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

Dynamic CalibrationSubject- Human being Input- Applied Force from human feet during

walkingOutput- M-Shape curve in Volts

Static Calibration Dynamic Calibration

Load Vs Voltage

(N)

539 646 735

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

To evaluate Gait Parameters which are used for Prosthetic Knee quantification

In clinical assessments to know data analysis of a patient

Inexpensive

[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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