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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.
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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 Calibration Techniques for Indigenously Developed GRF Measurement System in comparison to Standard Reference Tool
OVERVIEW • Introduction • Objective • Materials and Methods • Observations • Results • Conclusion • References
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
Objective • To measure static & dynamic calibration of Developed FP • Comparison of their (kistler FP & Developed FP) results
GRF MEASUREMENT WITH Kistler FP Subject walking on force plate Kistler Data Acquisition Unit PC with Analysis Software Vertical component of ground reaction force
Kistler FP • Type- 9286B (Switzerland) • Sensing Devices- Piezoelectric sensors • Cost-17 lacks • Plates- aluminum
Kistler Interfacing device • DAQ system for Bioware software • Type-5691A
Bioware Software • To measure & analyze the acquired signal • Force calculation • Moment calculation • Center of pressure (COP) calculation
Force Plate Design Plates (2)-Brass Sensors- Linear Pot Length- 60 cm Breadth- 36 cm Height- 7.4 cm Springs arrangement
NI-DAQ –Interfacing Device • NI USB-6259 • 32 inputs,16 bit,32Ms/s • Multifunction I/O with correlated digital I/O for USB
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
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
Dynamic Calibration • Subject- Human being • Input- Applied Force from human feet during walking • Output- M-Shape curve in Volts
Results • Static Calibration Dynamic Calibration Load Vs Voltage
Comparison of Both the Plates 539 646 735 (N)
Observations Developed FP Kistler FP
Uses & Conclusions • To evaluate Gait Parameters which are used for Prosthetic Knee quantification • In clinical assessments to know data analysis of a patient • Inexpensive
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]. HyndD.,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 InstnEngrs 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.