Title: Calibration Techniques for Indigenously Developed GRF Measurement System in comparison to Standard Reference Tool
1Calibration 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
2OVERVIEW
- Introduction
- Objective
- Materials and Methods
- Observations
- Results
- Conclusion
- References
3Introduction
- 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
4Objective
- To measure static dynamic calibration of
Developed FP - Comparison of their (kistler FP Developed FP)
results
5 GRF MEASUREMENT WITH Kistler FP
Subject walking on force plate
Kistler Data Acquisition Unit
PC with Analysis Software
Vertical component of ground reaction force
6Kistler FP
- Type- 9286B (Switzerland)
- Sensing Devices- Piezoelectric sensors
- Cost-17 lacks
- Plates- aluminum
7Kistler Interfacing device
- DAQ system for Bioware software
- Type-5691A
8Bioware Software
- To measure analyze the acquired signal
- Force calculation
- Moment calculation
- Center of pressure (COP) calculation
9Materials Methods
10Force Plate Design
Plates (2)-Brass Sensors- Linear Pot Length- 60
cm Breadth- 36 cm Height- 7.4 cm Springs
arrangement
11Sensor Arrangement
12Experimental Setup
13NI-DAQ Interfacing Device
- NI USB-6259
- 32 inputs,16 bit,32Ms/s
- Multifunction I/O with correlated digital I/O for
USB
14Software 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
15Calibration 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
16- Dynamic Calibration
- Subject- Human being
- Input- Applied Force from human feet during
walking - Output- M-Shape curve in Volts
17Results
- Static Calibration Dynamic Calibration
Load Vs Voltage
18Comparison of Both the Plates
539
646
735
(N)
19Observations
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
20Uses Conclusions
- To evaluate Gait Parameters which are used for
Prosthetic Knee quantification - In clinical assessments to know data analysis of
a patient - Inexpensive
21References
- 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. -
22