Calibration Techniques for Indigenously Developed GRF Measurement

Document Sample
Calibration Techniques for Indigenously Developed GRF Measurement Powered By Docstoc
					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
   Introduction
   Objective
   Materials and Methods
   Observations
   Results
   Conclusion
   References
   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




Subject walking on   Kistler Data Acquisition Unit   PC with Analysis Software
   force plate




                        Vertical component of
                        ground reaction force
   Type- 9286B (Switzerland)
   Sensing Devices- Piezoelectric sensors
   Cost-17 lacks
   Plates- aluminum
   DAQ system for Bioware software
   Type-5691A
   To measure & analyze the acquired signal
        Force calculation
        Moment calculation
        Center of pressure (COP) calculation
Plates (2)-Brass
Sensors- Linear Pot
Length- 60 cm
Breadth- 36 cm
Height- 7.4 cm
Springs arrangement
 NI USB-6259
 32 inputs,16
  bit,32Ms/s
 Multifunction I/O
  with correlated
  digital I/O for USB
   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-       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
   Static Calibration   Dynamic Calibration
       Load Vs Voltage                             Weight Vs Voltage
                           8

                           7

                           6

                           5




                           voltage (V)
                           4                                              S…

                           3

                           2

                           1

                           0
                                         0   200   400        600   800
                                                   Weight (N)
539   646         735


            (N)
Range of Weight   Sensitivity of Kistler   Sensitivity of Developed
( Kg)             FP (mv/N)                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.
THANK YOU!

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:3/23/2011
language:English
pages:22