Kistler 9287C Series - COP Correction Algorithm for Force Plates

Multicomponent Force Plate for Biomechanics Type 9287C…
8.4.3 COP Correction Algorithm for Force Plates
The COP errors of a force plate are largely systematic and
can be reduced by a factor of 3.5 using the following algo-
rithm.
Remarks
The coefficients apply only if the force plate is mounted
on a rigid foundation according to Kistler specifications
(mounting frame or steel plate grouted on concrete
foundation).
Formulae
Input parameters are the measured COP coordinated ax-
measured and aymeasured
Output parameter are the corrected COP coordinates ax
cor-
rected
and aycorrected
ax
m
= ax
measured
ax
corrected
= ax
measured
–Dax
Dax = ((P
1x
·ay
m
4
+P
2x
·ay
m
2
+P
3x
)·ax
m
3
+(P
4x
·ay
m
4
+P
5x
·ay
m
2
+P
6x
)·ax
m
)
ay
m
= ay
measured
ay
corrected
= ay
measured
–Day
Day = ((P
1y
·ax
m
4
+P
2Y
·ax
m
2
+P
3Y
)·ay
m
3
+(P
4Y
·ax
m
4
+P
5Y
·ax
m
2
+P
6y
)·ay
m
)
Type 9281E11 Type 9281E and 9281EA (SN: 616 901)
P1x 2.51997E–15 P1y 2.83750E–15 P1x 1.1604E–14 P1y 1.27251E–14
P2x –2.18826E–10 P2y –1.00051E–10 P2x –8.39091E–10 P2y –3.13238E–10
P3x –2.69254E–07 P3y –2.05349E–06 P3x –1.44293E–6 P3y –3.33888E–6
P4x –4.85912E–11 P4y –1.16374E–10 P4x –2.85927E–10 P4y –6.49641E–10
P5x 4.55731E–06 P5y 4.71553E–06 P5x 2.05575E–5 P5y 1.53937E–5
P6x –4.18892E–02 P6y 6.89265E–02 P6x –0.113525 P6y 1.12624E–01
Type 9281E und 9281EA (SN: 616 902) Type 9287C, 9287C, 9287CA
P1x 7.92063E–15 P1y 8.82869E–15 P1x 1.72454E-16 P1y 2.20428E–16
P2x –5.821E–10 P2y –2.48554E–10 P2x –4.82275E-11 P2y –1.80864E–11
P3x –2.77102E–6 P3y –1.76282E–6 P3x 3.30016E-07 P3y –7.30249E–07
P4x –1.76083E–10 P4y –4.22186E–10 P4x –9.46569E-12 P4y –3.03080E–11
P5x 1.29695E–5 P5y 1.2091E–5 P5x 2.78736E-06 P5y 2.64974E–06
P6x –0.0413979 P6y 5.16279E–02 P6x –8.20399E-03 P6y 5.41166E–02
Pag
e 36 9287C_002-462e-03.11