Piezo Engineering Tutorial
QNP3 Hardware Manual
C.3.4.3 Displacement With an External Spring Load
illustrates a case where a piezo actuator or stage is driving against an external spring load.
In the case of a piezo stage or actuator without any applied load (case 1), the stroke of the piezo is given as
ΔL
1
. For case 2 when driving against a spring load, the piezo stage stiffness (
k
p
) and the external stiffness
(
k
e
) act in series and decrease the overall stroke of the actuator. The stroke in case 2 is given by:
Equation 4
It is evident upon inspection of Equation 4 that in order to maximize the stroke of the piezo stage, the piezo
stage stiffness (
k
p
) should be much larger than the external spring stiffness (
k
e
).
Figure C-5:
Displacement of a piezo stage or actuator driving against an external spring
of stiffness
k
e
48
Appendix C
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