The nano piezo engine is used in applied bionics for nano positioning system, dampen mechanical vibrations, adaptive optics, ring quantum generator, scanning microscopy, works with DNA.1–18 Its scheme is constructed by method mathematical physics for lumped parameters or distributed parameters of nano piezo engine.
Schemes
Let us consider the scheme of the nano piezo engine for lumped parameters. The scheme of nano piezo engine is determined by method mathematical physics with using the equation of the reverse piezo effect and the equations forces of engine in dynamics.16–57
The equation of the reverse piezo effect has the form3–59
here the indexes i, j, m and
are the relative displacement, the strength electric field, the strength mechanical field, the piezo module, and the elastic compliance at
Than the Laplace transform general force
of the nano piezo engine is founded
We have the transform general force by using the voltage
on the piezo capacitor in the form
The Laplace transform general force of the nano piezo engine is written
here
is the reverse coefficient in the form
The equation direct piezo effect has form3–43
here
is the permittivity.
Than the direct coefficient
is founded in the form
The Laplace transform voltage for the first feedback on the velocity of the second end is founded on Figure 1 in the form
by using the Laplace transform velocity the second end
of the nano engine.
The transform force at the second end
and the load force
are subtracted on Figure 1. The Laplace transform force for the second feedback has the form
here
are the elastic load stiffness, the stiffness piezo engine, the coefficient of viscous friction. This Laplace transform the load force has form the sum of the elastic force and the viscous friction force.
The scheme for lumped parameters of the nano piezo engine is constructed on Figure 1 at the first fixed end, the elastic inertial load with the mass load
and the voltage control.
The transfer function for lumped parameters of the nano engine on Figure 1 has the form
Figure 1 Scheme for lumped parameters nano engine.
,
,
At
the transfer function is founded in the form
,
At nano PZT engine
= 1 kg,
= 0.4×107 N/m,
= 1.2×107 N/m its parameters are determined
= 0.25×10-3 s,
= 4×103 s-1.
At PZT drive
= 0.2∙nm/V,
= 20,
= 0.33 its transfer coefficient is founded
= 3 nm/V.
Let us consider the scheme in general of the nano piezo engine for distributed parameters.
The scheme of nano engine is constructed by method mathematical physics with the equation of the reverse piezo effect and the equations forces in dynamics at the boundary conditions the differential equation of engine.
The ordinary differential equation of the nano piezo engine has form8–49
here ,
, s,
are the Laplace transform displacement, the coordinate, the parameter, the propagation coefficient and the general length
the nano piezo engine, For the nano piezo engine at
and at
,
The solution of the ordinary differential equation has the form
and the boundary conditions are determined
The Laplace transform of the general force of the nano piezo engine has the form
here
The general scheme and model for distributed parameters of the engine on Figure 2 are determined at voltage or current control
Figure 2 General scheme for distributed parameters nano piezo engine.
here
,
,
,
The general scheme for distributed parameters of the nano engine on Figure 2 is used in applied bionics and biomechanics.
The displacement matrix has the form
with the transfer functions in the form
here
The static displacements of the transverse engine are determined
At the transverse PZT engine
= 0.25 kg,
= 1 kg,
= 0.2 nm/V,
= 10,
= 150 V the static displacements are founded
= 300 nm and
= 240 nm,
= 40 nm.