Research Article Volume 8 Issue 4
National Research University of Electronic Technology, MIET, Russia
Correspondence: SM Afonin, National Research University of Electronic Technology, MIET, Moscow, Russia, Tel +74997314441
Received: December 06, 2024 | Published: December 18, 2024
Citation: Afonin SM. Structural model and scheme of a piezoengine for aeronautics and aerospace. Aeron Aero Open Access J. 2024;8(4):212-217. DOI: 10.15406/aaoaj.2024.08.00213
In the work the structural model and the structural scheme of a piezoengine are calculated for aeronautics and aerospace. The matrix equation of a piezoactuator is determined. The mechanical characteristic and the parameters of the PZT piezoactuator are obtained in control systems for aeronautics and aerospace. A piezoengine is used for nanoalignment and nanopositioning, compensation of temperature and gravitational deformations in aeronautics and aerospace, nanoresearh for tunel microscopy, adaptive optics, astronomy for compound telescope and satellite telescope. The linear change in the size of a piezoengine occurs by the electric field changes. A piezoengine is a piezomechanical device for converting electrical energy into mechanical energy and for actuating mechanisms, systems or its controlling by using inverse piezoeeffect. Piezoceramics include barium titanate or ferroelectric ceramics, based on lead zirconate titanate type PZT, are widely used for the production of piezoengines. The PZT piezoengine is characterized by high accuracy, small overall dimensions, simple design and control, reliability and cost effectiveness. The structural general model, the scheme and the functions a piezoengine are obtained for aeronautics and aerospace. Method of applied mathematical physics is applied for determinations the characteristics of a piezoengine with using the piezoelasticity equation and the differential equation. The static and dynamic characteristics of the PZT piezoengine are determined.
Keywords: piezoengine, structural model and scheme
A piezoengine is used for aeronautics and aerospace.1–19 This piezoengine is applied in adaptive optics system for compound telescope and satellite telescope, astrophysics, deformable mirrors, interferometers, damping vibration, scanning microscopy.14–59 The structural model and scheme of a piezoengine are constructed.
For the structural model a piezoengine is used method of mathematical physics with the solution the piezoelasticity equationfor reverse piezoeffect and differential equation at the voltage control.8–41
Si=dmiEm+sEijTjSi=dmiEm+sEijTj
and at current the control
Si=gmiDm+sDijTjSi=gmiDm+sDijTj
here SiSi ,EmEm ,dmidmi ,TjTj ,dmidmi ,gmigmi ,sEijsEij are the relative displacement, the electric field strength, the electric induction, the mechanical field strength, its modules, the elastic compliance, the indexes i, j, m. The ordinary differential equation a piezoengine 8–41 has form
d2Ξ(x,s)dx2−γ2Ξ(x,s)=0d2Ξ(x,s)dx2−γ2Ξ(x,s)=0
here Ξ(x,s)Ξ(x,s) ,xx ,ss ,γγ are the transform of the displacement, its coordinate and parameter, the propagation coefficient and the general length l={ l, δ, bl={l,δ,b an engine. For the transverse engine for x=0x=0, Ξ(0,s)=Ξ1(s)Ξ(0,s)=Ξ1(s) ;and x=hx=h ,Ξ(h,s)=Ξ2(s)Ξ(h,s)=Ξ2(s) .
Its transverse solution is written
Ξ(x,s)={Ξ1(s)sh[(h−x)γ]+Ξ2(s)sh(xγ)}/sh(hγ)Ξ(x,s)={Ξ1(s)sh[(h−x)γ]+Ξ2(s)sh(xγ)}/sh(hγ)
here Ξ1(s)Ξ1(s) , Ξ2(s)Ξ2(s) ;are the transforms its end displacements.
The system equations of the boundary conditions for the transverse piezoengine is determined
T1(0,s)=1sE11dΞ(x,s)dx|x=0−d31sE11E3(s)T1(0,s)=1sE11dΞ(x,s)dx∣∣x=0−d31sE11E3(s)
T1(h,s)=1sE11dΞ(x,s)dx|x=h−d31sE11E3(s)T1(h,s)=1sE11dΞ(x,s)dx∣∣x=h−d31sE11E3(s)
From the reverse piezoeffect of a piezoengine at the voltage control the Laplace transform of the force causes displacement is determined
F(s)=dmiS0Em(s)sEijF(s)=dmiS0Em(s)sEij
hereS0S0 is cross sectional area.
The transform of the force causes displacement for the transverse piezoengine at the voltage control is written
F(s)=d31S0E3(s)sE11F(s)=d31S0E3(s)sE11
Then the reverse coefficient at the voltage control with U(s)=Em(s)δU(s)=Em(s)δ is determined in the form
kr=F(s)U(s)=dmiS0δsEijkr=F(s)U(s)=dmiS0δsEij
The transverse reverse coefficient at the voltage control is obtained
kr=F(s)U(s)=d31S0δsE11kr=F(s)U(s)=d31S0δsE11
Its transverse model is determined
Ξ1(s)=(M1s2)−1{−F1(s)+(χE11)−1×[d31E3(s)−[γ/sh(hγ)] ×[ch(hγ)Ξ1(s)−Ξ2(s)]]}
Ξ2(s)=(M2s2)−1{−F2(s)+(χE11)−1×[d31E3(s)−[γ/sh(hγ)]×[ch(hγ)Ξ2(s)−Ξ1(s)]]}
χE11=sE11/S0
For the longitudinal piezoengine its longitudinal solution of the differential equation is written
Ξ(x,s)={Ξ1(s)sh[(δ−x)γ]+Ξ2(s)sh(xγ)}/sh(δγ)
The system of the boundary conditions for the longitudinal piezoengine is obtained
T3(0,s)=1sE33dΞ(x,s)dx|x=0−d33sE33E3(s)
T3(δ,s)=1sE33dΞ(x,s)dx|x=δ−d33sE33E3(s)
The transform of the force causes displacement for the longitudinal piezo engine at the voltage control is written
F(s)=d33S0E3(s)sE33
The longitudinal reverse coefficient at the voltage control is obtained
kr=F(s)U(s)=d33S0δsE33
Its longitudinal structural model is determined
Ξ1(s)=(M1s2)−1{−F1(s)+(χE33)−1×[d33E3(s)−[γ/sh(δγ)] ×[ch(δγ)Ξ1(s)−Ξ2(s)]]}
Ξ2(s)=(M2s2)−1{−F2(s)+(χE33)−1×[d33E3(s)−[γ/sh(δγ)]×[ch(δγ)Ξ2(s)−Ξ1(s)]]}
χE33=sE33/S0
From the differential equation of for the shift piezoengine its shift solution is written
Ξ(x,s)={Ξ1(s)sh[(b−x)γ]+Ξ2(s)sh(xγ)}/sh(bγ)
The system of the boundary conditions for the shift piezoengine is obtained
T5(0,s)=1sE55dΞ(x,s)dx|x=0−d15sE55E1(s)
T5(b,s)=1sE55dΞ(x,s)dx|x=b−d15sE55E1(s)
The transform of the force causes displacement for the shift piezo engine at the voltage control is written
F(s)=d15S0E3(s)sE55
The shif reverse coefficient at the voltage control is obtained
kr=F(s)U(s)=d15S0δsE55
Its structural shift model is determined
Ξ1(s)=(M1s2)−1{−F1(s)+(χE55)−1×[d15E1(s)−[γ/sh(bγ)] ×[ch(bγ)Ξ1(s)−Ξ2(s)]]}
Ξ2(s)=(M2s2)−1{−F2(s)+(χE55)−1×[d15E1(s)−[γ/sh(bγ)]×[ch(bγ)Ξ2(s)−Ξ1(s)]]}
χE55=sE55/S0
The equation of inverse piezo effect 3–41 is written in the general form
Si=νmiΨm+sΨijTj
here Ψm=Em, Dm is control parameter at the voltage or current control.
At x=0 and x=l for l={ δ, h, b the system of the boundary conditions for a piezoengine is obtained
Tj(0,s)=1sΨijdΞ(x,s)dx|x=0−νmisΨijΨm(s)
Tj(l,s)=1sΨijdΞ(x,s)dx|x=l−νmisΨijΨm(s)
The transform of the force causes displacement has the general form
F(s)=νmiS0Ψm(s)sΨij
The general structural model and scheme are obtained on Figure 1
Ξ1(s)=(M1s2)−1{−F1(s)+(χΨij)−1×[νmiΨm(s)−[γ/sh(lγ)]×[ch(lγ)Ξ1(s)−Ξ2(s)]]}
Ξ2(s)=(M2s2)−1{−F2(s)+(χΨij)−1×[νmiΨm(s)−[γ/sh(lγ)]×[ch(lγ)Ξ2(s)−Ξ1(s)]]}
χΨij=sΨij/S0
here
vmi={d33,d31,d15g33,g31,g15 ,
,Ψm={E3,E3,E1D3,D3,D1 ,sΨij={sE33,sE11,sE55sD33,sD11,sD55 ,γ={γE, γD ,
cΨ={ cE, cD
The general structural model and scheme of a piezoengine on Figure 1 are used to calculate systems in aeronautics and aerospace. The displacement matrix is written
(Ξ1(s)Ξ2(s))=(W(s)) (Ψm(s)F1(s)F2(s))
(W(s))=(W11(s)W12(s)W13(s)W21(s)W22(s)W23(s))
here its functions
W11(s)=Ξ1(s)/Ψm(s)=νmi[M2χΨijs2+γth(lγ/2)]/Aij
Aij=M1M2(χΨij)2s4+{(M1+M2)χΨij/[cΨth(lγ)]}s3++[(M1+M2)χΨijα/th(lγ)+1/(cΨ)2]s2+2αs/cΨ+α2
W21(s)=Ξ2(s)/Ψm(s)=νmi[M1χΨijs2+γth(lγ/2)]/Aij
W12(s)=Ξ1(s)/F1(s)=−χΨij[M2χΨijs2+γ/th(lγ)]/Aij
W13(s)=Ξ1(s)/F2(s)==W22(s)=Ξ2(s)/F1(s)=[χΨijγ/sh(lγ)]/Aij
W23(s)=Ξ2(s)/F2(s)=−χΨij[M1χΨijs2+γ/th(lγ)]/Aij
The settled longitudinal displacements at the voltage control are used
ξ1=d33UM2/(M1+M2)
ξ2=d33UM1/(M1+M2)
To the PZT piezoengine d33 = 4×10-10 m/V, U = 50 V, M1 = 0.5 kg, M2 = 2 kg we have displacements ξ1+ξ2 = 20 nm, ξ1 = 16 nm, ξ2 = 4 nm with 10% error.
For the voltage control the equation of the direct piezo effect is written8–41
Dm=dmiTi+εEmkEk
here i, m, k are the indexes,εEmk is the permittivity. The direct coefficient kd ;for the engine at the voltage control is founded
kd=dmiS0δsEij
At the voltage control the transform of the voltage for the feedback on Figure 2 is obtained
Ud(s)=dmiS0RδsEij•Ξn(s)=kdR•Ξn(s) ,n=1, 2
here the number n of the ends engine.
Let us consider the elastic compliance of a piezoengine. At voltage control its maximum parameters are written
Tjmax=Emdmi/sEij
Fmax=EmdmiS0/sEij
At current control the maximum force is founded
Fmax=UδdmiS0sEij+FmaxS0dmiSc1εTmkSc/δ1δdmiS0sEij
here Sc , C0 are the sectional area of the capacitor, its capacitance.
Then at current control the parameters are written
Tjmax=Emdmi(1−k2mi)sEij
kmi=dmi/√sEijεTmk
here kmi is the coefficient of electromechanical coupling.
At current control of the parameters are founded
Tjmax=Emdmi/sDij,sDij=(1−k2mi)sEij
The elastic compliance sij is written sEij>sij>sDij , here sEij/sDij≤1.2 . ThenCEij=S0/(sEijl) is the stiffness of the engine at voltage control, CDij=S0/(sDijl) is the stiffness at current control,CEij<C<ijCDij , Cij=S0/(sijl) is a general stiffness of an engine.
The mechanical characteristic of a piezoengine 8–41
Si(Tj)|Ψ=const=νmiΨm|Ψ=const+sΨijTj
The adjustment characteristic
Si(Ψm)|T=const=vmiΨm+sΨijTj|T=const
Then the mechanical characteristic is written
Δl=Δlmax(1−F/Fmax)
Δlmax=νmiΨml ,Fmax=Tj maxS0=νmiΨmS0/sΨij
here Δlmax , Fmax are the maximum of the displacement and the force. The transverse mechanical characteristic is founded
Δh=Δhmax(1−F/Fmax)
Δhmax=d31E3h ,Fmax=d31E3S0/sE11
To the PZT piezoengine d31 = 2∙10-10 m/V, E3 = 0.25∙105 V/m, h = 2.5∙10-2 m, S0 = 1.5∙10-5 m2, sE11 = 15∙10-12 m2/N the parameters are determined Δhmax = 125 nm and Fmax = 5 N with 10% error.
The relative displacement at elastic load
Δll=νmiΨm−sΨijCeS0Δl ,F=CeΔl
The adjustment characteristic
Δl=νmilΨm1+Ce/CΨij
The general elastic compliance
sij=kssEij ,(1−k2mi)≤ks≤1
The scheme on Figure 3 we have at the voltage control the piezoengine with first fixed end and elastic-inertial load.
The function at the voltage control with fixed first end and elastic-inertial load on second end for Figure 3 has the form
W(s)=Ξ2(s)/U(s)=kr/(a3p3+a2p2+a1p+a0)
a3=RC0M2 ,a2=M2+RC0kv
a1=kv+RC0C+ijRC0C+eRkrkd ,a0=C+eCij
The function withis obtained
W(s)=Ξ(s)U(s)=kU31 T2ts2+2Ttξts+1
kU31=d31(h/δ)/(1+Ce/CE11)
Tt=√M2/(Ce+CE11) ,ωt=1/Tt
To the PZT piezoengine M2 = 4 kg, Ce = 0.1×107 N/m, CE11 = 1.5×107 N/m the parameters are founded Tt = 0.5×10-3 s, ωt = 2×103 s-1 with 10% error.
To d31 = 2∙10-10 m/V, h/δ = 22, Ce/CE11 = 0.1 the coefficient is determined kU31 = 4 nm/V with 10% error.
A piezoengine is used for aeronautics and aerospace in system of adaptive optics for compound telescope and satellite telescope, deformable mirrors, interferometers, damping vibration, astrophysics for displacements of mirrors and scanning microscopy. The structural model and scheme of a piezoengine are constructed by applied method mathematical physics. For a piezoengine its displacement matrix is obtained. The schemes with the feedbacks at the voltage control are determined.
The structural model and scheme of a piezoengine for aeronautics and aerospace are obtained taking into account equation of piezoeffects and decision wave equation. We have the general structural model and scheme of a piezoengine for the longitudinal, transverse and shift deformations. The structural scheme of the piezoactuator for longitudinal, transverse, shift piezoelectric effects at voltage control converts to the general structural scheme of the piezoactuator for aeronautics and aerospace with the replacement of the following parameters:
Ψm=E3,E3,E1 ,νmi=d33,d31,d15 sΨij=sE33,sE11,sE55 ,
,l=δ,h,b .
It is possible to construct the general structural model and scheme, the transfer functions in matrix form of the piezoengine, using the solutions of the wave equation of the piezoactuator and taking into account the features of the deformations actuator along the coordinate axes. The general structural model and scheme of the piezoengine after algebraic transformations are produced the transfer functions of the piezoengine. The piezoengine with the transverse piezoeffect compared to the piezoengine for the longitudinal piezoeffect provides greater range its displacement and less force.
The general structural model model and the scheme of a piezoengine are obtained. The systems of equations are determined for the structural models of the piezoengines for aeronautics and aerospace. Using the obtained solutions of the wave equation and taking into account the features of the deformations along the coordinate axes, it is possible to construct the general structural model and scheme of a piezoengine for systems of adaptive optics and to describe its dynamic and static properties. The transfer functions in matrix form are described the deformations of the piezoengines during its operation as a part of systems of adaptive optics.
The general structural scheme and the transfer functions of a piezoengine for aeronautics and aerospace are obtained from the structural model of a piezoengine for the transverse, longitudinal, shift piezoelectric effects. The displacement matrix is founded. The parameters of the piezoengine at the voltage control are determined for aeronautics and aerospace. The static and dynamic characteristics of the PZT piezoengine are obtained.
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The author declares that there are no conflicts of interest.
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