shiv
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hello sir, need help in simulating this code using hspice..
want to perform AC analysis for frequency response plot ..
please help in writing the sp file for it to simulate..
given : The beam - driver model is defined as a three port system. The port defined are two drivers (VD1 and VD2) and the beam (VC). ports are bi-directional, so the current can flow in any direction depending on the configuration used to excite the beam and to perform the electrical readout.
At Driver 1 (input side), an ac voltage is applied superimposed with dc volate. At driver 2 (output side ), a dc voltage is applied.
`include “constants.vams” `include “disciplines.vams” `define yes 1 `define no 0
module model_v1(D1 , D2 , C , Z , Vc);
// definition of input / output ports ------------------
inout D1 , D2 , C ; // drivers and cantilever electrical D1 , D2 , C ;
inout Z ; // nominal displacement kinematic Z ;
inout Vc ; // cantilever velocity kinematic_v Vc ;
// Cantilever design parameters ------------------------------
parameter real Lc = 830e-6; // Cantilever Length parameter real Tc = 10e-6; // cantilever thickness parameter real Wc = 100e-6; //cantilever width parameter real gap = 2e-6; // cantilever – driver gap
parameter real xa = 3e-6; // driver initial position parameter real xb = 7e-6; // driver final position
parameter real Qf = 300; // mechanical Q-factor parameter real E = 170e9; // young modulus parameter real Ro = 2.233e3; // mass density
parameter real k3 = 0; // cubic spring coefficient // electrical design parameters
parameter real alpha = 0; // fringing field factor
// capacitance parassites parameter integer N = 6 ; // cantilever sections parameter integer clamped2 = `yes ;
// nodes declaration ---------------------------------
real W, Ra, Ma, k, k1, Meff, Zmax, Zx, D, W0, Cx; integer ii, j; real dx, xn; real Ci[0:10]; // array of Ci coefficients real Ai[0:10]; // array of the Ai coefficients electrical Cd1, Cd2, DCd1, DCd2 ; electrical dVd1 , dVd2 ; real FF; // Finging field component kinematic Zk3; // cubic nonlinearity component kinematic FG1, FG2; //Electrical forces
// parameters calculation -------------------------
Analog begin @(initial_step) begin if (clamped2 == `yes) begin
// clamped-clamped cantilever
k = 16*E*Tc*pow(Wc,3) /pow(Lc, 3); // stiffness constant k1 = 2.365 ; // 1st mode constant Meff = 12*R0*Lc*Wc*Tc/pow(k1,4); // effective mass W0 = pow(k/Meff,0.5); // Natural resonance frequency D = W0*Meff/Qf ; // Damping factor
W = 1; // reference force density Ra = (W/(2*pow(Lc,3)))*((Lc + xb)*pow(xa,3) – (Lc + xa)*pow(xb,3)); \\ force reaction Ma = (W/(12*pow(Lc,2)))*(pow(xa,4))-pow(xb,4)) – Lc*Ra/3 ; // moment reaction FF = 1 + alpha*(gap/Tc)*pow(Wc/Tc),0.222); // fringing field contribution
// calculation of the Ci and Ai coefficients
for(ii=0; ii < N+1; ii=ii +1)begin dx = (xb - xa)/N ; // section length Xn = ii*dx + xa; // section position
A[ii] = 1;
// deflection profile Zx = ((xa - xb)*W/(2*k))*((pow(Xn,3)/3) – (xa + xb)*pow(Xn,2)/2) + pow(Xn – xa, 4)*W/(24*k)
// maximum deflection Z(Lc)
Zmax = ((xa - xb)*W/(2*k))*((pow(Lc,3)/3) – (xa + xb)*pow(Lc,2)/2) + (pow(Lc-xa,4) – pow(Lc – xb, 4))*W/(24*k);
Cx = Zx/Zmax; // normalized deflection profile
Ci[ii] = Cx;
end end
//---------------------------------------------------- Ai[0] = 0.5; Ai[N] = 0.5;
end
// cantilever velocity
Vel(Vc) <+ ddt(Pos(Z));
// cubic nonlinearity
Pos(Zk3) <+ k3*pow(Pos(Pos(Z),3));
// electrical force calculation : Fel (x,t)
for( j=0; j<N+1; j=j+1) begin
F(FG1) <+ - ((`P_EPS0*dx*Tc/2)*(pow(V(D1,C),2))*Ai[j]/(pow(gap + Ci[j]*Pos(Z),2))*FF; F(FG2) <+ ((`P_EPS0*dx*Tc/2)*(pow(V(D2,C),2)*Ai[j]/(pow(gap – Ci[j]*Pow(Z),2)))*FF; end
// movement equation
Pos(Z) <+ ((F(FG1) + F(FG2)) – D*Vel(Vc) – Meff*ddt(Vel(Vc)) – Pos(Zk3)) / k;
// Capacity calculation
for(j=0; j<N+1; j=j+1) begin
V(Cd1) <+ ((`P_EPS0*dx*Tc)*Ai[j]/(gap +Ci[j]*Pos(Z)))*FF; V(Cd2) <+ ((`P_EPS0*dx*Tc)*Ai[j]/(gap – Ci[j]8Pos(Z)))*FF;
// current calculation
V(dCd1) <+ ddt(V(Cd1)); V(dCd2) <+ ddt(V(Cd2));
V(dVd1) <+ ddt(V(D1,C)); V(dVd2) <+ ddt(V(D2,C));
I(D1,C) <+ V(Cd1)*V(dVd1) + V(D1,C)*V(dCd1); I(D2,C) <+ V(Cd2)*V(dVd2) + V(D2,C)*V(dCd2);
end endmodule
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