function Z = WFD_optimization(para)
global theta mu Ks y_bar A Omega Psi Mw Md ag eqt g yd;
global tspan G dtt tResult xResult tf N_react t_react F_hor t_hor xw_abs aw_abs G_all;
global set_time stick_slip Fric_force;
angle = 20;
Ks = para(1);
pre_t = para(2);
wedge_damper_input_v1
theta = angle*pi()/180;
y_bar=pre_t/Ks;
global A1 A2 B1 B2 C1 C2 Phi1 Phi2 Hpp Hpm Hmm Hmp ;
global count1 count2 count3 count4 count5 count6;
dt = dtt;
para = [theta;mu;E;I;L;Mw;Md;Ks;g;y_bar];
tspan = 0:dt:tf ;
tResult = [];
xResult = [];
[A1,A2,B1,B2,C1,C2,Psi,Phi1,Phi2,Hpp,Hpm,Hmm,Hmp] = get_const(para);
G_dir = 'E:\IITB\MTP\MATLAB\New\Chevron v2\Results\Actual EQ\elcentro vibrationdata\Input\';
G = earthquake_data(0.02,1/5,2,G_dir);
PGA=max(abs(G(:,3)));
eqn = 1;
count=0;
while t0<tf-dtt
[t,x] = wedge_inte(dt,eqn,t0,x0);
if (sign(x(end,1)) ~= sign(x0(1,1)) && t0~=0)
[eqn,t0,x0,dt] = y1_change(t0,x0,t,x,eps,dt,eqn);
elseif sign(x(end,2)) ~= sign(x0(1,2))
[eqn,t0,x0,dt] = y2_change(t0,x0,t,x,eps,dt,eqn);
else
t0 = t(end,1);
x0 = x(end, : );
tResult = cat(1, tResult, t0);
xResult = cat(1, xResult, x0);
end
end
Z(1) = max(abs(xResult(:,1)));
end
