function ydot = Fun_xinjian4freedom(t,y)
m1=5800;a1=1.4;b1=2.0;c=1.64;
Iz1=50737;
m2=19080;a2=4.58;b2=2.28;
Iz2=138437;
B1=11.275;C1=1.56;D1=-2296.7;E1=-1.999;B2=18.631;B3=18.631;C2=1.56;C3=1.56;D2=-1534.8;D3=-1145.6;E2=-1.7908;E3=-1.7908;
Flf=0;deltf=0;
Fyf=2*(Flf*sin(deltf)+cos(deltf)*D1*sin(C1*atan(B1*(atan((y(1)+a1*y(2))/y(5))-deltf))));
Fyr1=4*D2*sin(C2*atan(B2*(atan((y(1)-b1*y(2))/y(5)))));
Fyr2=8*D3*sin(C3*atan(B3*(atan(y(4)+(y(1)-(c+a2+b2)*y(2)+(a2+b2)*y(3))/y(5)))));
Fxf=2*(Flf*cos(deltf)-sin(deltf)*D1*sin(C1*atan(B1*(atan((y(1)+a1*y(2))/y(5))-deltf))));
Fxr1=0;
Fxr2=0;
ydot=[(((a1+c)*Fyf+(c-b1)*Fyr1-c*m1*y(5)*y(2))*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)-Iz1*(((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*Fyr2*cos(y(4)))-a2*c*m1*m2*cos(y(4))*(((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*(a2*m2*(Fyf+Fyr1)*cos(y(4))-(b2*(m1+m2)+a2*m1)*Fyr2)-((m1+m2)*Iz2+a2*(c*cos(y(4))+a2)*m1*m2)*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*(Fyr2*cos(y(4)))))))/c*m1*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2);
(((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*Fyr2*cos(y(4)))*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))-a2*c*m1*m2*cos(y(4))*(((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*(a2*m2*(Fyf+Fyr1)*cos(y(4))-(b2*(m1+m2)+a2*m1)*Fyr2)-((m1+m2)*Iz2+a2*(c*cos(y(4))+a2)*m1*m2)*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*(Fyr2*cos(y(4))))))/((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2);
-(((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*(a2*m2*(Fyf+Fyr1)*cos(y(4))-(b2*(m1+m2)+a2*m1)*Fyr2)-((m1+m2)*Iz2+a2*(c*cos(y(4))+a2)*m1*m2)*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*(Fyr2*cos(y(4)))))/((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2));
y(3);
(c*m1*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*((Fxf+Fxr1)*cos(y(4))+(m1+m2)*y(1)*y(2)*cos(y(4))-m2*(c*cos(y(4))+a2)*y(2)*y(2)+2*a2*m2*y(2)*y(3))-(((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*Fyr2*cos(y(4)))*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))-a2*c*m1*m2*cos(y(4))*(((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*(a2*m2*(Fyf+Fyr1)*cos(y(4))-(b2*(m1+m2)+a2*m1)*Fyr2)-((m1+m2)*Iz2+a2*(c*cos(y(4))+a2)*m1*m2)*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*(Fyr2*cos(y(4))))))*c*c*m1*m2*sin(y(4))+(((a1+c)*Fyf+(c-b1)*Fyr1-c*m1*y(5)*y(2))*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)-Iz1*(((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*Fyr2*cos(y(4)))-a2*c*m1*m2*cos(y(4))*(((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*(a2*m2*(Fyf+Fyr1)*cos(y(4))-(b2*(m1+m2)+a2*m1)*Fyr2)-((m1+m2)*Iz2+a2*(c*cos(y(4))+a2)*m1*m2)*((a1*(m1+m2)+c*m2)*Fyf+(c*m2-b1*(m1+m2))*Fyr1-c*m1*(Fyr2*cos(y(4)))))))*(m1+m2)*sin(y(4)))/c*m1*(m1+m2)*((m1+m2)*(m1+m2)*Iz1*Iz2+(c*c*Iz2+a2*a2*Iz1)*m1*m2*(m1+m2))*((m1+m2)*Iz1+c*(c+a2*cos(y(4)))*m1*m2)*cos(y(4))];
