Combined slip corrections in Pajecka's magic tire model

clear all
close all 
clc
Sxp=0.09;alpha_p=4;By=0.27;Cy=1.2;Dy=2900;Ey=-1.6;
Shy=0;Svy=0;Bx=25;Cx=1.15;Dx=3200;Ex=-0.4;Shx=0;Svx=0;
for i=1:4
Sx=(i-1)*0.03;
for j=1:21
slip_angle(j)=(j-1)+0.00001;
alpha=slip_angle(j);
Sx_star=Sx/Sxp; 
alpha_star=alpha/alpha_p;
S_star=((Sx_star)^2 + (alpha_star)^2) ^ 0.5; 
Sx_mod=S_star*Sxp; 
alpha_mod=S_star*alpha_p; 
alpha_final=alpha_mod + Shy; 
fy(i,j)=(alpha_star/S_star)*Dy*sin(Cy*atan(By*alpha_final-Ey*(By*alpha_final-atan(By*alpha_final)))); 
Fy(i,j)=fy(i,j) + Svy; 
Sx_final=Sx_mod + Shy;
fx(i,j)=(Sx_star/S_star)*Dx*sin(Cx*atan(Bx*Sx_final-Ex*(Bx*Sx_final-atan(Bx*Sx_final))));
Fx(i,j)=fx(i,j) + Svy;
end
end
figure(1); plot(slip_angle, Fy)
xlabel('Slip angle (deg)'); 
ylabel('Fy (N)')
legend('slip ratio=0%', 'slip ratio=3%', 'slip ratio=60%','slip ratio=9%')
figure(2); plot(slip_angle, fx)
xlabel('Slip angle (deg)'); 
ylabel('Fx (N)')
legend('slip ratio=0%', 'slip ratio=3%', 'slip ratio=6%','slip ratio=9%')

%ALTEREING SLIP ANGLES
Sxp=0.09;alpha_p=4;By=0.27;Cy=1.2;Dy=2921;Ey=-1.6;Shy=0;Svy=0;
Bx=25;Cx=1.15;Dx=3100;Ex=-0.4;Shx=0;Svx=0;
for i = 1:4
slip_angle(i) = (i-1)*2;
alpha = slip_angle(i);
for j = 1:30
Sx(j) = (j-1)*0.02+0.00001;
Sx_star = Sx(j)/Sxp;
alpha_star = alpha/alpha_p;
S_star = ((Sx_star)^2 + (alpha_star)^2) ^ 0.5; 
Sx_mod = S_star*Sxp;
alpha_mod = S_star*alpha_p; 
alpha_final = alpha_mod + Shy;
fy(i,j) = (alpha_star/S_star)*Dy*sin(Cy*atan(By*alpha_final-Ey*(By*alpha_final-atan(By*alpha_final))));
Fy(i,j) = fy(i,j) + Svy; 
Sx_final = Sx_mod + Shy; 
fx(i,j) = (Sx_star/S_star)*Dx*sin(Cx*atan(Bx*Sx_final-Ex*(Bx*Sx_final-atan(Bx*Sx_final))));
Fx(i,j) = fx(i,j) + Svy; 
end
end
figure(3); plot(Sx*100, Fx)
xlabel('Skid (%)'); ylabel('Fx (N)')
legend('slip=0', 'slip=2 deg', 'slip=4 deg','slip=6 deg')
figure(4); plot(Sx*100, Fy)
xlabel('Skid (%)'); ylabel('Fy (N)')
legend('slip=0', 'slip=2 deg', 'slip=4 deg','slip=6 deg')