How to make a curve smooth in spline block

Hi, i need to make a cam model in simulink so i use a spline block to model the curve.Here is my code:

clear
clc
s=0:0.005:1;i=0;
 for t1=0:0.005:0.125;
     i=i+1;
    s(i)=(pi*t1-0.25*sin(4*pi*t1))/(pi+4);
 end
for t2=0.130:0.005:0.875;
    i=i+1;
    s(i)=(2+pi*t2-(9/4)*sin((pi+4*pi*t2)/3))/(pi+4);
end
for t3=0.880:0.005:1
    i=i+1;
    s(i)=(4+pi*t3-0.25*sin(4*pi*t3))/(pi+4);
end
T=0:0.005:1;
% plot(T,s);
r=1:1:21;n=0;
for m=1:5:201
    n=n+1;
    r(n)=(232^2+264.2^2-2*232*264.2*cos(deg2rad(20.69+18.5*s(m))))^(1/2);
end
th=60:(110/40):170;
x1=r.*cos(deg2rad(th));
y1=r.*sin(deg2rad(th));
% figure(2);
th2=170:0.5:190;
x2=169.*cos(deg2rad(th2));
y2=169.*sin(deg2rad(th2));
th3=300:(-110/40):190;
x3=r.*cos(deg2rad(th3));
y3=r.*sin(deg2rad(th3));
x3=fliplr(x3);
y3=fliplr(y3);
th4=-60:5:60;
x4=94.55.*cos(deg2rad(th4));
y4=94.55.*sin(deg2rad(th4));
x=[x1,x2,x3,x4];
x=x';
y=[y1,y2,y3,y4];
y=y';
% subplot(5,3,1);
% plot(x,y);
% axis([-150,150,-150,150]);
CAM=[x,y];

But the curve is not smooth,please tell me what is the problem.

Answer 1

[Massimo Zanetti]

If you want to approximate a set of points by a smooth curve you need a smoothing spline, not just a spline. Moreover, in your case you need the smoothing spline to be a closed curve, therefore with periodic conditions.

I have done a function to do exactly that, check it out:

https://it.mathworks.com/matlabcentral/fileexchange/59463-smoothing-cubic-splines-with-periodic-conditions

[dk2507]

Thank you very much for the answer.But i have a problem using your function in 2015b.

error using ./ matrix dimensions must agree
error spcsp (line 83)
d = ([c(2:end,:);c(1,:)]-c)./(3*h);

ps: the code works well in 2016b under Mac,but as the model is linked with Soildworks i have to use it in 2015b under Windows

[Massimo Zanetti]

Mmmm, can't see why it doesn't work. What's the size of inputs x and Y you are providing to the function?

[dk2507]

I have fixed the problem .Though there are now new problems coming out,still,thank you very much ,helps a lot.

[Massimo Zanetti]

Glad to know you have fixed. If this answer helped you, please accept it.