How to fit a helix in 3D using cftool?

I am trying to fit some helical data to a helical parametric equation, so as to find the pitch, radius and angle with respect to the z-axis.

If I use the cftool, this is what I am allowed to do in terms of customization (see pic below). There is no option for parametric equations, where the z data can be used as a time variable. Is there any way that this can be done? If not, what functions/tools/methods do you suggest?

Answer 1

[Navya Seelam]

Hi,

Assuming the helical parametric equations to be

x=a*sin(z)

y=b*cos(z)

z=t

“fittype” can be used to assign the model type to fit in order to obtain the parameters a & b.

myfittype=fittype('a*sin(x)'); 
ft1=fit(z,x,myfittype);  

The same procedure can be used to obtain parameter b as well.