Hi,

Is there a way to find out the points on a clothoid, i.e. their coordinates, if one knows the start point and the end point of the clothoid and its curvature?

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- Jul 30th 2011, 12:05 PMschmimonaCalculate Points on a Clothoid
Hi,

Is there a way to find out the points on a clothoid, i.e. their coordinates, if one knows the start point and the end point of the clothoid and its curvature? - Feb 5th 2015, 12:30 AMRebesquesRe: Calculate Points on a Clothoid
You can do that for any planar curve with known curvature, $\displaystyle k(s)$.

Let the curve be $\displaystyle a(s)=(x(s),y(s)),s\in [0,1]$, parametrized for arclength.

Then $\displaystyle |a'(s)|=1$, which implies there exists a function $\displaystyle \theta(s),s\in [0,1]$ such that

$\displaystyle x(s)=\cos\theta(s),y(s)=\sin\theta(s)$.

From the formula for curvature, $\displaystyle k(s)=x'(s)y''(s)-y'(s)x''(s)=\theta'(s)$,

and so the curve is $\displaystyle a(s)=(\int \cos(\int k(u)du+c_1)ds+c_2, \int \sin(\int k(u)du+c_3)ds+c_4)$.

Now use $\displaystyle a(0)=p,a(1)=q$ to determine the constants.