What's the meaning of the constant binormal vector?
Andrew Henderson
I read a paper about robotics. It inform me 'To ensure constant plane curvature, the curvature and unit binormal vector of the curve must possess constant values as given in the following.'
I don't understand that the meaning of binormal vector is constant.
As far as I know, the binormal vector $B$ is a vector vertical to osculating plane which is configured of the tangent vector, $T$, and normal vector $N$ by $B=T\times N$.
$\endgroup$1 Answer
$\begingroup$Yes, and if $B$ is constant, the curve lies in a plane with that normal vector. The osculating plane never changes, and so the curve stays in that fixed plane. Note that if the curve is parametrized by $g(t)$, then indeed $g(t)\cdot B$ has derivative $0$ and is therefore constant.
$\endgroup$