在曲线微分几何中，踩踏板曲线是从给定曲线所创造的曲线，构造方法像自行车用脚踩踏在原有曲线上，故称为踩踏板曲线，又译作垂足曲线。给定一个曲线和一个定点P（称为垂足点或踩踏点(Pedal Point)）。在曲线的任何一条切线T上，都存在唯一的一个点X，要幺是P本身，要幺与P形成的直线与T垂直。垂足曲线是符合这种性质的所有点X所组成的集合。

垂足曲线不一定是连通的，例如对于多边形来说，它仅仅是一些孤立的点。

如果P是垂足点，c是曲线的一个参数方程，则垂足曲线的参数方程为：

如果垂足点是原点，则垂足曲线为：

The pedal curve results from the orthogonal projection of a fixed point on the tangent lines of a given curve. More precisely, for a plane curve C and a given fixed pedal point P, the pedal curve of C is the locus of points X so that the line PX is perpendicular to a tangent T to the curve passing through the point X. Conversely, at any point R on the curve C, let T be the tangent line at that point R; then there is a unique point X on the tangent T which forms with the pedal point P a line perpendicular to the tangent T (for the special case when the fixed point P lies on the tangent T, the points X and P coincide) – the pedal curve is the set of such points X, called the foot of the perpendicular to the tangent T from the fixed point P, as the variable point R ranges over the curve C.