On Animating Whip-type Motions

This paper presents algorithmic methods to generate progressive, whip-type motions, characteristic of experienced humans in high speed athletic activities like throwing and striking. In deriving these methods, we deduce boundary conditions for dynamic quantities by analyzing the motion of a two-link system. A control algorithm based on cascading gains is introduced and is shown to be e cient when compared to xed-gain proportional control. Principles of energy redistribution within links are used to explain the mechanical advantage gained by a whip-type motion, and the e ciency of cascading gain control. The results can be applied in motion synthesis for animation which is demonstrated through simulation of a multi-link system. Our aim has been to obtain biomechanically plausible solutions which approximate natural motions.