Kinematics

People often confuse kinetics and kinematics. What are they, and which one can you derive from motion capture data? Kinematics Kinematic analysis concerns the geometric aspects of motion, including position, velocity, and acceleration. When dealing with motion capture, you typically get either position (from a camera-based system) or something similar to acceleration (from accelerometers). These are related, and since I have now figured out how to make equations here on the blog, here you get a summary of high school physics: ...

A useful thing to do with position data (e.g. from a motion capture system) is to calculate the first and second derivatives. These will give you the velocity and acceleration, respectively. But it doesn’t stop there. In fact, it is possible to continue calculating derivatives of derivatives. Here are the names for the first 10 ones: original: position velocity (1st) acceleration (2nd) jerk (3rd) snap/jounce (4th) crackle (5th) pop (6th) Lock (7th) Drop (8th) Shot (9th) Put (10th) Whether these are useful or not is another question…