CAPTURE OF MOVING TARGETS - A MODIFICATION OF FITTS LAW

A simple mathematical model for capture time of a moving target was developed. The model, in several forms, was tested with the experimental data of Jagacinski et al. (1980a) for both positon and velocity control systems and was found to give an excellent fit. The major modification to Fitts' Law with a moving target occurs through a steady-state position error which reduces the effective target width. With stationary targets, the model reduces to the classical Fitts' Law. The model predicts a critical speed, beyond which the target cannot be captured; this prediction is in accord with the experimental data of Jagacinski et al.