Control Systems Analysis of Computer Pointing Devices

Abstract

A theoretical framework for the ergonomic evaluation of manual pointing devices is discussed. Pursuit tracking is suggested as an alternative to the conventional “target acquisition” approach to evaluating pointer performance. Subjects' ability to control the position of a pointer on a CRT display was evaluated in a series of two-dimensional pursuit tracking tasks in which the frequency of target movement was varied. Performance was compared under identical conditions using a mouse and an isometric joystick. Quality of control was measured by RMS error and stability of the controlled variable. The mouse allowed better control of pointer position. The superiority of the mouse was most evident with low-frequency target movements. The results indicate the importance of evaluating pointing devices under user-friendly conditions.