For multiple DO? systems, it is important to determine how accurately operators can control each DOF, and what the influence of the perceptual, infonnation processing and psychomotor components on performance is. Sixteen right-handed male students participated in 2 experiments: one involving positioning and one involving tracking with 3 translational DOFs.We used two control-display mappings that differed in the coupling of the vertical and depth dimensions to the up-down and fore-aft control axes, to separate perceptual and psychomotor effects. We observed infonnation processing effects in the positioning task: Initial error correction on the vertical dimension lagged in time behind the horizontal dimension. The depth dimension enor correction lagged behind both, which was ascribed to the poorer perceptual information. We observed this perceptual effect also in the tracking experiment: Tracking error along the depth dimension was 3.8 times larger than along the other dimensions. Motor effects were also present, with tracking errors along the up-down axis of the handcontroller being 1.1 times larger than along the fore-aft axis. These results indicate that all three components contribute to control performance. Actual applications of this research include interface design for remote control and virtual reality applications.
words 3 DOF control 2Requests for reprints should be sent to Jan , 1980; McKinnon & Kruk, 1991). In such situations, integrating DOFs in one handcontroller is advantageous for two reasons. First, the numbo' of input devices, and thus the number of limbs needed, is reduced. Second, control performance can be improved with integrated controls, especially when an integrated multiple DOF display is used (Regan, 1960;Chernikoff & LeMay, 1963;Fracker & Wickens, 1989).Understanding the limitations of the human operator in manual control tasks with multiple DOFs is necessary for an adequate design of systems that require the simultaneous control of multiple DOFs. The question arises how accurately the human operator is able to control each translational DOF, when an integrated control device in combination with an integrated display is used. A common observation is that the tracking accuracy in the depth dimension of the display is worse than in the vertical and horizontal dimensions (e.g., Massimino, Sheridan & Roseborough, 1989;Kim, Tendick & Stark, 1991;Zhai & Milgram, 1993. Li addition, performance differences between these last two DOFs have also been observed (Zhai, Milgram & Rastogi, 1997). Three factors can contribute to asymmetrical control performance between the DOFs: differences in perceptual infonnation, in information processing, or in psychomotor capabilities. These factors will be briefly discussed in the next section.In most applications the infonnation on actual and preferred position will be displayed visually, although auditory, haptic, and tactile displays are possible as well. Differences in the quality of the displayed visual information for each dimension may occur, s...