Small Objects Manipulation in Immersive Virtual Reality

In this pilot study, we analyze how the user approaches the manipulation of small virtual objects using different technologies, such as the HTC Vive controllers, the Leap Motion, and the Manus Prime haptic gloves. The aim of the study is to quantitatively assess the effectiveness of the three devices in a pick-and-place and simple manipulation task, specifically the assembling of a three-dimensional object composed of several mechanical parts of different shapes and sizes. 12 subjects perform the proposed experiment in a within-subjects study. We measured the total time to complete the entire task, the partial timing and the errors as the number of objects lost, to understand which are the most difficult actions. Moreover, we analyze the user feelings with the User Experience Questionnaire (UEQ), and the System Usability Scale (SUS). Both timing measurements and user experience reveal the weaknesses of the gloves, which suffer from problem in correctly tracking the thumb, thus in allowing grasping actions. Controllers are still a good compromise, though some fine tasks could not be correctly performed. The vision-based solution of the Leap Motion is appreciated by users, and it is stable enough to perform the given task.