A User Study of a Cable Haptic Interface with a Reconfigurable Structure

Cable-based visuo-haptic interfaces usually adopt simple structures, either being wearable devices, like gloves or jackets, or grounded interfaces with fixed anchor points and many cables providing force feedback. Regarding the latter type of interface, the force and visual feedbacks are often not co-located. While planar cable haptic interfaces with variable structures have been designed, the benefits of such structures have not been investigated. Likewise, co-located visual feedback using head-mounted display (HMD) is always discarded when using grounded cable interfaces. This paper presents a desktop-sized cable-driven parallel robot with a three-degree-of-freedom variable structure and six cables. Our objective is to evaluate the potential benefits or drawbacks of this structure and the use of an HMD through user-based experiments. For this purpose, a manipulation task where the users have to push a sphere along a line and a free exploration task were designed. The performances of the participants are evaluated in terms of trajectory accuracy and task execution time, and their experiences are collected with a questionnaire. Results indicate that the variable configuration presents slightly reduces the perceived physical and cognitive load with minimal impact on performance and that the HMD improves immersion and manipulation by providing more stereo-scopic cues.