Validation of a Soft Pneumatic Unit Cell (PUC) in a VR Experience: A Comparison Between Vibrotactile and Soft Pneumatic Haptic Feedback

Soft pneumatic displays have shown to provide compelling soft haptic feedback. However, they have rarely been tested in Virtual Reality applications, while we are interested in their potential for haptic feedback in the metaverse. Therefore, we designed a fully soft Pneumatic Unit Cell (PUC) and implemented it in a VR button task, in which users could directly use their hands for interaction. Twelve participants were asked to enter six-digit sequences, while being presented with PUC feedback, vibration feedback (VT), or no haptic feedback. Metrics on task performance, kinematics and cognitive load were collected. The results show that both vibration and PUC feedback resulted in participants pressing through the back of buttons less. The kinematic data showed that participants moved more smoothly during PUC feedback compared to vibration feedback. These effects were also reflected in the questionnaire data: participants felt more successful when using either PUCs or VTs, but they perceived the lowest level of stress when using PUCs. Feedback preference ratings also showed that PUC was the most preferred kind of feedback. Concluding, our array of metrics confirm that PUCs are good alternatives for haptic feedback in VR tasks in which electromechanical vibration motors typically excel: creating virtual button clicks.