Soft Pneumatic Fingertip Actuator Incorporating a Dual Air Chamber to Generate Multi-Mode Simultaneous Tactile Feedback

Abstract

A complete set of diverse haptic feedbacks is essential for a highly realistic and immersive virtual environment. In this sense, a multi-mode haptic interface that simultaneously generates multiple kinds of haptic signals is highly desirable. In this paper, we propose a new silicone-made pneumatically controlled fingertip actuator to render pressure and vibrotactile feedback concurrently to offer a realistic and effective haptic sensation. A new silicone-based stacked dual-layer air chamber was designed. The volume of the chambers is controlled by pneumatic valves with compressed air tanks. The top/upper air chamber renders vibration feedback, whereas the bottom/lower air chamber renders pressure feedback. The proposed silicone-made fingertip actuator is designed so that it can be easily worn at the fingertips. To demonstrate the potential of the system, a virtual environment for rendering three different types of haptic textures was implemented. Extensive performance evaluation and user studies were carried out to demonstrate the proposed actuator’s effectiveness compared to an actuator with single vibrotactile feedback.

Fabrication and Characterization of Pneumatic Unit Cell Actuators

“…Recent work on elastomeric actuators has shown potential in addressing these challenges [6]. Dielectric elastomeric actuators [6,[12][13][14][15] and pneumatic actuators [6,7,[16][17][18][19][20] have demonstrated their capacity to offer both static-pressure and vibrotactile feedback at a relatively smaller form factor and weight. Despite their compactness, dielectric elastomeric actuators often demand high operating voltages and can require intricate fabrication procedures [12][13][14][15].…”

“…Inflatable soft pneumatic actuators have demonstrated a wide range of performance, reporting a maximum deformation of up to 6 mm [26] and a blocking force of up to 12.5 N [17]. Recent investigations into soft pneumatic actuators have also revealed the potential of inflatable actuators for vibrotactile feedback, achieving frequencies of up to 250 Hz [7,[16][17][18][19][20].…”

“…Within pneumatic actuator designs, the primary objective is to localize deformation during inflation-deflation cycles by introducing contrast in the stiffness. The literature offers a range of solutions, with the most notable design approaches involving the use of fabric and silicone [7,16,17,19,20], the bonding or laminating of soft elastomers to relatively rigid substrates [18,[27][28][29], and the integration of elastomers between rigid components [26].…”