Design and Characterisation of Multi-cavity, Fluidic Haptic Feedback System for Mechano-tactile Feedback

Numerous studies have indicated that the use of a closed-loop haptic feedback system, which offers various mechano-tactile stimuli patterns with different actuation methods, can improve the performance and grasp control of prosthetic hands. Purely mechanical-driven feedback approaches for various mechano-tactile stimuli patterns, however, have not been explored. In this paper, a multi-cavity fluidic haptic feedback system is introduced with details of design, fabrication, and validation. The multi-cavity haptic feedback system can detect the physical touch with direction at the fingertip sensor. The direction of the force is reflected in the form of pressure deviation in the multi-cavity fingertip sensor. The feedback actuator generates various mechano-tactile stimuli patterns according to the pressure deviation from the fingertip sensor. Hence, users can identify the force with direction according to the stimuli patterns. The haptic feedback system is validated through two experiments. The initial experiment characterises the system and establishes the relationship between the fingertip sensor and feedback actuator. The subsequent experiment, a human interaction test, confirms the system's capability to detect force with directions and generate corresponding tactile stimuli in the feedback actuator. The outcomes corroborate the idea that participants are generally capable of discerning changes in angle.