The Impact of Simultaneously Applying Normal Stress and Vibrotactile Stimulation for Feedback of Exteroceptive Information

Abstract

Commercially available prosthetic hands do not convey any tactile information, forcing amputees to rely solely on visual attention. A promising solution to this problem is haptics, which could lead to new prostheses in which tactile information is conveyed between the amputee and the artificial limb. However, the haptic feedback must be optimized so that amputees can use it effectively; and although several studies have examined how specific haptic feedback systems can transmit certain types of tactile information, there has not yet been much research on the effects of superposing two or more types of feedback at the same location, which might prove to be more effective than using a single type of feedback alone. This paper investigates how the simultaneous application of two different types of haptic feedback-vibration and normal stress-impacts the human sensory perception of each separate feedback type. These stimuli were applied to glabrous skin on the forearms of 14 participants. Our experiments tested whether participants experienced more accurate sensory perception, compared to vibration or normal stress alone, when vibration was applied at the same time as the normal stress, at either the same location, or at a different location 6 cm away. Results indicate that although participants' perception of the normal stress diminished when vibration was applied at the same location, the same combination improved their perception of the vibration. Apparently, vibration has a negative impact upon the ability to perceive normal stress, whether applied at the same or a different location; whereas the opposite is true for the effect of normal stress upon the perception of vibration.

On‐Skin Stimulation Devices for Haptic Feedback and Human–Machine Interfaces

“…Human skin can perceive multimode stimuli at the same time. [76][77][78][79][80][81] Thus, different stimulation modes can be combined or organized in particular order to provide enriched sensation from skin. For instance, in a prosthesis system with both mechanotactile and electrotactile stimulation for grasping feedback, the mechanotactile mode can be used to indicate touch with a normal object, while the electrotactile stimulation can be executed when touching sharp objects or a cup of hot beverages, as the rather uncomfortable tingles will keep the prosthesis wearer alert for safety, and can be avoided during nonhazardous grasping tasks for comfort.…”

Biorealistic hand prosthesis with compliance control and noninvasive somatotopic sensory feedback

“…It can mimic tactile sensations when the skin is pressed or stretched. The mechanotactile stimulation can provide sufficient sensory information for object identification [108,123,124] or grasp control [87,123,125,126]. On the other hand, the miniaturization and integration of mechanotactile stimulation are challenging.…”

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

“…To this end, Premarathna et al presented a soft tactile display that produces force and vibration feedback using a pneumatic balloon and electromagnetic coil [18]. A haptic device was also designed to show the impact of simultaneously applying normal stress and vibrotactile stimulation [19]. They used a piston with a DC motor to apply normal force to the skin and two shaftless cylindrical vibrator motors to generate vibrotactile stimulus.…”