Three-Axis Pneumatic Haptic Display for the Mechanical and Thermal Stimulation of a Human Finger Pad

Abstract

Haptic displays have been developed to provide operators with rich tactile information using simple structures. In this study, a three-axis tactile actuator capable of thermal display was developed to deliver tactile senses more realistically and intuitively. The proposed haptic display uses pneumatic pressure to provide shear and normal tactile pressure through an inflation of the balloons inherent in the device. The device provides a lateral displacement of ±1.5 mm for shear haptic feedback and a vertical inflation of the balloon of up to 3.7 mm for normal haptic feedback. It is designed to deliver thermal feedback to the operator through the attachment of a heater to the finger stage of the device, in addition to mechanical haptic feedback. A custom-designed control module is employed to generate appropriate haptic feedback by computing signals from sensors or control computers. This control module has a manual gain control function to compensate for the force exerted on the device by the user’s fingers. Experimental results showed that it could improve the positional accuracy and linearity of the device and minimize hysteresis phenomena. The temperature of the device could be controlled by a pulse-width modulation signal from room temperature to 90 °C. Psychophysical experiments show that cognitive accuracy is affected by gain, and temperature is not significantly affected.

A Soft Electro-Hydraulic Pneumatic Actuator with Self-Sensing Capability toward Multi-Modal Haptic Feedback

“…For instance, the output displacement at 5 kV increased by 0.8 mm compared to that at 0 kV, at the pressure 5 kPa. Compared with the reported experimental results, the output displacement of the film could at least reach 5 mm, which is much larger than the reported displacement of some actuators [1,[15][16][17]20,22].…”

“…According to the driving modes, the existing soft haptic actuators can be categorized into pneumatic drives, electro-hydraulic drives, electromagnetic drives, and so on. Lee et al [15] designed a three-axis pneumatic haptic actuator, where the device provided a lateral displacement of ±1.5 mm for shear haptic feedback and a vertical inflation of the balloon of up to 3.7 mm for normal haptic feedback. Li et al [16] proposed a multi-fingered palpation method, in which the employed pneumatic haptic feedback actuators, with the produced displacements of 4.5 mm at 100 kPa, allowed users to experience haptic sensations at multiple fingers while carrying out remote soft tissue palpation.…”

Feel-Good Requirements: Neurophysiological and Psychological Design Criteria of Affective Touch for (Assistive) Robots

“…Along with mechanical enhancements, the response of CT fibers to thermal stimulation is still undiscovered as experiments to date have been performed at ambient temperature. Based on findings regarding responses of C-tactile afferents to thermal stimuli (Nordin, 1990 ; Ackerley et al, 2014 , 2018 ), it would be benign to consider effects of different temperatures of touch in interface design by adapting mechanical and thermal stimulators, such as pneumatic haptic display (Lee et al, 2021 ).…”

A 2-DOF Impact Actuator for Haptic Application

“…Using the property, researchers have developed light haptic interfaces with fast reaction times [17][18][19][20][21][22]. Another solution is a pneumatic haptic actuator that uses air pressure to stimulate the end-effector of a haptic interface [23][24][25][26][27][28][29][30][31]. The pneumatic haptic actuator has various advantages, including a light end-effector, a fast reaction time, high-intensity tactile sensations, and possibly multi-DOF feedback, depending on the functionalities of the air compressor.…”