A Feasibility Study of a Vibrotactile System Based on Electrostatic Actuators for Touch Bar Interfaces: Experimental Evaluations

Abstract

Vibrotactile feedback is a very desirable feature for many touchscreen applications, creating a more engaging and effective user experience. Although it is common in small electronic devices, this feedback is often absent in large touchscreen devices because it is difficult to provide vibration sensations and control the magnitude throughout the display. Because of their long shape (over 20 cm), touch bar displays are susceptible to the same challenges that other large display types face. Thus, there is a need for a vibrotactile actuation system capable of generating a freely positionable and fully controllable point of stimulation with satisfying force output at any point of a touch bar display. This study proposes a new spring boundary condition vibrotactile system as a way to provide such feedback in touch bar interfaces. A prototype system was created using two electrostatic resonant actuators and a thin, narrow aluminum beam to study the effect of different actuator excitation parameters on the beam′s response. By varying the number of actuators excited, magnitude, excitation frequency, and signal duration, a minimum vibration of 24.5 m/s2 could be created in the beam, with the majority of the beam able to exceed 40 m/s2. These results show that a targeted vibrotactile response at a given location in the beam can be achieved and sustained. This demonstrates a promising potential for generating a freely positionable and fully controllable point of vibrotactile stimulation at any point of a touch bar display.

Modeling and Experimental Evaluation of Haptic Localization Using Electrostatic Vibration Actuators

“…They are limited in vibration intensity due to the snap-in phenomenon, which limits the displacement range [16]. Modified dual electrode electrostatic actuators termed electrostatic resonant actuators (ERAs) are found to have sufficient vibration intensity for large TSDs [12], [17].…”

“…This can be attributed to the use of conventional boundary conditions such as fixed and pinned. For example, a fixed boundary condition requires a drastic change in the actuator's frequency of excitation to change the vibration mode shape of the touch surface [17]. Therefore, there is a need to explore nonconventional (mostly not found in literature) boundary conditions to eliminate dead zones of vibration and to conveniently make haptic feedback available across the whole surface of a large TSD.…”