Influence of design parameters on the physical and perceptual performance of soft liquid dielectric actuators

Wearable haptic devices often fail to reproduce the full range of tactile sensations perceivable by human skin, particularly across the 4–400 Hz vibrotactile range. Liquid dielectric actuators (LDAs) offer a flexible, lightweight solution but require kilovolt-level drive signals, and bi-state control introduces harmonic distortion that may degrade feedback quality. We present a systematic physical and perceptual characterization of a liquid dielectric actuator (LDA), analyzing the effects of pouch size, liquid infill volume, viscosity, and electrode coverage on broadband frequency response and total harmonic distortion (THD). Using laser Doppler vibrometry and frequency-response analysis, we show that optimized designs achieved relatively uniform vibration amplitudes across the tactile band, with harmonic components reduced compared to non-optimized variants, often falling several decibels below the fundamental. A perceptual study with 27 participants compared LDA feedback against a voice-coil reference across three perceptual dimensions (“Shaky,” “Weak,” “Tingling”). Results indicate that LDAs can elicit perceptually similar sensations, with perceptual dissimilarity (mean Euclidean distance 0.15–0.18) strongly correlated with Total Harmonic Distortion (THD) (r = 0.61–0.78, p 0.05). These findings provide design guidelines for understanding harmonic contamination and demonstrate that LDAs can deliver high-fidelity, broadband tactile feedback in a form factor suitable for wearable applications. • Broad-band vibrotactile actuation using liquid dielectric actuators (LDAs) from 4–400 Hz. • Systematic design parameter study on pouch size, infill volume, viscosity, and electrode coverage. • Quantified harmonic distortion effects and correlation with perceptual dissimilarity metrics. • Lightweight, compact alternative to voice-coil actuators for wearable haptic applications.