A tuned mass amplifier for enhanced haptic feedback

TL;DR

This paper introduces a tuned mass amplifier that enhances vibro-tactile feedback by engineering resonance mode shapes with embedded mass, achieving significantly higher forces without increasing stiffness or frequency.

Contribution

It presents a novel design method for vibro-tactile amplifiers using resonance mode shape engineering and neural network optimization, validated through experiments.

Findings

Achieves 7.7 times higher tactile forces

Maintains low resonance frequency

Validated with 3D printed prototypes

Abstract

Vibro-tactile feedback is, by far the most common haptic interface in wearable or touchable devices. This feedback can be amplified by controlling the wave propagation characteristics in devices, by utilizing phenomena such as structural resonance. However, much of the work in vibro-tactile haptics has focused on amplifying local displacements in a structure by increasing local compliance. In this paper, we show that engineering the resonance mode shape of a structure with embedded localized mass amplifies the displacements without compromising on the stiffness or resonance frequency. The resulting structure, i.e., a tuned mass amplifier, produces higher tactile forces (7.7 times) compared to its counterpart without a mass, while maintaining a low frequency. We optimize the proposed design using a combination of a neural network and sensitivity analysis, and validate the results with experiments on 3-D printed structures. We also study the performance of the device on contact with a soft material, to evaluate the interaction with skin. Potential avenues for future work are also presented, including small form factor wearable haptic devices and remote haptics.