A vibrational resonant cantilever beam device is a type of tactile vision substitution device for the visually impaired that has the potential to achieve a high resolution in a small space. In order to realize a device of this type, it is necessary to accurately model the resonant behavior of the mesoscale (0.1–1.0 mm) metal cantilever beams of which the device is composed. Specifically, the natural frequencies and damping ratios of these beams must be analytically modeled in order to design beam dimensions for the device. In this paper, the resonant frequencies and damping ratios of a set of A2 tool-steel mesoscale cantilever beams are obtained using three different methods: calculation based on a mass–spring–damper model of the beams; a forced response experiment; and a free response experiment. The results are compared, and the size effect on stiffness and elastic modulus is investigated. Based on the modified couple stress theory, the length scale parameter is calculated. The damping ratio difference depending on the dimension of material in the mesoscale is also investigated.

This study addresses the clinical requirements of a transoral surgery-assisting continuum robot. This application requires both high bendability and stiffness in order to ensure precise positioning and stable fixation of surgical tools. To meet these needs, we developed a tendon-driven discrete continuum robot unit featuring a ball–socket joint and superelastic Nitinol rods. One to three serially connected robot units were tested by applying proximal tendon tension ($T_l$) in the range of 100–1000 g while distal tension ($T_s$) was continuously increased to induce bending. During bending, the curves were interpolated using third-order to fifth-order polynomials at discrete $T_l$ levels. The interpolated inverse statics were validated experimentally and compared with finite element simulations using ANSYS. Furthermore, we propose a planar path planning algorithm and numerically evaluate it for a three-unit robot following an arc-shaped trajectory. The inverse statics successfully captured the nonlinear bending behavior of the tendon-driven robot. Validation experiments showed average angular errors of 2.7%, 6.6%, and 5.3% for one, two, and three connected units, respectively. The proposed path planning method achieved an average positional deviation from the reference trajectory ranging from 0.95 mm to 19.77 mm. This work presents a practical and generalizable experimental mapping framework for the inverse statics of tendon-driven discrete continuum robots, avoiding the need for complex analytical models.

One type of assistive device for the blind has attempted to convert visual information into information that can be perceived through another sense, such as touch or hearing. A vibrotactile haptic display assistive device consists of an array of vibrating elements placed against the skin, allowing the blind individual to receive visual information through touch. However, these approaches have two significant technical challenges: large vibration element size and the number of microcontroller pins required for vibration control, both causing excessively low resolution of the device. Here, we propose and investigate a type of high-resolution vibrotactile haptic display which overcomes these challenges by utilizing a ‘microbeam’ as the vibrating element. These microbeams can then be actuated using only one microcontroller pin connected to a speaker or surface transducer. We propose that this approach could solve the low-resolution problem currently present in all haptic displays. In this paper, we present the results of an investigation into the manufacturability of such a device, simulation of the vibrational characteristics, and prototyping and experimental validation of the device concept.

Resonant vibrotactile microbeams use the concept of resonance to excite the vibration of cantilever beams, which correspond to pixels of an image. The primary benefit of this type of tactile display is its potential for high resolution. This paper presents the concept of the proposed system and human skin contact experiments to explore user perception challenges related to beam vibration during skin contact. The human skin contact experiments can be described in five phases: dried skin contact to metal beam tips, wet and soaped skin contact to metal beam tips, skin contact with a constraint, normal force measurement, and skin contact to the tips of silicone rubber beams attached to metal beam tips. Experimental results are analyzed to determine in what cases of skin contact the beams stop vibrating. It is found that the addition of silicone rubber beams allows the primary metal beams to continue vibrating while in contact with skin. Thus, the vibration response of a metal beam with silicone rubber beams is investigated for the better understanding of the effect of silicone rubber beams on the metal beam vibration.

1. Wearable tactile interfaces are increasingly explored as alternative or complementary channels for conveying information when vision is unavailable, overloaded, or impractical (Adame et al., 201...