Ramiro Velázquez

A low-cost highly-portable tactile display based on shape memory alloy micro-actuators

This paper presents a new concept of low-cost, high-resolution, lightweight, compact and highly-portable tactile display. The prototype consists of an array of 8 /spl times/ 8 upward/downward independent moveable pins based on shape memory alloy (SMA) technology. Each actuator is capable of developing a 320 mN pull force at 1.5 Hz bandwidth by using simple forced-air convection. The proposed concept allows the development of 60 g weight tactile devices of compact dimensions easily carried in the users hand. SMA active element, tactile actuator and tactile display are presented and discussed.

Tactile Rendering With Shape-Memory-Alloy Pin-Matrix

This paper presents a novel pin-matrix tactile-display device that exhibits some advantageous features for the blind: low cost, lightweight, compactness, and high portability. The prototype consists of 64 tactile pins actuated by shape memory alloys with 2.6-mm spatial resolution (Braille-like). Unlike existing devices, the full display weighs only 200 g, and its compact dimensions make it easy to carry. A technical overview of the system is presented, as well as preliminary results on shape recognition, to evaluate its performance on tactile rendering.

Miniature Shape Memory Alloy Actuator for Tactile Binary Information Display

This paper presents a new miniature actuator, which is currently being used to design and develop high resolution, lightweight and compact interfaces for tactile binary information representation such as Braille. Since the main drawback of these devices is their high cost, the proposed actuator exploits the simplicity of its design to provide a low-cost actuation alternative. Based on shape memory alloy (SMA) technology, the actuator consists of an antagonist arranged pair of NiTi helical springs. The actuator of 1.5 mm diameter and 150 mg weight is capable of developing a 320 mN pull force and 1.5 Hz bandwidth by using simple forced-air convection. A combined computational/experimental study on the thermomechanical properties of both SMA active element and actuator is presented to evaluate characteristics such as actuation speed, force and stroke. In conclusion, the prototype and performance results are reported and discussed.

Intelligent glasses: A multimodal interface for data communication to the visually impaired

This paper introduces the concept of bimodal visual-tactile interface, named Intelligent Glasses (IG), designed for assistance of the visually impaired in their daily tasks such as access to information and mobility. The IG architecture is outlined and its preliminary evaluation through original experiments with healthy blindfolded subjects is provided. The collected results show that the IG system can be used as a support for the considered tasks.

IMAGE MATCHING OPTIMIZATION VIA VISION AND INERTIAL DATA FUSION: APPLICATION TO NAVIGATION OF THE VISUALLY IMPAIRED

Autonomous navigation by humans or robots is usually based on stereo image matching. However, classic image matching methods are not suitable for wearable real-time navigation systems. This paper proposes a new image-matching algorithm which fuses information from both images and inertial data. A preliminary evaluation of the algorithm shows that it is effective for indoor navigation.

THE TACTOBOOK: A PORTABLE ELECTRONIC TACTILE READING DEVICE FOR THE BLIND

Abstract This paper introduces a novel concept on reading assistive technologies for the blind/visually impaired: the TactoBook , a system that is able to translate entire text books to Braille code and to reproduce them in portable electronic touch stimulation devices. The TactoBook consists of a computer-based system that translates fast and automatically any text book into Braille. The Braille version of the book is then stored in a USB memory drive which is later inserted and reproduced in a compact, lightweight and highly-portable tactile display. The user freely explores the information displayed and is able to read comfortably the book without carrying the burdensome tactile print one.

Design and characterization of a shape memory alloy based micro-actuator for tactile stimulation

This paper describes the design, modeling and implementation of a novel shape memory alloy (SMA) based micro-actuator intended for high resolution tactile displays. In order to evaluate the characteristics of SMA devices, existing constitutive models are used to predict their dynamic behavior. In particular, thermal and mechanical properties are studied and analyzed. Time domain and force-displacement open loop experimental results are presented to validate simulation performance. The accuracy of the models may be used to design actuators under specifications of dimension, force and speed. Inspired by a simple retractable ballpoint pen-like mechanism, the actuators design concept is described in detail. In conclusion, the prototype and preliminary results are presented and discussed.

Touch stimulation through an SMA-actuated micro-mechanism

The aim of this paper is to present a new micro-actuator, which is currently being used to design and develop high resolution, lightweight and compact interfaces for tactile information representation. Based on shape memory alloy (SMA) technology, the actuator is capable of producing a mechanic deformation on the skin of the users fingertip in order to re-create a realistic touch sensation. This actuator of 1.5 mm diameter, 5 cm length, 150 mg weight, 0.7 mm total excursion, 170 mN pull force and 4 Hz bandwidth represents a high spatial and temporal resolution actuation principle for tactile feel displays. The SMA actuators design concept, modeling and implementation are presented and described in detail. In conclusion, the prototype and preliminary performance results are reported and discussed.

On cognitive dynamic map and its use for navigation in space

The paper addresses experimental results on peri-space geometry and topology perception with a touch sense. A dedicated “perception-action” platform, involving artificial vision and a hand tactile stimulation device as well as convenient touch-space perception experiments have been designed. The proposed gravitation representation of the space is based upon nearest object edge displays on tactile device, which dynamically modifies with subject navigating in the plate form. This representation has been evaluated on voluntary blindfolded healthy male and female subjects. The collected data show that it is possible to navigate in space using the touch stimulating device.