Papers by Keyword: Tactile Display

Abstract: This paper proposes one of the possible techniques for interacting for shape memory alloy (SMA) actuator based tactile display, which can act as demonstrator devices. This work is focused on developing a model of a pair of antagonistic high strain SMA tension actuators with independent control of force and displacement. The technology employed utilizes two Flexinol 100 micron heat actuated wires of Titanium-Nickel (NiTi) shape-memory alloy which contract when heated under pre-stress and produces up to 5% strain recovery. This phenomenon, which provides a unique mechanism for actuation, is associated with the unique interaction between the martensite and austenite crystal structures of the SMA. Physical measurements of the behaviour of the actuator elements were performed using a laser displacement sensor to verify the fidelity of response to software commands, and to measure step response to pulse-width modulated (PWM) current control at different frequencies and duty cycles. Results yielded high accuracy across a wide range of frequencies and duty cycles, proving the SMA actuation technique has potential to present and convey useful tactile information of surface deformation for virtual environment applications.

Abstract: This paper presents an innovative tactile interactive interface graphical display for visually impaired people, information technology (IT) access application. The display consists of matrix of dots. Each dot is an electro rheological fluid micro actuator. The micro-actuator designed based on linear vertical movement principles. The actuator design and development process is presented in this paper. An advanced software tools and embedded system based on voltage matrix manipulation are developed to provide the display near real time control. Prototype size 124x4 dots, on a matrix form, of 2.54mm pitch, was manufactured. The experimental tests carried out into the prototype showed that each actuator of the matrix was able to provide a vertical holding force of 100 to 200 mN and vertical movement of 0.7 mm. The stroke and dynamic response tests showed the practicability of the developed micro actuation system, for tactile display IT access applications.

Abstract: In order to study the relation between tactile sense and finger pad deformation during a tactile exploration task, a non-contact technique to measure the finger pad deformation was proposed in this paper. The finger pad deformation can be measured with high temporal and spatial resolution via laser displacement sensor installed on an XY movement workbench. The experimental results of the finger pad deformation in different conditions show that the characteristic of finger skin is viscoelastic. The parameters of viscoelastic model can be calculated by fitting method using the Kelvin model. They are helpful for modeling the mechanoreceptor responses in skin to improve the understanding of the mechanical behavior of the finger pad and of the relation between mechanical stimuli and tactile perception.

Abstract: According to the situation that conditional Braille book is difficulty in publication and its amount is small. This paper puts forward a tactile display system which can transform content of common e-book to Braille information, and the blind comprehend the text by touching the Braille formed by the tactile display device. This Braille tactile display system extracts Chinese characters by OCR technology. The text recognized is segmented into word blocks according to the rule of Braille word segmentation before transforming to double-phoneme mandarin Braille. It uses dsPIC30F2010 to receive Braille signal and then controls the piezoelectric actuator array to output corresponding displacement.

Abstract: Providing realistic impressions about a virtual ambient for interaction with human’s auditory, visual, and tactile perception is one of the core challenges of modern imaging systems. However, particularly tactile displays with high spatial resolution implemented as a large-scale integrated microelectromechanical system are not yet realized. Here, we report on a multimodal display with thousands of actuator pixels, which generates both visual and tactile impressions of a virtual surface. The fully polymeric, monolithically integrated device consists of an actuator array made from poly(N-isopropylacrylamide). This material is a stimuli-responsive, particularly temperature-sensitive hydrogel. Controlling the actuator temperature via an optoelectrothermic interface between an upper and lower temperature the actuator can be switched from the swollen to the shrunken state (volume change up to 90%) in several hundred milliseconds. To benefit from this highly dynamic behaviour it is necessary to use a control unit which provides the required temperature changes also in the range of milliseconds. For characterizing the time behaviour of our optoelectrothermic control unit we use the change in transparency of PNIPAAm caused by the phase transition. In this paper we preferably discuss the time behaviour of the display devices.

Abstract: This paper describes a tactile display for softness feelings with a function of controlling contact area and pressure distribution. Contact area between a fingertip and a display is controlled by wrapping a flexible film around a finger. An active tensioner controls the tension of the flexible film to modify the contact pressure distribution. Controlling both area and pressure distribution realizes rendering of wider range of softness feelings. The effect was verified using photoelastic phenomenon. The experimental results show that the display can render the different contact conditions that arise from two differently-felt sponge samples with different thicknesses.

Abstract: This work is the first step to develop a programmable tactile array based on ER/MR fluid technology. Prototypes of display incorporating controllable fluids such as electrrheological (ER) fluid or magnetorheological (MR) fluid have been developed and investigated. Surface force responses of these tactile displays under various electric/magnetic fields have been measured while a probe moving across the upper surface. As the applied external electric or magnetic field varied, the sensed surface profiles changed in synchronisation with the field strength. With the controllable fluid actuator, the displayed surface information is stable and repeatable.