A Method for Roughness and Texture Simulation via Tactile Displays

Author(s):  
Maura Mengoni ◽  
Paolo Morichetti ◽  
Margherita Peruzzini ◽  
Michele Germani

This paper presents a tactile synthesis method to provide roughness and texture coarseness sensations using a selective stimulation approach implemented by a tactile display. Digitizing, elaborating and processing real material surfaces obtain signals. The selection of their frequency range is based on the reactive frequencies of SAI and FAI types receptors. An electro-tactile display provided with a mechanical vibration to stimulate FAII units located at the deeper skin layers has been developed. A SW tool allows to manage selective signals modulation and configuration according to the displayed material. The research aims at overcoming a crucial problem concerning the signals adopted by most electro-tactile displays to stimulate skin mechanoreceptors. The paper focuses on the description of the adopted method and of the implemented software tool to control the tactile display. Preliminary experimentations were carried out to measure the system’s latency, accuracy and reliability. Experimental sessions show a promising system response: minimal latency (30ms), good reliability (>98%) and acceptable accuracy (>70%).

Author(s):  
Maura Mengoni ◽  
Paolo Morichetti ◽  
Margherita Peruzzini ◽  
Michele Germani

Materials simulation in virtual prototyping is one of the most challenging issues as not completely fulfilled by current devices. It allows Virtual Reality-based interfaces to provide multisensory interaction and to enhance product experience by mainly stimulating user emotional response. In this context the paper presents a new tactile simulation approach based on material surface properties elaboration and processing to stimulate roughness and texture coarseness perception. The developed approach leads to the development of a tactile display and a software tool to manage the configuration of selective stimulating signals. The main problem the research aims at overcoming, regards with the nature of signals adopted by most electrotactile displays and the way to stimulate skin mechanoreceptors. The paper focuses on the description of the adopted approach and of the implemented software tool in order to control the tactile display.


Author(s):  
Margherita Peruzzini ◽  
Maura Mengoni ◽  
Michele Germani

This paper presents a novel study on the simulation of material texture by means of electro-tactile stimuli and details the effects on the users’ ability to recognize and discriminate different material classes. The research exploits a novel tactile display to simulate material texture and validates the adopted simulation strategy by experimental testing. The tactile system elaborates data from real material samples and combines electrical stimuli and mechanical vibration to reproduce both roughness and texture coarseness sensations. Then, an experimental protocol based on the theory of Psychophysics is defined to carry out system calibration and tests with users. The research aims at validating the proposed simulation strategy and checking the user response on virtual tactile stimuli. Experimentations were carried out to reproduce virtual material texture and measure the users’ ability to distinguish different virtual materials and to recognize the material class. Experimental results provide interesting details about tactile perception mechanisms and validate the adopted approach for tactile signals’ recognition and material class discrimination.


2021 ◽  
Author(s):  
Maximilian Peter Dammann ◽  
Wolfgang Steger ◽  
Ralph Stelzer

Abstract Product visualization in AR/VR applications requires a largely manual process of data preparation. Previous publications focus on error-free triangulation or transformation of product structure data and display attributes for AR/VR applications. This paper focuses on the preparation of the required geometry data. In this context, a significant reduction in effort can be achieved through automation. The steps of geometry preparation are identified and examined with respect to their automation potential. In addition, possible couplings of sub-steps are discussed. Based on these explanations, a structure for the geometry preparation process is proposed. With this structured preparation process it becomes possible to consider the available computing power of the target platform during the geometry preparation. The number of objects to be rendered, the tessellation quality and the level of detail can be controlled by the automated choice of transformation parameters. We present a software tool in which partial steps of the automatic preparation are already implemented. After an analysis of the product structure of a CAD file, the transformation is executed for each component. Functions implemented so far allow, for example, the selection of assemblies and parts based on filter options, the transformation of geometries in batch mode, the removal of certain details and the creation of UV maps. Flexibility, transformation quality and time savings are described and discussed.


Author(s):  
Maximilian Peter Dammann ◽  
Wolfgang Steger ◽  
Ralph Stelzer

Abstract Product visualization in AR/VR applications requires a largely manual process of data preparation. Previous publications focus on error-free triangulation or transformation of product structure data and display attributes for AR/VR applications. This paper focuses on the preparation of the required geometry data. In this context, a significant reduction in effort can be achieved through automation. The steps of geometry preparation are identified and examined concerning their automation potential. In addition, possible couplings of sub-steps are discussed. Based on these explanations, a structure for the geometry preparation process is proposed. With this structured preparation process, it becomes possible to consider the available computing power of the target platform during the geometry preparation. The number of objects to be rendered, the tessellation quality, and the level of detail can be controlled by the automated choice of transformation parameters. Through this approach, tedious preparation tasks and iterative performance optimization can be avoided in the future, which also simplifies the integration of AR/VR applications into product development and use. A software tool is presented in which partial steps of the automatic preparation are already implemented. After an analysis of the product structure of a CAD file, the transformation is executed for each component. Functions implemented so far allow, for example, the selection of assemblies and parts based on filter options, the transformation of geometries in batch mode, the removal of certain details, and the creation of UV maps. Flexibility, transformation quality, and timesavings are described and discussed.


2017 ◽  
Vol 72 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Mircea A. Comanescu ◽  
Cyril Muehlethaler ◽  
John R. Lombardi ◽  
Marco Leona ◽  
Thomas A. Kubic

This research presents a study in surface-enhanced Raman quantitation of dyes present in mixtures of alizarin and purpurin using standard calibration curves and Langmuir isotherm calibration models. Investigations of the nature of competitive adsorption onto silver nanoparticles by centrifugation indicates that both dyes in the mixture interact with the nanoparticles simultaneously, but only the stronger adsorbing one is seen to dominate the spectral characteristics. Calibration can be carried out by careful selection of peaks characteristic to each dye in the mixture. Comparisons of peak height and peak area calibrations reveal that peak heights, when selected by the maximum value and accounting for peak shifts, prove the better model for quantitation. It is also shown that the microwave nanoparticle synthesis method produces stable nanoparticles with a shelf-life of at least one year that give very little variation within and between uses.


2015 ◽  
Vol 56 (1) ◽  
pp. 59-83
Author(s):  
Dafydd Gibbon ◽  
Katarzyna Klessa ◽  
Jolanta Bachan

AbstractThe study of speech timing, i.e. the duration and speed or tempo of speech events, has increased in importance over the past twenty years, in particular in connection with increased demands for accuracy, intelligibility and naturalness in speech technology, with applications in language teaching and testing, and with the study of speech timing patterns in language typology. H owever, the methods used in such studies are very diverse, and so far there is no accessible overview of these methods. Since the field is too broad for us to provide an exhaustive account, we have made two choices: first, to provide a framework of paradigmatic (classificatory), syntagmatic (compositional) and functional (discourse-oriented) dimensions for duration analysis; and second, to provide worked examples of a selection of methods associated primarily with these three dimensions. Some of the methods which are covered are established state-of-the-art approaches (e.g. the paradigmatic Classification and Regression Trees, CART , analysis), others are discussed in a critical light (e.g. so-called ‘rhythm metrics’). A set of syntagmatic approaches applies to the tokenisation and tree parsing of duration hierarchies, based on speech annotations, and a functional approach describes duration distributions with sociolinguistic variables. Several of the methods are supported by a new web-based software tool for analysing annotated speech data, the Time Group Analyser.


2012 ◽  
Vol 134 (6) ◽  
Author(s):  
R. E. Spears ◽  
S. R. Jensen

Nonlinearities, whether geometric or material, need to be addressed in seismic analysis. One good analysis method that can address these nonlinearities is direct time integration with Rayleigh damping. Modal damping is the damping typically specified in seismic analysis Codes and Standards (ASCE 4-98, 1998, “Seismic Analysis of Safety-Related Nuclear Structures and Commentary,” American Society of Civil Engineers, Reston, Virginia and ASCE/SEI 43-05, 2005, “Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities,” American Society of Civil Engineers, Reston, Virginia.). Modal damping is constant for all frequencies where Rayleigh damping varies with frequency. An approach is proposed here for selection of Rayleigh damping coefficients to be used in seismic analyses that is consistent with given modal damping. The approach uses the difference between the modal damping response and the Rayleigh damping response along with effective mass properties of the model being evaluated to match overall system response levels. This paper provides a simple example problem to demonstrate the approach. It also provides results for a finite element model representing an existing piping system. Displacement, acceleration, and stress results are compared from model runs using modal damping and model runs using Rayleigh damping with coefficients selected using the proposed method.


Author(s):  
Yasushi Ikei ◽  
Shuichi Fukuda

Abstract The authors have developed tactile displays which have vibrating pins to convey the surface texture sensation of object surfaces to the user’s fingertip. The tactile sensation intensity scaling was performed to obtain a sensation scale of the display by means of the JND (just noticeable difference) method. One dimensional curves on the scale were displayed to investigate the human sensitivity to an intensity change rate. A tactile texture presentation method based on the image of an object surface is introduced. Two kinds of experiment were performed to discuss the feature of the method. Texture discrimination is the first one, in which the effect of texture element size to the correct separation was discussed. Then the sensations produced by the display and those by real objects were compared regarding several samples that had a major feature of vertical lines and of not containing low frequencies. The results are summarized, which is followed by the future research work.


Author(s):  
Kylie Gomes ◽  
Scott Betza ◽  
Sara Lu Riggs

Objective To evaluate the effects that movement, cue complexity, and the location of tactile displays on the body have on tactile change detection. Background Tactile displays have been demonstrated as a means to address data overload by offloading the visual and auditory modalities. However, change blindness—the failure to detect changes in a stimulus when changes coincide with another event or disruption in stimulus continuity—has been demonstrated to affect the tactile modality and may be exacerbated during movement. The complexity of tactile cues and locations of tactile displays on the body may also affect the detection of changes in tactile patterns. Limitations to tactile perception need to be examined. Method Twenty-four participants performed a tactile change detection task while sitting, standing, and walking. Tactile cues varied in complexity and included low, medium, and high complexity cues presented to the arm or back. Results Movement adversely affects tactile change detection as hit rates were the highest while sitting, followed by standing and walking. Cue complexity affected tactile change detection: Low complexity cues resulted in higher detection rates compared with medium and high complexity cues. The arms exhibited better change detection performance than the back. Conclusion The design of tactile displays should consider the effect of movement. Cue complexity should be minimized and decisions about the location of a tactile display should take into account body movements to support tactile perception. Application The findings can provide design guidelines to inform tactile display design for data-rich, complex domains.


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