Roughness Encoding in Human and Biomimetic Artificial Touch: Spatiotemporal Frequency Modulation and Structural Anisotropy of Fingerprints

The influence of fingerprints and their curvature in tactile sensing performance is investigated by comparative analysis of different design parameters in a biomimetic artificial fingertip, having straight or curved fingerprints. The strength in the encoding of the principal spatial period of ridged tactile stimuli (gratings) is evaluated by indenting and sliding the surfaces at controlled normal contact force and tangential sliding velocity, as a function of fingertip rotation along the indentation axis. Curved fingerprints guaranteed higher directional isotropy than straight fingerprints in the encoding of the principal frequency resulting from the ratio between the sliding velocity and the spatial periodicity of the grating. In parallel, human microneurography experiments were performed and a selection of results is included in this work in order to support the significance of the biorobotic study with the artificial tactile system

Artificial Roughness Encoding with a Bio-inspired MEMS- based Tactile Sensor Array

A compliant 2×2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad

Microfabricated tactile sensors for biomedical applications: a review

During the last decades, tactile sensors based on different sensing principles have been developed due to the growing interest in robotics and, mainly, in medical applications. Several technological solutions have been employed to design tactile sensors; in particular, solutions based on microfabrication present several attractive features. Microfabrication technologies allow for developing miniaturized sensors with good performance in terms of metrological properties (e.g., accuracy, sensitivity, low power consumption, and frequency response). Small size and good metrological properties heighten the potential role of tactile sensors in medicine, making them especially attractive to be integrated in smart interfaces and microsurgical tools. This paper provides an overview of microfabricated tactile sensors, focusing on the mean principles of sensing, i.e., piezoresistive, piezoelectric and capacitive sensors. These sensors are employed for measuring contact properties, in particular force and pressure, in three main medical fields, i.e., prosthetics and artificial skin, minimal access surgery and smart interfaces for biomechanical analysis. The working principles and the metrological properties of the most promising tactile, microfabricated sensors are analyzed, together with their application in medicine. Finally, the new emerging technologies in these fields are briefly described

Friction Induced Vibration Based Pattern Detection On An Artificial Skin By Preload Control

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012Bu çalışma, kayma hızı, önyükleme kuvveti ve tip çapı gibi farklı tasarım parametreleri altında, yapay olarak yapılan yüzeyin deseninin algılanmasını ve sürtünme özelliklerini ortaya koymaktadır. İsteğe göre yapılmış olan yarı otonom sürtünme deney düzeneğinde, düz şeffaf polimer kullanılarak yapılan sürtünme testlerinin neticesinde, düzenek gerçeklenmiş ve uygun çalışma şartları belirlenmiştir. Desen algılama deneyleri, kayma sırasında yüzeye uygulanan önyükleme kuvveti, kuvvet geribesleme kontrolcüsü tarafından sabit tutulurken, sert cam tipe karşı sürtülen, eşit aralıklarla dağıtılmış tümsekleri olan yapay deri üzerinde gerçekleştirilmiştir. Yüzey taraması esnasında oluşan sürtünmenin yol açtığı titreşimler, yapay derinin desenine ait olan ve taranan yüzeyin tümseklerinin yükseklik ve dalgaboyu gibi bilgisini taşıyan frekansın algılanmasına olanak tanımıştır. Bu arada test sonuçlarına göre önyükleme kuvveti, düşük kayma hızı ve yüksek kuvvet altında minimum hata yüzdesiyle sabit kalmaktadır. Buna ek olarak, önyükleme kuvvet hatasının azaltılmasında ve sinyal harmoniklerinin filtrelenmesinde tip çapının etkisi de gözlemlenmiştir.This study exhibits pattern detection and frictional properties of the artificially made surface under different design parameters such as sliding velocity, preload, and tip diameter. In consequence of frictional tests on the custom built semi-autonomous friction set-up using flat soft polymer, the set-up is validated, and proper working conditions are determined. The pattern detection experiments are realized on an artificial skin with evenly distributed ridges rubbed against a rigid glass tip while the preload applied to the surface is kept constant during sliding by the force-feedback controller. The friction induced vibrations occurred during surface scanning allowed to detect the frequency belonging to the pattern of the artificial skin, and carrying the information of the scanned surface like height and wavelength of ridges. Meanwhile, according to the results of the tests, the preload remains consistent with a minimum percentage of error at low sliding velocity and under high preload value. In addition, tip diameter effect on reducing the preload error, and filtering harmonics of the signal is also observed.Yüksek LisansM.Sc

Haptics Rendering and Applications

There has been significant progress in haptic technologies but the incorporation of haptics into virtual environments is still in its infancy. A wide range of the new society's human activities including communication, education, art, entertainment, commerce and science would forever change if we learned how to capture, manipulate and reproduce haptic sensory stimuli that are nearly indistinguishable from reality. For the field to move forward, many commercial and technological barriers need to be overcome. By rendering how objects feel through haptic technology, we communicate information that might reflect a desire to speak a physically- based language that has never been explored before. Due to constant improvement in haptics technology and increasing levels of research into and development of haptics-related algorithms, protocols and devices, there is a belief that haptics technology has a promising future

Mems sensors controlled haptic forefinger robotic aid

The ability to feel the world through the tools we hold is Haptic Touch. The concept of sensory elements transforming information into touch experience by interacting with things remotely is motivating and challenging. This paper deals with the design and implementation of fore finger direction based robot for physically challenged people, which follows the direction of the Forefinger. The path way of the robot may be either point-to-point or continuous. This sensor detects the direction of the forefinger and the output is transmitted via RF transmitter to the receiver unit. In the receiver section RF receiver which receives corresponding signal will command the microcontroller to move the robot in that particular direction. The design of the system includes microcontroller, MEMS sensor and RF technology. The robot system receives the command from the MEMS sensor which is placed on the fore finger at the transmitter section. Therefore the simple control mechanism of the robot is shown. Experimental results for fore finger based directional robot are enumerated

Wearable haptic systems for the fingertip and the hand: taxonomy, review and perspectives

In the last decade, we have witnessed a drastic change in the form factor of audio and vision technologies, from heavy and grounded machines to lightweight devices that naturally fit our bodies. However, only recently, haptic systems have started to be designed with wearability in mind. The wearability of haptic systems enables novel forms of communication, cooperation, and integration between humans and machines. Wearable haptic interfaces are capable of communicating with the human wearers during their interaction with the environment they share, in a natural and yet private way. This paper presents a taxonomy and review of wearable haptic systems for the fingertip and the hand, focusing on those systems directly addressing wearability challenges. The paper also discusses the main technological and design challenges for the development of wearable haptic interfaces, and it reports on the future perspectives of the field. Finally, the paper includes two tables summarizing the characteristics and features of the most representative wearable haptic systems for the fingertip and the hand

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility