• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.942-947
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• 2003

An important signal processing problem in PVDF sensor is the restoration of surface information from electric sensing signals. The objectives of this research are to design a new texture sensing system and to develop a new signal processing algorithm for signals from the sensor to be tangibly displayed by tangible interface systems. The texture sensing system is designed to get surface information with high resolution and dynamic range. First, a PVDF sensor is made of piezoelectric polymer (polyvinylidene fluoride) strips molded in a silicon rubber and attached in a rigid cylinder body. The sensor is mounted to a scanning system for dynamic sensing. Secondly, a new signal processing algorithm is developed to restore surface information. The algorithm consists of the two-dimensional modeling of the sensor using an identification method and inverse filtering from sensing signals into estimated surface information. Finally the two-dimensional surface information can be experimentally reconstructed from sensing signals using the developed signal processing algorithm.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.229.1-229.1
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• 2014

Tactile sensors have widely been researched in the areas of electronics, robotic system and medical tools for extending to the form of bio inspired devices that generate feeling of touch mimicking those of humans. Recent efforts in adapting the tactile sensor have included the use of novel materials with both scalability and high sensitivity [1]. Graphene, a 2-D allotrope of carbon, is a prospective candidate for sensor technology, having strong mechanical properties [2] and flexibility, including recovery from mechanical stress. In addition, its truly 2-D nature allows the formation of continuous films that are intrinsically useful for realizing sensing functions. However, very few investigations have been carrier out to investigate sensing characteristics as a device form with the graphene subjected to strain/stress and pressure effects. In this study, we present a sensor of vertical forces based on single-layer graphene, with a working range that corresponds to the pressure of a gentle touch that can be perceived by humans. In spite of the low gauge factor that arises from the intrinsic electromechanical character of single-layer graphene, we achieve a resistance variation of about 30% in response to an applied vertical pressure of 5 kPa by introducing a pressure-amplifying structure in the sensor. In addition, we demonstrate a method to enhance the sensitivity of the sensor by applying resistive single-layer graphene.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.3
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• pp.188-192
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• 2012

In this study, a carbon nanotube (CNT) flexible strain sensor was fabricated with CNT based epoxy and rubber composites for tactile sensing. The flexible strain sensor can be fabricated as a long fibrous sensor and it also may be able to measure large deformation and contact information on a structure. The long and flexible sensor can be considered to be a continuous sensor like a dendrite of a neuron in the human body and we named the sensor as a biomimetic artificial neuron. For the application of the neuron in biomimetic engineering, an ANMS (Artificial Neuron Matrix System) was developed by means of the array of the neurons with a signal processing system. Moreover, a strain positioning algorithm was also developed to find localized tactile information of the ANMS with Labview for the application of an artificial e-skin.

• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.89-101
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• 2006

Tactile sensation is one of the most important sensory functions for human perception of objects. Recently, there have been many technical challenges in the field of tactile display as well as tactile sensing. In this paper, we propose an innovative tactile display device based on soft actuator technology with ElectroActive Polymer(EAP). This device offers advantageous features over existing devices with respect to intrinsic flexibility, softness, ease of fabrication and miniaturization, high power density, and cost effectiveness. In particular, it can be adapted to various geometric configurations because it possesses structural flexibility, so it can be worn on any part of the human body such as finger, palm, and arm etc. It can be extensively applied as a wearable tactile display, a Braille device for the visually disabled, and a human interface in the future. A new design of the flexible actuator is proposed and its basic operational principles are discussed. In addition, a wearable tactile display device with $4{\times}5$ actuator array(20 actuator cells) is developed and its effectiveness is confirmed.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.97.6-97
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• 2002

In this paper, we present an arrayed flexible tactile sensor, which can detect contact normal forces as well as positions. The tactile sensor is developed using Polyvinylidene Fluoride (PVDF) that is known as piezoelectric polymer, and the surface electrode is fabricated using silk-screening technique with silver. We develop a charge amplifier in order to amplify the small signal from the sensor, and a fast signal processing unit by using a DSP chip. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In the future, the developed sensor is applied to a dexterous robotic hand...$\textbullet$ Tactile sensing, PVDF, Robot hand

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.1
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• pp.60-65
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• 2004

A flexible tactile sensor away with 8 H 8 tactile elements is designed and fabricated. The material of the sensor is PVDF(polyvinylidene fluoride) film and flexible circuitry is used in the fabrication fur the flexibility of the sensor The experimental results on static and dynamic properties of the sensor are obtained and examined. The signals of a contact pressure to the sensor are sensed and processed in the DSP system in which the signals are digitalized and filtered. The processed signals of the sensor outputs are visualized in a personal computer for illustrating the shape and force distribution of a contact object. The reasonable performance for the detection of contact state is verified through sensing examples.

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.646-654
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• 2002

The human sense of touch provides us with an important source of information about our surroundings. Because of its unique position at interface between our bodies and the out world, touch sensation supplies sensory data which helps us manipulate and recognize objects and warn of harmful situation. But tactile sensation was recognized less important than visual sense and auditory sense but it plays an important immersing role in virtual reality and computer game. Tactile sensation can be used to influence to objects according to power and supplied sensory feedback to the player in a virtual environment. This paper investigated the characteristics of tactile sensation of human being and proposed method of sturdy using force sensing sensor, simple force modeling and data structure form for virtual reality and computer game. As a result, force distribution, depth, center point can be calculated using sensor output and this information is very effective to specific position for actions and reactions. This study can used as basic information for tactile sensation and it's application in computer game and virtual realty.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.131-134
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• 2011

In this study, we propose an optimal design and new fabrication method for a slim tactile sensor. Slim tactile sensor can detect 3-axial forces and has suitable flexibility for intelligent robot fingers. To amplify the contact signal, a unique table-shaped structure was attempted. A new layer-by-layer fabrication process for polymer micromachining that can make a 3D structure by using a sacrificial layer was proposed. A table-shaped epoxy sensing plate with four legs was built on top of a flexible polymer substrate. The plate can convert an applied force to a concentrated stress. Normal and shear forces can be detected by combining responses from metal strain gauges embedded in the polymer substrate. The optimal positions of the strain gauges are determined using the strain distribution obtained from finite element analysis.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1272-1274
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• 1996

This paper presents the development of tactile sensor systems for robot hand which are truly usable, robust, reliable and cheap system. The sensor incorporates multiple sensing subsystems for detecting distributed contact forces and surface characteristics. The fabrication and experimental evaluation of the tactile system and its electric interfaces are described. The results indicate that the system provides reasonable performances for practical applications requiring manipulation with tactile feedback.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.364-372
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• 2006

In this paper, we present a finger tip tactile sensor which can detect contact normal force as well as slip. The sensor is made up of two different materials, such as polyvinylidene fluoride (PVDF) known as piezoelectric polymer, and pressure variable resistor ink. In order to detect slip on the surface of the object, two PVDF strips are arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, a tactile sensing system is developed, which includes miniaturized charge amplifier to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.