• 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.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.157-164
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• 2014

In this paper, we design a gripping force control system using tactile sensor to prevent slip when gripper tries to grasp and lift an object. We use a flexible tactile sensor for measuring uniplanar pressure on gripper's finger and develop an algorithm to detect the onset of slip using the sensor output. We also use a flexible pressure sensor to measure the normal force. In addition, various signal processing techniques are used to reduce noise included in the sensor output. A 3-finger gripper is used to grasp and lift up a cylindrical object. The tactile sensor is attached on one of fingers, and sends output signals to detect slip. Whenever the sensor signal is similar to the slip pattern, gripper force is increased. In conclusion, this research shows that slip can be detected using the tactile sensor and we can control gripping force to eliminate slip between gripper and object.

• Smart Structures and Systems
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• v.9 no.6
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• pp.535-547
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• 2012

Controlling the balance of motion in a context involving a biped robot navigating a rugged surface or a step is a difficult task. In the present study, a $3{\times}5$ flexible piezoelectric tactile sensor array is developed to provide a foot pressure map and zero moment point for a biped robot. We introduce an innovative concept involving structural electrodes on a piezoelectric film in order to improve the sensitivity. The tactile sensor consists of a polymer piezoelectric film, PVDF, between two patterned flexible print circuit substrates (FPC). Additionally, a silicon rubber bump-like structure is attached to the FPC and covered by a polydimethylsiloxane (PDMS) layer. Experimental results show that the output signal of the sensor exhibits a linear behavior within 0.2 N ~ 9 N, while its sensitivity is approximately 42 mV/N. According to the characteristic of the tactile sensor, the readout module is designed for an in-situ display of the pressure magnitudes and distribution within $3{\times}5$ taxels. Furthermore, the trajectory of the zero moment point (ZMP) can also be calculated by this program. Consequently, our tactile sensor module can provide the pressure map and ZMP information to the in-situ feedback to control the balance of moment for a biped robot.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.42-50
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• 2016

Traditional tactile controls that include push buttons and rotary switches may cause significant visual and biomechanical distractions if they are located away from the driver's line of sight and hand position, for example, on the central console. Gestural controls, as an alternative to traditional controls, are natural and can reduce visual distractions; however, their types and numbers are limited and have no feedback. To overcome the problems, a driver interface combining gestures and visual feedback with a head-up display has been proposed recently. In this paper, we investigated the effect of this type of interface in terms of driving performance measures. Human-in-the-loop experiments were conducted using a driving simulator with the traditional tactile and the new gesture-based interfaces. The experimental results showed that the new interface caused less visual distractions, better gap control between ego and target vehicles, and better recognition of road conditions comparing to the traditional one.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1025-1028
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• 1993

In this paper, an intelligent control scheme with multi-stage fuzzy inference is developed for a myoelectric prosthesis to achieve natural control with tactile feedback based on fuzzy control strategies. Strain gauges and a potentiometer are added to the prosthesis for tactile feedback with a PWM motor driver developed to save the battery power. According to the multi-stage fuzzy inference, the prosthesis can determine the stiffness of the object and hold an object without injuring it, meanwhile, the hysteresis phenomenon is an 80196KC single-chip microcontroller to replace the original controller.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.1
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• pp.17-22
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• 2016

In smart factories, the entire manufacturing process from design to the final product is simulated in a virtual manufacturing environment and optimized before starting production. Suppliers and customers make decisions based on the simulation results. Therefore, effective rendering of the information of the virtual products to suppliers and customers is essential for this manufacturing paradigm. In this study, a method of rendering the surface roughness of the virtual products using a tactile display is presented. A tactile display device comprising a $3{\times}3$ array of individually controlled piezoelectric stack actuators is constructed. The surface topology of the virtual products is rendered directly by controlling the piezoelectric stack actuators. A series of experiments is performed to evaluate the performance of the tactile display device. An electrical discharge machined surface is rendered using the proposed method.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.149-156
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• 2014

Flexible tactile sensors can provide valuable feedback to intelligent robots about the environment. This is especially important when the robots, e.g., service robots, are sharing the workspace with human. This paper presents a flexible tactile sensor that was manufactured by direct writing technique, which is one of 3D printing method with multi-walled carbon nano-tubes. The signal processing system consists of two parts: analog circuits to amplify and filter the sensor output and digital signal processing algorithms to reduce undesired noise. Finally, experimental setup is implemented and evaluated to identify the characteristics of the flexible tactile sensor system. This paper showed that this type of sensors can detect the initiation and termination of contacts with appropriate signal processing.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.88-96
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• 2022

Objective: Purpose of this study was to compare muscle activity ratio of multifidus to erector spinalis according to various cueing including tactile stimulation to provide an effective strategy to provide verbal and tactile feedback during exercise to provoke multifidus muscle activation. Design: Cross-sectional study. Methods: Participants of this study included 28 healthy adults. Muscle activities of the multifidus and erector spinalis were measured while the participants performed tasks according to the three different methods of verbal cueing and three different tactile stimulation. Surface EMG was used to measure the muscular activity of the muscles during all the tasks. Results: Tactile stimulation to abdomen and lumbar vertebrae showed no significant difference in the muscle activity ratio (p>0.05). However, muscle activity ratio of the multifidus in relation to the erector spinalis was increased when subjects were given verbal instructions to make lumbar curvature with little force and to make lumbar curvature while pulling navel (p<0.05). However, it was decreased when they were provided with verbal instruction to make lumbar curvature with strong force (p<0.05). Conclusions: According to the results, proper verbal instruction was an effective tool to increase the muscular activity of multifidus. This study aimed to find and provide the most appropriate verbal cueing while doing exercises to activate multifidus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.4968-4974
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• 2012

A haptic device is regarded as the human machine interface technology for easier, more accurate, and intuitive operation. The purpose of this paper is to study how to improve the cognitive ability of the existing vehicle haptic device used only tactile feedback. In this study, usability evaluation used the multi-sensory feedback which is adding auditory feedback to the existing tactile feedback. The emotional factor that drivers have on the haptic device is extracted by the sensibility analysis. The result of study provides some consideration and direction to need in implementation of a haptic device and it also confirms their possibility meaningfully. And it is possible to suggest the design direction that satisfies the driver.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.583-588
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• 2015

Flexible tactile sensors can provide valuable feedback to intelligent robots regarding the environment around them. This is especially important when robots such as, service robots share a workspace with humans. This paper presents a contact force measurement algorithm of a flexible tactile sensor. This sensor is manufactured by a direct-writing technique, which is one 3D printing method, using multi-walled carbon nano-tubes. An analog signal processing circuit has been designed and implemented to reduce noise contained in the sensor output. In addition, a digital version of the Butterworth filter was implemented by software running on a microcontroller. Through various experiments, characteristics of the sensor system have been identified. Based on three traits, an algorithm to detect the contact and measure the contact force has been developed. The entire system showed a promising prospect to detect the contact over a large and curved area.