Development of Direct Printed Flexible Tactile Sensors

Ju-Kyoung Lee,Kyung-Chang Lee,Hyun-Hee Kim 한국산업융합학회 2017 한국산업융합학회 논문집 Vol.20 No.3

This paper proposes a structure of direct-printed flexible tactile-sensor. These flexible tactile sensors are based on pressure-sensing materials that allow pressure to be measured according to resistance change that in turn results from changes in material size because of compressive force. The sensing material consists of a mixture of multi walled carbon nanotubes (MWCNTs) and TangoPlus, which gives it flexibility and elasticity. The tactile sensors used in this study were designed in the form of array structures composed of many lines so that single pressure points can be measured. To evaluate the performance of the flexible tactile sensor, we used specially designed signal-processing electronics and tactile sensors to experimentally verify the sensors’ linearity. To test object grasp, tactile sensors were attached to the surface of the fingers of grippers with three degrees of freedom to measure the pressure changes that occur during object grasp. The results of these experiments indicate that the flexible tactile sensor-based robotic gripper can grasp objects and hold them in a stable manner.

광경화성 수지와 다중벽 탄소나노튜브 혼합물을 이용한 신축성 센서 소재

우상구(S. G. Woo),Morteza Vatani,이인환(I. H. Lee),Jae Won Choi,김호찬(H. C. Kim),조해용(H. Y. Cho) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Recently, advancement of science enable robots to introduce at the many fields, along with a variety of sensors. The use of the tactile sensor has increasingly interest to the robots. The tactile sensor help robots to operate safely and sensitively by mechanical contact from external environment. In this regards, many kinds of tactile sensors were developed. However, in these sensors, electrode was used as a detector that leads to complex fabrication process. Furthermore, the use of electrode impede manufacturing of large scale tactile sensor. Moreover, to improve the performance of the sensor, it should be atteched on the curved surface. This study is on the fabrication of flexible tactile sensor using a photocureable resin and MWCNTs, which is possible to make large scale tactile sensor using direct writing as simple fabrication process. The MWCNTs are used as a conductive material, because it has excellent piezo resistance effect. The MWCNTs are mixed with photocureable polymer by ultrasonic dispersion method. The photocureable polymer has the flexiblity after curing process by ultraviolet rays. Therefore, the mixture has similar chracteristics with photocureable polymer as well as piezo resistance effect. To use the MWCNTs mixture at the flexible tactile sensor as a wire, it is dispensed by direct writing. This paper suggests conductive material and fabrication process for flexible tactile sensor.

Compliant Ultrasound Proximity Sensor for the Safe Operation of Human Friendly Robots Integrated with Tactile Sensing Capability

조일주,이형규,장선일,윤의식 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.1

The robot proximity and tactile sensors can be categorized into two groups: grip sensors and safety sensors. They have different performance requirements. The safety sensor should have long proximity range and fast response in order to secure enough response time before colliding with ambient objects. As for the tactile sensing function, the safety sensor need to be fast and compliant to mitigate the impact from a collision. In order to meet these requirements, we proposed and demonstrated a compliant integrated safety sensor suitable to human-friendly robots. An ultrasonic proximity sensor and a piezoelectric tactile sensor made of PVDF films have been integrated in a compliant PDMS structure. The implemented sensor demonstrated the maximum proximity range of 35 cm. The directional tolerance for 30 cm detection range was about ±15° from the normal axis. The integrated PVDF tactile sensor was able to detect various impacts of up to 20 N in a controlled experimental setup.

Development of Direct Printed Flexible Tactile Sensors

이주경,이경창,김현희 한국산업융합학회 2017 한국산업융합학회 논문집 Vol.20 No.3

This paper proposes a structure of direct-printed flexible tactile-sensor. These flexible tactile sensors are based on pressure-sensing materials that allow pressure to be measured according to resistance change that in turn results from changes in material size because of compressive force. The sensing material consists of a mixture of multi walled carbon nanotubes (MWCNTs) and TangoPlus, which gives it flexibility and elasticity. The tactile sensors used in this study were designed in the form of array structures composed of many lines so that single pressure points can be measured. To evaluate the performance of the flexible tactile sensor, we used specially designed signal-processing electronics and tactile sensors to experimentally verify the sensors’ linearity. To test object grasp, tactile sensors were attached to the surface of the fingers of grippers with three degrees of freedom to measure the pressure changes that occur during object grasp. The results of these experiments indicate that the flexible tactile sensor-based robotic gripper can grasp objects and hold them in a stable manner.

Compliant Ultrasound Proximity Sensor for the Safe Operation of Human Friendly Robots Integrated with Tactile Sensing Capability

Il-Joo Cho,Hyung-Kew Lee,Sun-Il Chang,Euisik Yoon 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.1

The robot proximity and tactile sensors can be categorized into two groups: grip sensors and safety sensors. They have different performance requirements. The safety sensor should have long proximity range and fast response in order to secure enough response time before colliding with ambient objects. As for the tactile sensing function, the safety sensor need to be fast and compliant to mitigate the impact from a collision. In order to meet these requirements, we proposed and demonstrated a compliant integrated safety sensor suitable to human-friendly robots. An ultrasonic proximity sensor and a piezoelectric tactile sensor made of PVDF films have been integrated in a compliant PDMS structure. The implemented sensor demonstrated the maximum proximity range of 35 cm. The directional tolerance for 30 cm detection range was about ±15° from the normal axis. The integrated PVDF tactile sensor was able to detect various impacts of up to 20 N in a controlled experimental setup.

Development of Direct Printed Flexible Tactile Sensors

Lee, Ju-Kyoung,Lee, Kyung-Chang,Kim, Hyun-Hee The Korean Society of Industry Convergence 2017 한국산업융합학회 논문집 Vol.20 No.3

This paper proposes a structure of direct-printed flexible tactile-sensor. These flexible tactile sensors are based on pressure-sensing materials that allow pressure to be measured according to resistance change that in turn results from changes in material size because of compressive force. The sensing material consists of a mixture of multi walled carbon nanotubes (MWCNTs) and TangoPlus, which gives it flexibility and elasticity. The tactile sensors used in this study were designed in the form of array structures composed of many lines so that single pressure points can be measured. To evaluate the performance of the flexible tactile sensor, we used specially designed signal-processing electronics and tactile sensors to experimentally verify the sensors' linearity. To test object grasp, tactile sensors were attached to the surface of the fingers of grippers with three degrees of freedom to measure the pressure changes that occur during object grasp. The results of these experiments indicate that the flexible tactile sensor-based robotic gripper can grasp objects and hold them in a stable manner.

Development of a Tactile Sensor Array with Flexible Structure Using Piezoelectric Film

Yu, Kee-Ho,Kwon, Tae-Gyu,Yun, Myung-Jong,Lee, Seong-Cheol The Korean Society of Mechanical Engineers 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.10

This research is the development of a flexible tactile sensor array for service robots using PVDF (polyvinylidene fluoride) film for the detection of a contact state in real time. The prototype of the tactile sensor which has 8${\times}$8 array using PVDF film was fabricated. In the fabrication procedure, the electrode patterns and the common electrode of the thin conductive tape were attached to both sides of the 281$\mu\textrm{m}$ thickness PVDF film using conductive adhesive. The sensor was covered with polyester film for insulation and attached to the rubber base for a stable structure. The proposed fabrication method is simple and easy to make the sensor. The sensor has the advantages in the implementing for practical applications because its structure is flexible and the shape of the each tactile element can be designed arbitrarily. The signals of a contact force to the tactile sensor were sensed and processed in the DSP system in which the signals are digitized and filtered. Finally, the signals were integrated for taking the force profile. The processed signals of the output of the sensor were visualized in a personal computer, and the shape and force distribution of the contact object were obtained. The reasonable performance for the detection of the contact state was verified through the sensing examples.

Simple Structured Tactile Sensor for Tissue Recognition in Minimal Invasion Surgery

Joon Ho Kwon,Daehie Hong,Jung-Hoon Hwang 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

In this research we present new tactile sensor with simple structure and small size. This sensor is for recognition of tissue stiffness in minimally invasive surgery(MIS) in which surgeon cannot directly palpate. Tactile sensor should be work in vivo and it should be small to be used in MIS. For this reason, we developed simple structure tactile sensor and also made many sensing points using semiconductor strain gage. We will attach this sensor to gripper of automated surgical instruments and try to palpate tissue automatically. In this paper we show how to design our sensor and how to verify sensor performance to present the effectiveness of sensor.

Compliant Ultrasound Proximity Sensor for the Safe Operation of Human Friendly Robots Integrated with Tactile Sensing Capability

Cho, Il-Joo,Lee, Hyung-Kew,Chang, Sun-Il,Yoon, Euisik The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.1

The robot proximity and tactile sensors can be categorized into two groups: grip sensors and safety sensors. They have different performance requirements. The safety sensor should have long proximity range and fast response in order to secure enough response time before colliding with ambient objects. As for the tactile sensing function, the safety sensor need to be fast and compliant to mitigate the impact from a collision. In order to meet these requirements, we proposed and demonstrated a compliant integrated safety sensor suitable to human-friendly robots. An ultrasonic proximity sensor and a piezoelectric tactile sensor made of PVDF films have been integrated in a compliant PDMS structure. The implemented sensor demonstrated the maximum proximity range of 35 cm. The directional tolerance for 30 cm detection range was about ${\pm}15^{\circ}$ from the normal axis. The integrated PVDF tactile sensor was able to detect various impacts of up to 20 N in a controlled experimental setup.

수직력과 수평력 측정이 가능한 다축 힘 측정 촉각 센서에 관한 연구

황상균(Sang-Kyun Hwang),권오민(Oh-min Kwon),황희윤(Hui-Yun Hwang) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Various studies have been carried out on flexible sensors that can simultaneously detect multi axis loads (normal force and horizontal force) acting on the sensors in the field of tactile sensor with a structure in which a sensor fiber was arranged inside polymer matrix materials. These sensors have a form in which sensor fiber: piezoelectric sensor or optical fiber sensor was inserted in ductile materials such as silicon, polyester and PDMS. Among them, various studies have been carried out on the tactile sensor using a piezoelectric sensor, but the basic research on signal characteristics and technique of separation when a multi axis force is detected is lacking. Accordingly, this study manufactured a tactile sensor in which PVDF fiber was inserted in PDMS, which was arranged to detect a multi axis force, and various experiments on performances were conducted so as to understand the performances and characteristics of the sensor. The results obtained from the experiments were compared to the results from a finite element analysis, so that its efficacy was confirmed.