• Journal of the Korean Geotechnical Society
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• v.27 no.6
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• pp.17-26
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• 2011

Ground anchor method is one of the most popular reinforcing technology in Korea. For the sound monitoring of slope reinforced by permanent anchor for a long period, monitoring the tension force of ground anchor is very important. However, special technology except conventional load cell has not been developed for this purpose. In this paper, a new method is described to replace the conventional strain gauge and V.W. type load cell which has been commonly used as a prestress force monitoring tool for a short-term and long-term. Four 11.5 m long strain detectable tension type anchors were made using FBG sensor embedded tendon since FBG sensor is smaller than strain gauge type load cell and does not have noise from electromagnetic wave. Each two set strain detectable tension type anchors were installed into the different ground conditions, i.e., soft rock and weathered granite soil. Prestress force of ground anchor was monitored during the loading-unloading step from in-situ pullout test using proposed FBG sensor embedded in the tendon and the conventional load cell Test results show that the prestress force monitored from FBG sensor may well be used practically, for it almost matches with that measured from expensive load cell.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.3
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• pp.165-171
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• 2014

In this paper, we propose the hardware and software of a test-bed of a hovering AUV (autonomous underwater vehicle). Test-bed to develop as the underwater robot for the hovering -type is planning to apply for marine resource development and exploration for deep sea. The RTU that controls a azimuth thruster and a vertical thruster of test-bed is a intergrated-type thruster. The main control unit that collects sensor's data and performs high-speed processing and controls a movement of test-bed is a underwater hybrid navigation system. Also it transfers position, posture, state information of test-bed to the host PC of user using a wireless communication. The host PC checks a test-bed in real time by using a realtime monitoring system that is implemented by LabVIEW.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.6
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• pp.339-346
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• 2019

Multi-axis servo systems are widely used in various fields such as industiral systems for improving production efficiency, robotics and complex systems where many mechanical devices and sensor systems are connected. Such a servo system requires that the servo control technique to realize the synchronization of the drive shaft in the steady state and transient conditions and to control so as to follow the target track in order to improve product precision and production efficiency. In addition, embedded type hardware is required for smooth control of the entire multi-axis system. Therefore, this paper uses hardware based on FPGA which is widely used in digital signal processing field and various control system because hardware design change is easy and parallel processing is possible. In addition, Labview based servo motor control program was studied that can control the servo motor by ensuring the performance and flexibility of the FPGA and follow the target trajectory according to various speed processing and accurate timing synchronization.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.58-59
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• 2020

The change of temperature and humidity in early-age concrete has a great influence on the durability of the structure. In this study, a reliable wireless sensor network system and a concrete embedded type Compressive strength prediction sensor were designed using the Arduino platform. The accuracy of the compressive strength prediction sensor was verified through a mock-up experiment, and it was confirmed that the experiment had sufficient accuracy to be used in the field environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.133-138
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• 2016

Force control and collision detection for a robot are usually conducted using a 6-axis force/torque sensor mounted at the end-effector. However, this scheme suffers from high-cost and the inability to detect collisions at the robot body. As an alternative, joint torque sensors embedded in each joint were used, which also suffered from various errors in torque measurement. To resolve this problem, a robot joint module with an improved joint torque sensor is proposed in this study. In the proposed torque sensor, a cross-roller bearing and disk-type coupling are added to prevent the moment load from adversely affecting the measurement of the joint torque under consideration. This joint design also aims to reduce the stress induced during the assembly process of the sensor. The performance of the proposed joint torque sensor was verified through various experiments.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.4
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• pp.280-286
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• 2011

In this research, the oil detection method and the characteristic of sensor using the selective reaction of silicone rubber in response to hydrocarbon oil will be described. As a sensing principle, the swelling property of silicone rubber in response to hydrocarbon fuel is used, also a strain gauge is used to transduce the volume change to an electrical signal. The sensor core is manufactured with a strain gauge embedded in silicone rubber by the curing process and experiments for characteristics of sensor core with various oils were carried out. It is shown that the sensor core can be used as an oil spill detection sensor. Also, for the application to the sea area, a buoy type sensor platform is integrated with a sensor core and a strain amplifier and it is tested in the simulated oil spill condition. In this study, it is proven that the integrated sensor can be used for the detection of various oils.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.746-755
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• 2009

Recently, NMEA2000 became the de facto standard of the communication protocol for the instrument level network in vessels, and it is anticipated that most of the vessels will be equipped with the sensors and actuators based on this protocol. The conventional serial communication specifications such as RS-232, RS-485, or even NMEA0183 are single-talker/multiple-listener and interconnection among multiple sensors and/or actuators usually results in a bundle of wires. On the other hand, NMEA2000 is a true bus type(multiple-talker/multiple-listener) protocol and theoretically up to 256 instruments can be hot-plugged. With the advent of the protocol, it is necessary to consider a new type of monitoring system for the instruments in vessels: In most traditional serial communication environments, a dedicated monitor or user interface was necessary for each sensor or actuator as it was simply not easy to collect data in a single place. With NMEA2000, the collection of various types of information is simple. An embedded system can be employed to combine, to arrange and to display informations from various types of devices. Assuming that the actuators and sensors on a vessel are interconnected by NMEA2000 standard, we devise a tentative interactive vessel monitoring system in which the following 4 kinds of informations are collected and delivered: the navigation, engine, weather and tanks informations.

• Tribology and Lubricants
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• v.10 no.4
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• pp.27-32
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• 1994

The capacitive type transducers measure the displacement of rotating shaft using the voltage difference which is formed between the sensor plates and rotor so that the measured signal is not affected by the magnetic field generated by the magnetic bearing. In this paper, the capacitive transducers are embedded inside of the magnetic bearing. In order to verify the support characteristics of the capacitance sensor-magnetic bearing system, we experimented and analyzed the magnetic bearing-rotating shaft system up to 12,000 rpm. The magnetic bearing system proposed in this paper, successfully supports the rotating shaft and we can remain the maximum displacement below $5 \mu m$ at 12,000 rpm.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1125-1131
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• 2012

According to abrupt decrese in number of farmer and ageing society, there has been a need for development of low cost agricultural robot. In this paper, a H/W and S/W platform of caterpillar type agricultural chemical dusting robot based on XP embedded system were described. The developed agricultural robot has 2 d.o.f caterpillar type driving wheel and 2 d.o.f chemical dusting spray mechanical system. The H/W platform of the agricultural robot consists of robot controller, remote controller and sensor controller. In S/W platform, 5 processes work concurrently, which are task manager, TCP-IP communication process, localization process, wheel control, and sensor control process. This robot platform has been developed for chemical dusting robot. We proved this system's validity through field test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.223-236
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• 1999

The need to monitor and undertake remidial works on large structures has greatly increased in recent years due to the appearance of widespread faults in large structures such as bridges and buildings, etc, of 20 or more years of age. The health condition of structures must be monitored continuously to maintenance the structures. In order to do in-situ monitoring, the sensor is necessary to be embedded in the structures. Fiber optic sensors can be embedded in the structures to get the health information in the structures. The fiber sensor was constructed with $3{\times}3$ fiber couplers to sense the multi-point strains and failure instants. The 4 RC (reinforced concrete) beams were made to 2 of A type, 2 of B type beams. These beams were reinforced by the reinforcing bars, and were tested under the flexural loading. The behavior of the beams was simultaneously measured by the fiber optic sensors, electrical strain gages, and LVDT. The states of the beams were interpreted by these all signals. By these experiments, There were verified that the fiber optic sensors could measure the structural strains and failure instants of the RC beams, The fiber sensors were well operated until the failure of the beams. It was shown that the strains of the reinforcing steel bar can be used to monitor the health condition of the beams through the flexural test of RC beams. On the other words, the results were arrived that the two strains in the reinforcing bar measured at the same point can give the information of the structural health status. Also, the failure instants of beams were well detected from the fiber optic filtered signals.