• The Journal of Korea Robotics Society
• /
• v.5 no.2
• /
• pp.120-126
• /
• 2010

This paper presents to study the path tracking method of AGV(autonomous guided vehicle) which has a laser guidance system. An existing automatic guided vehicles(AGVs) which were able to drive on wired line only had a automatic guidance system. However, the automatic guidance systems that those used had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the laser guidance system which is consisted of a laser navigation and gyro, encoder. That is robust against noise, and flexible according to working environment through sensor fusion. The laser guidance system can do a perfect autonomous driving. However, the commercialization of perfect autonomous driving system is difficult, because the perfect autonomous driving system must recognize the whole environment of working space. Hence, this paper studied the path tracking of AGV using laser guidance system without wired line. The path tracking method is consisted of virtual path generation method and driving control method. To experiment, we use the fork-type AGV which is made by ourselves, and do a path tracking experiments repeatedly on same experimental environment. In result, we verified that proposed system is efficient and stable for actual fork-type AGV.

• Journal of Sensor Science and Technology
• /
• v.22 no.6
• /
• pp.428-432
• /
• 2013

This paper described the development of electrostatically driven peristaltic micropump. The proposed micropump consists of a flexible membrane and a single chamber which electrodes are inserted. The single chamber is divided into smaller cells by the electrodes. The fabricated micropump was operated with four electrodes in the membrane and a various phase sequencing actuation. We studied the changes in the flow rate corresponding to the actuating signal applied to the micropump under the zero hydraulic pressure difference between lnlet port and outlet port. The pump was operated from 60 to 130 V. Whereas the maximum flow rate in basic actuating signal is about 83 ${\mu}1/min$ at 15 Hz, the maximum flow rate in optimized actuating signal is about 114 ${\mu}l/min$ at 10 Hz.

• Journal of Ocean Engineering and Technology
• /
• v.32 no.6
• /
• pp.511-517
• /
• 2018

This paper proposes a vision-based underwater laser scanner with separate structures for an underwater camera and a line laser projector. Because the two devices can be adaptively placed regardless of the features of the unmanned underwater vehicle (UUV), the scanner has significant advantages in relation to its availability and flexibility. Position calibration between the underwater camera and laser projector guarantees a 3D measuring performance with high accuracy. To verify the proposed underwater laser scanner, a test-bed system was manufactured, which consisted of the laser projector, camera, Pan&Tilt, and Attitude and Heading Reference System (AHRS). A camera-laser calibration test and simple 3D reconstruction test were performed in a water tank and the experimental results are reported.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.17 no.6
• /
• pp.16-23
• /
• 2018

A polymer porous sheet, which can be applied to diverse wearable devices, has some advantages such as light-weight, high flexibility, high elongation, and so many others. In order to fabricate a porous sheet, water-soluble particles like sugar were utilized frequently, and there has been great advances. However, with our best knowledge, there are not enough reports on the mechanical behavior of porous sheets having different porosity. So, in this work, we tried to find out the relationship between porosity and mechanical deformation of a porous sheet. The process parameters such as a particle size, sheet thickness and PDMS mixing ratio with curing agent were analyzed on the effect of increasing the porosity of a sheet. Also, mechanical deformation of a sheet was tested using a tensile experiment. Through the experimental results, we make a conclusion that a highly porous sheet with thin thickness has high flexibility, and it deformed nearly double elongation comparing to worst one among nine cases.

• Journal of Sensor Science and Technology
• /
• v.28 no.4
• /
• pp.251-255
• /
• 2019

We propose a two-step lithography process to minimize edge-bead issues caused by thick photoresist (PR) coating. In the conventional PR process, the edge bead can be efficiently removed by applying an edge-bead removal (EBR) process while rotating the silicon wafer at a high speed. However, applying conventional EBR to the production of desired PR mold with unique negative patterns cannot be used because a lower rpm of spin coating and a lower temperature in the soft bake process are required. To overcome this problem, a two-step lithography process was developed in this study and applied to the fabrication of a polydimethylsiloxane (PDMS) film having super-hydrophobic characteristics. Following UV exposure with a first photomask, the exposed part of the silicon wafer was selectively removed by applying a PR developer while rotating at a low rpm. Then, unique PR mold structures were prepared by employing an additional under-exposure process with a second mask, and the mold patterns were transferred to the PDMS. Results showed that the fabricated PDMS film based on the two-step lithography process reduced the height difference from 23% to 5%. In addition, the water contact angle was greatly improved by spraying of hydrophobic nanosilica on the dual-scaled PDMS surface.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.2
• /
• pp.91-96
• /
• 2019

For a wireless sensor network in general, efficient routing decision is important because wireless connections are not stable, sensitive to external interference, and topology changes dynamically. RPL standard of IETF is not flexible to various environmental changes and causes packet loss and delay due to topological imbalance. Sending packets through multipath can partially remedy this problem. The multipath routing, however, can introduce significant delay overhead by allocating unnecessary timeslots. This paper proposes an RPL using multipath adaptively according to network conditions. We show by simulations that the proposed algorithm is more efficient than the basic RPL and the multipath RPL.

• The Journal of Korea Robotics Society
• /
• v.18 no.3
• /
• pp.241-250
• /
• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• The Journal of Korea Robotics Society
• /
• v.18 no.3
• /
• pp.293-298
• /
• 2023

The military is facing a continuous decrease in personnel, and in order to cope with potential accidents and challenges in operations, efforts are being made to reduce the direct involvement of personnel by utilizing the latest technologies. Recently, the use of various sensors related to Manned-Unmanned Teaming and artificial intelligence technologies has gained attention, emphasizing the need for flexible utilization methods. In this paper, we propose four dataset construction methods that can be used for effective training of robots that can be deployed in military operations, utilizing not only RGB image data but also data acquired from IR image sensors. Since there is no publicly available dataset that combines RGB and IR image data, we directly acquired the dataset within buildings. The input values were constructed by combining RGB and IR image sensor data, taking into account the field of view, resolution, and channel values of both sensors. We compared the proposed method with conventional RGB image data classification training using the same learning model. By employing the proposed image data fusion method, we observed improved stability in training loss and approximately 3% higher accuracy.

• Ocean and Polar Research
• /
• v.45 no.2
• /
• pp.33-42
• /
• 2023

Dissolved oxygen (DO) is a crucial parameter for assessing environmental conditions in aquatic ecosystems. However, commercial in situ dataloggers for oxygen optodes can be relatively expensive and limited in their specifications. In this paper, we present a novel design for a DO datalogger system based on the control boards family with RP2040 MCU chipset. Our design includes two types of dataloggers: a simple logging system and a programmable system for sampling rates via magnetic switches underwater for divers. We provide detailed descriptions of the system, including the MicroPython source code and drawings to aid in construction. We also discuss the various applications of our DO datalogger system in monitoring dissolved oxygen concentration in coastal waters and assessing the benthic metabolism of aquatic ecosystems. Our DO datalogger system provides an affordable and flexible option for researchers to accurately monitor DO concentrations in aquatic environments, and thereby improve our understanding of these complex ecosystems.

• Journal of Sensor Science and Technology
• /
• v.32 no.2
• /
• pp.124-130
• /
• 2023

Implementing flexible production systems in domestic and foreign automotive design parts assembly has increased demand for automation and power reduction. Consequently, transition to a hybrid production method is observed where multiple vehicles are assembled in a single assembly line. Multiple robots, 3D vision sensors, mounting positions, and correction software have complex configurations in the automotive glass mounting system. Hence, automation is required owing to significant difficulty in the assembly process of automobile parts. This study presents a primer lighting and inspection algorithm that is robust to the assembly environment of real automotive design parts using high power 'ㄷ'-shaped LED inclined lighting. Furthermore, a 2D camera was developed in the primer coating inspection system-the core technology of the glass mounting system. A primer application demo line applicable to the actual automobile production line was established using the proposed high power lighting and algorithm. Furthermore, application inspection performance was verified using this demo system. Experimental results verified that the performance of the proposed system exceeded the level required to satisfy the automobile requirements.