In this study, we developed a hydraulic manipulator to assist firefighters and rescue personnel at disaster sites. In the design procedure, we analyzed the manipulator considering the hydraulic actuators as well as the manipulator kinematics and dynamics. For the user interface, a macro/manual operation concept was proposed to provide an effective response in emergency and disaster situations. To cope with abnormalities of the disaster site operator, a protocol for switching local/remote operations was developed. The effectiveness of the hydraulic manipulator and operating system was verified through task implementation experiment.
This paper presents a novel method of designing an efficient locomotion pattern generating algorithm for snake robots by a genetic algorithm (GA). In search and rescue operations in disaster areas, a snake robot requires multiple locomotion patterns. To overcome the complexity of snake robot control, we used a central pattern generator (CPG)-based control method which mimics the motion of a biological snake. GA was used to optimize CPG parameters to maximize locomotion performance. The locomotion performance according to the CPG parameters change was analyzed using the snake robot simulator. The proposed locomotion pattern generation algorithm evolved quickly for the target performance and obtained CPG parameters for the desired locomotion.
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A Study on I-PID-Based 2-DOF Snake Robot Head Control Scheme Using RBF Neural Network and Robust Term Sung-Jae Kim, Jin-Ho Suh Journal of Korea Robotics Society.2024; 19(2): 139. CrossRef
A Study on the Design of Error-Based Adaptive Robust RBF Neural Network Back-Stepping Controller for 2-DOF Snake Robot’s Head Sung-Jae Kim, Maolin Jin, Jin-Ho Suh IEEE Access.2023; 11: 23146. CrossRef
This paper introduces PongBot, a quadruped robot developed for preparation in the Dronebot Challenge held in Jangseonggun, Jeollanam-Do, South Korea in November 2020. The Dronebot Challenge, hosted by the Army Headquarters, is a competition to demonstrate that drones and robots can be useful for military purposes. In 2020, this competition consisted of a total of 8 events and we participated in the ‘Traveling on rough terrain’ event, which consisted of various terrains, such as, slopes, unpaved roads, and streams. PongBot is a quadruped robot that uses an electric motor and can walk for more than an hour on various terrains. Also, according to the rules of the competition, the robot had a system which could be remotely controlled from a ground control station. In addition, by applying the SLAM algorithm, the robot operator received information about its surrounding environment, thereby deriving records to facilitate the operation. The performance of this robot system and SLAM algorithm was verified through this competition.
Complex disaster has disabled the ordinary communication system. For example, fire on LTE routers and their power supply interrupted communication. In our disaster react robot system, we suggested a portable and battery-powered Wi-Fi module dropped by reconnaissance robots. As a result, the communication speed was extremely limited. In this paper, we proposed a global map generation strategy to overcome this communication limit. Our key approach involved the conversion of heterogeneous local maps to 2D occupancy grid maps. The 2D map was treated as an image and image stitching algorithm was applied to build the global map. We made various local map scenarios and applied our global map building algorithms. In conclusion, our proposed strategy was verified with the real robot test.
This paper proposes an integrated control system for multi-disaster response robots based on Robot Operating System (ROS). The contributions of this paper were as follows: 1) A multi-score-based system concept was proposed in consideration of network instability issues which might frequently occur in compound disaster environments; 2) A detailed ROS based software structure was implemented to apply the proposed system to real robots; 3) Hardware cockpit and graphical user interface (GUI) for an operator were implemented; 4) through the experiment, the problem of the system based on common ROS structure, the out-of-control state, was confirmed and we verified the proposed system using the scenario.
Lithium-ion batteries are one of the main parts of electrical devices and are widely used in various applications. To safely use lithium-ion batteries, fault diagnosis and prognosis are significant. This paper analyzes resistance parameters from electrochemical impedance spectroscopy (EIS) to detect the fault of lithium-ion batteries. The internal fault mechanisms of batteries are so complex; it is difficult to detect abnormalities by direct current-based methods. However, by using alternating-current-based impedance by EIS, the internal degradation processes of the batteries can be detected. Impedance variation from EIS is verified under accelerated degradation test conditions and normal cycling test conditions. The results showed a significant relationship between fault and increase in resistance.
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Research into the Detection of Faulty Cells in Battery Systems Using BMS Cell Balancing Counts Hyunjun Kim, Woongchul Choi Transaction of the Korean Society of Automotive Engineers.2025; 33(8): 637. CrossRef
PEDOT:PSS‐Based Prolonged Long‐Term Decay Synaptic OECT with Proton‐Permeable Material, Nafion Ye Ji Lee, Yong Hyun Kim, Eun Kwang Lee Macromolecular Rapid Communications.2024;[Epub] CrossRef
Lithium-Ion Batteries (LIBs) Immersed in Fire Prevention Material for Fire Safety and Heat Management Junho Bae, Yunseok Choi, Youngsik Kim Energies.2024; 17(10): 2418. CrossRef
Recently, as various damages are expected due to the risk of falling space debris, many studies are being carried out to acquire space object information. In this research, an optical-based space object surveillance system was developed to acquire information about space objects. To acquire orbit information by photographing a space object with this system, the accuracy of position data of the space object is important. The telescope coordinate is located in the 2D CCD plane of the telescope, and the space objects are in the celestial coordinate. The two coordinates have a non-linear relation caused by a deflection of the mechanical system, a scattering of the atmosphere and so on. In this study, we propose an alignment method for two coordinate systems. First, a model that analyzes the geometric relation between the telescope system on earth and space objects is explained. Then, we also propose a second model with the addition of correction parameters. As a result of performing coordinate alignment according to the method and procedure proposed in this study, the pointing accuracy is lowered below 3 arcsec.
Currently, the number of construction cases using large-diameter and high-strength steel and high-strength concrete is increasing due to the trend of large buildings. In the case of reinforcing bars that serve as the framework of a structure, the continuous state is the best in terms of structural stability. However, for convenience, it is transported and assembled to a predetermined standard. In this study, a coupler was developed applying SCM440 material with excellent mechanical properties, not S35C and S45C materials, generally used as coupler materials. To this end, high-frequency carburizing and heat treatment was applied to the element parts taking into account the taper angle and stress results, reflecting the results of low- and high-cycle fatigue tests and structural analysis for the applied material. Finally, in the case of a reinforced coupler fastened with hydraulic SD500 reinforcement bars with diameter D25, a reliability test was carried out using the mechanical joint inspection method of reinforced concrete reinforcement bars. Results were obtained that satisfied the characteristic performance values.
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Analysis of Mechanical Properties of Heat Treated SCM440 Steel for Rebar Couplers Ji-Ho Lee, Geon An, Min-Sik Choi, SangJun Moon, Cha-Soo Jun, San Kim Journal of the Korean Society of Manufacturing Process Engineers.2023; 22(11): 43. CrossRef
Research on the application of additively manufactured polymer (AMP) to the conventional manufacturing process is underway. In this study, an additively manufactured die-set (AMDS) was used and applied to the warm forming of the magnesium alloy. Heat transfer and coupled temperature-displacement analysis were conducted in the V-Bending and UBending processes to study the applicability of the AMDS to the warm-forming process of the magnesium alloy sheet (AZ31B). A heat transfer experiment was conducted to determine the thermal contact conductance between the AZ31B material and two types of die-set, the metal and AMP. V-Bending and U-Bending experiments were conducted at 373 and 423 K; reduction in temperature between metal die-set and the additively manufactured polymer die-set were compared. The springback after the bending process with different initial temperatures and die materials was investigated. The simulation model showed good agreement. The springback of AZ31B was more decreased with the additively manufactured polymer die-set than with the metal die-set. The stress of the additively manufactured polymer die-set in the bending process was very small. It was confirmed that in the AZ31B material, the additively manufactured polymer die set helps increase the formability and decrease springback by keeping the temperature of AZ31B better.
The lifting-and-lowering type drone station is very useful when lifting and lowering the battery charging station for safe installation, maintenance, and energy efficiency of drone operation. Therefore, understanding the coupling motion between cable and pulley is important for evaluating characteristics like safety and dynamic stability of the lifting-and-lowering type drone station. Although multibody dynamics (MBD) is widely used for numerically analyzing the dynamic behavior of interconnected bodies, attempts to analyze the coupling motion between cable and pulley have been made only recently, within the last decade. Therefore, this paper attempts to develop the MBD model for the lifting-and-lowering type drone station, including cables, pulleys, and winches using MotionSolve (Altair). The results of the winch torque obtained analytically and numerically were compared to verify the effectiveness of the proposed MBD model.
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A Study on Improving the Sensitivity of High-Precision Real-Time Location Receive based on UWB Radar Communication for Precise Landing of a Drone Station Sung-Ho Hong, Jae-Youl Lee, Dong Ho Shin, Jehun Hahm, Kap-Ho Seo, Jin-Ho Suh Journal of the Korean Society for Precision Engineering.2022; 39(5): 323. CrossRef
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