Ceiling inspections present challenges due to limited accessibility and structural constraints. To ease the burden on security personnel, who would otherwise need to manually disassemble, inspect, and restore ceiling components, this study proposes a robotic system for detecting hazardous objects within ceiling environments. The proposed system features several key innovations: a hollow-structured track mechanism designed to reduce vibrations from jolting while traversing structural beams and to improve localization accuracy. We optimized the robot’s mass distribution and required drive torque through dynamic simulations to ensure stable mobility in confined ceiling spaces. For effective hazardous object detection, we developed a YOLOv8-Seg-based background learning algorithm that suppresses ceiling-structure patterns, allowing for the identification of unknown objects without prior class-specific training. Additionally, we introduced a frame-based filtering algorithm to enhance detection reliability by reducing false positives caused by motion blur during movement. The system's effectiveness was validated through experiments conducted in a ceiling-structured testbed, demonstrating its capability for accurate hazardous object detection under realistic operating conditions.
In this study, a module combining various types of sensors was developed to increase search efficiency inside collapsed buildings. It was designed to be less than 70 mm in diameter so that it can be put into narrow spaces, and is equipped with a small & high-performance processor to process multiple sensor data. To increase sensor data processing efficiency, multi thread based software was configured, and the images were combined and transmitted to ensure time synchronization of multi-channel video data. A human detection function based on sound source detection using two microphones was implemented. The developed multi-sensor module was tested for operation by mounting it on a snake-type robot in a test bed simulating a disaster site. It was confirmed that the visible range of the robot to which the multi-sensor module was applied was expanded, and the ability to detect human and low-light human detect was secured.
Tire-related crashes account for a large proportion of all types of car accidents. The causes of tire-related accidents are inappropriate tire temperature, pressure, and wear. Although temperature and pressure can be monitored easily with TPMS, there exists no system to monitor tire wear regularly. This paper proposes a system that can estimate tire wear using a 3-axis accelerometer attached to the tread inside the tire. This system utilizes axial acceleration, extracts feature from data acquired with the accelerometer and estimates tire wear by feature classification using machine learning. In particular, the proposed tire wear estimation method is designed to estimate tread depth in four types (7, 5.6, 4.2, and 1.4 mm) at speeds of 40, 50, and 60 kmph. Based on the data obtained during several runs on a test track, it has been found that this system can estimate the tread depth with reasonable accuracy.
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A Study on Wheel Member Condition Recognition Using 1D–CNN Jin-Han Lee, Jun-Hee Lee, Chang-Jae Lee, Seung-Lok Lee, Jin-Pyung Kim, Jae-Hoon Jeong Sensors.2023; 23(23): 9501. CrossRef
In this study, we proposed microphone array and algorithm for sound source localization based on GCC-PHAT for the robot searching victims in a narrow space. Through frequency domain analysis, we designed filter to make algorithm react only to the sound with a human voice frequency. Additionally, calibration algorithm was integrated to solve the problem of the update cycle of result value becoming very short when passing through the filter, presenting difficulty in checking the value. Results obtained through experiments verified the performance of the proposed microphone array and sound source localization algorithm.
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A Study on the Survivor Detection Module and Least-Squares Sound Source Localization Algorithm for Victim Search in Narrow Spaces Yun-Jeong Seok, Sung-Jae Kim, Seo-Yeon Park, Jin-Ho Suh Journal of Korea Robotics Society.2025; 20(1): 120. CrossRef
Multi-sensor Module Design and Operation of Snake Robot for Narrow Space Exploration Dong-Gwan Shin, Meungsuk Lee, Murim Kim, Sung-Jae Kim, Jin-Ho Suh Journal of the Korean Society for Precision Engineering.2024; 41(8): 633. CrossRef
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
From the past, productivity improvement has been a problem to be solved, and various methods have been continuously developed. Recently, the demand for electric vehicles has increased along with the domestic and international environmental policies. Researches on the electrode production facilities have been actively conducted to increase the productivity of secondary batteries. Dispensers required for bonding the separator of the secondary battery, the cathode material and the anode material are also increasing in demand. The dispensers that spray a certain amount of adhesive quickly contribute to productivity improvement. However, Piezo type, which is currently being developed and used widely, has a higher performance than some industry, and its more expensive. In this study, we design a dispenser with lower performance than the conventional piezo type and lower the unit price and analyze the results.
Various chemicals are used for semiconductor process. In particular, the most important element in the etching and cleaning process is chemical liquid. An ultrasonic flow meter is used to monitor the supplying amount of chemical solution. If the ultrasonic flow meter contains bubble inside the liquid, measurement cannot be performed or measurement error will be occurred. In this research, the waveform was improved by zero-crossing processing so that the influence on measurement performance is negligible even if the bubble in the chemical solution is included. Consequently, the amplitude of the sound wave is attenuated. Existing flow meters monitor the amplitude value to determine the authenticity of the signal and to filter the noise. The improved method in this study distinguishes noise waves and monitors signal frequency. Flow measurement was carrying out even when the amplitude was resulting only less than 3% of input level volt. The system developed of this study has shown an exact measuring performance compared with the other make’s flow meters.
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Investigation on the influence of wall thickness on the reception signal in a PFA-made ultrasonic flow sensor Liang Hu, Chengwei Liu, Rui Su, Weiting Liu Sensor Review.2024; 44(2): 149. CrossRef
Control Speed Improvement of Chemical Liquid Flow Control Device for Semiconductor Manufacturing Process Il Jin Bae Journal of the Korean Society for Precision Engineering.2021; 38(6): 405. CrossRef
Reactors are needed to produce polymeric polymers as materials for OLED (Organic Light Emitting Diode). There are many types of reactors that assist in producing chemical reactions. One type, called a coil type, is a continuous reactor that has many advantages compared to other reactors. It can not only manufacture products continuously, but is cheaper and therefore cost efficient. A continuous coil type reactor was designed and manufactured for this study. A precise flow rate cannot be determined because of the numerous variables. An experimental flow rate is obtained when combining the following information: the valve opening angle, the revolution velocity of the screw and the temperature of the reaction. As a result, the study is considered that people who use this device will refer to this to control flow rate and time for reaction.
Commercial air-conditioning systems are widely used for buildings of various sizes. Design and installation of these systems follow a certain guideline developed by the manufacturer. The guideline also includes the adequate amount of refrigerant to be charged into the system. However, the guideline is often insufficient to reflect all the characteristics of installation, which results in too little or too much refrigerant. Inadequate amount of refrigerant usually causes more power consumption and reduced air-conditioning / heating capacity. This paper focuses on identifying the relationship between adequate refrigerant amount and various state variables such as condensation temperature of the air-conditioning system. This is based on regression analysis of data obtained through the experiments under controlled temperature and humidity.
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Review of the advances and applications of variable refrigerant flow heating, ventilating, and air-conditioning systems for improving indoor thermal comfort and air quality Napoleon Enteria, Odinah Cuartero-Enteria, Takao Sawachi International Journal of Energy and Environmental Engineering.2020; 11(4): 459. CrossRef
Inverter-Type refrigerators are known to consume less energy by varying the inverter frequency according to indoor temperatures and refrigerant pressure through indoor-outdoor communication. However, many commercial operators cannot afford to replace indoor units with ones capable of communication. In a non-communication configuration, indoor units are connected with an inverter-type outdoor unit without intercommunication abilities. The research goal is finding appropriate operating parameters to achieve energy efficiency. Thus, an operation algorithm with two modes is proposed, i.e., one to search the best operating parameters and one for normal operation with the best parameters. The experimental evaluation showed 11.27% reduction in energy consumption, indicating a good applicability of the algorithm.
Generally, a working excavator has only one directional bucket tilting angle, which is up-forward. However, side direction rotation of the bucket would allow variety of working output. We designed a hydraulic rotary actuator comprising a double rod hydraulic cylinder with a rack-pinion gear set for use in excavator bucket with side tilting mechanism, thus converting the linear to angular motion. The proposed side tilting rotary actuator was designed with parts suitable for medium size of heavy duty excavator. These mechanical parts were inexpensive to purchase and the manufacturing cost was reasonable. The proposed mechanism is potentially useful for excavator with variety of working output.
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A Gain-Adaptive Intelligent Nonlinear Control for an Electrohydraulic Rotary Actuator Nguyen Minh Tri, Dang Xuan Ba, Kyoung Kwan Ahn International Journal of Precision Engineering and Manufacturing.2018; 19(5): 665. CrossRef
A Review of Recent Advances in Design Optimization of Gearbox Zhen Qin, Yu-Ting Wu, Sung-Ki Lyu International Journal of Precision Engineering and Manufacturing.2018; 19(11): 1753. CrossRef
This paper presents the development of a magneto-optical encoder for higher precision and smaller size. In general, optical encoders can have very high precision based on the position information of the slate, while their sizes tend to be larger due to the presence of complex and large components, such as an optical module. In contrast, magnetic encoders have exactly the opposite characteristics, i.e., small size and low precision. In order to achieve encoder features encompassing the advantages of both optical and magnetic encoders, i.e., high precision and small size, we designed a magneto-optical encoder and developed a method to detect absolute position, by compensating for the error of the hall sensor using the linear table compensation method. The performance of the magneto-optical encoder was evaluated through an experimental testbed.
The best method of measuring wood diameter is a contact-type device: however, obtaining an accurate result can be problematic under certain circumstances. In this study, we used a laser beam and a CCD camera that did not require contact with wood. The wood is illuminated by the laser beam, and the CCD camera captures this illumination. The measurement results were determined by processing of the captured image sequences. This paper explains the use of image processing and laser systems for measurement of wood under circumstances in which physical contact is impossible.
Unlike household refrigerators, commercial refrigerators are composed of separate indoor and outdoor units. The outdoor unit of most commercial refrigerators is designed to run at a fixed speed, which results in low energy efficiency and loud fan noise. Moreover, it cannot respond flexibly to changing thermal load in the indoor unit. Inverter type outdoor units can address such problems through speed changes based on information obtained from the indoor unit. However, using two units from different manufacturers is often not a viable solution. If condition changes in the indoor unit can be detected without communication between the two units, it is possible to adjust the speed of the outdoor unit. This paper attempts to analyze the signal from the outdoor unit when the condition of the indoor unit changes by varying the thermal load.
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