• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.97-103
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• 2022

Low fertility rates and increased life expectancy further exacerbate the process of an aging society. This is also reflected in the gradual increase in the proportion of vulnerable groups in the social population. The demand for improved mobility among vulnerable groups such as the elderly or the disabled has greatly driven the growth of the electric-assisted mobility device market. However, such mobile devices generally require a certain operating capability, which limits the range of vulnerable groups who can use the device and increases the cost of learning. Therefore, autonomous driving technology needs to be introduced to make mobility easier for a wider range of vulnerable groups to meet their needs of work and leisure in different environments. This study uses mini PC Odyssey, Velodyne Lidar VLP-16, electronic device and Linux-based ROS program to realize the functions of working environment recognition, simultaneous localization, map generation and navigation of electric powered mobile devices for vulnerable groups. This autonomous driving mobility device is expected to be of great help to the vulnerable who lack the immediate response in dangerous situations.

• 문화기술의 융합
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• 제6권1호
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• pp.135-145
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• 2020

이 연구에서 우리는 안전보건경영시스템이 기업경영성과에 미치는 영향과 전기공사업체의 운영능력이 조절효과를 분석하였다. 첫째, 경영, 조직관리 및 자원 준비가 전기공사의 관리능력에 정(+)의 영향을 미칠 것이다. 이는 표준시공을 통한 고객 만족, 작업 안전 확보, 자연환경 보전 및 사회적 책임 추구가 조직 내에 잘 전달되고 이해가 높을수록, 시공계획서, 장비관리 상태가 적합 할수록 전기공사 관리능력에 긍정적인 영향을 미치는 것으로 평가되었다. 둘째, 경영, 조직관리 및 자원 준비는 기업경영성과에 정(+)의 영향을 미쳤다. 이는 산업 안전보건법규가 강화되고 기업들의 안전보건활동 안전문화 등 관련 정보가 공개되어 조직관리가 원활하게 소통되면서 시공계획서와 장비관리를 OHSA의 기준에 적합할수록 측청결과도 높을 때 기업의 경영성과에도 긍정적인 영향을 미친 것으로 보인다. 마지막으로, 경영, 조직관리 및 자원 준비가 기업경영성과에 미치는 영향에 대해 전기공사의 관리능력은 매개 효과가 나타났다. 이는 독립변수인 경영조직이 기업경영성과에 미치는 직접효과는 .401 간접효과는 .168 총효과.658로 나타났으면, 자원 준비가 기업경영성과에 미치는 직접효과는 .423,간접효과는 .178, 총효과 .643으로 분석되었다.

• 센서학회지
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• 제32권6호
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• pp.481-486
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• 2023

Anomaly detection holds paramount significance across diverse fields, encompassing fraud detection, risk mitigation, and sensor evaluation tests. Its pertinence extends notably to the military, particularly within the Warrior Platform, a comprehensive combat equipment system with wearable sensors. Hence, we propose a data-compression-based anomaly detection approach tailored to unlabeled time series and sequence data. This method entailed the construction of two distinctive features, typicality and atypicality, to discern anomalies effectively. The typicality of a test sequence was determined by evaluating the compression efficacy achieved through the pattern dictionary. This dictionary was established based on the frequency of all patterns identified in a training sequence generated for each sensor within Warrior Platform. The resulting typicality served as an anomaly score, facilitating the identification of anomalous data using a predetermined threshold. To improve the performance of the pattern dictionary method, we leveraged atypicality to discern sequences that could undergo compression independently without relying on the pattern dictionary. Consequently, our refined approach integrated both typicality and atypicality, augmenting the effectiveness of the pattern dictionary method. Our proposed method exhibited heightened capability in detecting a spectrum of unpredictable anomalies, fortifying the stability of wearable sensors prevalent in military equipment, including the Army TIGER 4.0 system.

• 대한안전경영과학회지
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• 제19권1호
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• pp.15-25
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• 2017

The findings were summarized as follows. The safety check by manufacturer showed that 6 of 13 companies are over the average occurrence of defects. It was expected that there would be a difference between manufacturing technology capability and production system of each manufacturer. Consequently, manufacturers should institutionally improve and strengthen certification items for the upward standardization of safety certification before factory. Second, the safety check by year showed that the results of this study accord with those of previous studies on defect time. Consequently, manufacturers should classify the 3-year-old equipment for vehicle-mounted MEWP into a special check subject to do a nondestructive test according to proven results, and also reflect the test in a safety test system to do regular preventive activities of equipment defects. Third, the safety check by part showed that the boom and outrigger parts of vehicle-mounted MEWP have the most defects. Stress concentration resulted in defects as the boom part was most frequently operated in the structural parts for a real work. To prevent this, it is suitable to improve the hardness of boom materials. The outrigger part needs improvement in safety devices with materials. As an outrigger supports the overturning moment of equipment, it is most affected by its load based on the operating radius, resulting in fatigue crack.

• 유공압시스템학회논문집
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• 제2권1호
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• pp.15-22
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• 2005

The purpose of this study is to find the effective dynamic characteristics of an improved pneumatic cushion cylinder with a spring type needle valve. The dynamic model represented the peak pressure control method when the pneumatic cushion cylinder is moving forward or backward in the horizontal direction. It was found from the simulation results that the peak pressure in the cushion chamber is affected by the spring, which helps to understand the performance of the pneumatic cushion cylinder and to improve or design a better cushion needle valve component. From the simulation results, the stability of pneumatic cushion cylinder with a spring type needle valve was superior and its cushion capability was also better than that without the spring.

• 한국기계가공학회지
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• 제17권2호
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• pp.145-152
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• 2018

This study deals with the method of determining the tip-over stability of a truck mounted on a high place operation car that is frequently used to carry out high-altitude work. Multibody Dynamics Program and Zero Moment Point (ZMP) theory are used to include dynamic effects during the car's high place operation. Through a combination of the Multibody Dynamics Program and ZMP, understanding the dynamic effects of the car's operating parts and building a detailed tip-over model of the car permitted a more precise prediction of the car's tipping-over behavior. It is also expected to help reduce the car's development time due to the time-effective simulation and provide safer work levels for the operating guide (in terms of working radius and lifting capability) with the dynamics effects.

• Ecology and Resilient Infrastructure
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• 제8권4호
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• pp.194-203
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• 2021

최근에 상하수관로, 지역난방 열공급관로 등의 유지보수가 증가하면서, 도로절단기에 의한 도로절단 작업도 급증하고 있다. 이러한 도로절단 작업은 소음과 함께 분진(절단슬러지)을 많이 발생시키므로, 저소음, 분진회수 등 친환경적인 기술이 적용될 필요가 있다. 기존에 이러한 문제점을 해결하고자 분진을 회수하는 장비가 개발된 사례가 있으나, 친환경성이 정량화되지 않았다는 한계가 있었다. 이에 본 연구에서는 소음 및 분진과 같은 환경위해요인의 발생원인을 근본적으로 제거할 수 있는 저소음·분진회수형 도로절단기를 개발하고, 이 절단기로 수행하는 도로절단작업 과정에 대한 친환경성을 평가하였다. 이를 위하여 본 연구에서는 진공장치와 슬러지흡입부로 구성된 수냉-슬러지회수 통합시스템을 개발하고, 개발된 시스템을 도로절단기에 적용하였다. 그리고 개발된 장비를 테스트 베드에 적용하고, 친환경성 관련 데이터를 수집하여, 친환경성을 평가하였다. 평가 결과, 개발된 장비의 절단슬러지 회수율은 83% 이상이었으며, 소음도는 82~83 dB, 음향파워레벨은 115 dB 수준이었다. 본 연구의 결과는 향후 도로절단기를 개선하는 과정에서 절단슬러지 회수성능과 저소음 성능을 향상시키는 데에 기초자료로 활용될 예정이다.

• 동력기계공학회지
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• 제2권2호
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• pp.47-54
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• 1998

Underwater robotic vehicles(URVs) have been an important tool for various underwater tasks such as pipe-lining, data collection, hydrography mapping, construction, maintenance and repairing of undersea equipment, etc because they have greater speed, endurance, depth capability, and safety than human divers. As the use of such vehicles increases, the vehicle control system is one of the most critical subsystems to increase autonomy of the vehicle. The vehicle dynamics are nonlinear and their hydrodynamic coefficients are often difficult to estimate accurately. It is desirable to have an intelligent vehicle control system because the fixed-parameter linear controller such as PID may not be able to handle these changes promptly and result in poor performance. In this paper we described and analyzed a new type of fuzzy model-based controller which is designed for underwater robotic vehicles and based on Takagi-Sugeno-Kang(TSK) fuzzy model. The proposed fuzzy controller: 1) is a nonlinear controller, but a linear state feedback controller in the consequent of each local fuzzy control rule; 2) can guarantee the stability of the closed-loop fuzzy system; 3) is relatively easy to implement. Its good performance as well as its robustness to parameter changes will be shown and compared with those of the PID controller by simulation.

• 유공압시스템학회논문집
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• 제7권2호
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• pp.1-6
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• 2010

A new type fiber optic sensing system has been developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensor, for the purposes of monitoring large scaled structures, preserving natural environments and measuring physical phenomenons. The sensing system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended to measure such physical quantities as displacement, distortion, pressure, binary states and liquid adhesion. The experiment study has been performed to examine the performance to a pseudo-cracking experiment in the outdoor situation, and to clarify temperature influences to the system in terms of the coupling of optical connectors and the OTDR stability. It has been verified that the sensing system is robust to the temperature change ranging from the general condition to the hard condition. Especially, in this study, the specification and performances of the pressure sensor have been demonstrated to show the capability of inspecting various physical quantities.

• 수산해양기술연구
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• 제33권4호
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• pp.290-297
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• 1997

Underwater robotic vehicles(URVs) are used for various work assignments such as pipe-lining, inspection, data collection, drill support, hydrography mapping, construction, maintenance and repairing of undersea equipment, etc. As the use of such vehicles increases the development of vehicles having greater autonomy becomes highly desirable. The vehicle control system is one of the most critic vehicle subsystems to increase autonomy of the vehicle. The vehicle dynamics is nonlinear and time-varying. Hydrodynamic coefficients are often difficult to accurately estimate. It was also observed by experiments that the effect of electrically powered thruster dynamics on the vehicle become significant at low speed or stationkeeping. The conventional linear controller with fixed gains based on the simplified vehicle dynamics, such as PID, may not be able to handle these properties and result in poor performance. Therefore, it is desirable to have a control system with the capability of learning and adapting to the changes in the vehicle dynamics and operating parameters and providing desired performance. This paper presents an adaptive and learning control system which estimates a new set of parameters defined as combinations of unknown bounded constants of system parameter matrices, rather than system parameters. The control system is described with the proof of stability and the effect of unmodeled thruster dynamics on a single thruster vehicle system is also investigated.