• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.1
• /
• pp.124-131
• /
• 2019

A design study of gas turbine engine simulation duct was conducted to investigate the operating characteristics and control gain tunning of the Altitude Engine Test Facility(AETF). The simulation duct design involved testing variable spike nozzle and ISO standard choking nozzle to verify the measurements such as mass flow rate and thrust. The simulation duct air flow area was designed to satisfy Ma 0.4 at the aerodynamic interface plane(AIP) at engine design condition. The test conditions for verifying the AETF controls and measurement devices were deduced from 1D analysis and CFD calculation results. The spike-cone driving part was designed to withstand the applied aero-load, and satisfy the axial traversing speed of 10 mm/s at whole operation envelops.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.1
• /
• pp.183-190
• /
• 2021

This study is a study on the implementation and operation of smart air cleaning system to improve indoor air quality. Recently, the problem of indoor air quality is getting serious due to various environmental factors. In this study, to improve the problems of indoor air quality, we implement an air cleaning system using IoT sensor. In particular, we proposed a system that can measure air pollution in real time and change different air flow paths according to pollution level. Through this, we examined efficient air quality improvement, extension of filter life, and system energy reduction. In addition, the main functions of the indoor air quality improvement system were constructed and prototypes were manufactured to confirm the operability. Finally, the utility of fine dust resolution through the implementation of the indoor air quality improvement system was examined.

• Journal of IKEEE
• /
• v.26 no.2
• /
• pp.265-270
• /
• 2022

This paper proposes the detection algorithm for switch open fault of asymmetric 6-phase PMSM based on stationary reference frame dq-axis currents. In this paper, target motor has an asymmetric structure in which two upper three windings have an electrical phase difference of 30° and a neutral point is separated. As a result, dual 3-phase PWM inverters and the detection techniques due to open failures of switch are definitely required. In this paper, the dual dq-axis current control method is used for driving the asymmetric 6-phase PMSM and the open fault switch should be detected by using variable all pass filter and low pass filter in order to detect the current amplitude. The effectiveness and usefulness of the proposed method is verified by several experiments.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.4
• /
• pp.679-686
• /
• 2022

In this paper, we implemented an algae removal device that recognizes and removes algae existing in water using Raspberry Pi camera and DO (Dissolved Oxygen) sensor. The Raspberry Pi board recognizes the color of green algae by converting the RGB values obtained from the camera into HSV. Through this, the location of the algae is identified and when the amount of dissolved oxygen's decrease at the location is more than the reference value using the DO sensor, the algae removal device is driven to spray the algae removal solution. Raspberry Pi's camera uses OpenCV, and the motor movement is controlled according to the output value of the DO sensor and the result of the camera's green algae recognition. Algae recognition and spraying of algae removal solution were implemented through Arduino and Raspberry Pi, and the feasibility of the proposed portable algae removal device was verified through experiments.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.6
• /
• pp.919-925
• /
• 2023

Modern drones are equipped with miniaturized mission equipment capable of performing various tasks such as surveillance and reconnaissance. Consequently, these mission equipment are exposed to disturbances like wind loads and motor rotations, which can lead to instability in the operation of the Electro-Optical Targeting System (EOTS). Specifically, simple step inputs for changing the line of sight in EOTS can cause abrupt changes in speed, inducing overshoot and potentially creating instability along with other disturbances. To address this, a velocity profile was designed so that the angular velocity moves in a trapezoidal shape when changing the EOTS line of sight. A Double-loop controller was designed to apply this profile as an input to the external loop receiving position feedback. The system's stability was then compared, and the velocity profile was optimized within a stable range by varying maximum speed and acceleration.

• Journal of Aerospace System Engineering
• /
• v.18 no.3
• /
• pp.76-85
• /
• 2024

Recently, from a global perspective, the use of small unmanned aerial vehicles in terrorism and warfare is increasing, and the need for anti-drone shooting training targeting small UAVs is increasing. However, in reality, there are many cases in Korea where anti-drone shooting training is restricted, due to complaints such as noise. In this paper, we describe the development and testing of an electric-powered direct strike type high-speed, low-noise small aerial target drone. To achieve the flight speed and endurance required for shooting training, target drone sizing was performed, and aerodynamic performance analysis was conducted using a CFD program. Based on the performance analysis, the motor propulsion system was selected and a variable pitch propeller system was designed, and performance tests were performed on a ground test rig. Finally, the target flight speed, flight time, and flight noise level were confirmed through flight tests.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.1
• /
• pp.465-470
• /
• 2024

Kitchen cabinets are widely used for their spacious storage and efficient use of space, but their high installed location makes it difficult for the elderly and disabled to access. Therefore, in this paper, we propose a new height-adjustable kitchen cabinet that can be used more easily and safely. The lift-down range of cabinet was set considering the installation location of cabinet for efficient use of kitchen space and the maximum height accessible to the elderly and disabled, and the link geometry and driving method of the complex link mechanism were determined through the mechanism design procedure to ensure that the selected floor come down safely along the optimal descend path. In addition, the appropriate motor and control algorithm were added to allow the user to descend to the desired height with a simple button operation. It was confirmed through actual production that the proposed linkage mechanism performs the desired lift-down motion.

• Journal of Korean Society of Forest Science
• /
• v.97 no.1
• /
• pp.61-70
• /
• 2008

This study was conducted to develop a mobile tower-yarder with tractor for agriculture and forestry that is the efficient yarder in steep terrains, thinning operation and small scale logging operation. It was designed and manufactured that the power source of tower-yarder is equiped three hydraulic pump connected to PTO of tractor, and three hydraulic pump is used to operate the four motor for drum, the cylinder for clutch of interlocker, the cylinder for tower expanding and the out-rigger cylinder. It was to adopt the running skyline system and the inter-lock function, and to equip the double capstan drum, the storage drum and the clutch for interlock in the development of tower-yarder. It was to develop the tower-yarder which the winch torque of double-capstan drum, the traction force of double-capstan drum, the number of rotation of double-capstan drum and the line speed is $191kg{\cdot}m$, 1,910 kgf, 220.5 rpm and 138.5 m/min, respectively. And it was known that the optimum flange diameter of the main and haulback storage drum is about 360 mm and about 460 mm in order to storage the main line length of 250m and the haulback line length of 450 m. The carriage was made to adopt the running skyline system and to equip the lock function in order to the convenience of chocking and the fall down preventing of tree. It was provided to develop the wire remote controller for the inter-lock function, the convenience of control and the efficiency of yarding. In development process, this tower-yarder was attached the 3-point linkage hitch equipment and the tire wheel for the traction and moving of tower-yarder. Also, it was equipped that the out-rigger and the guy line in order to raise the safety and efficiency of yarding of tower-yarder.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.53-53
• /
• 2017

연구목적: 국내 과일 산업의 한 단계 도약과 대외 경쟁력을 높이기 위해서는 수확작업의 기계화가 시급함. 이 연구는 국내외 과일 수확 기계화 현황과 문제점을 분석하고, 향후 수확작업 기계화 방향을 제시하고자 수행 수확기계 실용화 현황 및 고찰 (국내) 과일을 직접 수확이 아닌 수확 작업을 보조해주는 고지 작업기(수동형, 모터 진동형)와 고소 작업차가 대부분임. 수동형은 사과 감 등을 수확하지만, 작업능률이 낮고 작업자가 쉽게 피로하여 장시간 작업이 불가능하므로 실질적인 대안이 되지 못함. 진동형은 자체 동력을 이용하여 나무에 진동을 가하여 주로 대추 매실 등 소과류 수확에 이용되고, 수확능률은 우수하나 충격 손상이 많아 개선이 요구됨. 고소작업차는 동력원에 따라 충전식과 엔진식으로 구분되고, 충전식은 엔진식에 비해 진동 소음이 적어 쾌적하지만, 작업시간이 배터리 용량에 제한을 받음. 또한 작업대 작동방식에 따라 리프트형과 붐형으로 구분함. 리프트형은 리프트를 이용하여 작업대를 상하로 구동하는 방식으로 높은 위치의 과실 수확이 어렵고, 작업대 넓이 만큼의 작업 공간(과수간의 거리)이 필요함. 붐형은 필요한 곳으로 접근성이 우수하나 무거운 무게를 지탱하기 어렵기 때문에 본체를 무겁게 하거나 수시로 수확된 과일을 하차시켜야 함. (국외) 수확 후 가공되는 과일류와 포도 올리브 오렌지 매실 등 소과류 수확이 기계화되었지만, 사과 복숭아 등 신선과일은 아직도 외국의 값싼 노동자들에 의존하여 수확되고 있음. 현재 실용화된 수확 기계는 진동식 수확기계와 터널식 수확기계가 대표적임. 진동식은 집게형의 부착기를 나무 줄기에 고정한 후 트랙터 동력원으로 나무에 진동을 가하여 수확하고, 올리브 대추 등과 같은 소과류와 과피가 두꺼운 오렌지 등에 적용되고, 수확 작업능률이 매우 높으나 과일의 낙하 상처를 피할 수 없는 단점이 있음. 터널형은 규격화(과수 크기 및 형태, 재식거리)된 과수원에 잘 적응하도록 설계 제작되어, 과수 위를 지나가면서 내부에 설치된 진동장치와 컨테이너로 과일을 수확하고, 와인용 포도 수확기가 대표적임. 기계수확이 가능하도록 과수원 조성단계에서부터 재배양식(과수 좌우 및 전후 거리)을 기계의 제원(바퀴 간격, 작업부 간격 등)에 맞추어 재배함. 과일 수확로봇에 관한 연구는 활발하고 일부에서 실증시험단계에 있음. 결론: 구체적인 추진방향을 제시하면, 단기적으로는 과일 수확작업자의 작업편이성과 노동강도를 줄일 수 있도록 소형 저가 범용성이 우수한 보조기구/기계의 보급을 확대하고, 중장기적으로는 수확기계/수확로봇 개발을 위한 연구개발비 투자를 늘리는 동시에, 기계/로봇이 과수원에 잘 적응할 수 있도록 수형 재식거리 등 재배양식의 표준화가 추진되어야 함.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.1-8
• /
• 2020

Air ducts installed for ventilation inside buildings accumulate contaminants during their service life. Robots are installed to clean the air duct at low cost, but they are still not fully automated and depend on manpower. In this study, an intersection detection algorithm for autonomous driving was applied to an air duct cleaning robot. Autonomous driving of the robot was achieved by calculating the distance and angle between the extracted point and the center point through the intersection detection algorithm from the camera image mounted on the robot. The training data consisted of CAD images of the duct interior as well as the cross-point coordinates and angles between the two boundary lines. The deep learning-based CNN model was applied as a detection algorithm. For training, the cross-point coordinates were obtained from CAD images. The accuracy was determined based on the differences in the actual and predicted areas and distances. A cleaning robot prototype was designed, consisting of a frame, a Raspberry Pi computer, a control unit and a drive unit. The algorithm was validated by video imagery of the robot in operation. The algorithm can be applied to vehicles operating in similar environments.