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김연수(Y. S. Kim),이대현(D. H. Lee),김용주(Y. J. Kim),정선옥(S. O. Chung),김태형(T. H. Kim),최창현(C. H. Choi) 유공압건설기계학회 2015 유공압건설기계학회 학술대회논문집 Vol.2015 No.10
This research is conducted to develop automatic steering system for unmanned agricultural machine developing, and performance of the system was evaluated by parallel parking of conventional vehicle. The automatic steering system consist MDPS (motor drivven power steering) to control steering, ESC (electronic stability control) to acquire wheel speed, ultrasonic sensor to recognize parking space, and controller to communicate and handle data. Parallel parking process using automatic steering control consist parking space recognition, backward path generation, and steering control for path tracking. To recognize parking space length and width of parking space were measured using ultrasonic sensor and calculated traveling distance. The path for parallel parking was generated based on kinematic model of conventional vehicle, and PI controller was used to control steering angle for path tracking. Parallel parking simulation was conducted to determine minimum speed of steering angle control, because too low speed of steering angle control increase error of vehicle position and too high speed of steering angle control has cause MDPS slip. The result of the simulation was that 500 °/s of control speed was selected as minimum speed of steering angle. In order to evaluate performance of the automatic steering system tests for performance evaluation of parking space recognition, position control of steering angle, parallel parking were conducted. The results of performance evaluation test were that measured area of parking space using ultrasonic sensor was smaller than the actual are in every case and standard error became larger when the speed of the car was faster. The performance of the position control of steering angle was that maximum overshoot increased if the speed and steering angle increased when checking at angles of 60, 120 and 180. Delay time was 0.3 seconds with fix time of 2 seconds was measure and the rate of error was mostly below 1% which showed outstanding performance. However, when measuring at 240 degree, the slip of MDPS occurred which caused no result to show. Parallel parking using automatic steering control was conducted by vehicle speed condition, the results show that the errors on x-axis and y-axis were below 0.54 m and 0.14 m, respectively, and error on steering angle was less than 1°; therefore it is possible that parallel parking using automatic steering control system for conventional vehicle.
S.H.Ahn,E.J.Choi,홍병식,S.J.Hong,D.H.Kang,T.J.Kim,K.S.Lee,박성근,W.J.Park,M.S.Ryu,심현하,심광숙,S.W.Youn,김용주,Y.U.Kim,S.K.Nam,S.R.Jung,Y.L.Lee,J.T.Rhee,S.J.Lee,D.G.Koo,S.Y.Bahk 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.41 No.5
We present the beam-test results for a real-size prototype resistive plate chamber (RPC) for the endcap region of the Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC). The chamber built with relatively low resistivity bakelite was tested at the Gamma Irradiation Facility (GIF) at CERN under a high photon-flux environment with an effective cluster rate up to about 1.2 kHz/cm2. The characteristics of the present chamber are compatible with the previous results for the muon detection effciency, time resolustion, mean travel time, and rate capability, which were obtained using a higher resistivity bakelite. The present beam-test results ensure that the RPC made of relatively low resistivity bakelite is also suitable for the CMS muon trigger detector. In addition, we study the position resolution of the endcap RPC of the CMS. By using the median position of the cluster strips, the position resolution can be reduced to only half of the strip width.
논문 : 노외기계시스템공학 ; 로타리 경운작업 시 트랙터 PTO 가혹도 평가
김용주 ( Y. J. Kim ),정선옥 ( S. O. Chung ),최창현 ( C. H. Choi ),이대현 ( D. H. Lee ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.3
Analysis of load on major parts of the tractor power drive line is critical for efficient and optimum design of a tractor. The purpose of this study was to evaluate severeness of the tractor PTO driving axle during rotary tillage operation. First, S-N (stress vs. number of cycle) curve of a PTO driving gear was obtained through the fatigue life test using a PTO dynamometer. Second, PTO severeness was evaluated during rotary tillage operation. Torque measurement system was constructed with strain-gauge sensors to measure torque of a PTO axle, an I/O interface to acquire the sensor signals, and an embedded system to calculate severeness. The severeness of PTO was analyzed using measured torque data during rotary tillage. In the PTO gear life fatigue test, breakage time and bending stress of the gear were measured by tooth widths and torque change during the fatigue life test. The S-N curve showed a good linear relationship between bending stress and number of cycle (life) with a coefficient of determination of 0.97. For PTO severenss evaluation, rotary tillage operations were conducted at two PTO rotational speeds (level-1, level-2) under different paddy and upland field sites with different soil conditions. Results of averaged relative severeness for PTO level-1 and PTO level-2 were 1.96 and 3.34, respectively, at paddy field sites, and they were 1.36 and 2.51, respectively, at upland field sites. The results showed that the PTO driving axle experienced more severe load during rotary tillage at paddy fields than at upland sites, and relative severeness was greater at the higher PTO rotational speed under all of the soil conditions.
전압형 고주파 인버터를 이용한 간접유도가열 열유체 에너지시스템과 그 성능평가
김용주(Y J Kim),신대철(D C Shin),김기환(K H Kim),내굴 의융(Y Uchihori),천촌 태삼(Y Kawamura) 전력전자학회 2001 전력전자학술대회 논문집 Vol.2001 No.7
This Paper the state-of-the art indirect induction heated boiler and induction heated hot air producer using the voltage-fed series resonant high-frequency inverter whice can operate in the frequency range from 20kHz to 50kHz. A specially-designed induction heater composed of laminated stainless assembly with many tiny holes and interconnected spot welding points between stainless plates is inserted into the ceramic type vessel with external working coil connected to the inverter and tubelence fluid through this induction heater to moving fluid generates in the vessel. The operating performances of this unique appliance in next generation and its effectiveness are evaluated and discussed from a practical point of view.
논문 : 노외기계시스템공학 ; 농업용 트랙터의 주요 농작업 소요동력 분석
김용주 ( Y. J. Kim ),정선옥 ( S. O. Chung ),박승제 ( S. J. Park ),최창현 ( C. H. Choi ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.2
The purpose of this study was to analyze power requirement of an agricultural tractor by major field operations. First a survey was conducted to obtain annual usage ratio of agricultural tractor by field operation. Plowing, rotary tillage, and loader operations were selected as major field operations of agricultural tractor. Second, a power measurement system was constructed with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. Third, the major field operations were experimented under fields with different soil conditions following planned operation paths. Power requirement was analyzed during the total operation period consisted of actual operation period (plowing, rotary tillage, and loader operations) and period before and after the actual operation (3-point hitch operating, forward and reverse driving, braking, and steering). Power requirement of tractor major components such as driving axle part, PTO part, main hydraulic part, and auxiliary hydraulic part were measured and calculated to determine usage ratio of agricultural tractor power. Results of averaged power requirement for actual field operation and total operation were 23.1 and 17.5 kW, 24.6 and 19.1 kW, and 14.9 and 8.9 kW, respectively, for plowing, rotary tillage, and loader operations. The results showed that rotary tillage required the greatest power among the operations. Averaged power requirement of driving axles, PTO axle, main hydraulic part, and auxiliary part during the actual field operation were 8.1, 7.8, 3.4, and 1.5 kW, respectively, and the total requirement power was about 70% (20.8 kW) of the rated power. Averaged power requirement of driving axles, PTO axle, main hydraulic, and auxiliary hydraulic for the total operation period were 6.5, 6.0, 2.1, 0.9 kW, respectively, and total requirement power was about 52% (15.5 kW) of the rated power. Driving axles required the greatest amount of power among the components.