http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
장효환,전윤식,Chang, Hyo-Whan,Jun, Yoon-Sik 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.3
Shift quality of an automatic transmission in a vehicle is mainly affected by transient pressures in the hydraulic system during shifting. In this study, dynamic modelings of the hydraulic system and the power train of an automatic transmission are made systematically by a bond-graph method. The dynamic characteristics of the line pressures and clutch/brake pressures during shiftings are investigated by simulations and verified by experiments. The effects of clutch/brake pressures on the shift torque are also investigated through driving simulation.
가스보조식 이중행정 유압브레이커의 민감도 해석에 의한 성능 향상
류택직(Taek Jik Ryoo),장효환(Hyo Whan Chang) 유공압건설기계학회 2009 유공압건설기계학회 학술대회논문집 Vol.2009 No.11
A gas-assisted hydraulic breaker uses both hydraulic and pneumatic energies and an appropriate balance between two energies mostly effects its performance. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected and nearly optimized to maximize the output power as well as the impact energy for long and short strokes. As the results, the impact energy and output power are increased significantly compared with the current design. The dynamic characteristic of the piston displacement is also improved by the design change.
ANFIS 기반 경로추종 운동제어에 의한 모형차량의 자동주차
장효환(Hyo Whan Chang),김창환(Chang Hwan Kim) Korean Society for Precision Engineering 2009 한국정밀공학회지 Vol.26 No.12
In this study an ANFIS-based trajectory tracking motion control algorithm is proposed for autonomous garage and parallel parking of a model car. The ANFIS controller is trained off-line using data set which obtained by Mandani fuzzy inference system and thereby the processing time decreases almost in half. The controller with a steering delay compensator is tuned through simulations performed under MATLAB/Simulink environment. Experiments are carried out with the model car for garage and parallel parking. The experimental results show that the trajectory tracking performance is satisfactory under various initial and road conditions.
전윤식,장효환,Jun, Yoon-Sik,Chang, Hyo-Whan 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.3
Most of feedback shift controllers developed in the past have fixed control parameters tuned by experts using a trial and error method. Therefore, those controllers cannot satisfy the best control performance under various driving conditions. To improve the shift quality under various driving conditions, a new self-organizing controller(SOC) that has an optimal control performance through self-learning of driving conditions and driver's pattern is designed in this study. The proposed SOC algorithm for the shift controller uses simple descent method and has less calculation time than complex fuzzy relation, thus makes real-time control passible. PCSV (Pressure Control Solenoid Valve) control current is used as a control input, and turbine speed of the torque converter is used indirectly to monitor the transient torque as a feedback signal, which is more convenient to use and economic than the torque signal measured directoly by a torque sensor. The results of computer simulations show that an apparent reduction of shift-transient torque is obtained through the process of each run without initial fuzzy rules and a good control performance in the shift-transient torque is also obtained.
[동력전달계부문] 가변용량 펌프형 자동변속기 유압시스템 최적설계에 관한 연구
이주항(Joo Hang Lee),장효환(Hyo Whan Chang) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Due to the complexity in an automatic transmission, it is difficult to analyze the dynamic characteristics of a hydraulic system in the automatic transmission, and also to evaluate the sensitivity of each design parameters on the shift transient torque. In this study the effects of design parameters for the main components of a hydraulic system on the pressure profiles and transient torques are investigated through the simulation by Taguchi method. Key design parameters of the hydraulic control system are extracted at each shift stage and optimal design parameters are suggested in order to minimize the shift transient torque using Taguchi method. Taguchi method was used in the purpose of effectively optimizing the simulation. It is shown that the transient torques is reduced effectively at each shift stage after optimization.