http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Path Tracking Controller Design and Simulation for Korean Lunar Lander Demonstrator
Yang, Sungwook,Son, Jongjun,Lee, Sangchul The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020's. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.
On-Orbit Estimation of Dynamic Properties for STSAT3
Sungwook Yang,Dong-Ik Cheon,Sangchul Lee,Hwa-Suk Oh 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10
Reliable and efficient attitude control requires the accurate dynamic properties. On orbit, the mass and inertia values are to be changed by some activities such as the propellant use, the solar panel deployment, etc. To obtain the accurate mass properties, the estimation should be performed. For the initial on-orbit estimation of the mass properties, the gyro-based attitude data is applied for the batch method. The gyro-based attitude data includes the noise, which affects the estimation accuracy. We suggested several filtering methods including the extended Kalman filtering algorithm to obtain the well-conditioned attitude data. Applying the proper filters, we can obtain the reliable estimation result of the mass properties of STSAT3.
Path Tracking Controller Design and Simulation for Korean Lunar Lander Demonstrator
Sungwook Yang,Jongjun Son,Sangchul Lee 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
In Korea, Lunar exploration program has been prepared with the aim of launching in the 2020’s. As a part of it, a lunar lander demonstrator was developed, which was the model for verifying the system such as structure, propulsion, and control system, before launching into the deep space. This paper deals with the path tracking performance of the lunar lander demonstrator with respect to the thruster controller based on Pulse Width Pulse Frequency Modulator (PWPFM) and Pulse Width Modulator (PWM). First, we derived equations of motion, considering the allocation of the thrusters, and designed the path tracking controller based on Euler angle. The signal generated from the path tracking controller is continuous, so PWPFM and PWM modulator are adopted for generating ON/OFF signal. Finally, MATLAB simulation is performed for evaluating the path tracking ability. We compared the path tracking performances of PWPFM and PWM based thrust controller, using performance measures such as the total impulse and the position error with respect to the desired path.
신경 신호 측정을 위한 마이크로 모터 기반 마이크로 드라이브
양성욱(Sungwook Yang),박기태(Kitae Park),전효진(Hyojin Jeon),조제원(Jeiwon Cho),신희섭(Hee-Sup Shin),윤의성(Eui-Sung Yoon) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The miniature motorized microdrive which is applicable to the neural signal recording in gene-modifiable mice is presented. The microdrive is manipulated with direct driving method of micro motor within the range of 2.8㎜, with the resolution of 0.742 ㎜. A moving electrode in a mouse brain is monitored with an integrated MR(Magneto-Resistive) sensor. This microdrive, which is trapezoidal, has the length of 7.1㎜, the width of 5㎜, the height of 22.5 ㎜ and the weight of 1.45g only. The displacement of the microdrive was evaluated and verified in the range of 1000 ㎛. The neural signal of the mouse in anesthesia was recorded successively with the microdrive moving.
The Effect of Unobservable Efforts on Contractual Efficiency
Sungwook Kang,Hongsuk Yang 한국경영과학회 2013 Management Science and Financial Engineering Vol.19 No.2
An interesting puzzle in business practices is that although many researchers emphasize the benefits of a revenue-sharing contract, a wholesale contract has remained to be the most common contractual form. By introducing the concept of unobservable efforts, we examine the contractual efficiency of a wholesale contract and a revenue-sharing contract. The multi-task agency model and experimental design approach are used to analyze the relationship between the contractual efficiency and parameters. A major finding of our study is that a wholesale contract coordinates unobservable efforts, while it fails to coordinate the order quantity decision. Because unobservable efforts have mixed effects on the contractual efficiency, the superiority of contract type depends on parameters. This finding implies that a wholesale contract can be a competitive contract, especially when unobservable efforts are heavily involved. Our conclusion is that the current popularity of a wholesale contract is manager’s rational response to complex supply chain environments rather than irrational behaviors.
Sungwook Choi,Hyunchul Yang,Hyunseong Kang,Gyeong Min Kim 대한견주관절학회 2019 대한견주관절학회지 Vol.22 No.4
Background: Clinical outcomes and prognosis of large and massive rotator cuff tears are known to be unpredictable not only in degeneration of the rotator cuff, but also due to a high rate of retear. Methods: Totally, 81 patients who had undergone arthroscopic rotator cuff repair from May 2008 to February 2016 were evaluated in our study. Clinical and functional evaluations were performed with the Constant score and the University of California, Los Angeles (UCLA) score, as well as full physical examination of the shoulder. All patients were confirmed to have magnetic resonance imaging (MRI) of tendon healing at least 1 year postoperatively. Results: The average age at the time of surgery was 65 years (range, 47–78 years). The average duration of postoperative time in which a follow-up MRI was performed was 36.1 months (range, 12–110 months). Large tears were present in 48 cases (59.3%) and massive tears in 33 cases (40.7%). Overall, there were 33 retear cases (40.7%). All the average clinical outcome scores were significantly improved at the last follow-up (p<0.001), although repair integrity was not maintained. Compared to type A, types C, and D of the Collin’s classification showed significantly higher retear rates (p=0.036). Conclusions: Arthroscopic rotator cuff repair yields improved clinical outcomes and a relatively high degree of patient satisfaction, despite the repair integrity not being maintained. Involvement of the subscapularis muscle or infraspinatus muscle had no effect on the retear rate.