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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.
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.
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.
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.
( Sungwook Son ),( Changbae Lee ),( Ju Yeon Lee ),( Dong Seok Yang ),( Chung Reen Kim ) 대한물리치료학회 2020 대한물리치료학회지 Vol.32 No.3
Purpose: The aim of this study was to identify the change in hand grip strength (HGS) for consecutive 6 months in breast cancer survivors (BCS) undergoing postoperative adjuvant chemotherapy (adjCTX) and to determine the factors relevant to HGS after chemotherapy completion Methods: This study was a retrospective observational cohort study. BCS (N=38) who underwent breast cancer surgery and subsequent adjCTX were enrolled. The HGS of both sides was measured before adjCTX and 3 weeks, 2 months and 6 months after adjCTX. And we also collected body composition, anthropometric measurements, social demographics and clinical data. Then we analyzed the changes in HGS over time, and correlation of collected data with HGS at 6 months. Results: A significant increase in HGS of the unaffected side was observed within the first 3 weeks of adjCTX and maintained up to 6 months. In correlation analysis, HGS of both sides was positively correlated with the ipsilateral HGS at 3 weeks, and contralateral HGS at 6 months. And skeletal muscle mass was also positively correlated with the HGS of the unaffected side. In addition, subjects treated with targeted therapy had lower HGS of the unaffected side. However, HGS of the affected side was significantly lower in subjects with breast reconstruction and treated without radiotherapy. Conclusions: To maintain the early recovery of HGS, active and continuous exercise intervention for strengthening might be necessary.
Inverted-load network for high-power Doherty amplifier
Sungwook Kwon,Minsu Kim,Sungchan Jung,Jonghyuk Jeong,Kyunghoon Lim,Van, J.,Hanjin Cho,Hyungchul Kim,Wansoo Nah,Youngoo Yang IEEE 2009 IEEE microwave magazine Vol.10 No.1
<P>In this article, a high-power, high-efficiency inverted Doherty power amplifier (PA), having a more compact load network than that of the conventional Doherty amplifier, was designed and implemented for wide-band code-division multiple access (WCDMA) base-station applications. Its configuration and working principle are compared with the conventional Doherty amplifier. For experimental verification, we implemented an inverted Doherty amplifier, using a 190 W peak-envelope-power (PEP) laterally diffused metal-oxide-semiconductor (LDMOS) field-effect transistors (FETs). Using a four-carrier down-link WCDMA signal, we achieved a high power-added efficiency (PAE) of 32% and an average output power level as high as 46.3 dBm at a given adjacent channel leakage ratio (ACLR) level of -30 dBc. This is a 9.5% improvement in efficiency and 1 dB improvement in output power under the same ACLR conditions from those of the balanced class-AB operation using the same devices.</P>