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A Control Strategy for Hemispherical Resonator Gyros Using Feedback Linearization
Jaehwan Pi,Hyunsam Myung,Hyochoong Bang 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10
Hemispherical resonator gyroscope is one of the vibratory gyroscopes that can work as an angle sensor as well as an angular rate sensor. Vibratory gyroscopes have advantages that it has relatively long operation time since it has no moving part, it has relatively larger measurement range, and so on. These types of gyros are based on the principle of Coriolis effect. To operate the vibratory gyros, its resonance should be performed and maintained at first. Then the external rotation of the platform causes the precession of the vibratory gyros so that one can measure the amount of external rotation reversely. Since there exist several facts that disturb the resonance of the gyros, a control scheme to maintain its resonance is required. In this paper, a mathematical model of the hemispherical resonator gyros is introduced and analyzed. By using the mathematical model introduced, a control strategy for operating hemispherical resonator gyros using feedback linearization is presented.
Operational Study for Earth Observation Satellites by Minimum Command Effort
Jaehwan Pi,Donghun Lee,Hee Seob Kim,Hyochoong Bang 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10
Nowadays, Earth observation satellites are widely used to acquire high quality, and the satellites should have more observation missions at the same time. In this case, it is useful to develop a systematic command generation method for satellite pointing to acquire wide area image efficiently. In this paper, three efficient methods are proposed to operate Earth observation satellite attitude pointing missions. Analysis of each method with numerical simulation results is also discussed.
Pi, Jaehwan,Bang, Hyochoong The Korean Society for Aeronautical and Space Scie 2013 International Journal of Aeronautical and Space Sc Vol.14 No.4
The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.
Jaehwan Pi,Hyochoong Bang 한국항공우주학회 2013 International Journal of Aeronautical and Space Sc Vol.14 No.4
The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.