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고체형 정밀 공진 자이로스코프를 위한 이차 PLL 루프필터 기반 위상제어루프 설계
박상준(Sang-Jun Park),용기력(Ki Ryeok Yong),이영재(Young Jae Lee),성상경(Sangkyung Sung) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.6
This paper suggests a design method of an improved phase control loop for tracking resonant frequency of solid type precision resonant gyroscope. In general, a low cost MEMS gyroscope adapts the automatic gain control loops by taking a velocity feedback configuration. This control technique for controlling the resonance amplitude shows a stable performance. But in terms of resonant frequency tracking, this technique shows an unreliable performance due to phase errors because the AGC method cannot provide an active phase control capability. For the resonance control loop design of a solid type precision resonant gyroscope, this paper presents a phase domain control loop based on linear PLL (Phase Locked Loop). In particular, phase control loop is exploited using a higher order PLL loop filter by extending the first order active PI (Proportion-Integral) filter. For the verification of the proposed loop design, a hemispherical resonant gyroscope is considered. Numerical simulation result demonstrates that the control loop shows a robust performance against initial resonant frequency gap between resonator and voltage control oscillator. Also it is verified that the designed loop achieves a stable oscillation even under the initial frequency gap condition of about 25 Hz, which amounts to about 1% of the natural frequency of a conventional resonant gyroscope.
확장형 미지입력 관측기를 이용한 위성 반작용 휠의 고장 검출
진재현(Jaehyun Jin),용기력(Ki-Ryeok Yong) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.11
This article deals with the problem of fault detection of a spacecraft’s actuators. The authors introduce an extended unknown input observer for nonlinear systems. This is an extended form of unknown input observers which are used for linear systems. Since faults are not available, those are considered as unknown inputs. Unknown input observers can estimate states without full information of inputs if some conditions are satisfied. The authors suggest a continuous-time extended UIO (eUIO) and prove the convergence of state estimation errors. Since the dynamic equation of a spacecraft is nonlinear, an extended UIO can be applied. Three eUIOs are designed to monitor three reaction wheels. The moving averages of each eUIO’s residuals are selected for decision logic. The proposed method is verified by numerical simulations.