In this paper, we consider six degree of freedom (dof) nonlinear control of flexible spacecraft. Firstly, the motion equation of the six dof flexible spacecraft is described and the error system is derived. Secondly, static output feedback controller is derived by passivity-based control method as the case of the attitude control. Thirdly, based on the results, we design the dynamic output controller without velocity measurement. Finally, effectiveness of the control methods is verified by simulations.
In this paper, we discuss the identification of continuous linear time invariant systems with non-Gaussian observation noise. First we analyze the stochastic property of actual observation noise in terms of mixture distribution. Then we consider the method of data processing that converts the stochastic distribution of the noise in the actual observation to Gaussian distribution and propose a new identification method based on this data processing. Finally, we demonstrate the proposed identification method in both simulation and experiment.
In this paper, we propose a fault detection scheme of examining if a human operator controlling a switched system stays in normal condition. Our attention focuses on an expert who manually operates a system with on-off switches. To keep the system in an acceptable state, we expect that the expert flips switches almost always with impeccable timing when the expert is in good condition. Therefore, dispersion of the timing of flipping on-off switches is a reliable indicator of the condition of the expert. The proposed fault detection scheme is based on on-line statistical hypotheses testing between the dispersion being significantly wider than usual and not so.
A novel method to measure thickness of a thin multi-layer film (TMLF) is proposed by using the Daubechies wavelet (DBW) and the Maximum entropy method (Burg algorithm). A signal is a reflective spectrum measured by a spectroscope when visible light is normally incident upon a TMLF. This spectrum is composed of interference and sometimes absorption. The DBW is very effective to separate them. It is impossible to achieve the same effect by an ordinary low pass filter. After this pre-processing, thickness is calculated by the Burg algorithm. It is more accurate to estimate spectrum than the FFT algorithm. And also the tapered Burg algorithm that is to minimize error variance for the estimation of frequency is more effective for this objective. Now a thickness gage has been developed that has a very high sensitive detector of a CCD area sensor that has plural rows of a CCD array with binning operation based on this novel method. It becomes possible to measure thickness of a TMLF in-line that means in production line in a non-destructive manner.