Abstract:The Hinode satellite (formerly Solar-

Abstract:The Hinode satellite (formerly Solar-

No abstract

The X-ray Telescope (XRT) aboard the Hinode satellite is a grazing incidence X-ray imager equipped with a 2048 × 2048 CCD. The XRT has 1 arcsec pixels with a wide field of view of 34 × 34 arcmin. It is sensitive to plasmas with a wide temperature range from < 1 to 30 MK, allowing us to obtain TRACE-like low-temperature images as well as Yohkoh/SXT-like high-temperature images. The spacecraft Mission Data Processor (MDP) controls the XRT through sequence tables with versatile autonomous functions such as exposure control, region-of-interest tracking, flare detection, and flare location identification. Data are compressed either with DPCM or JPEG, depending on the purpose. This results in higher cadence and/or wider field of view for a given telemetry bandwidth. With a focus adjust mechanism, a higher resolution of Gaussian focus may be available on-axis. This paper follows the first instrument paper for the XRT (Golub et al., Solar Phys. 243, 63, 2007) and discusses the design and measured performance of the X-ray CCD camera for the XRT and its control system with the MDP.

The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ∆E ≦ 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.

An innovative method of hybrid vibration suppression using piezoelectric materials is proposed. It combines bang-bang active vibration suppression and energy-recycling semiactive vibration suppression. The piezoelectric materials are electromechanically coupled and convert mechanical energy into electrical energy and vice versa. With this method, a part of the electrical energy needed for suppressing vibration is obtained from the mechanical energy of the vibrating structures and is efficiently recycled. Furthermore, the actively supplied energy is stored in the transducers and is reused many times for vibration suppression. Therefore, the hybrid method has better performance than the case where the bang-bang active method and the energy-recycling semiactive method are both used, but independently. The hybrid method saves the actively supplied energy and is thus a low-energyconsumption vibration control. Its effectiveness in suppressing vibrations was proven in numerical simulations and experiments using a 10-bay truss structure. Moreover, a novel method to prevent undesired control chattering is proposed to further save energy supplied from the external source. NomenclatureB p = input matrix b p = piezoelectric constant of piezoelectric transducer C p = diagonal constant-elongation capacitance matrix C S p = constant-elongation capacitance of piezoelectric transducer I rms = performance index in simulations; Eq. (28) I 2rms = performance index in experiments; Eq. (42) K = constant-charge stiffness matrix of structure k p = constant-charge stiffness of piezoelectric transducer L = inductance in electric circuit L = diagonal inductance matrix M = mass matrix of structure Q = electric charge given to piezoelectric transducer Q = charge vector Q T = target charge vector obtained from active control q = modal displacement vector R = electric resistance in electric circuit R = diagonal resistance matrix u 1 , u 2 = x-directional displacements at tip and central nodes V a = voltage generated by piezoelectric effect V ext = externally supplied voltage V p = voltage across piezoelectric transducer V p = voltage vector V ref = reference voltage for chattering prevention V 1 , V 2 = noise intensity matrices for Eqs. (33) and (35), respectively W 1 , W 2 = weighting matrices; Eq. (12) w = external force vector x = displacement vector of structure z = state vector; Eq. (10) δ rms = rms of displacements of all truss nodes ζ = modal damping coefficient φ i = eigenvector of ith vibration mode ω i = angular frequency of ith vibration mode Subscripts and Superscript j = jth piezoelectric transducer or electric circuit (for C S p , L, Q, Q T , R, V ext , V p , and V ref ) p = piezoelectric transducer = estimated value based on Kalman filter

This paper presents an extensive investigation on the LR-switching method (also called the energy-recycling semi-active method). Compared with the energy-dissipative R-switching method, the LR-switching method has been shown to have significantly better vibration suppression performance. However, certain essential issues affecting a system employing the LR-switching method remained to be dealt with. In particular, we had to clarify its vibration suppression mechanism from the viewpoint of mechanical and electrical energy exchange. Second, the robustness of the method against model errors and control time delays had to be verified. The experiments and numerical simulations that we conducted on a 10-bay truss structure demonstrate that the LR-switching method outperforms other suppression methods under sinusoidal and random excitations, which are more common in real systems and more difficult to deal with than transient vibrations. This paper provides fundamental insights on the LR-switching method and gives the method a guarantee for actual applications.