Design and validation of an MPC controller for CMG-based testbed

In the last years, Control Moment Gyros (CMGs) are widely used for high-speed attitude control, since they are able to generate larger torque compared to “classical” actuation systems, such as Reaction Wheels . This paper describes the attitude control problem of a spacecraft, using a Model Predictive Control method. The features of the considered linear MPC are: (i) a virtual reference, to guarantee input constraints satisfaction, and (ii) an integrator state as a servo compensator, to reduce the steady-state error. Moreover, the real-time implementability is investigated using an experimental testbed with four CMGs in pyramidal configuration, where the capability of attitude control and the optimization solver for embedded systems are focused on. The effectiveness and the performance of the control system are shown in both simulations and experiments

これまでのプレイスメントテスト実施を振り返る

2002年度の工学部カリキュラム改正において,「基礎科目」が設置されるとともに,基礎教養科目等で習熟度別クラス編成による授業が行われることとなった。このクラス分けのために,現在,本学新入学学生は4月最初にいわゆるプレイスメントテストを受けている。プレイスメントテストについては毎年度,簡単な報告を行ってきたが,2002年度以来5回の実施を経たいま,これまでの経過報告を含めた全体報告を行おうと考えている。まず,プレイスメントテストに関しての経緯・状況を述べ,プレイスメントテストで得られたデータからいくつかの事実を報告する。次に各実施科目でのプレイスメントテストの状況報告を行う。In 2002, we started a new educational program for the freshmen in the faculty of engineering. We put new introductory courses for several subjects in the new program. Then the freshmen in our university started their study in classes to which they are arranged according to their proficiency level. For this classification, the freshmen have to take the "Placement Test" in the beginning of April. Every year since 2002, we have reported the results of the Placement Test briefly. In this article, we will report the processes and results of these five years

An Omnidirectional Stereo Vision-Based Smart Wheelchair

To support safe self-movement of the disabled and the aged, we developed an electric wheelchair that realizes the functions of detecting both the potential hazards in a moving environment and the postures and gestures of a user by equipping an electric wheelchair with the stereo omnidirectional system (SOS), which is capable of acquiring omnidirectional color image sequences and range data simultaneously in real time. The first half of this paper introduces the SOS and the basic technology behind it. To use the multicamera system SOS on an electric wheelchair, we developed an image synthesizing method of high speed and high quality and the method of recovering SOS attitude changes by using attitude sensors is also introduced. This method allows the SOS to be used without being affected by the mounting attitude of the SOS. The second half of this paper introduces the prototype electric wheelchair actually manufactured and experiments conducted using the prototype. The usability of the electric wheelchair is also discussed

DNAから探る北辺のイチョウ

イチョウは人が植栽・管理することによって生きてきた樹種であり，人の手によって分布が拡大してきた。イチョウは13~14世紀に中国大陸から日本に伝来し，全国に広がっていったと考えられるが，その詳細は不明な点が多い。しかし，DNA分析からイチョウの移動の歴史をある程度浮かび上がらせることができる。東北地方は日本の中で特に巨樹イチョウが多く，それらは同一のDNAタイプである。一方，北海道は巨樹イチョウに乏しく，DNAは多様性に高く，それらは開拓者の出身地域と対応する

Comparison of the Mesomorphic Behaviour of 1:1 and 1:2 Mixtures of Charged Gay-Berne GB(4.4,20.0,1,1) and Lennard-Jones Particles

We present a Molecular Dynamics study of mixtures of charged Gay-Berne (GB) ellipsoids and spherical Lennard-Jones (LJ) particles as models of ionic liquids and ionic liquid crystals. The GB system is highly anisotropic (GB(4.4,20.0,1,1)) and we observe a rich mesomorphism, with ionic nematic and smectic phases in addition to the isotropic mixed phase and crystalline phases with honeycomb structure. The systems have been investigated by analyzing the orientational and translational order parameters, as well as radial distribution functions. We have directly compared 1:1 mixtures, where the GB and LJ particles have a charge equal in magnitude and opposite in sign, and 1:2 mixtures where the number of LJ particles is twice as large compared to the GB and their charge half in magnitude. The results highlight the role of the long-range isotropic electrostatic interaction compared to the short-range van der Waals anisotropic contribution, and the effect of the stoichiometry on the stability of ionic mesophases