Search

A looper optimal multivariable control system based on an optimal regulator theory has been developed. Goal of controlling the hot strip finishing mill loopers is to stabilize rolling operation and to maintain product quality by controlling the tension applied to the strip and the looper angle within their reference values.The most difficult problem in looper control is to achieve simultaneously the interfering tension control and looper angle control. In recent years, a non-interactive control employing cross-controllers has been adopted and brought a dramatic increase in control accuracy, although the response time is limited. Thus, a new method with improved response time is desirable.In this paper, a looper optimal multivariable control based on the optimal regulator theory employing a looper drive system with speed control loop is proposed. Other topics discussed includes the results of an investigation of simplifying the control system by the use of a programmable controller. In addition, it is demonstrated that the optimal multivariable control is effective compared with the conventional control and the non-interactive control as employed in the hot strip finishing mill of Hirohata Works of Nippon Steel Corporation.

Effects of a yaw angle on the vortex shedding frequency from a fixed circular cylinder were examined using a wind tunnel. Then, oscillations of an elastically supported cylinder whose motion was confined normal to its axis and the flow were investigated. The cosine law was confirmed to be applicable to the larger value of Reynolds number and/or the yaw angle for the vortex shedding frequency fro ma fixed cylinder. For an elastically supported cylinder a purely translational mode oscillation was observed at a low velocity. However, a rotaional mode oscillation was often superposed for higher velocities. The frequencies of these two modes of an oscillation were equal to their natural frequencies fnz and fnθ irrespective of the vortex shedding frequency fvm. The translation mode oscillation had two resonance peaks at f /fnz=1 and 2.6, whereas the rotation mode had only one peak at fvm/fnθ=2.8. A yaw angle made the vortex shedding irregular, making the resonance phenomena unclear for both the translation and the rotation modes.

MAXI (Monitor of All-sky X-ray Image) is the first astrophysical payload for Japanese Experiment Module (JEM) to be designed for all sky X-ray monitoring. MAXI is a slit scanning camera which consists of two kinds of X-ray detectors; one is one-dimensional position sensitive proportional counters with total area of about 5000 cm2 (here we call GSC) and the other is an X-ray CCD array with total area of about 200 cm2 (here we call SSC). The GSC subtends a field of view with an angular dimension of 1° × 180°, while the SSC has a field of view of 1° × 90°. Thus, in the course of one station orbit, MAXI can scan almost all sky with a precision of 1 degree and with X-ray energy range of 0.5-30 keV. MAXI with a total weight of about 500 kg will be attached to JEM exposed facility (JEM-EF) in 2004. Furthermore, the future ASM with more sensitive detectors having a wide energy band and with better time response/resolution will follow the MAXI mission.