In this paper, the history of Hayabusa project is summarized. The major objective of Hayabusamission is to verify and demonstrate technologies inevitable for future solar system exploration missions suchas sample return from asteroids and comets. Being propelled by ion engines, Hayabusa performed Earthswingby one year after its perfect launch in 2003, and approached its target, asteroid Itokawa in 2005. After twomonths rendezvous flight, Hayabusa landed twice on the surface of Itokawa. The spacecraft overcame severemalfunctions happened during its final take-off, and we expect it will return to Earth in 2010.
The objective of this article is to encourage mainly researchers in the area of control theory to
look out of their academic communities and make contributions to the public, society, and world. Control
engineering can do many things for sustaining the earth and promoting the quality of life. The researchers
should know their potential ability, that is, what they can do for innovations.
Organic light-emitting devices (OLEDs) are expected to be the next generation flat panel displays and have been commercialized for mobile phones and car audios. In addition, the performance of white-light-emitting OLEDs have been steadily improved and, today, they are considered to be the light source of the next generation. In this talk, the recent development of high performance OLEDs will be discussed.
This lecture is concerned with a numerical study of the hole-tone feedback problem, involving sound generation from a round jet impinging on a plate with a hole of same diameter as the jet nozzle. The sound-generating flow is modelled by a discrete vortex method; the sound generation is evaluated by the Powell-Howe theory of vortex sound and the boundary element method. The fundamental dynamics is studied in terms of an axi-symmetric model. Following this, sound control by piezoelectric actuators placed around the inner circumference of the jet mouth is studied in terms of a full three-dimensional model.
The energy based control approach has been shown effective for designing and analyzing the control systems for underactuated systems with underactuation degree (the difference between the numbers of generalized coordinates and controlinputs) being one. For underactuated systems of underactuation degree greater than one, it is still an open and challenging problem to analyze the behavior of the resulting closed loop system governed by a controller designed by using the energy based control approach. In this study, we investigate an unsolved problem of how to analyze energy based swing-up control a double pendulum on a cart, which is an example of an underactuated system of underactuation two. We present an original analysis of the convergence of the energy of the cart-double pendulum system. We show that for all initial states of the cart-double pendulum system, if the convergent value of the energy is not equal to the energy at the up-up equilibrium point, then the cart-double pendulum remains at its up-down, down-up, and down-down equilibrium points. Moreover, we show that these three equilibrium points are unstable. This shows that for almost all initial states of the cart-double pendulum system, as time approaches infinity, the energy of the cart-double pendulum system can be controlled to its energy at the upright equilibrium point. This paper provides insight into the energy based control approach to underactuated systems of underactuation degree greater than one.