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.

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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.

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Yamagata University is trying to activate the local industries and society through the education of engineers and researchers, the collaboration based on research activities of academic stuff and so on. In this paper, several unique examples will be reported and the reason why such instances have been produced in Yamagata University will also be discussed.

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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.

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[in Japanese]

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In this paper, we propose a design method of an adaptive PID controller based on output feedback for nonlinear systems with a higher order relative degree and a disturbance. To realize an adaptive PID control system, we introduce a PFC for a nonlinear system which does not satisfy OFEP(Output Feedback Exponentially Passive) conditions and design an adaptive feedforward input with a structure of RBF (Radial Basis Fuction) neural networks in order to remove the steady-state bias error from the PFC output. The proposed method can design a robust adaptive PID controller with higher accuracy on tracking control.

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We have already proposed a design scheme of model reference adaptive control system (MRACS) in which the surrogate model control (SMC) law is always satisfied. It is accomplished with a high order tuner having smooth parameter projection algorithm. However, the stability of MRACS was not always satisfied under existence of modeling error; system disturbance, measurement noise and parasitic dynamics. We derive here a sufficient condition for robustly stabilizing MRACS based on SMC when a robust high order tuner is used.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Ankle-Foot Orthoses (AFOs) are orthotic devices supporting movements of ankles of disabled persons for example hemiplegia, polio, peroneal nerve palsy, etc. In our previous research, we developed some kinds of passive controllable AFO which can control ankle torque with Compact Magneto-rheological fluid brakes. One of the remarkable key points of its control is damping control at initial contacts. We think that a prediction of the initial contact is effective for its control because it ends very instant moment of about 0.1s. In this paper, we describe basic control method of our controllable AFO and prediction method of the initial contact for it. Finally, we could predict instant contacts before 0.1s with the absolute error of 0.020s.

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Passive type MR dampers which use permanent magnets and can adjust the damping characteristics in response to its motion are proposed. The prototype has been manufactured and the dynamic performance is verified by displacement excitation test. The test demonstrates that the damping characteristics depend on its displacement, that is, the damper behaves as a linear viscous damper under smaller vibrations and develops much higher damping force under large vibrations.

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[in Japanese]

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[in Japanese]

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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.

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[in Japanese]

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[in Japanese]

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In a continuous inkjet printer, pressurized ink is ejected from the nozzle vibrating at constant frequency. Ink droplets are formed due to hydrodynamic instability. The droplet formation process is visualized and measured by the experiment. It is found that the droplet formation patterns are controlled by the straight length of the nozzle, the droplet formation constant defined by the ratio of the perturbation wave length to the initial jet diameter, the applied voltage to the piezoelectric vibrator, and the viscosity of ink. These patterns are classified by the droplet formation constant versus the applied voltage to the piezoelectric vibrator diagram. The range of satellite-free control conditions is determined. Preliminary numerical simulation of the droplet formation process from a liquid round jet was also conducted to obtain similar results as compared with the experimental observations.

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1/f fluctuation analysis of the non-life-bearing, life-bearing and self driven particle targets is carried out. As a result, it is clarified the followings. State transition, e.g., melting an ice to water, of all the non-life-bearing targets exhibits 1/f fluctuation frequency characteristics.Namely, all the non-life-bearing materials exhibit 1/f fluctuations when changing their state aspect such as solid, liquid and gas. On the other side, 1/f fluctuations can be observed the creative works, e.g., artistic paints when transitioning mental situation from depression to mania of life-bearing target, i.e., his or her. In the other words, a life-bearing target typically human exhibits 1/f fluctuation characteristics via his own creative work when changing his mental situation.

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Previously we have revealed that Preisach magnetization model is one of the generalized representations of cellar automaton when not be innovated the cellar automaton concept. In the present paper, after we classified the magnetization curve of a ferromagnetic material into three magnetization regions, i.e., reversible domain movement, irreversible domain movement and rotation of magnetizing vector regions, according to the way of classical magnetic domain theory, we applied the Preisach type cellar automaton model to each of three magnetizing regions. As a result, it is shown that entire magnetization curves can be represented by means of the cellar automaton type model.

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In addition to the highest functionalperformance, a series of various modern machines should be equipped the more sophisticated human interface in order to use, handle or drive them. In such mening, modern fuman engineering has to provide the easiness of machine handling in addition to take the user mental impression into account. Sound is one of the most impressive emotional signals to the human sensing ability so that the sound accompanying of the machine operation is of paramount importance in machine designing. This paper describes with the extraction of 1/f fluctuation frequency from music sound data.By menas of Fourier transform in cooperated with least squares, 1/f fluctuation frequenct components are extracted. As a result, it is revealed that 1/f fluctuation components in music sound are syatematicall compoed in frequency domain.

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[in Japanese]

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[in Japanese]

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In order to reduce power consumption, pipe wear and conveying velocity, a pneumatic conveying system that a dune model is installed in pipeline is proposed in this paper. An experimental study focuses on the effect of installed dune model in the horizontal pneumatic conveying system in terms of the pressure drop and particle flow patterns. The test pipeline consisted of a horizontal smooth acrylic tube with an inside diameter of 80 mm and a length of about 5 m. The polyethylene spherical particles with a diameter of 3.1 mm and density of 952 kg/m3 are used as conveying material. The mean air velocity is varied from 8 m/s to 17 m/s, and the solid mass flow rate from 0.22 kg/s to 0.42 kg/s. Results indicate that in the lower air velocity range, the pressure drop of the pneumatic conveying with an installed dune model is lower than that of the conventional pneumatic conveying system. The reduction rate of the lower pressure drop in the case of dune models is apparently large for high solids mass flow rate. The case fixing the dune model on the bottom of pipe at the inlet of particle feed is more effective for saving-energy conveying. The particle flow patterns also show that the dune model reduced the deposition of particles and result in the reduction of the pressure drop.

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A door mirror is mounted on the vehicle body as a projection. When the vehicle moves at high speed, the complex flow structures are generated behind the mirror. Here, reduction of the aerodynamic drag is demanded. From the previous study, it has been understood that the separation vortices are originated from the tip and end portion of the mirror, especially the high-frequency vortex produced by the mirror tip is associated with the aerodynamic drag. In this study, the separation region behind the mirror is controlled by improving the tip shape of the door mirror, and the flow structures are quantitatively evaluated by the wind tunnel and PIV (Particle Image Velocimetry).

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The flow drag of body is closely related to the wake structure. In this study, several wake flows, which are produced by several experimental models based on cylinder (cylinder, cylinder with plate wing and heated cylinder with plate wing), are visualized. From the visualization results, the characteristics of wake structures generated from different bodies are discussed.

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Water striders Gerridae are insects of characteristic length 1 cm and weight 10 dynes that reside on the surface of ponds, rivers, and the open ocean. Their weight is supported by the surface tension force generated by curvature of the free surface, and they propel themselves by driving their central pair of hydrophobic legs in a sculling motion. Previous experiments reveal that the hydrodynamic propulsion of the water strider relies on transferring momentum to the underlying fluid through hemispherical vortices and capillary waves shed by its driving legs. The aim of this paper is to quantify the exchange of momentum between a water strider and the fluid underneath during the insect's rapid stroke. The technique of digital particle image velocimetry (DPIV) is used to visualize water flow and quantify the effect of water strider's rapid leg stroke on water movement and hence to estimate propulsion efficiency of water strider.

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[in Japanese]

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[in Japanese]

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In recent years, a realization of haptic system is strongly desired in industry applications. We succeeded in realization of the law of action and reaction by bilateral control. In this paper, a haptic equalizer is proposed to process the acquired haptic information using Fourier transformation. It is possible to change the reproduced haptic sensation from the remote environment. The numerical simulation and experimental results show viability of the proposed method.

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[in Japanese]

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[in Japanese]

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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.

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Recent extensions of the disturbance cancellation controller design proposed by the authors in 1996 are discussed. First, it is pointed out that the disturbance cancellation controller design can be regarded as a non-standard LQG problem. Second, the non-standard LTR method proposed for minimum phase plants is extended to the non-minimum phase case.

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In this paper, we propose the parametrization of all stabilizing modified Smith predictors and examine a design method for stabilizing modified Smith predictors for non-minimum-phase time-delay plants. At first, the definition of modified Smith predictor is given. Next, we propose the parametrization of all stabilizing modified Smith predictors for stable and unstable non-minimum-phase time-delay system. The control characteristics of the control system are also given.

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In control system design we mostly have dealt with system identification and controller synthesis as separate two steps although many researchers have pointed out that those two steps should be integrated in some ways. The above problematic two-step approach is often adopted mainly because we do not have well-established techniques for the integration of system identification and controller synthesis in contrast to the fact that the complete tool to get the optimal solution only for the corresponding single step itself exists, e.g., the predictive error methodology for system identification and the Riccati or LMI-based paradigm for controller synthesis. In this report an LMI-based method for iterative system identification and controller design is considered. With the fact that a class of system identification problem results in an LMI problem, an identification procedure with a constraint on the closed-loop performance in an approximate sense is proposed. By combining the proposed identification method with the conventional LMI-based controller design procedure we can get a framework to integrate two steps, system identification and controller design. A design example is presented to show effectiveness of the proposed design concept.

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[in Japanese]

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his paper presents a new method to realize a tracking task for the use of rehabilitation and training systems. The developed system is formulated on the basis of man-machine systems, where variations of human forces exerted on the grip is considered as model uncertainty, and global convergence and stability of the system are preserved based on the developed control law. When we apply the impedance control method to a 3 dimension tracking task, the steady-state error remains for the pre-viously mentioned reasons. The proposed method shows a good tracking and parameter adaptation performances in the presence of model uncertainty. Finally, some experi-mental results will be showed to investigate the useful-ness of the proposed method.

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We have achieved walking simulation with a three dimensional musculo-skeletal model which has a CPG controller. However, the robustness is weak in comparison with actual human walking. In this report, we have proposed a method for feedback control in lower dimensional space. The method is based on reducing the dimension of the human model state space, which is treated by principal component analysis. It is shown in the walking simulations with external disturbances on the body that the designed feedback controller can achieve better robustness.

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This paper proposes methods of the sensor failure detection and the data reconciliation for entry-control systems. The entry data recorded by the entry-control system is often corrupted by instruments error or passing gates without correct authentication. The proposed method identifies the inconsistency in the entry data by adjusting those data so that the adjusted values obey the conservation laws between rooms in the controlled area. The results of the case study demonstrate the usefulness of the proposed methods.

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A FDI filter that decouples actuator faults and sensor faults using the sliding mode observer and the disturbance observer is proposed. The proposed FDI filter can obtain an accurate fault estimation signal when actuator faults and/or sensor faults occur.

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This paper presents an on-line detection system of SOC (State-of-Charge) in lead acid battery on the basis of SOC characteristic. The detection system consists of multiple detectors and their selector using the characteristic decision model. The multiple detectors and the characteristic decision model are constructed using Neural Network technique. The detection accuracies for different sized batteries and various degradation states are investigated by numerical simulations with the experimental data. As a result, the effectiveness of the proposed detection system is verified.

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[in Japanese]

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Steering feel might change by the secular change of a viscous friction or the change of the viscous friction with the temperature change of Electric Power Steering (EPS). If the changed viscous friction can be identified, the steering feel can be improved by adjusting the controller gains. For this purpose, the on-line identification method of the viscous friction in EPS has been proposed in the previous work. In this paper the effectiveness of the proposed method is verified using the EPS test bench and the apparatus for additional viscosity.

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[in Japanese]

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It is important for extracranial stereotactic radiotherapy (ERST) to give sufficient dose to tumor and to reduce normal tissue toxicity. To this end, real-time tumor-tracking radiotherapy (RTRT) system can be useful for observing the tumor motion. However, the RTRT system requires about 1 [sec] elapsed time for the estimation of tumor position. Therefore, it is available for reduction of internal target volume (ITV) to predict the actual tumor position at about 1[sec] ahead. In this study, we propose a novel system for predict such complex time series of internal organs motion. An essential core of the system is to convert time-varying seasonal dynamics into time invariant one in real time for high-accuracy modeling. We examined the prediction performance of the proposed system using Holt-Winters seasonal method and a seasonal ARIMA model as a respiratory motion prediction model.

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[in Japanese]

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