大槻 真嗣

Hayabusa spacecraft performed the final descents and touchdowns twice in November 2005. In final descent phase, terrain alignment maneuvers were accomplished to control both altitude and attitude with respect to the surface by using four beams Laser Range Finder onboard. Then Hayabusa spacecraft made dynamic touchdowns the surface of the asteroid by the sampler system to collect samples automatically. This paper presents the terrain alignment maneuver and touchdown scheme. This paper also describes the novel sample horn system and touchdown dynamics. Touchdown tests on the ground are presented. Then the flight results on descent and touchdown dynamics are shown and discussed.

Hayabusa spacecraft performed the final descents and touchdowns twice in November 2005. In final descent phase, terrain alignment maneuvers were accomplished to control both altitude and attitude with respect to the surface by using four beams Laser Range Finder onboard. Then Hayabusa spacecraft made dynamic touchdowns the surface of the asteroid by the sampler system to collect samples automatically. This paper presents the terrain alignment maneuver and touchdown scheme. This paper also describes the novel sample horn system and touchdown dynamics. Touchdown tests on the ground are presented. Then the flight results on touchdown dynamics are shown and discussed. Copyright © 2006 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

This paper presents the vibration control, using passive or semi-active dampers, for the transverse vibration of an elevator rope. The dampers are located in the vicinity of the top end of rope and the vibration of rope is reduced by impact with the dampers. The adequate gap width, location, and damping coefficient of the damping device are calculated for the case in which the arbitrary constant length of the rope is allocated and the building is subjected to various earthquakes. Further, the performance of the semi-active vibration control method for the suppression of the vibration of rope is verified; consequently, the usefulness for the proposed method is shown.

Vibration of a large transport system is induced by its motion and the vibration prevents the next motion as the settling time is extended. This paper presents the methodology to simultaneously control the motion and vibration of a cantilevered fork as one of the large transport system. Hence, the nonstationary robust control method considering modeling error of the controlled object as the unstructured uncertainty is applied to enhance the performance for the motion control and vibration suppression by switching the robust state feedback controllers smoothly due to the motion. The usefulness of the proposed methodology is verified through the experimental examinations; consequently, the settling time of the motion and vibration of the controlled object is considerably reduced in the comparison with the result by the conventional method.

The excitation of transverse vibration of an elevator rope is caused by the resonance with the building-sway by an earthquake or wind-induced vibration, hence, a useful active solution for its issue is demanded. In this paper, therefore, the vibration suppression for the elevator rope with the nonstationary sliding mode control using a time-varying switching hyperplane is performed by moving the rope directly near its boundary by use of a control device with gaps between actuator and rope. The nonstationary sliding mode controller has the effectiveness for the control of the object with time-varying characteristics and the robustness for the nonlinearity of the control device. The performance and robustness of the proposed controller are verified through the numerical calculation for the practical case, consequently, the good results are obtained.

Simultaneous control for position and vibration is demanded in the rapid positioning machine with flexible structure such as crane and transport systems in factory automation. Furthermore, the mass distribution, whose the positioning machine in XY plane, varies due to the positioning command, hence, it is classified into a time-varying system. This paper presents the simultaneous control of the rapid positioning and vibration for the flexible structure by the nonstationary robust control method with considering the time-varying characteristics of the controlled object and uncertainties due to its parameter variation. The good performance and robustness of the proposed method are shown through the numerical calculation.

This paper presents a synthesis method of non-stationary robust controller for a time-varying system considering various uncertainties. For the uncertainties, a scaled structured uncertainty is regarded as weightings for variations of parameters and a design function in the time domain. Meanwhile, an unstructured uncertainty is counted by a filter enveloping model errors of a control object in the frequency domain. A wire changing its length is adopted as the controlled object and then its vibration control is discussed as a practical problem for solution. The performances of controllers are demonstrated in the time and the frequency domains through the numerical calculations for the case that the object is subjected to disturbance and variation of parameters. The proposed controller designed by considering both uncertainties shows the advantages for the robustness.

A control method based on the theory of nonstationary sliding mode control is presented for an application to suppression of transeverse vibration of elevator rope. The transverse vibrations of ropes of high-speed elevator are caused by a resonance with sway of building which is subjected to an earthquake and big wind, hence, an effective solution is demanded. The nonstationary sliding mode control is effective for the control of elevator rope categorized by a time-varying system and robust for nonlinearity of a control device. In this paper, therefore, the vibration control for the elevator rope is performed based on the nonstationary sliding mode control using an input system which has gaps between an actuator and the rope because of preventing abrasions of rope. The suppression performance of the proposed method is examined by the numerical calculation on the condition of practical use. Consequently, the numerical results indicate that the performance of the proposed method is remarkable.

本論文では，線形時変システムのダイナミクスを陽に考慮した時変切換超平面，およびその傾きの微分項を含んだ非定常スライディングモード制御器の設計方法を提案する．時変切換超平面は非定常最適制御理論を基に設計され，このときの等価制御系と非定常スライディングモード制御器を含む制御系の安定性を証明する．また，例題を通して提案する制御手法の特性とその有効性を検証する．

In this paper, it is performed to suppress the transverse vibration of elevator-ropes caused by the resonance with sway of high-rise building. The elevator-rope has the characteristics due to its flexibility and the variation of its length. And also a control input system to suppress its vibrations requires gaps between an actuator and the rope because of preventing its abrasion. Therefore, we apply the nonstationary sliding mode control to reduce its vibrations with compensating the influence of time-varying characteristics and spillover and also the nonlinearity as the gap of input system. The suppression performance and the influence of nonlinearity are verified through the numerical calculations.

This paper presents a synthesis method of nonstationary sliding mode controller with time-varying switching hyperplane for reducing the vibrations of wire changing its length. The proposed method deals with a change of system in time domain continuously. First, we construct the model of controlled system including a wire and two mass points at both ends by non-dimensional synthesis method. Then the controller with time-varying hyperplane is designed with the time-varying Riccati equation. Finally, the performance of this controller is verified through the simulation in the two cases that the length is getting long and short.

This paper presents a synthesis method of nonstationary sliding mode controller with time-varying switching hyperplane for reducing the vibrations of rope of elevator. The proposed method deals with a variation of system in time domain continuously because the controller with time-varying hyperplane is designed based on the time-varying Riccati equation. The controlled system is modeled on a structure including an elevator system and it is implemented by the time-varying controller and VSS observer. Then the performance of this controller is verified through the numerical calculation in the two cases that the elevator descends and ascends when the structure is subjected to Chi-Chi earthquake.

For a control problem of wire changing its length such as elevator cables and crane ropes, a controller considering its nonstationary characteristics is effective in suppressing their vibrations. Additionally, the controller having robustness for various uncertainties is valid within suppressing the vibrations of object that has a flexible feature. Consequently, the main objectives of this paper are to propose a nonstationary robust control method and to reduce the transverse vibrations of wire. The vibration controller is designed based on H-infinity theory and a time-varying weighting for the worst disturbance is also optimized to have the appropriate robustness for the parametric uncertainties in time domain. The robust stabilization performances of controller is demonstrated through the numerical calculations and then the robust controller shows the advantage regarding the robustness on the various uncertainties in comparison with the optimal controller.

For a transverse vibration control of an elevator rope, a controller considering its nonstationary characteristics is effective in suppressing its vibrations, because the elevator rope is a kind of time-varying system. In addition, a length of elevator rope varies with time, hence, it is difficult to locate actuators and sensors for the control on arbitrary position such as center of rope and abdomen of modal vibration. As a result, we situate them at the end of rope or near the boundary based on the estimation of Hankel singular value expressing the degree to control and observe state values of controlled object. moreover, the controller having robustness for various uncertainties is valid within reducing the vibrations of object that has a flexible feature. Consequently, the main objectives of this paper are to suppress the transverse vibrations of elevator rope with nonstationary robust control methods. The suppression and robust stabilizing performances of controller are demonstrated through the numerical calculations for the case that the elevator system is subjected to shifts of tension of wire and disturbance from a building. Finally, we derive the sufficient suppression of transverse vibration of elevator rope.

For a control problem of wire changing its length such as elevator cables and crane ropes, a controller considering its nonstationary characteristics is effective in suppressing their vibrations. Additionally, the controller having robustness for various uncertainties is valid within suppressing the vibrations of object that has a flexible feature. Consequently, the main objectives of this paper are to propose a nonstationary robust control method and to reduce the transverse vibrations of wire. The vibration controller is designed based on H-infinity theory and a time-varying weighting for the worst disturbance is also optimized to have the appropriate robustness for the parametric uncertainties in time domain. The robust stabilization performances of controller is demonstrated through the numerical calculations and then the robust controller shows the advantage regarding the robustness on the various uncertainties in comparison with the optimal controller.

建物の特性や外乱情報に不確定要素が多く、建物の復元力特性も非線形挙動を示す。このような対象物の制御を扱うために、近年ソフトコンピューティング手法(知的制御等)が注目されている。その中の一つであるファジィ制御は、一般にIf-thenルールのみから構成されているが、本研究で用いた最適ファジィ制御は簡略な構造同定式を導入しメンバーシップ関数の最大化決定を用いている。本報告では、超高層ビルを対象とし、外乱による建物の振動を制御するための制御則について、最適ファジィ理論による振動制御のプログラムの構築と、その妥当性について検討する。その際、比較対象として最適制御を用いた。

This paper presents a synthesis method of nonstationary robust controller considering uncertainties of time-varying object such as variation of parameter and spillover due to ignored high order modes of object. The variation of parameter is experessed by a scaled structured uncertainty in the time domain. Meanwhile, the influence of spillover is given as a unstructured uncertainty in the frequency domain. In this research, a nonstationary robust vibration controller considering both uncertainties is designed by solving a time-varying Riccati equation derived from a differential game type criterion function. The proposed control method is applied to the transverse vibration control of wire changing its length. Through numerical calculations, the reduction performance of the proposed controller is verified and the advantage with respect to the robustness for the uncertainties is demonstrated.

This paper presents a vibration control method for a wire with time-varying length such as an elevator cable and a crane wire. The characteristics of the wire is varying with time, hence, a nonstationary controller which is designed depending on the time variation of controlled object is effective. Furthermore, since a wire is flexible structure, a spillover due to uncertainties and ignored high order modes is caused. Therefore, we propose the controller considering the robustness for the uncertainties of controlled system and its usefulness is verified through a numerical calculation.

This paper presents a synthesis method of nonstationary sliding mode controller with time-varying switching hyperplane for reducing the vibrations of wire changing its length. The proposed method deals with a change of system in time domain continuously. First, we construct the model of controlled system including a wire and two mass points at both ends by non-dimensional synthesis method. Then the controller with time-varying hyperplane is designed with the time-varying Riccati equation. Finally, the performance of this controller is verified through the simulation in the two cases that the length is getting long and short.

This paper presents a synthesis method of nonstationary optimal controller with time-varying criterion fuction for reducing vibration of the wire. We propose the two methods to decide the weightings of criterion function. One is to give weight the reflected waves, and the other is for each mode. Moreover, by using the disturbance accommdation control method, the weight on the state value of absolute coordinate system can performed, even if the observed state value is relative. Then, we model the objective system using the both relative and absolute coordinates, and compare their performance of nonstationary optimal controllers by the simulation.

This study presents a synthesis method of a nonstationary optimal controller with a time-varying criterion function for reducing the vibration of a time-varying object such as moving ropes of elevators and cranes. For the time-varying object a stationary optimal control is little effective in reducing vibration. Hence, a nonstationary optimal control method with time-varying weightings; on a control input, state values and reflected waves is applied to the time-varying object. As an illustration, the performance of reducing vibration with respect to the rope-sway problem on a high-rise building is examined through an experimental set up. Finally, the performance of this nonstationary optimal controller is compared with that of the stationary optimal controller for the case that the structure is subjected to a ground excitation.

This paper presents a vibration control method for a wire with time-varying length such as an elevator cable and a crane wire. The characteristics of moving wire are varying with time. When the wire is approximately modeled with such a method as FEM, it is possible to cause a spillover due to the ignored high order modes. Therefore, the robustness for the variation of tension, spillover of high order modes and rapid change of disturbance is important and a robust nonstationary control method is proposed by applying nonstationary H-infinity control theory in this study. For the moving wire such as crane string and elevator cable, it is possible to reduce the vibration by using only a nonstationary robust controller for the case that the mass at the tip of wire changes its weight, that is, the tension of wire varies. The robust controller then is designed based on a lower order model of wire with the frequency weightings. As a result, in the numerical calculations we show the robustness and the usefulness of the robust controllers are shown.

This study presents a synthesis method of a nonstationary optimal controller with a time-varying criterion function for reducing the vibration of a time-varying object such as moving ropes of elevators and cranes. For the time-varying object a stationary optimal control is little effective in reducing vibration. Hence, a nonstationary optimal control method with time-varying weightings on a control input, state values and reflected waves is applied to the time-varying object. As an illustration, the performance of reducing vibration with respect to the rope-sway problem on a high-rise building is examined through an experimental set up. Finally, the performance of this nonstationary optimal controller is compared with that of the stationary optimal controller for the case that the structure is subjected to a ground excitation.

This study presents a synthesis method of a nonstationary optimal controller with a time-varying criterion function for reducing vibration of a time-varying object such as rope of elevator and crane. Moreover, from the viewpoint of wave propagation, we also propose a method of reducing vibration with wave-absorbing controller to remove the reflected waves. As an illustration, the performance of reducing vibration with respect to the rope-sway problem on a high-rise building is examined through numerical calculation. These nonstationary optimal and wave-absorbing controllers are compared with the stationary optimal controller in case that the structure is subjected to Kobe earthquake.

This paper develops an approach for the control of the motion of a multiple-link manipulator possessing unactuated joints. A three-rigid-link arm with its shoulder joint actuated and two elbow joints unactuated is modeled as a nonlinear Affine system. The system is a case of second-order nonholonomy since the constraints at the passive joints contain terms of accelerations. In the proposed method to solve the problem of optimal positioning the control input is expressed as a general function of a Fourier basis parameter acquired by using the Ritz method; then this parameter is optimized through the application of the Newton method. Numerical simulations were carried out and tests with an experimental setting demonstrate the effectiveness of the approach.