Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/SII.2016.7843972

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/SII.2016.7843972

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

This paper presents an adaptive controller for a position tracking problem of a skid-steer mobile robot. First, a non-adaptive control law is designed by the backstepping method, where the reference signals are generated by a non-holonomically constrained kinematic model in order to make it easy to construct a Lyapunov function candidate. Then an estimator for unknown cornering stiffness is designed based on the Immersion and Invariance (I&I) approach, where the manifold is properly designed to reduce the effect of the estimation error on the tracking performance. Finally it is shown that the closed-loop system can be uniformly ultimately bounded, and numerical simulation shows the effectiveness of the proposed controller.

DOI： 10.1299/mej.15-00040

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

For high-speed trains, active control of the pantograph is crucial technology to collect electrical current from the overhead contact wire. In this paper, a mathematical model of the pantograph-catenary system is developed to design a controller, and then a sliding mode controller is proposed to regulate the contact force in the presence of variation in the equivalent stiffness of the catenary system. Although the proposed controller is based on the standard sliding mode control theory for output regulation problems, a design parameter is introduced to guarantee the existence of sliding mode from a practical point of view. Furthermore, the physical interpretation of the dynamics during sliding mode is given by analysis.

DOI： 10.1299/mej.15-00041

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/SII.2015.7405031

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/AIM.2015.7222671

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1115/DSCC2012-MOVIC2012-8861

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.78.126

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Language：English   Publishing type：Research paper (international conference proceedings)  

This paper presents a simple adaptive controller for a class of nonlinear systems based on Immersion and Invariance (I and I) approach. The I and I adaptive control theory proposed by Astolfi et.al. has many superior features compared to other conventional certainty-equivalence (CE) adaptive approaches. However, for a class of nonlinear systems which can be described in strict feedback form, the I and I adaptive controller, as well as the back-stepping (BS) controller and the adaptive back-stepping controller, has the problem of explosion of complexity caused by the repeated differentiations of virtual controls. That is, the complexity of the controller grows drastically as the order of the system increases. To overcome this problem, a design method of I and I adaptive control via dynamic surface control (DSC) approach is proposed for parametric strict-feedback systems. Copyright © 2012 by ASME.

DOI： 10.1115/DSCC2012-MOVIC2012-8774

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

Focusing on uncertain aerodynamic coefficients which characterize the thrust and torques, an adaptive controller for a four-rotor mini helicopter is designed based on Immersion and Invariance (I&I) approach. In order to deal with the complex multivariable parameter estimation, a relatively simple model parameterized with respect to a few unknown parameters is developed. For the estimation of those parameters, the I&I approach is employed and the design parameters of the resulting estimator are easy to adjust. With the estimates of the parameters, several tracking controllers are designed based on the backstepping methodology. Numerical simulation illustrates the robustness of the controller against the parametric uncertainties and external disturbances.

DOI： 10.1299/kikaic.77.3721

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/IECON.2010.5675184

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS LTD  

In this paper we deal with compensation for controller windup due to actuator saturation in the integral sliding mode control. It is shown that the actuator saturation in the integral sliding mode control causes windup problem similar to the so-called integrator windup, which often takes place in linear control systems with integral action. A simple modification for the switching function is presented in order to reduce the discontinuous component of the control input during saturation. This can be seen as a variable switching function. Furthermore, the proposed anti-windup compensation is applied to a power-assisted manipulator with a single degree of freedom. Simulation and experimental results show the effectiveness of the proposed method.

DOI： 10.1177/1077546309106143

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

This paper presents a new sliding mode controller based on the integral sliding mode control (ISMC). It is shown that the original ISMC, which was proposed by Utkin et al., together with the so-called proportional reaching law tends to bring about windup phenomena under actuator saturation since the dynamics of the switching function is not asymptotically stable. In order to overcome this problem, the dynamics of the auxiliary variable used in ISMC is modified so that the dynamics of the switching function should be asymptotically stable in a certain region of the state space even during the actuator saturation. Thus, the proposed controller guarantees that the sliding mode can take place under the actuator saturation much sooner than the conventional ISMC. In addition, without the actuator saturation, the proposed controller can be seen as a kind of the proportional reaching law. Numerical simulation and experimental results demonstrate the effectiveness of the proposed controller.

DOI： 10.1299/kikaic.75.2926

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IFAC Secretariat  

Focusing on the unmatched uncertainties with respect to the aero dynamic coefficients which characterize the thrust and torques developed on the airframe, a change of state variables with the unknown true model parameters is firstly proposed so as to transform the unmatched uncertainties to matched. Then a sliding mode observer is employed to estimate the new state variables robustly. Using the estimates, a sliding mode controller is effectively employed for the matched uncertainties. Numerical simulation illustrates the robustness of the proposed controller together with the author's previous controller designed by the backstepping method.

DOI： 10.3182/20090909-4-JP-2010.00009

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

This paper presents a nonlinear controller for electric power assist systems based on the sliding mode control. The proposed sliding mode controller is designed to achieve desired nonlinear properties including gravitational effect with robustness against disturbances such as friction force and modeling errors. Furthermore, so-called reaching phase is positively utilized so that the operator can feel disturbance torque of relatively large amplitude which should be noticed as information about environment, for example, when hitting an obstacle accidentally. Although the reaching phase can be designed from several points of view, the dynamics in the reaching phase is linearlized in order to use fruitful linear control theories such as H-infinity theory.

DOI： 10.1299/jsdd.1.159

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.72.2838

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.72.2877

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.11511/jacc.47.0.176.0

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC MECHANICAL ENGINEERS  

This paper deals with compensation for windup phenomena due to actuator saturation in sliding mode control systems with integral action. It is shown that the actuator saturation causes windup phenomena similar to integrator windup, which might take place in linear control systems with integral action, even if the linear component of the control input does not include any integral action. This means it is not sufficient just to apply the existing anti-windup methods for the linear controllers to the sliding mode controllers. In other words, the nonlinear component of the control input should be reconsidered. Therefore a simple modification for the switching function is presented in order to reduce the nonlinear component of the input during saturation. It is shown that this modification makes it possible to keep the plant state close to the ideal sliding mode. Simulation and experimental results show the effectiveness of the proposed method.

DOI： 10.1299/jsmec.46.960

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Japan Society of Mechanical Engineers  

This paper presents a design method of nonlinear controller for semi-active suspension systems with Magnetorheological (MR) dampers having nonlinear properties. A dynamic model of the MR damper, which consists of a nonliear static element followed by a linear dynamic element, is introduced and then a control law based on the integral sliding mode control proposed by V. Utkin and J. Shi is presented. It is shown that the proposed model enables us to reduce so-called chattering, which takes place due to the nonlinear properties of the damper and high frequency switching of the sliding mode control. Although this model includes more modeling error than other rigorous ones in the literature, the use of this model makes it easy to design the sliding mode controller. Numerical Simulations illustrate the effectiveness of the proposed method.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Japan Society of Mechanical Engineers  

This paper deals with compensation for windup phenomena due to actuator saturation in sliding mode control systems with integral action. It is shown that the actuator saturation causes windup phenomena similar to integrator windup, which might take place in linear control systems with integral action, even if the linear component of the control input does not include any integral action. This means it is not sufficient just to apply the existing anti-windup methods for the linear controllers to the sliding mode controllers. In other words, the nonlinear component of the control input should be reconsidered. Therefore a simple modification for the switching function is presented in order to reduce the nonlinear component of the input during saturation. It is shown that this modification makes it possible to keep the plant state close to the ideal sliding mode. Simulation and experimental results show the effectiveness of the proposed method.

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CiNii Books

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.68.1759

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.67.2863

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/kikaic.67.1449

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

This paper presents a new sliding mode controller for semi-active suspension systems with Magnetorheological (MR) dampers which have undesirable nonlinear properties. In the proposed controller, a desired semi-active suspension system is chosen as the reference model to be followed, and the control low is determined so that an asymptotically stable sliding mode will occur in the error dynamics between the plant and the reference model states. The advantages of the proposed controller are: (1) measurement of the damper force is not required, (2) the reference model specifies the desired performance considering the passivity constraint of the damper, (3) it is highly possible to maintain the sliding mode and achieve high robustness against model uncertainties and disturbances. Numerical simulations illustrate the effectiveness of the controller.

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Language：English   Publishing type：Research paper (scientific journal)  

This paper presents a design method of neural controllers for semi active suspensions with nonlinear devices such as electrotheological or magnetotheological dampers. It is shown that the use of two neural networks corresponding to each signs of the relative velocity is effective to realize the desired controllers, i. e., semi active controllers inherently include discontinuous mappings due to the passivity constraint and it is generally very difficult to realize them with single neural network. A model-following type controller with these neural networks is proposed, and two learning methods, the feedforward learning and the recurrent learning, for the controller are investigated from a viewpoint of system identification theories: the equation error method and the output error method. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

DOI： 10.1299/kikaic.67.3405

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Language：Japanese   Publishing type：Doctoral thesis  

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Language：Japanese Book type：Scholarly book

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Language：Japanese Book type：Scholarly book

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