Shun Yamamoto

A design method for two-degree-of-freedom multi-period repetitive controllers for multiple-input/multiple-output systems

Abstract Multi-period repetitive controller was proposed by Gotou et al., in order to improve the disturbance attenuation characteristic of modified repetitive control systems and that follows the periodic reference input with small steady state error. Recently, the parameterization of all stabilizing multi-period repetitive controllers was studied. However, when the parameterization of all stabilizing multi-period repetitive controllers is used, the input-output characteristic and the feedback characteristic cannot be specified separately. From the practical point of view, it is desirable to specify the input-output characteristic and the feedback characteristic separately. In addition, the parameterization is useful to design stabilizing controllers. Yamada et al. solved this problem by obtaining the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers. However, the method by Yamada et al. cannot be applied to multiple-input/multiple-output plants. Because, the method by Yamada et al. uses the characteristic of single-input/single-output system. In this paper, we propose the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers for multiple-input/multiple-output systems.

A Design Method for Two-Degree-of-Freedom Multi-Period Repetitive Control Systems

Multi-period repetitive controllers improve the disturbance attenuation characteristic of the modified repetitive control system that follows the periodic reference input with a small steady state error. Recently, the parameterization of all stabilizing multi-period repetitive controllers was studied. However, when the parameterization of all stabilizing multi-period repetitive controllers is used, the input-output characteristic and the feedback characteristic cannot be specified separately. From the practical point of view, it is desirable to specify the input-output characteristic and the feedback characteristic separately. In addition, the parameterization is useful to design stabilizing controllers. Therefore, the problem of obtaining the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers that can specify the input-output characteristic and the disturbance attenuation characteristic separately is important to solve. In this paper, we propose the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers.

A Design Method for Robust Stabilizing Modified Repetitive Controllers for Time-Delay Plants

In this paper, we examine the parameterization of all robust stabilizing modified repetitive controllers for time-delay plants. The modified repetitive control system is a type of servomechanism designed for a periodic reference input. When modified repetitive control design methods are applied to real systems, the influence of uncertainties in the plant must be considered. The stability problem with uncertainty is known as the robust stability problem. Recently, the parameterization of all stabilizing modified repetitive controllers was obtained. Since the parameterization of all stabilizing modified repetitive controllers was obtained, we can express previous study of robust stabilizing modified repetitive controller in a uniform manner and can design a stabilizing modified repetitive controller systematically. However, the parameterization of all robust stabilizing modified repetitive controllers for time-delay plants has not been obtained. In this paper, we clarify the parameterization of all robust stabilizing modified repetitive controllers for time-delay plants.

The Parametrization of All Robust Stabilizing Modified Repetitive Controllers for Time-Delay Plants with the Specified Input-Output Frequency Characteristic

The modified repetitive control system is a type of servo mechanism designed for a periodic reference input. Recently, the parametrization of all stabilizing modified repetitive controllers is obtained by Satoh and Yamada. Since the parametrization of all stabilizing modified repetitive controllers is obtained, we can express previous studies of modified repetitive control system in a uniform manner. In addition, a modified repetitive control system can be designed systematically. Yamada, Satoh and Mei pointed out that using the method by Satoh and Yamada, it is complicated to specify the input-output frequency characteristic and gave the parametrization of all robust stabilizing modified repetitive controllers with the specified input-output frequency characteristic. However, the parametrization of all robust stabilizing modified repetitive controllers for timedelay plants with the specified input-output frequency characteristic has not been considered yet. In this paper, for easy to specify the input-output frequency characteristic, we clarify the parametrization of all robust stabilizing modified repetitive controllers for time-delay plants with the specified input-output frequency characteristic.

A Design Method for Two-Degree-of-Freedom Multi-Period Repetitive Control Systems with the Specified Frequency Characteristic

Multi-period repetitive controllers improve the disturbance attenuation characteristic of themodified repetitive control system that follows the periodic reference input with small steady stateerror. Recently, the parameterization of all stabilizing multi-period repetitive controllers was studied.However, when the parameterization of all stabilizing multi-period repetitive controllers is used, theinput-output characteristic and the feedback characteristic cannot be specified separately. From thepractical point of view, it is desirable to specify the input-output characteristic and the feedback characteristicseparately. In addition, the parameterization is useful to design stabilizing controllers. Fromthis view-point, the parameterization of all stabilizing two-degree-of-freedom multi-period repetitivecontrollers those can specify the input-output characteristic and the disturbance attenuation characteristicseparately was solved by Yamada et al. However, when we design a stabilizing two-degree-offreedommulti-period repetitive controllers using the parameterization proposed by Yamada et al, thefrequency characteristic of the control system cannot be settled so easily. From the practical point ofview, the frequency characteristic of the control systems are required to be easily settled. This problemcan be solved by obtaining the parameterization of all stabilizing two-degree-of-freedom multi-periodrepetitive controllers with the specified frequency characteristic. In this paper, we propose the parameterizationof all stabilizing two-degree-of-freedom multi-period repetitive controllers with thespecified frequency characteristic.

The Parameterization of all Stabilizing Modified Repetitive Controllers for Multiple-Input/Multiple-Output Plants with the Specified Input-Output Frequency Characteristic

In this paper, we examine the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. The parameterization of all stabilizing modified repetitive controllers for non-minimum phase systems was solved by Yamada et al. However, when we design a stabilizing modified repetitive controller using the parameterization by Yamada et al., the input-output frequency characteristic of the control system cannot be settled so easily. The input-output frequency characteristic of the control systems is required to be easily settled. This problem is solved by obtaining the parameterization of all stabilizing modified repetitive controllers with the specified input-output frequency characteristic. However, no paper has proposed the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. In this paper, we propose the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic.

Achievement of low-sensitivity characteristics and robust stability condition for multi-variable systems having an uncertain number of right half plane poles

In the present paper, we consider a design method that provides low-sensitivity control with robust stability for multiple-input/multiple-output continuous time-invariant systems having an uncertain number of unstable poles. First, the class of uncertainty considered in the present paper is defined and the necessary and sufficient robust stability condition is presented for the system having this class of uncertainty under the assumption that the number of closed right half plane poles of the plant is equal to that of the nominal plant. The relationship between the plant and the nominal plant included in this class of uncertainty is clarified. Using this relationship, we will show the necessary and sufficient robust stability condition for the system having an uncertain number of right half plane poles.