著者

Hiroshi OKAJIMA Kenji SAWADA Joe KAIBE Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.48, no.6, pp.359-361, 2012 (Released:2012-06-30)

参考文献数

6

被引用文献数

2

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This paper aims at design of network control system for the remote control of robot. As the system includes a communication channel, quantization is required to satisfy communication capacity limitation. Dynamic quantizer is a kind of quantization methods and has been studied in control engineering field. Optimal quantizing width designed of dynamic has been designed based on invariant sets. However, quantizing width of dynamic quantizer designed based on invariant sets has maintainability than one of designed based on reachable sets and big maintainability and poor control performance. We need to design quantizing width of dynamic quantizer based on reachable sets. In this study, we propose design method of quantizing width of dynamic quantizer based on reachable sets. The effectiveness is shown by numerical example.

著者

Hiroshi OKAJIMA Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.47, no.4, pp.217-219, 2011 (Released:2011-12-19)

参考文献数

8

被引用文献数

2

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In the field of signal processing, AD/DA converter takes an important role for data compressing and circuits design. This paper proposes new design method of AD/DA system with pre-filter and post-filters for achieving small quantization noise effect. Both filters are designed to minimize noise and distortion toward original signal. The effectiveness is illustrated by numerical example.

著者

Hiroshi OKAJIMA Kenji SAWADA Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.47, no.2, pp.126-133, 2011 (Released:2011-12-19)

参考文献数

15

被引用文献数

4 2

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This paper proposes a design method of the dynamic quantizer for the networked control systems. In the networked control systems, the data size of the signals is limited because of the transmission rate of the communication channel. It is well known that feedback type dynamic quantizers such as Delta/Sigma modulator are effective for quantization of data series. The dynamic quantizer includes a set of the dynamic filter and the static quantizer. Many methods have been proposed to design the dynamic filter. However, the static quantizer part has not been designed although the quantization level number of the static quantizer has an effect on the data size. The simultaneous design of dynamic filter and the quantization level will be important issue to satisfy the given communication rate. In this paper, the integrated design method of the filter and the static quantizer is proposed based on the communication rate constraints. The proposed method is derived based on the invariant set analysis with LMIs. The effectiveness is shown by numerical examples.

著者

Koji Sasano Hiroshi Okajima Nobutomo Matsunaga

出版者

THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS (ISCIE)

雑誌

Transactions of the Institute of Systems, Control and Information Engineers (ISSN:13425668)

巻号頁・発行日

vol.23, no.11, pp.257-264, 2010 (Released:2011-05-21)

参考文献数

22

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Recently, the fractional order PID (FO-PID) control, which is the extension of the PID control, has been focused on. Even though the FO-PID requires the high-order filter, it is difficult to realize the high-order filter due to the memory limitation of digital computer. For implementation of FO-PID, approximation of the fractional integrator and differentiator are required. Short memory principle (SMP) is one of the effective approximation methods. However, there is a disadvantage that the approximated filter with SMP cannot eliminate the steady-state error. For this problem, we introduce the distributed implementation of the integrator and the dynamic quantizer to make the efficient use of permissible memory. The objective of this study is to clarify how to implement the accurate FO-PID with limited memories. In this paper, we propose the implementation method of FO-PID with memory constraint using dynamic quantizer. And the trade off between approximation of fractional elements and quantized data size are examined so as to close to the ideal FO-PID responses. The effectiveness of proposed method is evaluated by numerical example and experiment in the temperature control of heat plate.

著者

Hiroshi OKAJIMA Nobutomo MATSUNAGA Kenji SAWADA

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.46, no.6, pp.327-335, 2010 (Released:2011-11-03)

参考文献数

21

被引用文献数

6 3

---

This paper proposes the design method of the dynamic quantizer for the networked control systems. It is well known that feedback type dynamic quantizer such as Delta/Sigma modulator is effective for quantization of data series and many methods for designing the dynamics have been proposed. When it is required to control with network communication, the data size of signal should be minimized appropriately by quantizers. Since the quantizing width of the quantizer concern with the data size, determination of quantizing width is important problem in networked control systems. However, the quantizing width has not been designed analytically in the past researches. In this paper, we propose the design method of the quantizing width based on the LMIs. The quantizing width would be determined explicitly with the communication rate constraints. By the proposed method, the quantizing width guarantee that the signals are quantized appropriately within the given data size. The effectiveness is illustrated by numerical examples.

著者

Hiroshi OKAJIMA Tatsuya UMEMOTO Nobutomo MATSUNAGA Shigeyasu KAWAJI

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.46, no.3, pp.149-156, 2010 (Released:2011-11-03)

参考文献数

16

被引用文献数

5 4

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It is well known that plants with time delay are hard to be controlled by using traditional method. For this, controller with delay, such as Internal Model Control (IMC), Smith-method, have been proposed for input-delay systems. However, it would be difficult to realize the delay of controller because of memory limit of micro control unit(MCU). Also, the sampling time might be large in case of the application to the plant with large time delay, because of the limitation of the memory in MCU. Hence, the trade-off exists between sampling time and maximum quantizing error, and the assignment of the quantizer affects the quantization error. In this paper, dynamic quantizers are designed for achieving small quantizing error for input-delay control systems in MCU system. Also, the attainable performance caused by assignment of the quantizer is discussed. The effectiveness of the proposed method is shown by numerical example.

著者

Hiroshi OKAJIMA Nobutomo MATSUNAGA Shigeyasu KAWAJI

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.44, no.5, pp.458-460, 2008-05-31 (Released:2013-02-25)

参考文献数

4

被引用文献数

2 3

---

This paper is concerned with dynamic quantizer for controlling plants with discrete-valued input.l∞ norm of error between outputs with continuous-input and with quantized-input was guaranteed by the quantizer proposed by Azuma et al. In this paper, the degree of freedom of quantizer, which also guarantees the l∞ norm, is considered for treating the other objectives such as robustness, reduced-order controller etc. Then a design method of reduced-order quantizer is proposed by using the design parameter. The effectiveness of reduced-order quantizer is shown by numerical examples.

著者

Hiroshi OKAJIMA Toru ASAI Shigeyasu KAWAJI

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.45, no.6, pp.313-319, 2009 (Released:2011-11-03)

参考文献数

18

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In this paper, tracking performance limitations for plants with input delay are considered. It is important to know the performance limitations for plants to design controllers and to design plants. Our objective is to find the fundamental limitation of the transient response in tracking control problem. When plant have input delay, no one would deny that tracking performance becomes worse than the plants without input delay. However performance limitations for such plants have not been derived analytically. We derive the performance limitations based on internal model control framework. The difference between plants with delay and without delay is compared by numerical examples.

著者

Hiroshi OKAJIMA Toru ASAI Shigeyasu KAWAJI

出版者

The Society of Instrument and Control Engineers

雑誌

Transactions of the Society of Instrument and Control Engineers (ISSN:04534654)

巻号頁・発行日

vol.44, no.10, pp.793-801, 2008-10-31 (Released:2013-02-25)

参考文献数

19

被引用文献数

1 1

---

This paper is concerned with optimal reference tracking control problem for discrete time 1-DOF/2-DOF systems. It is well known that l2 norm of an error, which is defined by difference between an output and a reference, does not turn zero for all possible controllers when plant is given as a non-minimum phase system. Purpose of this research is to derive closed-form expression of the optimal value of l2 norm of the error and its controller. The references for tracking are e.g. step, sine, impulse train, triangle wave and linear combination of these signals. Therefore, we can handle various signals as a reference. Moreover, our results can also characterize impact of the relative degree of plant. Those effectiveness are shown by numerical examples.

著者

Hiroshi OKAJIMA Yuki MINAMI Nobutomo MATSUNAGA

出版者

The Society of Instrument and Control Engineers

雑誌

SICE Journal of Control, Measurement, and System Integration (ISSN:18824889)

巻号頁・発行日

vol.11, no.6, pp.510-516, 2018 (Released:2018-11-22)

参考文献数

18

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This study proposes a design method for unilateral control systems with communication rate constraints. In the case where it is necessary to control under a communication rate constraint, the effect of the quantization noise should be minimized using effective signal quantization methods. One of the effective methods for signal quantization is a feedback-type dynamic quantizer. We previously proposed a design method for a dynamic quantizer under communication rate constraints. In this paper, a unilateral control structure is proposed to minimize the effect of the quantization error. The design method for the quantizer is applied to the proposed structure. The effectiveness of the proposed system with the designed quantizer is assessed via numerical examples.

著者

Hiroshi OKAJIMA Hironori UMEI Nobutomo MATSUNAGA Toru ASAI

出版者

公益社団法人 計測自動制御学会

雑誌

SICE Journal of Control, Measurement, and System Integration (ISSN:18824889)

巻号頁・発行日

vol.6, no.4, pp.267-275, 2013 (Released:2013-08-01)

参考文献数

28

被引用文献数

9 38

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The robust control design method has been studied in recent decades. A control system works well under the modeling errors and disturbances if controller design is based on the robust control method. However, it is well known that in control systems, generally, there exists a trade-off between control performance and robustness. To overcome the trade-off problem, this paper proposes an internal model type compensator structure that minimizes the modeling gap between the nominal model and actual plant dynamics. By using the proposed compensator, the dynamics of the compensated system closes to that of the nominal model. Then, a design method of the compensator parameters is also proposed for minimizing a set of plant dynamics. The proposed design method is reduced to the standard µ design control problem. If we use the proposed compensator for control systems instead of the plant itself, the output performance might be better despite plant uncertainty. Given that the proposed compensator can be used for the control of not only linear but also nonlinear plants, we can easily achieve robust control of nonlinear systems. The effectiveness of the proposed method is shown by numerical examples.

著者

Gou ICHIMASA Hiroshi OKAJIMA Kosuke OKUMURA Nobutomo MATSUNAGA

出版者

公益社団法人 計測自動制御学会

雑誌

SICE Journal of Control, Measurement, and System Integration (ISSN:18824889)

巻号頁・発行日

vol.10, no.5, pp.468-475, 2017 (Released:2017-09-23)

参考文献数

13

被引用文献数

7

---

Design methods for control systems based on plant models have been developed for many years. If a mathematical model is accurately obtained from the input-output relation of a plant, then the designed controller for the model performs well for the control system connected with the plant. However, the desired control performance might not be achieved when there is an undeniable modeling error. To overcome this problem, the authors proposed the model error compensator (MEC) to minimize the effect of the modeling error between the plant and the model. The MEC works well for many control systems, such as unstable systems and non-linear systems. However applying the MEC to non-minimum-phase plants is difficult because of their control system structures. Non-minimum-phase plants are well known for being difficult to control. This paper proposes an MEC with a parallel feed-forward filter (PFF). The PFF is used to cancel the non-minimum-phase characteristics of the plant. The effectiveness of the proposed method is illustrated through numerical examples.