著者

蛯原 義雄 奥 宏史 片山 仁志 坂本 登 津村 幸治 平田 光男 西村 悠樹 澤田 賢治

出版者

公益社団法人 計測自動制御学会

雑誌

計測と制御 (ISSN:04534662)

巻号頁・発行日

vol.60, no.5, pp.385-394, 2021-05-10 (Released:2021-05-21)

参考文献数

10

著者

西村 悠樹 佐藤 訓志 澤田 賢治 大木 健太郎 星野 健太 佐藤 康之 定本 知徳

出版者

公益社団法人 計測自動制御学会

雑誌

計測と制御 (ISSN:04534662)

巻号頁・発行日

vol.60, no.5, pp.381-384, 2021-05-10 (Released:2021-05-21)

参考文献数

11

著者

藤田 真太郎 澤田 賢治 新 誠一 細川 嵩

出版者

公益社団法人 計測自動制御学会

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.57, no.8, pp.367-377, 2021 (Released:2021-08-20)

参考文献数

21

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Since the damage from cyber-attacks increases, there is an urgent need to research and develop security countermeasures for control systems. In the control system, the controller is an important device. This paper then considers a whitelisting system that models the normal operation sequence of a PLC (Programmable Logic Controller) and detects deviations from the model as abnormal. We propose three methods to auto-generate the whitelisting system by LD (Ladder Diagram): Petri net model generation, constraint condition derivation, and LD conversion. The first method generates Petri net models form SFCs (Sequential Function Charts) that are compatible with LDs. The second method derives whitelist conditions from Petri net models to check whether PLC performs the correct operation sequence. The third method implements the whitelist conditions into LD. The auto-generated whitelisting system enables us to monitor the state transitions of the PLC programs. Further, this paper carries out an experimental validation of the methods using a testbed system.

著者

山藤 勝彦 山本 建 澤田 賢治

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.852, pp.16-00553-16-00553, 2017 (Released:2017-08-25)

参考文献数

11

被引用文献数

1

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This paper describes self-excited oscillation caused by coulomb friction of electromagnetic proportional valve. Especially, this research focuses on a hydraulic system in which electromagnetic proportional and pressure proportional valves are located tandem. In the system, the coulomb frictional force effects on the displacement direction of the spool of the former valve and the piston is established in the downstream region of the latter valve. Each valve is stable, but, the connection of them causes instability. This paper analyzes the mechanism of this unstable vibration and then investigates an anti-vibration design method. In analysis, this paper clarifies that the vibration is caused by an elastic deformation delay of the oil in the piston. This delay increases the phase delay of the spool due to the coulomb frictional force. After replacing the coulomb frictional force with hysteresis, the proposed method uses the describing function method to express phase delay phenomenon due to the coulomb frictional force. The describing function is the complex function which expresses an amplitude ratio and phase difference with the input and output of nonlinear element. The delay of a vibration factor is linearized by converting coulomb friction into hysteresis. The effectiveness of the proposed method is demonstrated via practical experiment and non-linear simulation results.

著者

藤田 淳也 小倉 貴志 大河内 一弥 松本 典剛 澤田 賢治 金子 修

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌C(電子・情報・システム部門誌) (ISSN:03854221)

巻号頁・発行日

vol.142, no.3, pp.328-338, 2022-03-01 (Released:2022-03-01)

参考文献数

25

被引用文献数

2

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Threat modeling is a process to determine effective cybersecurity measures to secure industrial control systems (ICSs). However, deep cybersecurity knowledge is required to perform threat modeling processes and those results including prioritization of cyber attack scenarios are depended on security analysts. To reduce the dependency of analysts, it is required to express cyber attack scenarios with a structured model. In this study, a new structured model that expresses cyber attack scenarios for ICSs is proposed. The proposed model is based on the Diamond model and capable of expression behaviors of adversary in a targeted system by a structured form. The model makes it possible to express structured cyber attack scenarios and reduce dependency of analysts. This paper provides a detail of the proposed model and evaluation results of the model in terms of the usefulness of threat modeling.

著者

山藤 勝彦 橋本 真 山本 建 澤田 賢治

出版者

公益社団法人 計測自動制御学会

雑誌

計測自動制御学会論文集 (ISSN:04534654)

巻号頁・発行日

vol.57, no.7, pp.324-333, 2021 (Released:2021-07-17)

参考文献数

13

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Judder is well known as a vibration that occurs in a dry clutch. In order to maintain the ride quality and quietness of dry clutches, research on judder analysis and mechanical design to suppress judder is actively pursued. This paper describes the design and implementation of robust control techniques as an approach to suppressing judder during gear shifting in traction-controlled transmissions. This paper is concerned with transmissions that exhibit strongly nonlinear frictional characteristics that can only be approximated by higher order polynomials. Specifically, the coefficient of friction varies significantly nonlinearly with the rotational speed during gear shifting. In this paper, the controller is designed by expressing this nonlinear property as the uncertainty of the frequency. Simulation and bench test results are presented to validate the validity of such an approach. The results show that judder-free shifting is possible with the proposed approach. Furthermore, the requirements of three controllers are presented by analyzing the robust controllers.

著者

藤田 真太郎 秦 康祐 望月 明典 澤田 賢治 新 誠一 細川 嵩

出版者

自動制御連合講演会

雑誌

自動制御連合講演会講演論文集 第60回自動制御連合講演会

巻号頁・発行日

pp.132-135, 2017 (Released:2017-12-18)

著者

藤田 真太郎 澤田 賢治

出版者

一般社団法人 電気学会

雑誌

電気学会誌 (ISSN:13405551)

巻号頁・発行日

vol.142, no.4, pp.212-214, 2022-04-01 (Released:2022-04-01)

参考文献数

9

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1.はじめに産業用制御システム(Industrial Control System:ICS)は,発電や配水などの社会インフラとして重要な役割を担っている。特注品だったICSはここ約20年で設計開発の簡易化や標準化のための標準OS(Windows,Linux)の搭載や遠隔操作・監視のためのネットワーク化が

著者

若狭 拓馬 澤田 賢治

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌C(電子・情報・システム部門誌) (ISSN:03854221)

巻号頁・発行日

vol.142, no.3, pp.239-250, 2022-03-01 (Released:2022-03-01)

参考文献数

19

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This paper considers an interpolated distributed cooperative observer design and its online update for the situation that intelligent transport systems (ITS) and vehicles estimate vehicle platoons' positions in a two-dimensional plane. ITS observes some vehicles' absolute positions, and each vehicle interpolates its position based on the observed relative distance to the surrounding vehicles and the vehicles' estimated position. The observers of each vehicle use the interpolated positions to estimate their vehicles' positions. The interpolated positions are updated depending on the communication status of the surrounding vehicles using sparse modeling. We provide a distributed search algorithm to generate the shortest communication path that can share the estimated position among the observers in a short time. These methods enable us to estimate the distributed position of vehicle platoons under the condition that the positional relationship between vehicles changes on a two-dimensional plane.

著者

岡島 寛 澤田 賢治 松永 信智 南 裕樹

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌C(電子・情報・システム部門誌) (ISSN:03854221)

巻号頁・発行日

vol.131, no.10, pp.1767-1774, 2011-10-01 (Released:2011-10-01)

参考文献数

21

被引用文献数

1

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This paper proposes a design method of dynamic quantizers for MIMO networked control systems. It is well known that feedback type dynamic quantizers are effective for quantization of the data series in the meaning of noise shaping. The dynamic quantizers include a set of a dynamic filter and a static quantizer. When it is required to use the quantizer under the network communication, the data size of signal should be minimized appropriately by the quantizers. The authors have proposed a design method of the dynamic quantizers for SISO systems based on the communication rate constraint. In this paper, the design method is extended to MIMO systems. By this extension, we can handle the communication rate constraint for a kind of concentrated systems. In the setting of the quantizer for MIMO system, bit assignment is important matter for appropriate design of information flow. The effectiveness of proposed design method is shown by numerical examples.

著者

佐倉 衛 澤田 賢治 金子 修 新 誠一 松田 功

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌C(電子・情報・システム部門誌) (ISSN:03854221)

巻号頁・発行日

vol.140, no.9, pp.1064-1073, 2020-09-01 (Released:2020-09-01)

参考文献数

19

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In model-based development in the automotive industry, functional tests are performed using models made by CAE tools. The model needs to reproduce some physical properties of the target system correctly. The previous research of the current authors proposes energy balanced based verification (EBBV) that verifies the correctness of the model focused on the energy conservation law. EBBV confirms the balance of input and output energy of the model from output information of the model. In this paper, we develop three tools to automate EBBV processes. Also, we make a modeling guideline suitable for EBBV, which is composed of tagging and a hierarchical model structure. Through numerical experiments, we check that three tools automate EBBV processes for models according to the modeling guideline. The target model of the experiments is a mild hybrid electric vehicle model made by MATLAB/Simulink, MapleSim, and CarMaker.

著者

武田 健吾 澤田 賢治 横川 慎二 新 誠一

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌C(電子・情報・システム部門誌) (ISSN:03854221)

巻号頁・発行日

vol.139, no.7, pp.786-795, 2019-07-01 (Released:2019-07-01)

参考文献数

10

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In a system that suppresses power fluctuation caused by wind power and solar power generation by a storage battery (We call it wind turbine and photovoltaic power generation system, WPBHS), it is assumed that the number of constituent equipment is large. Therefore, by dividing the constituent equipment into a plurality of groups (We call it grouping), the operation plan is optimized dispersedly. In this case, it has been shown that WPBHS has fault tolerance by overlapping storage batteries in plural groups. Also, enumerating the grouping in advance allows us to switch the grouping and recover the system immediately when a system failure occurs. Motivated by this, we consider an overlapped grouping optimization problem focused on the performance deterioration and fault tolerance of the distributed management system. Enumerating the group, especially, the overlapped group requires large computational load with the more devices added. First, this paper formulates overlapped grouping optimization for WPBHS. Second, this paper proposes a graph representation method of the overlapped grouping and a near-optimal enumeration method.

著者

澤田 賢治

出版者

一般社団法人 システム制御情報学会

雑誌

システム/制御/情報 (ISSN:09161600)

巻号頁・発行日

vol.56, no.4, pp.188-191, 2012-04-15 (Released:2017-04-15)

参考文献数

5

著者

山藤 勝彦 山本 建 橋本 真 新 誠一 澤田 賢治

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."J101012-1"-"J101012-5", 2013-09-08

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Judder is well known oscillation occurring in dry clutches. To maintain riding comfort and silence in dry clutches, a lot of studies of judder analysis and machine design suppressing judder have been done. This paper describes the design and implementation of a robust control technique as a judder suppression approach for clutch during shifting. We address the automatic transmission using dry clutches of which the μ-V characteristics show a complicated nonlinearity. Specifically, their friction coefficient varies non-linearly with respect to the rotational speed during shifting. In this paper, it is clarified that the non-linear μ-V characteristic can be expressed as frequency uncertainties and then the control system is constructed with H∞ control. To verify the validity of such the approach, the results of simulation and bench testing are presented. As a result, we see that the proposed approach allows us to achieve the shifting without judder. Furthermore, we show the three controller requirements by analyzing the robust controllers.