著者

Shuntaro TAKEKUMA Shun-ichi AZUMA Ryo ARIIZUMI Toru ASAI

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (ISSN:09168508)

巻号頁・発行日

vol.E106-A, no.5, pp.715-720, 2023-05-01

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A hopping rover is a robot that can move in low gravity planets by the characteristic motion called the hopping motion. For its autonomous explorations, the so-called SLAM (Simultaneous Localization and Mapping) is a basic function. SLAM is the combination of estimating the position of a robot and creating a map of an unknown environment. Most conventional methods of SLAM are based on odometry to estimate the position of the robot. However, in the case of the hopping rover, the error of odometry becomes considerably large because its hopping motion involves unpredictable bounce on the rough ground on an unexplored planet. Motivated by the above discussion, this paper addresses a problem of finding an optimal movement of the hopping rover for the estimation performance of the SLAM. For the problem, we first set the model of the SLAM system for the hopping rover. The problem is formulated as minimizing the expectation of the estimation error at a pre-specified time with respect to the sequence of control inputs. We show that the optimal input sequence tends to force the final position to be not at the landmark but in front of the landmark, and furthermore, the optimal input sequence is constant on the time interval for optimization.

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

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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 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.