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Volume 47, Issue 6
Displaying 1-5 of 5 articles from this issue
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Paper
Control
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Hideyuki TANAKA, Yoshito OHTA, Yusuke OKIMURA2011 Volume 47 Issue 6 Pages 253-261
Published: 2011
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper studies linear-time-invariant (LTI) modeling of a twin-rotor MIMO system based on the dynamical models derived from the first principles and identification experiments, motivated by building LPV (Linear Parameter Varying) models. The present method proposes using the states of the first-principle-model and the identification-model. Continuous-time local LTI models with a consistent state are obtained in the frequency domain. It is also shown that an LPV model is computed from the local models.View full abstractDownload PDF (1296K) -
Hiroyuki KONDO, Yoshimasa OCHI2011 Volume 47 Issue 6 Pages 262-271
Published: 2011
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper proposes an I-PD (integral preceded by proportional-derivative) controller design with a more rational method of plant-order reduction to the second order than the method previously proposed by the authors, where parameter-space search was employed. In the new method, first, the fractional balanced reduction is applied to the original single-input-single-output plant. Then, the reduced-order model is adjusted via the homotopy method in terms of the ν-gap metric. The method can also be applied to a plant that is not stable but stabilizable by state feedback in the same way. The resultant PID controller designed based on the optimal servomechanism using the second-order plant model provides preferable properties as a linear quadratic regulator (LQR), if the ν-gap can be made sufficiently small. Moreover, it can be extended to a model-following type by adding a reference model and a feedforward compensator to improve the output responses without decreasing the stability margins. The effectiveness and usefulness of the proposed method are demonstrated through design examples including an application to flight control and numerical simulations.View full abstractDownload PDF (789K)
Systems and Information
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Yuko SANO, Akihiko KANDORI, Keisuke SHIMA, Yasuhiro TAMURA, Hiroshi TA ...2011 Volume 47 Issue 6 Pages 272-281
Published: 2011
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSWe tested the repeatability of a finger tapping device with magnetic sensors to determine its reliability. This device, which was developed to assist in the diagnosis of movement disorders such as Parkinson's disease (PD) and strokes, measures the distance between the first and index fingers during finger tapping movements (opening and closing the fingers repeatedly). We evaluated three types of repeatability based on ICC (interclass correlation coefficient) and Welch's test (test for equal means in a oneway layout): repeatability when measured at different times, when using different devices, and when using different measurers. We calculated these three types for three finger tapping tasks on both hands for 21 characteristics calculated from finger tapping waveforms. Results demonstrated that the repeatability when using different devices is high regardless of the task or hand. The repeatability when measuring at different times and when using different measurers is high at some tasks, but not all. One of the finger tapping tasks (finger tapping movement with the largest amplitude and highest velocity), which is used in a conventional PD diagnosis method (UPDRS), does not have enough repeatability, while other tasks show high repeatability. Results also showed that five characteristics have the highest repeatability (ICC ≥ 0.5 or significance probability of Welch's test ≥ 5% in all tasks): “total moving distance,” “average of local minimum acceleration in opening motion,” “average of local minimum acceleration in closing motion,” “average of local maximum distance” and “average of local minimum velocity”. These results clearly demonstrate the strong repeatability of this device and lead to more precise diagnosis of movement disorders.View full abstractDownload PDF (1118K)
System Integration
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Shinkichi INAGAKI, Tomoya NIWA, Tatsuya SUZUKI2011 Volume 47 Issue 6 Pages 282-290
Published: 2011
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSThis paper proposes a novel locomotion control, called Follow-the-Contact-Point (FCP) gait control, for a centipede-like multi-legged robot. The centipede-like multi-legged robot is composed by connecting segments, which have a trunk and a pair of legs, via a passive joint. This control method is motivated from behavioral knowledge of a centipede that each leg always contacts on the point which the anterior leg contacted. The FCP gait control realizes the walking behavior of centipede via decentralized event-driven control structure. In addition, merely by planning and allocating the contact point of legs of a head segment adequately, the robot can change the moving direction and also climb over an obstacle. We clarify the feasibility of the FCP gait control by showing the result of physical simulation of a 20-legged robot.View full abstractDownload PDF (1991K)
Short Paper
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Yuji TAKENAKA, Shuichi ADACHI2011 Volume 47 Issue 6 Pages 291-293
Published: 2011
Released on J-STAGE: December 19, 2011
JOURNAL FREE ACCESSIn this report, a system identification problem for multi-input, single-output (MISO) systems by least-squares method with finite impulse response (FIR) model is considered. It was difficult to generate a set of identification input sequences for MISO systems. This report proposes a new input generating method for MISO system identification problem. The inputs are easily generated from shifted M-sequences. Effectiveness of the proposed method is shown by a numerical simulation.View full abstractDownload PDF (260K)
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