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Volume 45, Issue 5
Displaying 1-7 of 7 articles from this issue
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Control
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—Stabilization and Rejection of Periodic Disturbances with Unknown Periods—Manabu YAMADA, Tomoyasu YABUKI, Naoki MIZUNO2009 Volume 45 Issue 5 Pages 243-250
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSIn this paper, a new approach to reject quickly any periodic signals with unknown multiple periods is proposed and a useful adaptive repetitive control system with a recursive identification of the multiple periods is presented. The contributions are as follows: Firstly, an effective periodic generator for the case of multiple periods is proposed. The proposed repetitive controller is implemented with much less memory elements than the previous ones. As a result, the degree of the controller is highly reduced and much faster convergence of the controlled error to zero is provided. Secondly, the proposed controller assures the stability of the adaptive repetitive control system. The proposed controller is obtained by solving a simple linear programming problem. The design effort is very small independent of the periods. Thirdly, a simple period identification algorithm is proposed to estimate the multiple periods. The parametric model to be estimated consists of a simple FIR model and the algorithm is based on the well-known recursive least squares method. The effectiveness is demonstrated by simulations.View full abstractDownload PDF (574K) -
Xin XIN, Jin-Hua SHE, Taiga YAMASAKI2009 Volume 45 Issue 5 Pages 251-260
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper concerns a swing-up control problem for an n-link revolute planar robot with any one of the joints being a passive joint. The goal of this study is to design and analyze a swing-up controller that can bring the robot into any arbitrarily small neighborhood of the upright equilibrium point with all links in the upright position. To achieve this challenging objective while preventing the robot from becoming stuck at an undesired closed-loop equilibrium point, first, we address how to iteratively devise two series of virtual composite links separated by the passive joint to be used for designing a coordinate transformation on the angles of all active joints. Second, we devise an energy based swing-up controller that uses a new Lyapunov function based on that transformation. Third, we analyze the global motion of the robot under the controller and establish conditions on control parameters that ensure attainment of the swing-up control objective. The results obtained here unify some previous results for the Pendubot, the Acrobot, and three-link robots with a passive first joint. Finally, we validate the theoretical results via a numerical simulation investigation to a 4-link robot with a passive joint.View full abstractDownload PDF (687K) -
Kentaro YANO, Masanobu KOGA2009 Volume 45 Issue 5 Pages 261-267
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper proposes a method to compute the verified solution of LQ control problem using floating point arithmetic. To this end, we propose a guaranteed accuracy algorithm to solve Riccati equation, and define a verification problem of LQ controller. The algorithm computes the basis of the eigenspace of the Hamilton matrix using verified numerical computation. Krawczyk method which is known as an interval version of Newton's method is also used to obtain a sharp interval. In the verification problem of LQ controller, the verification conditions which validate whether the numerical solution satisfies the requirements of LQ controller are proposed. Furthermore, we describe a method which finds the numerical solution of LQ control problem which minimizes an evaluation function for the design specification among the set of the verified solutions. Numerical examples are shown to demonstrate the effectivity of the proposed method.View full abstractDownload PDF (371K)
System Integration
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Kazuya OGAWA, Makoto MIZUKAWA, Yoshinobu ANDO2009 Volume 45 Issue 5 Pages 268-275
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSEfficient energy usage is crucial issue because energy consumption increases with the spread of RT (Robot Technology) application fields. Power consumption in a robot system changes according to a task and its operating environment. To adapt these conditions, we have proposed the system named the CEPC (Component for Electric Power Control) in a robot controller adopting distributed microprocessors. We defined the electric-power profiles as power consumption characteristics of the tasks. The robot's power consumption is predicted and controlled by using this profile.View full abstractDownload PDF (1815K) -
Yasuhisa HIRATA, Shinji KOMATSUDA, Kazuhiro KOSUGE2009 Volume 45 Issue 5 Pages 276-282
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSIn this paper, we propose a human modeling method for estimating the user states using intelligent walker. If intelligent walker can recognize the user states, it can select the several functions such as variable motion characteristics function, fall-prevention function, assist functions for standing up and sitting down, and so on, autonomously, so that the users, who do not have professional skills of the intelligent systems, could utilize the walker dependably and practically in real world environment. In this paper, we especially focus on the human modeling method of the user, in which we generate the human linkage model by using the laser range finders attached to the walker and calculate the center of gravity of the human during the usage of the walker. The proposed method is evaluated based on the human motion captured accurately by using the motion capturing system. In addition, the experiments using the walker with laser rang finders show that it can recognize the user states successfully based on the position of the center of gravity derived by the human model.View full abstractDownload PDF (1706K)
Short Paper
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Katsuhiko FUWA, Tatsuo NARIKIYO, Hisashi KANDOH2009 Volume 45 Issue 5 Pages 283-285
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSTwo design methods of IVC (Initial Value Compensation) gain which are called the J-min method and the zero-assign method have been proposed. In this note, the inverse proplem, namely, the problem which minimizes the performance index in the J-min method by a given IVC gain is investigated, and the relationship between design methods is clarified.View full abstractDownload PDF (179K) -
Yasuharu HATTORI, Shuichi ADACHI2009 Volume 45 Issue 5 Pages 286-288
Published: 2009
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSIn this study, it is considered to estimate state of a known nonlinear plant with input from an unknown nonlinear actuator. To estimate nonlinear systems, a mathematical model which accurately describes the system is required. So, it is necessary to take into account the unknown nonlinearity of the actuator. We propose an estimation method of state and input from the unknown actuator using simultaneous estimation by UKF (Unscented Kalman Filter). Using this method, we can treat the unknown nonlinearity as estimation problem of unknown parameters. Effectiveness of the proposed method is shown by numerical experiments.View full abstractDownload PDF (370K)
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