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Volume 44, Issue 2
Displaying 1-12 of 12 articles from this issue
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Yoshitaka KASHIWAGI, Noriyoshi YAMAUCHI, Toshikazu SAKATA2008 Volume 44 Issue 2 Pages 107-114
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, a hardware called a Hardware Task Engine is proposed to achieve an embedded controller ar-chitecture for signal processing. An interrupt task which is highest priority and executes a signal processing is executed by the Hardware Task Engine. The Hardware Task Engine works highly realtime, because of it has high-speed and flexible processing ability, and it reduces a start up delay from interrupt. A Prototype of a Sensor Signal Processing SoC using a Hardware Task Engine is made by FPGA, and is evaluated by actual magnetic encoder with magnetic sensors. A start up delay from interrupt of a hardware task is 41.60ns, and it is faster than software by 3.0 times at a half clock frequency, and temperature rise is reduced to 13.4%. As a result, we can corroborate availability of a Hardware Task Engine.View full abstractDownload PDF (11405K) -
Daisuke NARITA, Mitsuru BABA2008 Volume 44 Issue 2 Pages 115-123
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThe present paper describes a newly proposed method for measurement of the 3-D shape and estimation of the surface reflectance of a columnar object using a laser rangefinder. The laser rangefinder used for the method has the new image sensor, which is able to detect the incident position and incident angle of a light. Using this laser rangefinder, we measured the incident positions and the incident angles for determining the 3-D shapes, and measured the light intensity and the incident angle for determining the surface reflectance of a measured object. The original work of this method lies in the advantage that this laser rangefinder can measure the 3-D shape for both diffuse objects and specular objects, and the proposed method estimates the surface reflectance using the object itself that is used for the 3-D shape measurement. Experimental results show that the proposed method is applicable to non-contact industrial inspectionsView full abstractDownload PDF (16336K) -
Yosuke KURIHARA, Kajiro WATANABE, Hiroshi TANAKA2008 Volume 44 Issue 2 Pages 124-132
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn the measurement of sleep stages categorization using the R-K Method, which is the internationally standardized method, it is quite difficult to obtain the same results from all the measurements made by different scorers due to the interventions of the scorers interpretations. If the results can be corrected to eliminate these interventions by referring to a model that shows the commonly observed properties in normal sleeps, the sleep stage measurement will be of more credibility. This paper proposes a model that applies the test subjects body movements to change the Transition Probability Matrix in the Sleep Stage Transition Equation. The model then will be used as a basis for making the measuring equipment, and the probable emergency rate of each sleep stage will be estimated by using the sleep stage measurement results as well as the sleep stages obtained through the R-K method as input values, and also by applying the Pneumatic Method that we have continuously been proposing. As a result, the probabilities of the top three possible sleep stages out of six that two scorers selected have been evaluated for their coincidence with the selections made by the pneumatic method, using the K statistics. In the comparison among the data used for making the Transition Probability Matrix, the K statistics result between the two scorers was0.95. The results between the scorers and the pneumatic method were0.79 (scorer1) and0.76 (scorer 2). The results were also found to be effective for the data that were not used for making the Transition Probability Matrix, with the respective value of 0.93, 0.73, and 0.75.View full abstractDownload PDF (20181K) -
Hikaru MIZUNO, Kenji FUJIMOTO2008 Volume 44 Issue 2 Pages 133-138
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we propose a new approximate solution to a Hamilton-Jacobi equation used in nonlinear optimal control. First, the Galerkin approximation with Chebyshev polynomials is applied to Hamilton-Jacobi equations. Second, it is proved that the computational effort of the proposed algorithm is less than the existing one. Finally, a numerical example shows the effectiveness of the proposed method.View full abstractDownload PDF (7983K) -
Yuichi IKEDA, Takashi KIDA, Tomoyuki NAGASHIO2008 Volume 44 Issue 2 Pages 139-146
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we consider the position and attitude (six degrees of freedom) tracking control of rigid body spacecraft by PID-type state feedback control in order to remove the position and attitude error that are caused by step disturbance. Firstly, the relative motion equation of the six degrees of freedom rigid body spacecraft is derived. Secondly, we design PID type state feedback control law so that the closed loop system of the relative motion equation is asymptotically stabilized. Then, we extend the results to PID type adaptive state feedback controller with physical parameter update law. Finally, the effectiveness of the control methods is verified by simulations.View full abstractDownload PDF (4065K) -
Masakatsu KAWATA2008 Volume 44 Issue 2 Pages 147-155
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSRecently, it has been shown that the methods using PDLMI (Parameter-Dependent LMI) are effective for the robust H∞ performance analysis of the linear polytopic-type uncertain systems. Especially, the extended LMI approaches can avoid the product of the Lyapunov matrix and the system matrix by enlarging the size of LMI, and a less conservative analysis can be achieved by using these approaches. On the other hand, the redundant descriptor approaches are known as methods of consequentially enlarging the size of LMI by expanding the rep-resentation of the system. In this paper, we derive extended LMI conditions for the robust H∞ performance analysis from the standpoint of a redundant descriptor approach. Moreover, it is examined to decrease the number of concomitant variables of the extended LMI in order to shorten time to compute the solution.View full abstractDownload PDF (4242K) -
Jun ZHOU2008 Volume 44 Issue 2 Pages 156-163
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSBy the contraction mapping theorem and the harmonic Lyapunov equation theory, sufficient existence conditions of what we call the harmonic Riccati equations in finite-dimensional linear continuous-time periodic systems are explicated. Properties of the harmonic Riccati equations are also examined. Different from the Hamiltonian analysis, the approach reveals some analytic properties of periodic solutions of periodic matrix Riccati equations. An iterative algorithm is suggested for solving periodic matrix Riccati equations, which only involves algebraic Lyapunov equations and Fourier coefficients of periodically time-varying matrices.View full abstractDownload PDF (4039K) -
Kentaro HIRATA2008 Volume 44 Issue 2 Pages 164-173
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn this paper, we provide a state-space design method of H∞ delayed feedback controller for MIMO plants. The underlying technical machinery is an extension of a state-space characterization of Nevanlinna-Pick interpolation via the J-lossless conjugation for the scalar case. By utilizing the state-space representation, the proposed algorithm avoids recursive computation with complex-valued matrices, which is required in the classical Nevanlinna algorithm. Our procedure also reduces the computational load specific to the delayed feedback controller design compared to the plant augmentation approach. Finally, the controller synthesis result is demonstrated through numerical simulations and experiments.View full abstractDownload PDF (8469K) -
Tsutomu INAMOTO, Hisashi TAMAKI, Hajime MURAO2008 Volume 44 Issue 2 Pages 174-182
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSIn the present paper, a dynamic programming (DP) approach for elevator operation problems is reported, in which two kinds of the design of DP algorithms are introduced. One (Value Iteration; VI) is rather naive imple-mentation of DP concept to the problems, and the other (Dynamic Programming on Reduced Models; DPRM) isan improved version in computational efficiency by reducing the accuracy of the utilized state transition model. The basic idea of this reduction is as follows: it is expected that dropping some situational-inputs, which rep-resent the possible causes for each state transition, with low occurring probabilities may reduce the size of the state transition model without losing the essence of a system's behavior.
In computational illustrations, the VI and the DPRM are applied to two types of the problems of small sized, and it is observed that the computational time required in applying the DPRM is much less than that in applying the VI for each problem, while the results obtained by both methods are almost equal with respect to not only averaged but also maximum waiting time over passengers. Furthermore, the optimal and quasi-optimal plicies obtained by the VI and DPRM are compared with an existing elevator allocation rule (Call Dispatching; CD), and the results show both policies are statistically better than the CD.View full abstractDownload PDF (12468K) -
Distributed Metaheuristic Solution Based on Solution Space Decomposition for Route Planning ProblemsKazutoshi SAKAKIBARA, Manabu NOISHIKI, Hisashi TAMAKI, Ikuko NISHIKAWA2008 Volume 44 Issue 2 Pages 183-190
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSWe propose a distributed meta heuristic method to a class of transportation problem. The proposed method is based on the solution space decomposition and meta heuristics are applied on each decomposed space. In this paper, a pickup and delivery problem with time windows is dealt with as one of the practical and complicated transportation problems. This problem requires that any paired pickup and delivery locations have to be served by one vehicle and the pickup location has to be scheduled before the corresponding delivery location in the route. In designing our method, the solution space is divided into sub-spaces based on the number of customers loaded on each vehicle and then, each sub-space is solved by simulated annealing algorithms. In addition, we introduce genetic algorithms to choose appropriate sub-spaces for applying the simulated annealing method. The effectiveness and the potential of the proposed approach are evaluated by computational experiments.View full abstractDownload PDF (4816K) -
Tomoki HAMAGAMI, Hironori HIRATA2008 Volume 44 Issue 2 Pages 191-198
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper proposes a technique for realizing cooperation behavior emerging among intelligent wheel chairs (IWC). In order to acquire the behavior in various environments, a system with a broadcasting framework and a decision tree is implemented, which uses a frustration level indicating a dynamical internal state of an IWC. The system brings diversity among each IWC's, and resolves a deadlock of them. Moreover, in order to design an adaptive behavior, the decision tree is generated with the genetic programming. As results of experiment with simulation and real prototype IWC, we confirm the mutual concession behavior emerges in narrow aisle and cross road environmentView full abstractDownload PDF (26534K) -
Kazumoto MORITA, Michiaki SEKINE, Takeo OKADA2008 Volume 44 Issue 2 Pages 199-208
Published: February 29, 2008
Released on J-STAGE: February 25, 2013
JOURNAL FREE ACCESSThis paper examines which factor would mostly be related to the driver's braking timing by conducting indoor experiments using driving simulator. Fourteen participants drove a trailing vehicle and the lead vehicle was decelerated without notice. Participants applied brakes according to their subjective judgments on how best to prevent a rear-end collision. Various factors such as following car speed, distance between two vehicles, relative velocity, time-to-collision (TTC), rate of change of visual angle (which is the inverse of TTC) and others were examined in discriminant analysis. It was revealed that the rate of change of visual angle, which is the inverse of TTC, is most closely related to a driver's braking timing. The results were affirmed by the outdoor experimental results conducted on a test course using 7 participants. The findings can be used to determine the activation timing of adaptive braking system.View full abstractDownload PDF (12523K)
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