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Volume 53, Issue 2
Displaying 1-9 of 9 articles from this issue
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Paper
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—Effective Heat Diffusion by Small-scale Air Movement—Yohei KONO, Yoshihiko SUSUKI, Mitsunori HAYASHIDA, Takashi HIKIHARA2017 Volume 53 Issue 2 Pages 123-133
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSWe develop a methodology for modeling of heat transfer dynamics of building atriums based on observational data on temperature and air-conditioning system. We focus on the phenomenon of heat transfer mainly due to the air movement inside a practically-used atrium, where the air slowly moves on a length-scale smaller than the distance between rooms. The heat transfer is modeled as a two-dimensional heat diffusion equation with an effective diffusion coefficient. The coefficient is identified based on a spatio-temporal oscillatory pattern extracted from measurement data via Koopman mode decomposition. The identified coefficient is verified with the characteristic numbers of fluid flow in the atrium and its architectural geometry. In the companion paper [Y. Kono, Y. Susuki, and T. Hikihara, Trans. SICE (53-2)], we will consider the heat transfer due to the air movement over the length-scale of the distance between rooms.View full abstractDownload PDF (1711K) -
Yutaro KOYA, Yue BAO, Takayuki NAKATA, Mitsugu ARAKI2017 Volume 53 Issue 2 Pages 134-143
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSThe factories to manufacture the cloth textile products need an automatic defect detection system to improve efficiency. However, the warp knitted fabric often used for sports etc. uniforms has a complicated structure. Therefore, the defects of warp knitted fabric cannot be detected by the existing methods such as the methods using a laser beam. We had proposed a method to detect the defects of warp knitted fabric by using block division and two different filters. This method needs a number of parameters, such as coordinates of perspective transformation, the width of block division, and a revision value of the threshold value at the time of judgment. Therefore, it has the problem that a number of parameters needs to be set manually. This paper proposed an inspection method using the block division and two kinds of filters which does not need the manual setting before inspection. The procedure is as follows: 1. The angle of the texture pattern is calculated from the image of cloth captured by a camera. This captured image is rotated based on this calculated angle. 2. The suitable block width is determined by calculating the cycle of a cloth pattern of transformed image. 3. The existence of a defect is detected without setting the threshold value manually by comparing the tendency of distribution of the filters output with a normal distribution. Based on the experimental results, it was confirmed that the defects of different types of cloth were correctly detectable from the image captured by a camera attached to a weaving machine placed in factory by using the proposal method.View full abstractDownload PDF (4029K) -
Takaya ISHII, Kenji HIRATA, Akihiro OHORI, Nobuyuki HATTORI, Yoshito O ...2017 Volume 53 Issue 2 Pages 144-151
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSThis paper investigates the distributed voltage control problem of a distribution power grid in which a voltage rise occurs due to reverse load flow from distributed generators. A centralized operation to maintain the grid voltage becomes difficult, since the number of distributed generators being involved is large. This paper considers a real-time pricing strategy and distributed optimization by each distributed generator. An independent public commission or community manager called utility, who intends to maintain the grid voltage, tries to determine and provide an additional price, which conceptually represents tax or subsidy, to each distributed generator. The distributed generator decides its desired output by solving an individual optimization problem including the provided price. This feedback interaction between the utility and distributed generators eventually maintains the grid voltage. Effectiveness of the proposed real-time pricing and distributed decision making methodology is evaluated through numerical experiment.View full abstractDownload PDF (1063K) -
Masaya TANEMURA, Yuichi CHIDA, Shota SEKIGUCHI, Hiroyuki KOBAYASHI2017 Volume 53 Issue 2 Pages 152-161
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSMany methods have been proposed for unknown disturbance estimation problems. Several methods can be applied to non-minimum phase systems, but it is difficult to improve unknown disturbance estimation performances because of the phase lags of the systems. A method using a parallel feedforward model that enables good estimation performance for non-minimum phase systems has been proposed. In this paper, the effectiveness of the method is verified through numerical simulations and experiments.View full abstractDownload PDF (2202K) -
Kota TAKAHASHI, Ryo WATANABE2017 Volume 53 Issue 2 Pages 162-168
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSA railway crew scheduling problem treats assignment of railway crews to the given railway operation schedule. In this paper, we discuss an automatic railway crew scheduling method based on numerical optimization. The proposed method executes step by step optimization using partial pairings to avoid combinatorial explosion.View full abstractDownload PDF (763K) -
Keita SUYAMA, Yuki FUNABORA, Shinji DOKI, Kae DOKI2017 Volume 53 Issue 2 Pages 169-177
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSThis paper deals with the sensor fusion problem in mobile robot localization using particle filter. Sensor fusion has been a major technique to estimate robot's state from noisy sensor observation. Generally, the sensors are assumed to be in the nominal state of work. In realistic contexts, however, sensor characteristics may change online depending on sensor functioning conditions, and deteriorate estimation accuracy. For such situations, faulty sensors should be identified and the fusion rule should be updated accordingly to achieve robust localization. These processes should be done online without access to ground truth. The authors propose a new sensor fusion method for mobile robot localization utilizing the increasing and diversifying onboard sensors thanks to the technological development in recent years. Under the strong assumption that the majority of similar signals provide the truth and any dissimilar signal is the result of a sensor fault, faulty probability distributions computed from sensor observations by a particle filter are detected and isolated based on K-L Divergence, a measurement for difference between two probability distributions in information theory. The proposed method is examined on several experiments, showing the possibility of generating robustness to the mobile robot localization.View full abstractDownload PDF (1999K) -
Jun KINUGAWA, Akira KANAZAWA, Kazuhiro KOSUGE2017 Volume 53 Issue 2 Pages 178-187
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSWe have been developing a co-worker robot which works in cooperation with workers for an automobile assembly line. The co-worker robot is not directly involved in the assembly processes but carries out some nonessential tasks for supporting workers. In this paper, we improve our old system which decides a delivery timing based on logistic regression model. We propose a method to estimate a worker's current task for improving performance of timing decision system. To achieve these, the worker's behavior is modeled combining two probabilistic techniques: Gaussian mixture model for classifying areas corresponding to each task and hidden Markov model for modeling and recognizing a worker's action. By estimating a worker's behavior using a worker's kinetic information and supporting the worker at the proper timing, this system improves work efficiency and supplies the part to the worker effectively.View full abstractDownload PDF (1649K) -
—Advection by Large-scale Air Movement—Yohei KONO, Yoshihiko SUSUKI, Takashi HIKIHARA2017 Volume 53 Issue 2 Pages 188-197
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSWe develop a methodology for modeling of heat transfer dynamics of building atriums based on observational data on temperature and air-conditioning system. Following the companion paper [Y. Kono, Y. Susuki, M. Hayashida, and T. Hikihara, Trans. SICE 53-2], we focus on the phenomenon of heat transfer mainly due to the air movement inside a practically-used atrium, where the air slowly moves over the distance between individual rooms. The heat transfer is modeled as a two-dimensional advection equation with a coarse-grained velocity. The velocity is identified based on a spatio-temporal oscillatory pattern extracted from measurement data via Koopman mode decomposition. The identified velocity is verified with the characteristic numbers of fluid flow in the atrium and its architectural geometry.View full abstractDownload PDF (2797K) -
Tadashi SUMIOKA, Kenji NISHIMIYA, Yoshimitsu AKUTA2017 Volume 53 Issue 2 Pages 198-205
Published: 2017
Released on J-STAGE: February 17, 2017
JOURNAL FREE ACCESSIn this paper, we propose a vehicle trajectory and velocity planning method for autonomous driving. The proposed method includes a nonlinear model predictive control and a dynamic programing. The dynamic programing part calculates an optimal path and a driving corridor to satisfy the safe zone took into account other vehicles traffic situation. The optimal path and the driving corridor are used for nonlinear model predictive control part as a target value and a constraint. The nonlinear model predictive control part calculate a vehicle trajectory and velocity simultaneously for a comfortable drive. To confirm the effectiveness of these proposed methods, numerical simulations are demonstrated. Simulation results show that the proposed method can calculate a humanlike driving behavior. For example the velocity planning results show slowing down before corner entrances and the trajectory planning results show the out-in-out shape to reduce the curvature of the vehicle trajectory.View full abstractDownload PDF (2148K)
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