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No. 37 Apr. 2019
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<Feature-Ⅰ>Excavators & Cranes |
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Electric Motor HILS System Using Numerical Stabilization Technique for
Simulating Nonlinear Coupled System
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Kei MORITA
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This paper introduces a stabilization technique of
nonlinear coupled analysis for hydraulic excavators, in
which a rigid body system and a hydraulic system are
coupled. Also introduced is a "Hardware-In-the-Loop
Simulation (HILS)" for electric motors, in which the above
technique is exploited. The rigid body system consists of
a rotating element and a linear motion element, and the
stabilization technique converts the motion of the rotating
element into linear motion, enabling the motion of both
the systems to be described in an ordinary differential
equation without introducing any constraint conditions for
the rigid bodies. This enables a coupled analysis with one
motion equation that shares the state quantities of both
the systems, thus improving the stability of the numerical
analysis. This technique has been used to simulate in realtime
the actual load acting on the electric motor, which
has been reproduced on a motor-load testing apparatus
and has realized an electric motor HILS system.
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| 8 |
Duct Shape Design Technology Based on Evolutionary Algorithm Considering Noise
Attenuation Performance and Air Permeability
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Satoshi TABUCHI
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This paper relates to a technique for designing the
engine room of a hydraulic excavator equipped with
an Integrated Noise & Dust Reduction (iNDr) cooling
system. In order to improve the noise attenuation
performance, changes in cross-sectional area and bends
have been introduced into the muffler duct of the iNDr
structure. On the other hand, changes in cross-sectional
area and bending will deteriorate the air permeability
and decrease the cooling capacity. Thus, in a muffler
duct, the air permeability of the cooling air and noise
attenuation performance are in a trade-off relationship.
Against this backdrop, an optimum design technology has
been developed using a multi-objective genetic algorithm
(MOGA) to achieve both air permeability and noise
attenuation performance in the intake duct of the iNDr
structure of the engine room. This technology has enabled
the design of an engine-room shape taking both the air
permeability and noise attenuation performance into
account.
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| 15 |
Loss Analysis of Electric Motors in Hybrid Excavator
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Akira TSUTSUI, Ryo FUJISAWA, Kazuhide SEKIYAMA,
Yoichiro YAMAZAKI, Seiji SAEKI, Dr. Kazushige KOIWAI
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Kobelco Construction Machinery Co., Ltd. has launched
a new 20 tonne hybrid excavator, equipped with two types
of newly developed electric motors, namely, a permanent
magnet type, flat, high-torque generator motor, and a
compact high-output slewing motor. In an electric motor,
iron loss and copper loss occur, and these losses increase
as the internal temperature rises. Therefore, the challenge
in making compact electric motors with high torque
and high output is to release the heat generated inside
the motors to the outside and to prevent their internal
temperature from rising. A technique has been established
for the coupled analysis of an electrical/magnetic circuit
model and a heat transfer circuit model in an electric
motor that enables an optimal design of the heat transfer
path inside the motor, as well as making it possible to
efficiently find an appropriate electromagnetic circuit for
it. This has resulted in the development of electric motors
with high torque density.
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| 21 |
Disturbance Rejection Filter for Depth Sensor
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Masashi HAMAGUCHI, Dr. Takashi HIEKATA
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In recent years, data obtained from sensors attached
to excavators are being widely used in assisting
the operators. The processing unit logic of such a
sensor system has been developed to ensure flexibility
in the design of the sensor system. As a part of this
development, an effort has been made to solve the
problem of detecting disturbances, such as rain, snow,
and insects, when the depth sensor is used for outdoor
measurements. An object placed in front of a depth
sensor in a raining environment was moved back and
forth while continuously measuring the appearance of
the object. In the measured data, points with possible
disturbances were chosen. The speed, direction, and
acceleration between frames were calculated as feature
quantities, which led to the development of a disturbance
rejection filter that eliminates the points above set
thresholds. This filter has been confirmed to detect the
position of objects while ignoring the influence of rain in
real applications.
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Development of 20-tonne Class Hybrid Excavator, SK200H-10
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Yoichiro YAMAZAKI, Seiji SAIKI, Nobuhiro KOGA, Akira TSUTSUI,
Kazuhide SEKIYAMA, Kengo MAEDA
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Power electronics technology continues to evolve,
particularly in the automobile industry, with the aim of
reducing fuel consumption and the environmental burden.
This technology was adapted for a hybrid hydraulic
excavator, the SK200H-10, equipped with a lithiumion
battery, as introduced in this paper. A continuous
engine assist has been realized for the hydraulic
excavator by effectively using the regenerative energy
generated during slewing deceleration, due to the large
inertia of its slewing body, and by adopting a lithiumion
battery with high output and large capacity. As a
result, the fuel consumption of the excavator has been
reduced significantly. The scrap handling machine (with
magnet), the SK210DLC-10, has the same generator
motor as SK200H-10 and applies a hydraulic excavator
with a totally new power generation system, which was
formerly based on a hydraulic pump. This machine
enjoys a remarkably increased magnetic attraction and
considerably reduced fuel consumption, thanks to the
reduced energy loss during power conversion.
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| 31 |
Evolution and Development of iNDr
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Kazuhiro UEDA, Tomoyuki TSUCHIHASHI, Hajime NAKASHIMA,
Zenzo YAMAGUCHI, Kyoko MASUDA, Satoshi TABUCHI
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Integrated Noise & Dust Reduction (iNDr) is an advanced
proprietary cooling system with the two unique functions
of noise reduction and dust removal. It is installed in
an ultra-low-noise hydraulic excavator launched for
the first time in 2007. With its extremely low noise and
dust-proof performance, it is used preferentially at many
sites. Rather than becoming obsolete, it has gained in
popularity, thanks to its performance. Environmental
regulations are becoming increasingly stringent, and
the constraints on equipment have become increasingly
severe in connection with the development of smaller
models: for example, the addition of a new function,
mixing cooling exhaust and engine exhaust, is now
required. Due to these circumstances, design tools based
on fundamental theories, which allow more efficient
study, are being utilized to evolve the iNDr into a "crossover
duct" with a new structure, while maintaining its
extremely low-noise performance.
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<Feature-Ⅱ> Utilization of ICT
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| 36 |
Development of New Production Scheduling and Manufacturing Logistics System
for Takasago Machinery Plant
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Rihito IZUTSU, Toyohiro UMEDA, Hideo IKEDA, Yukihiro ONISHI,
Ryusuke MORISAKI
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For the machinery plant of the make-to-order (MTO)
type Machinery Center in the Takasago Works of Kobe
Steel, a system for scheduling and logistics management
has been developed to improve the product assortment
rate, an index for the rate of on-time delivery to the
subsequent assembly plant. For scheduling, a method was
devised for estimating excessive overloading to support
the determination of the amount to be outsourced. For
the logistics, a mechanism was established to collect
progress data and the locations of parts with RFIDs,
the information necessary for preparing schedules. The
introduction of this system has improved the assortment
rate by approximately 20% compared with the value
normalized by the average assortment rate before the
introduction of the system.
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| 41 |
Method for Predicting Gas Channeling in Blast Furnace
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Kazufumi KAMO, Kazuhisa HAMAMOTO, Dr. Hiroshi NARAZAKI,
Dr. Tomoyuki MAEDA, Masahiro YAKEYA, Yosuke TANAKA
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In order to maintain stable operation of a blast furnace,
deviations from the steady state should be quickly detected
and corrected. Because internal physical states are
difficult to measure directly, experienced operators play
a crucial role in integrating information from various
sources such as sensors and visual observations so as
to recognize, predict, and react to probable anomalies.
Overlooking undesirable symptoms or delayed actions
possibly leads to the excessive loss of heat, which, in
the worst case, can cause the abnormal shutdown of
operation. One of the events highly associated with the
risk of heat loss is gas channeling, which sets off an alarm
signaling to the operator to decrease the flow rate of input
hot gas. Gas channeling is judged to be imminent by the
integration of indices designed so as to detect unusual
changes in the variations and patterns of sensory data.
The precision of our prediction method is evaluated by
using actual data.
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| 48 |
Collision Warning System for Locomotives Carrying Molten Pig-iron in
Kakogawa Works
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Dr. Toshiharu IWATANI, Hiroshi KATSURA, Masahiro TAMURA
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This paper describes a collision alert system for
locomotives that carry molten pig iron in the Kakogawa
Works of Kobe Steel. This system comprises a process
computer that stores the positional information,
determined by the GPS, of locomotives along with their
railroad track information in order to generate warnings.
The railroad tracks laid in the steel works are more
complicated than those of railroad companies and may
cause various types of collisions. Hence, the railroad
tracks are represented in a computer on the basis of graph
theory to establish an algorithm for predicting collisions
accurately and quickly. The newly developed system has
been utilized continuously, promoting the safety of the
locomotive operation.
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| 56 |
Development of Prediction Technique for Temperature Distribution of
Molten Steel in Steelmaking
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Dr. Nobuyuki TOMOCHIKA, Dr. Takehiro NAKAOKA,
Takehiro TSUKUDA, Yoshiyuki NAGASE, Hiroshi KATSURA,
Kazuki SUMIDA
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To promote the transfer to younger workers through
operation support, a technique has been developed to
present, in a probability distribution, the deviation risk for
molten steel temperature in the converter furnace, molten
steel treatment, and continuous casting steps involved
in processing. This technique constructs a probability
distribution by converting and transferring massive
amounts of recorded data concerning past performance
into information corresponding to the current operational
state. It is based on a physical model, weighing the
information in accordance with the degree of similarity.
Its advantages are that calculable factors are separated
from uncertain factors in a deterministic manner, the time
change of the uncertain factors is taken into account on
the basis of thermal influence, and Just-In-Time modeling
is applied, which enables the systematic calculation of the
probability distribution even for different conditions of
such factors as steel types and facilities. This technique
has been applied to an actual steelmaking process, which
has reduced the deviation of casting temperature from the
target value to less than half of the conventional one.
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| 63 |
Development of Macro Simulation Model to Support Multi-product,
Mixed Flow Production of Aluminum Rolling
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Toyohiro UMEDA, Akihisa HORIO, Satoru YOSHINO,
Katsumasa UEDA
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The manufacturing processes for the sheets, plates, and
strips of steel, aluminum, and copper that are Kobe Steel's
main material products are characterized by the mixed
production of a great variety of products. Hence, for the
sake of productivity and quality, a plurality of workpieces
processed by an identical type of method are aggregated
together as one lot on the basis of the operating
conditions specific to each apparatus. A simulation model
has been developed to support production planning and
to help in considering operational rules as well as the
capital investment policy involved in such processes.
The model has a hierarchical queue structure to flexibly
express various lot-making operations. The model
further incorporates a mechanism for estimating the
time it takes before the minimum number of workpieces
required to organize a lot become available in order
to reduce the unwanted stagnation of jobs in the
process. The effectiveness of the proposed model has
been demonstrated by numerical experiments, while its
accuracy and applicability in the macro evaluation of
material flow have been verified using actual plant data
on aluminum rolling.
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| 72 |
Applications of ICT to Robot Welding System
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Takeshi KOIKE, Yoshihide INOUE, Atsushi FUKUNAGA
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In recent years there has been a rise in expectations for
the improvement of the productivity of robot welding
systems using information and communication technology
(ICT). To meet these customer needs, Kobe Steel has
developed a 3D-CAD link system that retrieves the data of
workpieces from the design department and automatically
detects welding lines to create a robot program. This has
eliminated the need for customers to teach robots and
has greatly improved their productivity. The company
also provides a production monitoring software, called
AP-SUPPORTTM. This software has the capability of
automatically collecting production data for the welding
robot system and outputting reports on production results,
thus contributing to the improvement of productivity at
customers' sites.
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| 77 |
Development of Image Sensing Technology for Automatic Welding
(Image Recognition by Deep Learning) |
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Tsuyoshi ASHIDA, Akira OKAMOTO, Keita OZAKI, Masatoshi HIDA,
Dr. Takayoshi YAMASHITA
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A system has been developed for automatic MAG welding
with ceramic backing. This system comprises a camera
to capture the images of the molten pool for recognizing
feature points to control the torch. A regression-based
deep convolutional neural network (DCNN), which
outputs continuous values from image inputs, was used
to recognize feature points such as arc center and the
leading end of the molten pool. This has enabled the
accurate recognition of the distance from the arc center to
the leading end of the molten pool, as well as the width of
the molten pool, with an average error of 0.44 mm or less.
The formation of a proper back bead has been confirmed
in a welding experiment on a test piece with a tapered gap
(from 3 to 10 mm).
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