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141.
142.
Development of a low-noise cooling fan for an alternator using numerical and doe methods 总被引:1,自引:0,他引:1
W. Kim W. -H. Jeon N. Hur J. -J. Hyun C. -K. Lim S. -H. Lee 《International Journal of Automotive Technology》2011,12(2):307-314
An alternator, which converts mechanical rotational energy into electrical energy, is an important component of a vehicle.
Alternators operate over a broad range of rotational speeds, typically from 3,000 RPM to 18,000 RPM, which demands a cooling
fan producing sufficient airflow, ideally with a minimum of noise. In the current study, an optimized alternator-cooling fan
was developed through a linked DOE(Design OF Experiment) process and numerical analysis. The SC/Tetra and FlowNoise S/W programs were used to calculate flow rates and noise levels, respectively, for the newly developed fan. Compared with
original model, the numerical results predicted a 3 dBA noise reduction; the measured reduction was 4 dBA. 相似文献
143.
H. G. Zhang E. H. Wang B. Y. Fan M. G. Ouyang S. Z. Xia 《International Journal of Automotive Technology》2011,12(2):173-182
Variable Nozzle Turbocharger (VNT) was invented to solve the problem of matching an ordinary turbocharger with an engine.
VNT can harness exhaust energy more efficiently, enhance intake airflow response and reduce engine emissions, especially during
transient operating conditions. The difficulty of VNT control lies in how to regulate the position of the nozzle at different
engine working conditions. The control strategy designed in this study is a combination of a closed-loop feedback controller
and an open-loop feed-forward controller. The gain-scheduled proportional-integral-derivative (PID) controller was implemented
as the feedback controller to overcome the nonlinear characteristic. As it is difficult to tune the parameters of the gain-scheduled
PID controller on an engine test bench, system identification was used to identify the plant model properties at different
working points for a WP10 diesel engine on the test bench. The PID controller parameters were calculated based on the identified
first-order-plus-dead-time (FOPDT) plant model. The joint simulation of the controller and the plant model was performed in
Matlab/Simulink. The time-domain and frequency-domain performances of the entire system were evaluated. The designed VNT control
system was verified with engine tests. The results indicated that the real boosting pressure traced the target boosting pressure
well at different working conditions. 相似文献
144.
J. H. Yoon B. J. Choi I. H. Yang J. E. Oh 《International Journal of Automotive Technology》2011,12(1):59-66
T-Hypoid gears are commonly used in rear-drive and 4WD (4 Wheel Drive) vehicle axles. Investigating their sensitivity to deflections
is one of the most important aspects of their design and optimization procedures. Therefore, a deflection test was performed
in this study in the actual gear mounting using completely processed gear. This test covered the full operating range of gear
loads from “no load” to “peak load”. Under peak load, the contact pattern extended to the tooth boundaries without showing
a concentration of the contact pattern at any point on the tooth surface. The transmission error was tested under an axle
assembly triaxial-real-car-load condition. 相似文献
145.
B. J. Yoon J. Y. Lee J. H. Kim C. S. Han 《International Journal of Automotive Technology》2011,12(1):111-118
A navigation algorithm is indispensable for Unmanned Ground Vehicles (UGVs). During driving, UGVs follow a global path. In
this study, we propose a navigation algorithm using Real Time Kinematic (RTK)-Differential Global Positioning System (DGPS)
units and encoders to complement global path planning. Sometimes GPS systems lose their signals and receive inaccurate position
data due to many factors, such as edifice and barrier obstructions. This paper shows that GPS deviations can be solved using
a Dead Reckoning (DR) navigation method with encoders and that position errors can be decreased through the use of RTK-DGPS
units. In addition to this method, we will introduce a new waypoint update algorithm and a steering algorithm using RTK-DGPS
units. 相似文献
146.
T. Y. Shin S. Y. Kim J. Y. Choi K. S. Yoon M. H. Lee 《International Journal of Automotive Technology》2011,12(1):103-110
This paper presents a modified lateral control method for an autonomous vehicle with both look-ahead and look-down sensing
systems. To cope with sensor noise and modeling uncertainty in the lateral control of the vehicle, a modified LMI-based H
lateral controller was proposed, which uses the look-ahead information of the lateral offset error measured at the front of
vehicle and the look-down information of the vehicle yaw angle error between the reference lane and the centerline of the
vehicle. To verify the safety and the performance of the lateral control, a scaled-down vehicle was developed, and the positioning
of the vehicle was estimated with USAT. The proposed controller, which uses both look-ahead and look-down information, was
tested for lane changing and reference lane tracking with both simulation and experiment. The simulation and experimental
results show that the proposed controller has better tracking and handling performance compared with a controller that uses
only the look-ahead information of the target heading angle error. 相似文献
147.
License plate extraction method for identification of vehicle violations at a railway level crossing
B. K. Cho S. H. Ryu D. R. Shin J. I. Jung 《International Journal of Automotive Technology》2011,12(2):281-289
The primary cause of most railroad accidents is vehicle entry into railway level crossings despite warning messages. To identify
drivers who violate railway level crossing regulations, vehicle license plate recognition can be applied at railway level
crossings. The purpose of this paper is to present an effective method for extracting the license plate region from vehicle
images taken at railway level crossings. The method proposed in this paper uses the variation in the gray-level values across
the image of a license plate. For license plate region extraction, the character region is first recognized by identifying
the character width and the difference between the background region and the character region. The license plate region is
then extracted by finding the inter-character distance in the plate region. In addition, the license plate type is identified
by the difference in the gray-level value between the background region and the character region. The proposed method is effective
in solving the current challenges in extracting the license plate region from the damaged frames of license plates issued
for domestic use, including new types of license plates. According to the experimental results, the proposed method yields
a high extraction rate of 99.5% for vehicle license plates. 相似文献
148.
K. Jang I. Park J. Han K. Lee M. Sunwoo 《International Journal of Automotive Technology》2011,12(4):589-597
Because the FlexRay protocol has more than 70 configuration parameters and these parameters correlate with each other, designing
a FlexRay network is a complex and difficult task. In this study, we propose a design framework that optimizes the two main
FlexRay network parameters that are highly relevant to the application algorithm. The design process is composed of two steps
for optimizing parameters. In the first step, the static slot length is optimized using a frame-packing algorithm. This algorithm
binds network signals into static frames based on their periods and signal groups. In the second step, the communication cycle
length is optimally designed with frame-scheduling algorithm and worst-case reponse time analysis. Based on the frame-scheduling
algorithm, the response times are analyzed. The proposed design framework was applied to a unified chassis control system
as a case study, and the analytical results were verified. 相似文献
149.
H. -Z. Li L. Li J. Song L. -Y. Yu 《International Journal of Automotive Technology》2011,12(5):679-686
A new comprehensive driver model is presented for critical maneuvering conditions with more accurate dynamic control performance.
In order to achieve a safe maneuvering mode, a new path planning scheme to maintain stability of the vehicle was designed.
A new steering strategy, considering the errors of vehicle position and yaw angle between the real track and the planned path,
was established to obtain the steering angle. Therefore, the vehicle can be adjusted to accurately follow the desired path
with the driver model, and the stability of the vehicle and the smoothness of the steering angle input were comprehensively
considered. Simulation results were used to validate the control performance in comparison with the optimal preview driver
model proposed by Macadam. 相似文献
150.