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排序方式: 共有1103条查询结果,搜索用时 15 毫秒
191.
冯正平 《上海交通大学学报(英文版)》2010,15(2):194-198
The design approach of H∞ autopilot for autonomous underwater vehicles (AUVs) is proposed. Comprised by the three sub-controllers,i.e. speed,heading and depth controllers,the designed autopilot has advantage over existing H∞ control of AUVs. The overshoot in speed,heading and depth control systems under step commands is restricted by refining the weighting function for robust stability. The dynamic performance of heading and depth control systems is improved by feeding back yaw rate and pitch angle,respecti... 相似文献
192.
Y. S. Kim E. Y. Kim Y. W. Shin S. K. Lee 《International Journal of Automotive Technology》2010,11(5):759-765
This paper presents a multi-body flexible dynamic analysis of a centrifugal turbo blower for a fuel cell electric vehicle
(FCEV) based on the application of computer-aided engineering (CAE) to predict the acceleration at the mount position of the
blower. This predicted acceleration is validated by using the measured acceleration data. The numerical simulation for the
multi-body flexible dynamics of the blower is used not only to identify the most effective mount among four mounts in an FCEV
by controlling the complex stiffness of the isolator, but also to suggest the range of complex stiffness of the isolator at
the most effective mount. This numerical simulation technology can be useful for the estimation of the variation of vibration
transmission for the structural modification of the turbo blower. 相似文献
193.
The importance of vehicle safety cannot be exaggerated in today’s mobile societies. Many manufacturers, associates related
to vehicles and universities make an effort to improve vehicle safety by developing new technologies, applying high strength
steel to the body structure etc. However, the majority of these efforts are focused on decreasing injury. It is absolutely
important to minimize injury, but a more important aspect is coping with vehicle accidents. That is, As undeniably important
as it is to minimize potential injuries, it is critical that experts focus on developing ways to keep drivers out of situations
likely to lead to crashes in the first place. The purpose of this paper is to determine what the most critical factor is when
coping with an unfamiliar driving situation. The answer is to provide a wide-open field of vision, especially for the driver.
The driver’s field of vision is obstructed by the vehicle’s A-pillar. To solve this, the A-pillar obstruction angle, which
is the angle between the driver’s eyes and the A-pillar should be decreased. This paper purposes three-methods for decreasing
this angle structurally and applying a slim A-pillar which is as the best solution to decrease the A-pillar obstruction angle
and ensure the drivers field of vision at the same time 相似文献
194.
This paper explores issues related to the electrical safety of Hybrid Electrical Vehicles (HEVs) during and after various
crash events. Japanese and American federal regulations regarding occupant protection against high voltages in Electric Vehicles
(EVs) and HEVs were surveyed and analyzed in this study. Front, side and rear impact tests for two types of HEVs were conducted
to investigate electrolyte spillage, the retention of the propulsion battery system and the electrical isolation of the occupant.
The test results met the related criteria. The test procedures and the criteria for occupant protection established through
this study were amended to Korean Motor Vehicle Safety Standard (KMVSS) No. 91 to add the crash protection of the EVs and
the HEVs. 相似文献
195.
H. J. Kim B. Han W. S. Hong W. H. Shin G. B. Cho Y. K. Lee Y. J. Kim 《International Journal of Automotive Technology》2010,11(4):447-453
A 3000 cc diesel engine attached to an engine dynamo was used to test three newly developed electrostatic Diesel Particulate
matter filtration Systems (DPS 1, 2, and 3) under four steady-state engine operating conditions: idle, 2000 rpm with no load,
and 2000 rpm under 25% and 50% loads. Of the two developed alternatives, DPS 1 and DPS 2, DPS 2 comprises an ionization section,
electrostatic field additional section and Flow-Through Filter (FTF), which achieved almost 90% removal of particulate matter
(PM) under the engine’s operating conditions, and the efficiency of the FTF was maintained between 20% and 50%. Comparing
the long-term performance of DPS 2 and DPS 3 (effectively a serial combination of two DPS 2s) with a commercially-available
Diesel Particulate Filter (DPF), the DPS 2 and DPS 3 achieved almost the same efficiency for removing PM as the DPF but had
significantly improved (75%∼90% lower) differential pressure drops. 相似文献
196.
G. -Q. Liu Y. -C. Yan J. Chen F. -F. Xu 《International Journal of Automotive Technology》2010,11(4):573-580
A hydraulic power-assist system is a hydraulic regeneration system that can significantly improve fuel economy when installed
on a conventional bus operating in urban traffic. This paper presents a methodology for matching a new hydraulic power-assist
system (HPA) to a conventional bus. The HPA and the conventional bus were modeled using the AMESim environment. The HPA was
optimized using a simulation-based orthogonal design method with two indexes, the fuel economy and the acceleration performance.
According to the simulation results, the volume of the accumulator was the primary factor affecting fuel economy, and the
gear ratio of the transfer case was the primary factor influencing the acceleration performance. As a result, tradeoffs between
the two indexes are required for a practical operational scenario. Experimental results demonstrated that the optimal HPA
installed on a conventional bus was able to satisfy the acceleration performance requirement of the vehicle and also reduced
fuel consumption by 25 percent. 相似文献
197.
Fault detection method for electric parking brake (EPB) systems with sensorless estimation using current ripples 总被引:1,自引:0,他引:1
C. W. Lee H. B. Chung Y. O. Lee C. C. Chung Y. S. Son P. Yoon 《International Journal of Automotive Technology》2010,11(3):387-394
A fault detection method with parity equations is proposed in this paper. Due to its low cost implementation, the velocity
of the motor is not measurable in electric parking brake (EPB) systems. Therefore, residuals are not reliable when estimating
the motor velocity with a low-resolution encoder. In this paper, we propose a fault detection method with sensorless estimation
using current ripples that estimates the position and velocity of the motor by detecting periodical oscillations of the armature
current caused by rotor slots. In addition, this method can estimate the position and velocity of the motor with less computational
effort than a state observer. Moreover, the method is less sensitive to motor parameters than model-based estimation methods.
The effectiveness of this method is validated with experimental data, and the simulation results show that various faults
have their own residual patterns. Therefore, we can detect the presence of faults by monitoring the residual signals. 相似文献
198.
Development of a new sound metric for impact sound in a passenger car using the wavelet transform 总被引:1,自引:0,他引:1
Vehicles can experience impacts due to harsh road conditions. Contact with an uneven road surface causes vehicles to vibrate,
which generates a loud impact sound. The attenuation of such noise is important because car passengers may complain about
the impact noise. However, perfect removal of impact noise is not possible because most of it is caused by external conditions.
More research is needed on the objective attributes of impact noise; however, the problem of impact noise is not a simple
matter because impact noise is transient in nature and reaches a high level instantaneously. In this paper, a new objective
attribute of impact noise is designed using the wavelet transform, which is appropriate for analyzing nonstationary signals,
such as an impact signal. The usefulness of the new objective attribute, which is a sound metric, is examined by comparing
the mean subjective ratings for real impact noise in passenger cars. The new sound metric has better correlation with the
mean subjective rating than currently existing sound metrics. 相似文献
199.
Pacejka’s tire model is widely used and well-known by the automotive engineering community. The magic formula describes the
brake force, side force and self-aligning torque in terms of the longitudinal slip and slip angle, plus several corrections.
This paper uses approximation theory to obtain different types of approximations to the magic formula: rational functions
(RA) resulting from the Remez algorithm, expansions in a series of Chebyshev polynomials (ACh), a series of Chebyshev rational
polynomials (ARChPs), a series of rational orthogonal functions (ORF) and a series of ARChPs that result from grade-1 ORFs.
The last expansion shows the fastest convergence and most effective computation. Jacobi rational polynomials can also be obtained
to complement this expansion and facilitate fine-tuning in specific areas of the error curve. This work is complemented by
obtaining the original rational approximations to the inverse tangent function, which take advantage of the curve symmetry
to reduce the computation load and provide models that include the influence of the vertical load. The convergence properties
of the development in series and the error values resulting from numeric examples for the three types of stress are shown.
The proposed final ARChP expressions show very low error (1%) compared to the original magic formula. They can be computed
20 times faster; they can be evaluated, derived and integrated analytically easily; and their coefficients can be obtained
from tests using common least-squares algorithms. 相似文献
200.
J. Kim J. Kang Y. Kim T. Kim B. Min H. Kim 《International Journal of Automotive Technology》2010,11(4):565-571
The power split type hybrid system transmits engine power by dividing it into the electrical unit and the mechanical unit.
Its power transmission efficiency is highest at the mechanical point (MP), where the full power is transmitted to the mechanical
unit. In this study, the equation for the MP was derived for the gear ratios of a general 4-node lever model. The MP characteristics
for the transmission ratio (TR) of the input split and compound split structures were examined using the equation derived.
Using the examined input split and compound split structures, a systematic design method for the dual mode power split transmission
was proposed. In the dual mode power split transmission, the MP could be positioned at the desired TR, and the input split
and compound split modes could be selectively used according to the clutch combination, which leads to the operation of the
vehicle within a high system efficiency range. 相似文献