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Technical Paper

Improvement of engine vibration isolating characteristic by using semi- active hydraulic mount

2000-06-12
2000-05-0321
In order to reduce the vibration energy transferred from engine to the chassis of a vehicle and improve the riding comfortability of the vehicle, a new semi-active controlled hydraulic mount is developed which could adjust the vibration isolating effect at wide frequency range. The dynamic characteristic of the new mount could be changed through adjusting the cross-sectional area of its inertia channel. The control strategy of the mount is based on a great deal of engine tests. Test results of the semi-active mount on an engine test bench show that it could optimize the isolation effect according to engine''s working condition.
Technical Paper

Fuzzy Observer for Nonlinear Vehicle System Roll Behavior with Coupled Lateral and Vertical Dynamics

2018-04-03
2018-01-0559
The study of vehicle state estimation performance especially on the aspect of observer-based control for improving vehicle ride comfort and road handling is a challenging task for vehicle industry. Since vehicle roll behavior with various road excitations act an important part of driving safety, how to accurately obtain vehicle state under various driving scenes are of great concern. However, previous researches seldom consider coupling relation between vehicle vertical and lateral response with steering input under various road excitation. To address this issue, comprehension analyses on vehicle roll state estimation with coupled input are present in this paper. A full-car nonlinear Takagi-Sugeno (T-S) fuzzy model is first created to describe vehicle lateral and vertical coupling dynamics.
Technical Paper

Road Classification Based on System Response with Consideration of Tire Enveloping

2018-04-03
2018-01-0550
This paper presents a road classifier based on the system response with consideration of the tire enveloping. The aim is to provide an easily applicable yet accurate road classification approach for automotive engineers. For this purpose, tire enveloping effect is firstly modeled based on the flexible roller contact (FRC) theory, then transfer functions between road input and commonly used suspension responses i.e. the sprung mass acceleration, unsprung mass acceleration, and rattle space, are calculated for a quarter vehicle model. The influence of parameter variations, vehicle velocity, and measurement noise on transfer functions are comprehensively analyzed to derive the most suitable system response thereafter. In addition, this paper proposes a vehicle speed correction mechanism to further improve the classification accuracy under complex driving conditions.
Technical Paper

Design and Development of a Real-time Dynamic AMT Test Bench for Simulating Total Road Forces of Vehicle

2008-06-23
2008-01-1682
In this paper the hardware and software of a real-time dynamic test bench for simulating the total road forces of vehicles fitted with Automated Manual Transmissions (AMT) is described. First, the purpose and meaning of this research are discussed. And then, we select the hardware components of the test bench system according to the application requirements and complete the system design. Statement of the structure, working principle and function of the system is also included in this part. According to the experimental procedure of simulating total road load forces of vehicle under real-time conditions on the dynamic test bench, the software system is designed using Visual C++ 6.0, CAN bus communication protocol, RS-232, and network technology. Finally, some experimental tests for the system are carried out with the results that this design corresponds to the real-time dynamic requirements.
Technical Paper

Prediction of Structural Acoustic Radiation for Compressor Considering Airflow Pulsed Load

2011-05-17
2011-01-1722
A coupled vibro-acoustic of a compressor modeling process was demonstrated for predicting the acoustic radiation from a vibrating compressor structure based on dynamic response data. FEM based modal analysis of the compressor was performed and the result was compared with experimental data, for the purpose of validating the FE model. Modal based force response analysis was conducted to calculate the compressor's surface vibration velocity on radiating structure, using the load which caused by mechanical excitation as input data. In addition, due to the coolant had oscillating gas pressure, the gas pulsed load was also considered during the dynamic response analysis. The surface vibration velocity solution of the compressor provided the necessary boundary condition input into a finite element/boundary element acoustic code for predicting acoustic radiation.
Technical Paper

Studies on Anti-Slip Regulation Technologies for AMT Vehicles

2007-04-16
2007-01-1314
In order to improve the tractive ability, steering capability and directional stability, etc. of automated mechanical transmission (AMT) vehicles running on the wet and slippery road, the anti-slip regulation (ASR) technologies for AMT vehicles are developed. The significance of ASR for AMT vehicles is introduced; a road friction recognition method based on the deceleration of driving wheels is investigated; a fuzzy anti-slip control system based on adjustment of engine torque is developed and the corresponding experimental verification is conducted. The experimental results denote that the proposed method is effective to eliminate the excessive slip when the AMT vehicle travels on the low friction road.
Technical Paper

Simulation of Straight-Line Type Assist Characteristic of Electric Power-Assisted Steering

2004-03-08
2004-01-1107
Electric Power-Assisted Steering (EPAS) is a new power steering technology that will define the future of vehicle steering. The assist of EPAS is the function of the steering wheel torque and vehicle velocity. The assist characteristic of EPAS is set by control software, which is one of the key issues of EPAS. The straight-line type assist characteristic has been used in some current EPAS products, but its influence on the steering maneuverability and road feel hasn't been explicitly studied in theory. In this paper, the straight-line type assist characteristic is analyzed theoretically. Then a whole vehicle dynamic model used to study the straight-line type assist characteristic is built with ADAMS/Car and validated with DCF (Driver Control Files) mode of ADAMS/Car. Based on the whole vehicle dynamic model, the straight-line type assist characteristic's influence on the steering maneuverability and road feel is investigated.
Technical Paper

Calculating Fractal Dimension of Worn Bearing's Vibration Signals in Automotive Transmission

2003-05-05
2003-01-1487
This paper first discusses the principles of how to identify whether a time series has chaotic characteristics, and explores a method of finding out the embedding dimension of a time series. Then Grassberger-Procaccia (G-P) algorithm is adopted to calculate correlative dimension. After the validity of G-P algorithm is confirmed using several traditional strange attractors, it is applied to calculate the fractal dimension of some vibration signals of an automotive transmission. This article presents how to apply chaos and fractal theories to diagnose the wearing of ball bearings in automotive transmissions based on the analysis of the transmission acceleration vibration signals. The results show that the vibration signals of automotive transmissions have fractal nature. There are certain correlations between a bearing's condition and the fractal dimension of its vibration signal.
Technical Paper

NVH Improvement of Vehicle Powertrain

2012-09-24
2012-01-2007
This paper provides an investigation to improve vehicle powertrain NVH performance via modification of excitation and radiation system of powertrain. First of all, considering different excitation mechanisms of the powertrain, the excitation forces are analyzed. The FEM/BEM coupled analysis and the acoustic transfer vector (ATV) calculation as well as panel contribution analysis are applied to investigating the acoustic characteristics of the powertrain. Then a hybrid approach which couples the transmission gear profile modification for attenuating gear system excitation and the transmission housing modification for reducing transmission housing noise radiation is proposed to improve powertrain NVH performance. Experiment validation is conducted in order to assess the modified results. The assessment shows that this hybrid approach can effectively predict and reduce powertrain noise and vibration.
Technical Paper

Response Decoupling Method in Mount Design with Emphasis on Transient Load Conditions

2019-01-18
2018-01-5046
This research examined the focused design, elastic design, energy decoupling, and torque roll axis (TRA) decoupling methods for mount optimization design. Requiring some assumptions, these methods are invalid for some load conditions and constraints. The linearity assumption is advantageous and simplifies both design and optimization analysis, facilitating engineering applications. However, the linearity is rarely seen in real-world applications, and there is no practical method to directly measure the reaction forces in the three locally orthogonal directions, preventing validation of existing methods by experimental results. For nonlinear system identification, there are additional challenges such as unobservable internal variables and the uncertainty of measured data.
Technical Paper

A Novel Dual Nonlinear Observer for Vehicle System Roll Behavior with Lateral and Vertical Coupling

2019-04-02
2019-01-0432
The study of vehicle coupling state estimation accuracy especially in observer-based vehicle chassis control for improving road handling and ride comfort is a challenging task for vehicle industry under various driving conditions. Due to a large amount of life safety arising from vehicle roll behavior, how to precisely acquire vehicle roll state and rapidly provide for the vehicle control system are of great concern. Simultaneously, uncertainty is unavoidable for various aspects of a vehicle system, e.g., varying sprung mass, moment of inertia and position of the center of gravity. To deal with the above issues, a novel dual observer approach, which combines adaptive Unscented Kalman Filter (AUKF) and Takagi-Sugeno (T-S), is proposed in this paper. A full-car nonlinear model is first established to describe vehicle lateral and vertical coupling roll behavior under various road excitation.
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