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The driveline torsional vibration issue is one of the most significant Noise, Vibration and Harshness (NVH) problems, especially in rear-wheel drive vehicles with manual transmission. In this article, a new driveline and rear axle coupled torsional vibration model (DRCTVM) is developed that considers the relationship between the driveline and the r...
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... typical driveline contains the engine, clutch, transmission, drive shafts, universal joints, main reducer, half shafts, and the wheels, as shown in Figure 1. Torsional vibration of the driveline is a phenomenon caused by engine cyclical excitation, the universal joint secondary couple (Roffey 2012), drive shaft imbalance, and runout, though engine cyclical excitation is the most important source ( Xia et al. 2013). ...
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... which D denotes the piston diameter and p g represents the cylinder pressure. The engine excitation torque can be computed by Equation (24), as shown in Figure 10. As outlined in Figure 10, there are two peaks in the excitation torque curve when the crankshaft rotates one circle (360 degree). ...
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... engine excitation torque can be computed by Equation (24), as shown in Figure 10. As outlined in Figure 10, there are two peaks in the excitation torque curve when the crankshaft rotates one circle (360 degree). Hence, the 2 nd order is the most important part of the engine excitation torque. ...
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... order to validate the accuracy of DRCTVM modal shapes, the modal frequencies and shapes are also obtained by the modal test. The installation sites of the torsional vibration sensors are shown in Figure 10. The engine itself is treated as the exciting source. ...
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... locations are the flywheel, the input shaft of the transmission, the drive shaft, the input shaft of the main reducer, and the half shafts. Because of the frequency range limit of the simulated model and test conditions, only the 3 rd to 5 th modes are tested (Figure 11). ...
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... frequencies obtained from both the traditional model and the DRCTVM are compared with the test values, as shown in Table 6. The modal shapes of the simulation and test are also compared, as shown in Figure 12. ...
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... 12, the numbers 1 to 9 denote the degree of freedom at correlative parts, as shown in Table 7. It can be seen from Table 6 and Figure 12 that the rear axle has a great influence on the torsional modal of the driveline. Unfortunately, the 4 th modal cannot be obtained by the traditional model due to the differences in degrees of freedom: the DRCTVM has 9 degrees of freedom, while the tradi- tional model has 8. ...
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... Fourier Transform (FFT) is conducted on the dynamic torque to calculate the mean and alter- nating torque of multiple harmonics of engine firing frequency. The results of the torque in frequency domain are shown in Figure 13. It is obvious that engine excitation has the characteristics of orders, and the 2 nd order is particularly remarkable. ...
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... 2 nd order torque of the engine is used as the excitation source. The angular acceleration at the flywheel, the input shaft of transmission, and the input shaft of the main reducer are calculated, as shown in Figure 14. Torsional vibration at the transmission and main reducer is much larger than that at the flywheel at about 1100 rpm and 1650 rpm (Figure 14). ...
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... angular acceleration at the flywheel, the input shaft of transmission, and the input shaft of the main reducer are calculated, as shown in Figure 14. Torsional vibration at the transmission and main reducer is much larger than that at the flywheel at about 1100 rpm and 1650 rpm (Figure 14). Additionally, the 2 nd order responses of the driveline simulation model agree with the interior noise in Figure 3 at the peak locations. ...
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... the 2 nd order responses of the driveline simulation model agree with the interior noise in Figure 3 at the peak locations. Figure 15 shows the acceleration response curves computed by the traditional model and the new DRCTVM. As expected, the second peak at 1650 rpm cannot be obtained by the traditional model. ...
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... contrast, the new DRCTVM with consideration of the coupling between the driveline and rear axle can predict both peaks at 1100 rpm and 1650 rpm, which agree with the interior noise. Results shown in Figure 15 demonstrate the advantages of the proposed DRCTVM compared with the traditional model. ...
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... Han, and Lu 2012) For an ideal normal distribution with a probability density function (PDF) f X (x), its corresponding PDF f X (x) of the truncated distribution can be defined by in which x L and x R are the lower and upper bounds of the parameter .., and a is an amplification coefficient. The curves of f X (x) and f X (x) are plotted in Figure 16. It is seen that the truncated distri- bution not only describes the probability distribution of the uncertain variables, but also considers the interval bounds of the variables. ...
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... sample points are generated by the Monte-Carlo Method. The 3 rd and 4 th modal frequencies and peaks of the vibration acceleration at the gearbox and rear axle are defined as the output variables, as shown in Table 11 and Figure 17. ...
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... can be seen from Table 11 and Figure 17 that rear axle peaks are very sensitive to driveline parameters; a slight change in driveline parameters, see dramatic changes in the peaks. Hence it is necessary to optimize the driveline torsional vibration performance based on robust-based design. ...
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... However, the realization of CM's whole potential is based on identifying reliable condition indicators (CIs) that are capable of accurately discerning incipient failures [5]. In particular, automotive applications deal with a wide range of uncertainties, e.g., a wide variety of operating conditions like temperature [6], road surface conditions [7], speed, and torque gradients [8] as well as driver input errors and highly dynamic disturbances like wideband torsional excitations through blocking wheels [9,10] or controller-based safety measures (Electronic Stability Programs (ESPs) and others) [11], which makes a limit monitoring approach using steady state limits unable to detect failures of mechanical components at early stages [12]. Modern development tools for automotive powertrains must reproduce these disturbances and withstand these conditions for long testing periods [13]. ...
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... The driveline system is a prominent source of noise and vibration in vehicles, spanning from cars to high-speed trains [1][2][3]. The vibrational properties of drivelines are currently an essential practical issue due to their potential to cause boom noise and gear rattle, which can negatively impact vehicle performance and passenger comfort [4][5][6]. The automotive driveline system includes various components, including the transmission, drive shafts, universal joints, and main reducer. ...
Utilizing a universal joint can lead to significant vibration within a driveline system. This study presents a model for analyzing the torsional and lateral vibrations of a driveline connected by a double universal joint. The governing equations of motion are derived, and the Runge-Kutta method computes steady-state responses across a spectrum of input rotational speeds. The focus is to examine the effect of system parameters, including static angular misalignment, load torque, and lateral stiffness. Relative amplification is used to analyze the effects of parameters on system vibration. Results indicated that the second-order component of input rotational speed induced by the universal joint was the factor that caused the vibrations. For the considered system, static angular misalignment significantly impacts both the torsional and lateral vibrations. Increasing the angular misalignment from 15° to 30° results in a threefold increase in lateral vibration amplification, while torsional vibration amplification is increased by nearly two times. The effect of load torque is almost linearly proportional to torsional vibration but is nonlinear to lateral vibration. Thus, lateral vibration is significantly impacted compared to torsional vibration for higher load torque. Changing the stiffness leads to a modification of the natural frequency. Increasing the lateral stiffness shifts the critical speed to a higher speed range, resulting in reduced lateral vibration amplitude. It is demonstrated that a slight fluctuation in angular misalignment due to lateral vibration will not affect the torsional vibration even if both vibrations are coupled. The findings may enhance understanding of how changing system parameters affects vibration.
... Hao et al. [25] The uncertainty method is used in the analysis of a vehicle driveline torsional vibration optimization, considering the interactions among drive and rear axles. The uncertainty is considered as a truncated normal distribution, enabling the probability distribution and the limits of uncertain variables. ...
Chassis dynamometers are one of the main test benches applied to vehicle development and homologation, however, vehicle experiments and simulations present associated uncertainties. Thus, aiming to allow previous analyses to assist the vehicle homologation process, this research analyzes uncertainties and their impacts on fuel consumption on a vehicle-dynamometer testing simulation on Matlab/Simulink™, under a driving cycle, and experimentally validated. The paper analyzes the developed model inputting variations (speed profiles, tire parameters, and rolling resistance coefficient) and quantifies the fuel consumption response and its uncertainties, comparing them with experimental results. The results showed the experimental fuel consumption (0.9985 ± 0.0522 (l)) compared to the ones submitted to input variations. Among these, the rolling coefficient was the most influential factor (0.9670 ± 0.1338 (l)). The final variation analysis presented the mean value closest to the experimental (0.9951 ± 0.0959 (l) and mean error of 0.33%). The simulation allows reproducing experiments virtually, mitigating experimental time and cost spent on real benches, and providing an analysis tool in order to help the vehicle homologation.
... For this reason, the genetic algorithm is also widely applied to the performance optimization of automobiles. For example, the robustness of driveline torsional vibration has been analyzed using the genetic algorithm [11], and the dynamic performance and economy of two-speed powertrain transmissions can also be improved based on the genetic algorithm [12]. Furthermore, the genetic algorithm has been adopted to perform multi-objective optimization for the lightweight design of suspension components [13]. ...
Intelligent manufacturing is developing rapidly nowadays, promoting the efficiency of manufacturing. In comparison, the design process has become a bottleneck in the product life cycle. In order to address this problem, this research develops an intelligent design method based on the automobile transmission system. Firstly, a mathematical model of the coupled vibration between the drive shaft and the main reducer was developed, and the vibration responses of the transmission system were simulated based on this mathematical model. Then, a test rig was developed to measure the vibration responses of the system; the measured results correlated well with the simulation results, indicating that the mathematical model can be used to investigate the coupled vibration between the drive shaft and the main reducer. Furthermore, the multiple parameters of the transmission system were optimized based on the mathematical model using the intelligent optimization algorithm. In particular, software was developed based on the intelligent optimization algorithm for the convenience of analysis, and the optimized results were acquired. The analysis results show that the vibration responses can be reduced when the optimized parameters are applied, indicating that the intelligent design method developed in this research is effective for the intelligent design of transmission system.
... ere are many sources of vehicle vibrations and noises, such as the engine, the tire, the transmission, and the road surface [1], in which the engine contributes the most [2]. In addition, the vibrations and noises caused by the engine will further produce transmission vibrations and noises [3]. Global emission regulation requires the automotive manufacturers to develop engines with lower level emissions. ...
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... Accepted manuscript to appear in IJCM 36 ...
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During the operation of vehicles, it is found that dramatic vibration occurs when the engine rotation speed reaches a certain value. In order to study this phenomenon, a theoretical model of automobile transmission system is developed in this paper. This model includes four sub-models of gearbox, drive shafts, main reducer and rear axle, which take into account the inhomogeneous transmission speed of universal joint of drive shafts as well as the effect of time-varying and nonlinear factors of main reducer gears. In this model, the transmission system is an elastic system characterized by mass, stiffness and damping. The torsional vibration responses of transmission system are simulated, and the natural frequencies of transmission system and corresponding mode shapes are calculated using this model. Simulation results indicate that the maximum amplitude of torsional vibration response appears at a certain speed. On the other hand, experimental investigation on the effect of rotation speed on torsional vibration is conducted to verify the theoretical model. Experimental results also show there is the maximum amplitude of torsional vibration response appearing at a certain speed. The results of FEA indicate that the excitation frequencies of drive shaft are quite close to the first order natural frequency of drive shaft, and the resonant vibration of drive shaft would induce the resonant vibration of transmission system, given that the first order natural frequency of drive shaft is quite close to the third order natural frequency of transmission system. In particular, it is discovered that deviations between the rotation speeds corresponding to the maximum amplitude of angular displacement and the rotation speeds corresponding to the maximum amplitude of angular acceleration exist for both theoretical simulation and experimental measurements.
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As a new torsional vibration absorber, the dual mass flywheel (DMF) contains a symmetric structure in which the damping element is a pair of springs symmetrically distributed along the circumference direction. Through reasonable matching parameters, the DMF functions in isolating torsional vibrations caused by the engine from the transmission system. Our work aims to solve the accuracy of matching models between the DMF and power transmission system. The critical structural parameters of each order modal are treated consecutively by two methods: Absolute sensitivity (e.g., under the idle condition and driving condition), and relative sensitivity. The operation achieves a separation of the parameters and diagnosis of the relationship between these parameters and the natural frequency in the system. In addition, the natural frequency range is determined based upon the area of the resonance speed. As a result, the matching model is established based on the sensitivity analysis method and the natural frequency range, which means the moment of inertia distribution (its coefficient should be used as one structural parameter in relative sensitivity analysis) and the torsional stiffness in multiple stages can be observed under the combined values. The effectiveness of the matching model is verified by experiments of a real vehicle test under the idling condition and driving condition. It is concluded that the analysis study can be applied to solve the parameters matching accuracy among certain multi-degree-of-freedom dynamic models.
A long rigid-flexible coupling transmission shaft (RFCTS) is usually used to connect the dynamometer with the device under test (DUT) in semi-anechoic chamber. However, due to the parameter error and torsional vibration characteristic of RFCTS, load emulation loading accuracy of the test bench is lower. Therefore, the research focused on establishing a control-oriented vehicle powertrain system test bench (VPSTB) model based on RFCTS to further improve the load emulation loading accuracy. First, a 14-degrees of freedom (DOF) high-order lumped mass model of VPSTB is established, and the stiffness and moment of inertia equivalent parameters are obtained. Subsequently, a 7-DOF simplified control-oriented VPSTB model is established based on 14-DOF model, and the model parameters are identified by the recursive least squares estimation (RLSE) method with forgetting factor. Simultaneously, the natural frequency of 14-DOF high-order model and 7-DOF simplified model is calculated, then un-damped vibration response of the two models are compared and analyzed. Finally, simulation and experimental are carried out under open-loop and closed-loop conditions, which show that the effectiveness of 7-DOF simplified model parameters, and it also indicate that the 7-DOF simplified VPSTB model can achieve better loading accuracy of load emulation.
div class="section abstract"> The towbarless aircraft taxiing system (TLATS) consists of the towbarless towing vehicle (TLTV) and the aircraft. The tractor realizes the towing work by fixing the nose wheel. During the towing process, the tractor driver may cause the aircraft to collide with an obstacle because of the blind spot of vision leading to the accident. The special characteristics of aircraft do not allow us to modify the structure of the aircraft to achieve collision avoidance. In this paper, three degrees of freedom (DOE) kinematic model of the tractor system is established for each of the two cases of pushing and pulling the aircraft, and the relationship between the coordinates of each danger point and the relatively articulated angle of the TLATS and the velocity of the midpoint of the rear axle is derived. Considering that there is an error between the velocity and relatively articulated angle measured by the sensor and the actual one, the effect of velocity and relatively articulated angle uncertainty on the traction trajectory of the aircraft-tractor system is investigated based on the Chebyshev expansion function. The calculation efficiency and the result range of Chebyshev method and those of Monte Carlo(MC) method are compared. An aircraft collision avoidance model on the apron is established based on Simulink. The simulation results show that the method can achieve the measurement of aircraft attitude and position and realize the anti-collision.
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