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A Study on Sliding Mode Control for Active Suspension Systems

South China University of Technology-Wu Qin, Huayuan Feng, Yi Sun
BYD Auto Co., Ltd.-Pu Xu
  • Technical Paper
  • 2020-01-1084
To be published on 2020-04-14 by SAE International in United States
A sliding mode control with a disturbance observer is proposed for suppressing the sprung mass vibration in a quarter-car with double-wishbone active suspension systems (ASSs). The suspension structure containing upper and lower control arms is considered in double-wishbone ASSs. The governing equations of ASSs are obtained by the balance-force analysis of the sprung mass in ASSs. Since ASSs include uncertainties in damping, stiffness, and external disturbance acting on the sprung mass, we design a disturbance observer based on a sliding mode control to estimate these uncertainties under the unknown road excitation. By the Lyapunov minimax approach, the uniform boundedness and the uniform ultimate boundedness for ASSs with the proposed control are proved. The efficacy of the design control is verified through co-simulation of ADAMS software and MATLAB/Simulink software for the road excitation of the step displacement. The sprung mass acceleration of ASSs is obtained with and without the proposed control. The results show that ASSs with the proposed control can yield better riding comfort performance of vibration attenuation of the sprung mass. Furthermore, the effects…
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Analysis for Dynamic Performances of Engine Front End Accessory Drive System under Accelerating Condition

South China University of Technology-Chujian Lin, Wen-Bin Shangguan, Shangbin Long, Yi Sun
  • Technical Paper
  • 2020-01-0399
To be published on 2020-04-14 by SAE International in United States
A model for a generic layout of an engine front end accessory drive system was established. The dynamic performance of the system were obtained via a numerical method. The dynamic performance consisted of the oscillation angle of tensioner arm, the slip ratio of each pulley and the dynamic belt tension. In modeling the system, the hysteretic behavior of an automatic tensioner, the loaded torque of the accessory pulley versus the engine speed, the torsional vibration of crankshaft and the creep of the belt were considered. The dynamic performance of the system at steady state and under accelerating condition were analyzed. An example was provided to validate the established models. The result shows that the torsional vibration of crankshaft is larger under accelerating conditions and the dynamic performance of the system is different, though the acceleration is small. In the end, the dynamic performance of the system using different belt with different Young’s modulus is studied by using the established model.
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An Efficient Analysis and Optimization Method for Generated Axial Force of Drive Shaft Systems Involving Interval Uncertainty

South China University of Technology-Huayuan Feng, Sabhash Rakheja
  • Technical Paper
  • 2020-01-0918
To be published on 2020-04-14 by SAE International in United States
The drive shaft system with a tripod joint is known to cause lateral vibration in a vehicle due to the axial force generated by the tripod joint. In the design and optimization of drive shaft system, the generated axial force (GAF) is an important design and optimization objective. Because of the uncertainty of drive shaft system operating environment, dimension parameters and material parameters, the GAF has uncertainty. To study the GAF more accurately and effectively, this paper introduces the interval uncertainty into the research focusing on the GAF of the drive shaft system. Firstly, based on Chebyshev polynomials, an interval uncertain model for calculating the GAF is proposed, in which the input torque, the articulation angle, the rotational angle of the drive shaft system, the pitch circles radius of the tripod joint and the friction coefficient between the rollers and tracks, which affect the GAF, are taken as interval variables. Secondly, based on the vertex method, a fast and accurate calculation method is proposed to calculate the upper and lower bounds of the GAF under…
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Research on Fractal Friction Model for Contact Pairs inside a Ball Joint

South China University of Technology-Huayuan Feng, XiHua Li
  • Technical Paper
  • 2020-01-1093
To be published on 2020-04-14 by SAE International in United States
During the operation of the ball joint, its service life is affected by the internal friction. Taking the ball joint as the research object, based on fractal theory, the friction between the steel ball and the raceway, the steel ball and the cage inside the ball joint of an automotive drive shaft system is studied in this paper. During the analysis, the friction between the steel ball and the raceway is regarded as the friction between a sphere and an arc raceway surface, and the friction between the ball and the cage is considered as the friction between a sphere and a plane. In order to describe the friction state between rough surfaces more accurately, this paper proposes a method to modify the size distribution function of contact asperities between two rough planes, and obtains the size distribution function of contact asperities between the rough sphere and the rough arc raceway surface and the rough sphere and the rough plane. Then based on the modified size distribution function, the fractal models for friction coefficient of…
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Modeling and Analysis of Front End Accessory Drive System with Overrunning Alternator Decoupler

South China University of Technology-Zhonghui Yin, Wen-Bin Shangguan, Shangbin Long, Yi Sun
  • Technical Paper
  • 2020-01-0398
To be published on 2020-04-14 by SAE International in United States
The generator is an important loaded component of a Front End Accessory Drive system (FEADS). With a huge moment of inertia and a very high running speed, the vibration and noise often occurs in operation, which has an effect on the service life. Thus an overrunning alternator decoupler (OAD) is used in the FEADS for reducing the vibration. In this paper, a model of FEADS with an OAD is established by the software Recurdyn. The influence of the OAD on the dynamic responses of pulley of generator and the system are analyzed, and is verified by bench experiments. And the influence of parameters, such as spring stiffness, moment of inertia of generator and loaded torque on the dynamic performances of the system are studied. Then an effective method is presented to optimize the oscillation of the tensioner arm and the slip ratio of the belt-generator pulley.
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Modeling and Validation for the Hysteretic Behavior of an Automatic Belt Tensioner

South China University of Technology-Shangbin Long, Xuezhi Zhao, Wen-Bin Shangguan
BYD Auto Industry Company Limited-Pu Xu
Published 2019-06-05 by SAE International in United States
An automatic tensioner used in an engine front end accessory drive system (EFEADS) is taken as a study example in this paper. The working torque of the tensioner, which consists of the spring torque caused by a torsional spring and the frictional torques caused by the contact pairs, is analyzed by a mathematic analysis method and a finite element method. And the calculation and simulation are validated by a torque measurement versus angular displacement of a tensioner arm. The working torques of the tensioner under a loading and an unloading process are described by a bilinear hysteretic model, and are written as a function with a damping ratio. The rule of the action for the damping devices is investigated based on the simulation and a durability test of the tensioner. A finite element method for the tensioner without damping device is established. Then the radial deformation for the torsional spring under an unconstrained state is obtained. The analysis results have a good correlation with the measurements. The method presented in this paper is beneficial for…
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Fault Feature Extraction of Elliptically Shaped Bearing Raceway

South China University of Technology-Yingying Guo, Xuezhi Zhao
Published 2019-06-05 by SAE International in United States
The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the fault features of ESB such as fatigue spalling and pitting are apt to be concealed by the excitation of impulses caused by alternating between major axis and minor axis. In order to diagnose the fault on raceway surfaces of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature. First, the formulas of feature frequency is deduced based on the geometry and kinematics characteristics of ESB; then the CMWT method is employed to decompose the fault signal of ESB; finally, the FH spectrum analysis is performed to extract the feature frequency of faulty ESB from the decomposition signal with the maximum kurtosis in the first several layers. Compared with the traditional FH method, the feature…
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A Novel Kind of Proportional Electromagnetic Dynamic Vibration Absorber

South China University of Technology-Tao FU
Published 2019-06-05 by SAE International in United States
A new proportional electromagnetic dynamic vibration absorber (EDVA) is proposed for control of engine vibration during idling. The device consists of an electromagnetic actuator attached to the primary structure through elastic element, where the driving force pair is implemented between the reaction-mass and the primary structure. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. A methodology is proposed to achieve magnetic force proportional to square of current and consistent with the disturbance frequency. The proportional EDVA is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies. The effectiveness of the hybrid proportional EDVA is evaluated through simulations and laboratory experiments under harmonic excitations in the 20-30 Hz frequency range. Both the simulation and measurements show that the hybrid proportional EDVA can yield effective attenuation of periodic…
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Kinematic Analysis and Simulation of the Double Roller Tripod Joint

South China University of Technology-Yinyuan Qiu, Wen-Bin Shangguan
Published 2019-06-05 by SAE International in United States
The kinematic model of the double roller tripod joint is established in order to analyze its kinematic characteristics and provide theoretical basis for its application and improvement. By means of spatial coordinate transformation, the translational and rotational motion equations of the rollers relative to the tracks and trunnions, the motion equation of the center of the tripod and the equations of the input/output angular displacement error and bending angle are derived. The motion simulation of the double roller tripod universal joint was carried out in ADAMS so as to verify the established kinematic model. The results show that the rollers of the double roller tripod joint only have periodic translational motions relative to the tracks while the rollers have both periodic translational and rotational motions relative to the trunnions. The tripod’s center does the circular motion on the tripod plane with the angular velocity 3 times of the input angular velocity. The input/output angular displacement error and bending angle have volatility, and their fluctuating frequency are 3 times of the input rotational frequency. Hence, the…
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A Control Strategy to Reduce Torque Oscillation of the Electric Power Steering System

South China University of Technology-Duo Fu, Wen-Jun Yan, Wen-Bin Shangguan
Concordia University Montreal-Subhash Rakheja
Published 2019-06-05 by SAE International in United States
This paper proposes a new evaluation method of analyzing stability and design of a controller for an electric power steering (EPS) system. The main purpose of the EPS system’s control design is to ensure a comfortable driving experience of drivers, which mainly depends on the assist torque map. However, the high level of assist gain and its nonlinearity may cause oscillation, divergence and instability to the steering systems. Therefore, an EPS system needs to have an extra stability controller to eliminate the side effect of assist gain on system stability and attenuate the unpleasant vibration. In this paper, an accurate theoretical model is built and the method for evaluating system quality are suggested. The bench tests and vehicle experiments are carried out to verify the theoretical analysis. The evaluation method proposed in this paper can not only guide the design of controller parameters, but also evaluate the control effect while the performance of several controllers are all excellent.
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