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Determination of Magic Formula Tyre Model Parameters Using Homotopy Optimization Approach

Huazhong University of Science and Technology-Kaidi Zhang, Yupeng Duan, Yunqing Zhang
Oshkosh Corporation-Xiaobo Yang
  • Technical Paper
  • 2020-01-0763
To be published on 2020-04-14 by SAE International in United States
Tyre behavior plays an important role in vehicle dynamics simulation. The Magic Formula Tyre Model is a semi-empirical tyre model which describes tyre behavior quite accurately in the handling simulation. The Magic Formula Tyre Model needs a set of parameters to describe the tyre properties; the determination of these parameters is nontrivial task due to its nonlinear nature and the presence of a large number of coefficients. In this paper, the homotopy algorithm is applied to the parameter identification of Magic Formula tyre model. A morphing parameter is introduced to correct the optimization process; as a result, the solution is directed converging to the global optimal solution, avoiding the local convergence. The method uses different continuation methods to globally optimize the parameters, which ensures that the prediction of the Magic Formula model can be very close to the test data at all stages of the optimization process. The results show that, compared with the general deterministic optimization methods and intelligent search algorithms, the homotopy algorithm has better global optimization ability and rapid convergence, which is…
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The Effect of Friction on Ride Comfort Simulation and Suspension Optimization

Ebco Inc.-Peijun Xu
Huazhong University of Science and Technology-Wang Xuwang, Xiaoyu Chen, Yunqing Zhang
  • Technical Paper
  • 2020-01-0765
To be published on 2020-04-14 by SAE International in United States
The design of suspension affects the vehicle dynamics such as ride comfort and handling stability. Nonlinear characteristics and friction are important characteristics of suspension system, and the influence on vehicle dynamic performance cannot be ignored. Based on the seven-degree-of-freedom vehicle vibration nonlinear model with friction, the vibration response process of the vehicle and the influence of suspension friction on vehicle ride comfort and suspension action process were studied. The results show that friction will significantly affects the simulation of ride comfort and coincide with the function of the shock absorber. The suspension shock absorbers of vehicles were optimized with and without suspension friction. The results showed that the suspension tended to choose softer shock absorbers when there was friction. However, both of the two optimizations are able to improve the ride comfort of vehicles, and the simulation results were similar. At the same time, it was found that the better the dynamic performance of the vehicle model, the greater the influence of suspension friction on the simulation results of ride comfort.
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Dynamics and Control of Gearshifts in Wet-Type Dual Clutch Transmission for BEVs

Huazhong University of Science and Technology-Zhenxiong Lou, Yupeng Duan, Yunqing Zhang
  • Technical Paper
  • 2020-01-0767
To be published on 2020-04-14 by SAE International in United States
The dual clutch transmission is one of the possible choices for electric vehicle drivelines. The basic principle and control mode of shifting of wet dual clutch transmission are introduced, and the dynamic process of shifting of wet double clutch transmission is studied. Combined with the dynamic model of the wet clutch engagement process, the difference between the dynamic characteristics of the dual clutch transmission modeling using the Coulomb friction model and the dual-clutch transmission model using the average flow model and the micro-convex contact theory is analyzed. The shift control strategy of the dual clutch transmission proposes a correction method to improve the shifting smoothness. Studies have shown that the torque response of the wet clutch has significant hysteresis, and the improved control algorithm can significantly improve the shifting smoothness of the wet dual clutch transmission. Based on the dynamic model of the wet clutch, the torque interruption of the shift control strategy of the dual clutch transmission is studied, and the method of improving the shift smoothness by the correction of the shift control…
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Multi-Mode Controller Design for Active Seat Suspension with Energy-Harvesting

Ebco Inc.-Peijun Xu
Huazhong University of Science and Technology-Zhenrui Zhang, Yunqing Zhang
  • Technical Paper
  • 2020-01-1083
To be published on 2020-04-14 by SAE International in United States
In this paper, a multi-mode active seat suspension with a single actuator is proposed and built. A one-DOF seat suspension system is modelled based on a quarter car model of commercial vehicle with an actuator which is comprised of a DC motor and a gear reducer. Aiming at improving ride comfort and reducing energy consumption, a multi-mode controller is established. According to the seat vertical acceleration and suspension dynamic travel signals, control strategies switch between three modes: active drive mode, energy harvesting mode and plug breaking mode. In active drive mode, the DC motor works in driving state and its output torque which calculated by LQR algorithm is controlled by a current-loop controller; In energy harvesting mode, the DC motor works in generator state by which induced current can charge the power source, in this mode, the DC motor is considered as a damper which damping coefficient is decided by the charging current and controlled by Skyhook algorithm; In plug breaking mode, the DC motor works in the plug breaking state and its inverse voltage…
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Filled Rubber Isolator’s Constitutive Model and Application to Vehicle Multi-Body System Simulation: A Literature Review

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Ebco, Inc.-Peijun Xu
Huazhong University of Science and Technology-Xingxing Feng, Yunqing Zhang
  • Journal Article
  • 10-02-02-0007
Published 2018-06-05 by SAE International in United States
Rubber elements present highly nonlinear mechanical properties affected by frequency and amplitude of excitation, prestrain and temperature, etc. Finite element (FE) models and lumped parameter models can be distinguished in the development of constitutive models of rubbers. Based on the concept of overlay model, different kinds of viscoelastic, or frequency-dependent models, and elastoplastic/friction, or amplitude-dependent models, are compared in terms of their modelling approach, parameters identification process and applications. Prestrain-dependent models and temperature-dependent thermo-mechanical models are also reviewed, including some special models which are not based on the concept of the overlay model. Experimental and computational studies of cylindrical bushings subjected to coupled deformation modes are analyzed and discussed. It is the hope that this literature review work can help clarify and guide the future research and development direction about rubber constitutive modelling.
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Experimental Study of Unbalanced Multiple Propeller Shaft

Huazhong University of Science and Technology-Penglei Fu, Yunqing Zhang
Wanxiang Qianchao Co. Ltd.-Baoxiang Qiu, Chao Ding, Bomei Shi
Published 2018-04-03 by SAE International in United States
The imbalance of propeller shaft is an excitation to the vehicle structure and causes noise and vibration. This paper presents an experimental study of effects of propeller shaft imbalance on vehicle vibration characteristics. A two-piece propeller shaft with unbalance is used in real vehicle test. The vehicle vibration is characterized by accelerations of the cabin floor and of the bearing which supports the propeller shaft. Through the experiment, some interesting phenomena are observed.
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FSAE Race Car Dynamics and Trajectory Optimization Considering Aerodynamic Effects

Huazhong University of Science and Technology-Ji Ma, Xiaoyu Chen, Yupeng Duan, Yunqing Zhang
Published 2018-04-03 by SAE International in United States
The aerodynamic effects not only directly affect the acceleration and the fuel economy of the race car, but also have a great influence on the handling of the race car. In this paper, the vehicle multibody dynamic model with “double-wishbone suspension” and “rack and pinion steering” is established, in order to obtain aerodynamic parameters, the aerodynamic model of the vehicle is established, and the aerodynamic parameters were calculated by using CFD. In order to obtain the optimal travel track, the track model is established, according to weights allocation of the smallest curvature of each curve and the shortest curve to optimize the optimal route for racing. The influence of aerodynamic effects on the stability of vehicle control is analyzed through simulation of Endurance Racing to evaluate the maximum lateral acceleration、roll angle and other performance. According to the racing speed characteristics and distribution of longitudinal acceleration and lateral acceleration, the racing performance limit is evaluated, Comparing the racing model with the aerodynamic device and the racing model without the aerodynamic device, the aerodynamic device is greatly…
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Influence of Dynamic Vibration Absorbers on Bending Vibration in Vehicle Propeller Shaft

Huazhong University of Science and Technology-Penglei Fu, Yunqing Zhang
Wanxiang Qianchao Co. Ltd.-Baoxiang Qiu, Bomei Shi, Chao Ding
Published 2018-04-03 by SAE International in United States
Increased focus on vehicle comfort and ride has led the automotive industry to look into low vibration, noise and hardness alternative designs for powertrain system components. In this paper, the vibration theory and dynamic vibration absorber (DVA) theory is presented. The modal analysis of propeller shaft assembly has been accomplished. Based on dynamic vibration absorber principle, performance parameters of dynamic vibration absorber are matched and structure is also designed. LMS equipment is applied to verify the natural frequency of absorber samples. The matching of stiffness and damping of DVA is presented. The dynamic response of drive shaft system based on the mass ratio of DVA is researched in this paper. Results from simulations and tests indicates that the amplitude of propeller shaft resonance can be effectively reduced by attaching a DVA to the long propeller shaft.
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Parameter Sensitivity Analysis of a Light Duty Truck Steering Returnability Performance

Dong Feng Automobile Co.,Ltd.-Yan Wang
Huazhong University of Science and Technology-Tianqi Lv, Xingxing Feng, Yunqing Zhang
Published 2017-03-28 by SAE International in United States
Steering returnability is an important index for evaluating vehicle handling performance. A systematic method is presented in this paper to reduce the high yaw rate residue and the steering response time for a light duty truck in the steering return test. The vehicle multibody model is established in ADAMS, which takes into consideration of the frictional loss torque and hydraulically assisted steering property in the steering mechanism, since the friction, which exists in steering column, spherical joint, steering universal joint, and steering gear, plays an important role in vehicle returnability performance. The accuracy of the vehicle model is validated by road test and the key parameters are determined by executing the sensitivity analysis, which shows the effect of each design parameter upon returnability performance. Analysis results indicate that the key parameters are the steering gear internal fluid resistance, mechanical friction, the caster angle and the torsion bar stiffness, which greatly influence the yaw rate residue and steering response time.
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Mount Model Dependent on Amplitude and Frequency for Automotive Powertrain Mounting System

Ebco Inc.-Peijun Xu
Huazhong University of Science and Technology-Tianqi Lv, Xingxing Feng, Yunqing Zhang
Published 2017-03-28 by SAE International in United States
Three constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
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