Improving The Manoeuvrability of Electric Vehicle with Four-Wheel Drive and Four-Wheel Steering – A Nonlinear Model Vehicle Dynamics Approach

The dynamics motion of a vehicle is inherently a nonlinear dynamics system especially at high speed. Majority of past researches on four-wheel steering (4WS) vehicle adopt easier way of modelling a control system based on vehicle with linear dynamic equation of motion. This paper study on the vehicle dynamics of an electric vehicle with 4WD and 4WS based on nonlinear vehicle dynamic approach. A numerical simulation was performed to analyse the variance of a linear model and nonlinear model during cornering at various constant speed. The results show that during low speed cornering at 10 km/h, the linear and nonlinear model produced similar steady state cornering based on the trajectory and yaw rotational speed. However, the variants of linear and nonlinear started to appear as the vehicle speed increase. By obtaining the steady state cornering speed, another numerical simulation was performed to analyse the characteristics of the 4WD and 4WS electric vehicle. A passive control of the rear wheels’ steer angle was implement in the simulation. The results show that the parallel steering mode decreased the yaw rotational speed which broaden the trajectory of the cornering, while the opposite steering mode increased the yaw rotational speed that led to a tighter trajectory during cornering.

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Numerical Simulation of Flowfield around High Speed Trains Passing by each other at the same Speed

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.97-98.698 ◽

2011 ◽

Vol 97-98 ◽

pp. 698-701

Author(s):

Ming Lu Zhang ◽

Yi Ren Yang ◽

Li Lu ◽

Chen Guang Fan

Keyword(s):

Numerical Simulation ◽

Wind Tunnel ◽

Flow Field ◽

Point Source ◽

High Speed ◽

Stokes Equations ◽

Field Structure ◽

Vehicle Speed ◽

Mesh Method ◽

High Speed Trains

Large eddy simulation (LES) was made to solve the flow around two simplified CRH2 high speed trains passing by each other at the same speed base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of resting train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field structure around train is completely different between wind tunnel experiment and factual running. Two opposite moving couple of point source and point sink constitute the whole flow field structure during the high speed trains passing by each other. All of streamlines originate from point source (nose) and finish with the closer point sink (tail). The flow field structure around train is similar with different vehicle speed.

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Numerical Simulation Analysis of an Oversteer In-Wheel Small Electric Vehicle Integrated with Four-Wheel Drive and Independent Steering

International Journal of Vehicular Technology ◽

10.1155/2016/7235471 ◽

2016 ◽

Vol 2016 ◽

pp. 1-12 ◽

Cited By ~ 5

Author(s):

Muhammad Izhar Ishak ◽

Hirohiko Ogino ◽

Yoshio Yamamoto

Keyword(s):

Numerical Simulation ◽

Steady State ◽

Critical Velocity ◽

High Speed ◽

Simulation Analysis ◽

Stability Limit ◽

Conventional Vehicle ◽

Wheel Drive ◽

On The Road ◽

Four Wheel Drive

Similar to conventional vehicle, most in-wheel small EVs that exist today are designed with understeer (US) characteristic. They are safer on the road but possess poor cornering performance. With recent in-wheel motor and steer-by wire technology, high cornering performance vehicle does not limit to sport or racing cars. We believe that oversteer (OS) design approach for in-wheel small EV can increase the steering performance of the vehicle. However, one disadvantage is that OS vehicle has a stability limit velocity. In this paper, we proposed a Four-Wheel Drive and Independent Steering (4WDIS) for in-wheel small EV with OS characteristic. The aim of implementing 4WDIS is to develop a high steer controllability and stability of the EV at any velocity. This paper analyses the performance of OS in-wheel small EV with 4WDIS by using numerical simulation. Two cornering conditions were simulated which are (1) steady-state cornering at below critical velocity and (2) steady-state cornering over critical velocity. The objective of the simulation is to understand the behavior of OS in-wheel small EV and the advantages of implementing the 4WDIS. The results show that an in-wheel small EV can achieve high cornering performance at low speed while maintaining stability at high speed.

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Handling Performance Improvement via Steering Reactive Torque Design Based on Integrated Driver-Vehicle Model

Volume 3: 19th International Conference on Advanced Vehicle Technologies; 14th International Conference on Design Education; 10th Frontiers in Biomedical Devices ◽

10.1115/detc2017-68139 ◽

2017 ◽

Author(s):

Shuai Cheng ◽

Jian Song ◽

Zhenghong Lu ◽

Wenlong Dong

Keyword(s):

Vehicle Dynamics ◽

High Speed ◽

Driving Simulator ◽

Longitudinal Velocity ◽

Design Procedure ◽

Vehicle Speed ◽

Lateral Stability ◽

Vehicle Model ◽

Handling Performance ◽

Speed Condition

In some specific driving conditions, the steering behavior of the driver is significantly influenced by the reactive torque of the steering system. According to the vehicle dynamics, the steering angle along with the longitudinal velocity determines the vehicle states as well as the driving feeling. Thus, the steering reactive torque shows a remarkable influence on the evaluation of the lateral stability in high-speed condition. Given that the steady state gain increases with the velocity, this effect is especially significant in the high speed condition. As a result, the steering reactive torque must be designed to match the vehicle speed properly. However, except for simple experiential method, no normative design procedure of the reactive torque is proposed at present. In this paper, the influence of the steering reactive torque on the driver’s steering behavior is studied on the basis of the integrated neuromuscular system (NMS) vehicle model, which shows that a larger reactive torque could effectively restrain the unnecessary rapid steering operations and thus improve the handling performance of the vehicle. Key states of the vehicle dynamics is selected as the parameterized index of the physiological perception of the lateral stability. A novel design approach of the steering reactive torque is then proposed on the basis of the correlation of the reactive torque and the vehicle states. By introducing a new design principle — maintaining the physiological-perception-related dynamics states, the evaluation of the lateral stability can remain favorable despite the increasing speed. Effectiveness of the proposed design procedure is validated by a driving simulator and promising results have been obtained.

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Investigation of a multi-ball, automatic dynamic balancing mechanism for eccentric rotors

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2007.2123 ◽

2007 ◽

Vol 366 (1866) ◽

pp. 705-728 ◽

Cited By ~ 26

Author(s):

K Green ◽

A.R Champneys ◽

M.I Friswell ◽

A.M Muñoz

Keyword(s):

Numerical Simulation ◽

Experimental Investigation ◽

Steady State ◽

Transient Response ◽

Nonlinear Model ◽

Practical Implementation ◽

Dynamic Balancing ◽

Qualitative And Quantitative ◽

Simulation Results ◽

Experimental Rig

This paper concerns an analytical and experimental investigation into the dynamics of an automatic dynamic balancer (ADB) designed to quench vibration in eccentric rotors. This fundamentally nonlinear device incorporates several balancing masses that are free to rotate in a circumferentially mounted ball race. An earlier study into the steady state and transient response of the device with two balls is extended to the case of an arbitrary number of balls. Using bifurcation analysis allied to numerical simulation of a fully nonlinear model, the question is addressed of whether increasing the number of balls is advantageous. It is found that it is never possible to perfectly balance the device at rotation speeds comparable with or below the first natural, bending frequency of the rotor. When considering practical implementation of the device, a modification is suggested where individual balls are contained in separate arcs of the ball race, with rigid partitions separating each arc. Simulation results for a partitioned ADB are compared with those from an experimental rig. Close qualitative and quantitative match is found between the theory and the experiment, confirming that for sub-resonant rotation speeds, the ADB at best makes no difference to the imbalance, and can make things substantially worse. Further related configurations worthy of experimental and numerical investigation are proposed.

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On Turbulent Secondary Flows by Using Linear and Nonlinear k–ω Model

Volume 1: 20th Computers and Information in Engineering Conference ◽

10.1115/detc2000/cie-14682 ◽

2000 ◽

Author(s):

B. Song ◽

R. S. Amano

Keyword(s):

Linear Model ◽

Nonlinear Model ◽

Vortex Structure ◽

Rotational Speed ◽

Nonlinear Models ◽

Suction Side ◽

Secondary Flows ◽

Pressure Side ◽

Square Duct ◽

Linear And Nonlinear

Abstract In the present study, the fully developed turbulent secondary flows inside rotating and non-rotating square duct are numerically simulated using the linear and nonlinear k–ω models. For non-rotating duct, an eight-vortex structure is well captured by the nonlinear k–ω model. For rotating duct, it is interesting to notice that the two vortices are generated when Ro = 0.05, four vortices are presented when Ro = 0.15, and two vortices appeared when the rotational speed is increased up to Ro = 0.35. Although the linear and nonlinear models all produce reasonable results, the different results are also exhibited with these models. For example, the nonlinear model produces a stable effect in the pressure side and predicts less distortion region than the linear model. In the suction side, the linear k–ω model produces greater gradients than the linear model which seems to be realistic.

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Hybrid Control of Electric Vehicle Lateral Dynamics Stabilization

Journal of Electrical Engineering ◽

10.2478/jee-2013-0007 ◽

2013 ◽

Vol 64 (1) ◽

pp. 50-54 ◽

Cited By ~ 3

Author(s):

Khatir Tabti ◽

Mohamend Bourahla ◽

Lotfi Mostefai

Keyword(s):

Electric Vehicle ◽

Vehicle Dynamics ◽

Hybrid Control ◽

Sensor Data ◽

Vehicle Speed ◽

Tire Force ◽

Multi Sensor Data Fusion ◽

Affine Functions ◽

Predictive Controller ◽

Piecewise Affine Functions

This paper presents a novel method for motion control applied to driver stability system of an electric vehicle with independently driven wheels. By formulating the vehicle dynamics using an approximating the tire-force characteristics into piecewise affine functions, the vehicle dynamics cen be described as a linear hybrid dynamical system to design a hybrid model predictive controller. This controller is expected to make the yaw rate follow the reference ensuring the safety of the car passengers. The vehicle speed is estimated using a multi-sensor data fusion method. Simulation results in Matlab/Simulink have shown that the proposed control scheme takes advantages of electric vehicle and enhances the vehicle stability.

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Numerical Simulation of Two High Speed Trains Passing by each other in a Long Tunnel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.117-119.670 ◽

2011 ◽

Vol 117-119 ◽

pp. 670-673

Author(s):

Ming Lu Zhang ◽

Yi Ren Yang ◽

Li Lu ◽

Chen Guang Fan

Keyword(s):

Numerical Simulation ◽

Wind Tunnel ◽

Flow Field ◽

Point Source ◽

High Speed ◽

Stokes Equations ◽

Field Structure ◽

Vehicle Speed ◽

Mesh Method ◽

High Speed Trains

Large eddy simulation (LES) was made to solve the flow around two simplified CRH2 high speed trains passing by each other at the same speed in a long tunnel base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of resting train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field structure around train is completely different between wind tunnel experiment and factual running. Two opposite moving couple of point source and point sink constitute the whole flow field structure during the high speed trains passing by each other. All of streamlines originate from point source (nose) and finish with the closer point sink (tail). The flow field structure around train is similar with different vehicle speed in a long tunnel, and they have a little difference with on the ground.

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