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International Journal of Automotive Technology

, Volume 18, Issue 6, pp 1121–1129 | Cite as

Analytical description of ride comfort and optimal damping of cushion-suspension for wheel-drive electric vehicles

  • Fuxing Yang
  • Leilei Zhao
  • Yuewei Yu
  • Changcheng Zhou
Article

Abstract

To provide initial design values of seat cushion and chassis suspension damping for wheel-drive electric vehicles (WDEVs), this paper presents an analytical estimation method and a practical damping parameters design method. Firstly, two formulae of the human body vertical acceleration in terms of the power spectrum density (PSD) and the root mean square (RMS) are deduced for WDEVs. Then, the coupling effects of the key vehicle parameters on ride comfort are revealed. Finally, with a practical example, the damping parameters of the cushion and the suspension are initially designed and analyzed. The results show that when every 10.0 kg increases for motor mass, the optimal damping values of the cushion and the suspension should be reduced by about 15.0 Ns/m and 50.0 Ns/m, respectively. However, the RMS acceleration increases 0.017 m/s2 with a decrease of 2.5 % for ride comfort.

Key words

Wheel-drive electric vehicles Coupling effects Comfort evaluation Initial design 

Abbreviations

WDEVs

wheel-drive electric vehicles

RMS

root mean square

PSD

power spectrum density, m2/s3

m3

human body mass, kg

m2

vehicle body mass, kg

m1

tire system mass, kg

m0

motor mass, kg

K3

cushion stiffness, N/m

K2

suspension stiffness, N/m

K1

tire stiffness, N/m

C3

cushion damping, N·s/m

C2

suspension damping, N·s/m

x3

human body bounce, m

x2

vehicle body bounce, m

x1

wheel hop, m

q

road excitation, m

ω3

approximate natural angular frequency of human body system, rad/s

ω2

approximate natural angular frequency of vehicle body system, rad/s

ω1

approximate natural angular frequency of tire system, rad/s

f3

approximate natural frequency of human body system, Hz

f2

approximate natural frequency of vehicle body system, Hz

f1

approximate natural frequency of tire system, Hz

ξ3

damping ratio of cushion system

ξ2

damping ratio of chassis suspension system

r2

mass ratio of human body and vehicle body

r1

mass ratio of vehicle body and unsprung mass

η1

stiffness ratio of cushion and chassis suspension

η2

stiffness ratio of tire and chassis suspension

α2

frequency ratio of human body system and vehicle body

α1

frequency ratio of tire system and vehicle body

a(t)

human body vertical acceleration, m/s2

σa

human body vertical RMS acceleration, m/s2

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Copyright information

© The Korean Society of Automotive Engineers and Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • Fuxing Yang
    • 1
  • Leilei Zhao
    • 1
  • Yuewei Yu
    • 2
  • Changcheng Zhou
    • 2
  1. 1.School of AutomationBeijing University of Posts and TelecommunicationsBeijingChina
  2. 2.School of Transportation and Vehicle EngineeringShandong University of TechnologyZiboChina

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