Vehicle - MapleSim Help

Online Help

All Products    Maple    MapleSim


Home : Support : Online Help : MapleSim Toolboxes : MapleSim Driveline Component Library : Vehicle and Tire : DrivelineComponentLibrary/vehicle

Vehicle

Longitudinal vehicle dynamics component

Note:  This component is used with the Tire component.

            

 

The Vehicle component models the longitudinal dynamics of a vehicle. The model has only one degree of freedom (longitudinal motion). Lateral and vertical motions as well as roll, pitch, and yaw are neglected. The Vehicle component is intended for use with two Tire components. The front and rear axles connections are modeled using a real output port for vertical force and a 1-D mechanical translation flange to transfer longitudinal force and motion between the vehicle and the axle.

 

 

Equations

The Vehicle equations are given by

sxr = s l + a  

sxf = s + a  

vx = ⅆⅆ ts 

ax = ⅆⅆ tv 

Where s  is the longitudinal DOF of the vehicle, l  is the vehicle wheel base, and  a  is the distance from the front axle to the projection point of the vehicle CG onto the line connecting front and rear axles

The equation of longitudinal motion is

m · ax = Fx  Fd  m · g · sinα  Fl

Where  Fl   is the external force on the vehicle and  Fx  is the traction force and is defined by

Fx = fxr + fxf

Also, Fd   is calculated as

Fd = 12Cd · ρ · A · vx  vw · vx  vw

The weight distribution for front and rear axles is calculated by the following equations:

l · fzf = h · m · ax+ Fd + m · g · sinα  Fl + m · g · cosα · l  a

l · fzf = h · m · ax+ Fd + m · g · sinα  Fl + m · g · cosα · a

where h is distance from the CG to the ground.

 

Connections 

Name

Condition

Description

ID

flangea

-

Front axle longitudinal flange

flange_xf

flangeb

-

Rear axle longitudinal flange

flange_xr

fzf

-

Real output port for front axle vertical force

f_zf

fzf

-

Real output port for real axle vertical force

f_zf

vx

-

Real output port for vehicle forward velocity (km/h)

speed

Fl

use external load = true

Conditional real input port for the externally applied longitudinal force

Fl

 

Parameters

Symbol

Default

Units

Description

ID

use external load

false

-

Enables/Disables external load:

true - external load (force) port is enabled

false - external load (force) port is disabled

useExternalLoad

g

9.81

ms2

Gravitational acceleration

g

α

0

rad

Ground inclination

alpha

h

0.5

m

Distance from CG to the ground

h

l

3

m

Wheel base

l

a

1.5

m

Distance from front axle to the normal projection point of CG onto the ground

a

m

1500

kg

Vehicle mass

m

A

1

m2

Vehicle effective cross-section

A

Cd

0.3

Coefficient of drag

Cd

ρ

1.2

kgm3

Mass density of air

rho

vw

0

ms

Wind speed

vw

 

Initial Conditions

Symbol

Condition

Default

Units

Description

ID

Vx0

ms

Initial forward velocity

vx

 

See Also

MapleSim Driveline Library Overview

MapleSim Library Overview

1-D Mechanical Overview

Tire Component Library

Vehicle and Tire

Tire

 

 

References

Pacejka, Hans B. Tire and Vehicle Dynamics. Second Edition. SAE International and Elsevier, 2005.

 

 

 


Download Help Document

Was this information helpful?



Please add your Comment (Optional)
E-mail Address (Optional)
What is ? This question helps us to combat spam