4569846498

Modelling and assembly of the full vehicle 389
Camber angle (deg)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
FRONT RIGHT TYRE – 100 km/h LANE CHANGE
Roll stiffness model
_ _ _ _ _ _ _
Linkage model __________
0.0
1.0
2.0
Time (s)
3.0
4.0
5.0
Fig. 6.60
Camber angle comparison – linkage and roll stiffness models
As discussed in Chapter 5 it is perhaps fortuitous in this case that for a passenger
car of the type used here the lateral tyre force produced due to slip
angle is considerably more significant than that arising due to camber
between the tyre and road surface. Further investigations can be carried out
to establish the significance of a poor camber angle prediction input to the
tyre model. In Figure 6.61 the linkage model has been run using an interpolation
tyre model where it has been possible to deactivate the generation
of lateral force arising from camber angle. In this plot it can be seen that the
prediction of yaw rate, for example, is not sensitive for this vehicle and this
manoeuvre to the modelling of camber thrust.
To conclude this case study it is possible to consider an alternative modelling
and simulation environment for the prediction of the full vehicle
dynamics. As discussed earlier the incorporation of microprocessor control
systems in a vehicle may involve the use of a simulation method that
involves:
(i) the use of multibody systems software where the user must invest in
the modelling of the control systems
(ii) the use of software such as MATLAB/Simulink where the user must
invest in the implementation of a vehicle model or
(iii) a co-simulation involving parallel operation of the multibody systems
and control simulation software
In this example the author (Wenzel et al., 2003) 2 has chosen the second of
the above options and a vehicle model (Figure 6.62) is developed from first
2 Wenzel et al. (2003) describe preliminary work undertaken in a collaborative
research project with Jaguar Cars Ltd, Coventry, UK and funded by the Control
Theory and Applications Centre, Coventry University, Coventry, UK. It forms the
PhD programme for Thomas A. Wenzel.