| Summary: | The aim of this research is to use numerical optimisation to investigate the on-limit
behaviour of an open wheel downforce type race car using the best compromise of
modelling accuracy and computational effort.
The current state of lap simulation methods are identified, and the GG speed diagram
is described. The use of constrained optimisation, which is a form of optimal control,
is used to develop the methods described in this thesis. A seven degree of freedom
vehicle model validated by other researchers is used for method validation purposes,
and is extended, where possible, to make the modelling of vehicle components more
physically significant, without adversely affecting the computational time.
This research suggests a quasi steady state approach that produces a GG speed diagram
and circuit simulation tool that is capable of optimising vehicle parameters and
subsystems in addition to the prevailing control vector of steer and throttle response.
The use of numerical optimisation to optimise the rear differential hydraulic pressure
and the roll stiffness distribution to maximise vehicle performance is demonstrated.
The optimisation of the rear differential hydraulic pressure showed a very
small improvement in vehicle performance in combined high speed braking and cornering,
but highlighted the ability of the differential to affect the cornering behaviour
of the vehicle. The optimisation of the roll stiffness distribution research showed that
a significant improvement in the lateral acceleration capability of the vehicle could be
achieved at all vehicle speeds between 20 and 80m/s, especially in combined braking
and cornering.
In addition, a parameter sensitivity study around a realistic Formula One vehicle
setup was conducted, looking at the sensitivity of vehicle mass, yaw inertia, tyres,
centre of gravity location and engine torque to vehicle performance. An investigation
into the importance of the path finding calculation is also reported.
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