O'Kane, Thomas G.
(2018)
High Fidelity Modelling of
Motorcycle Dynamics.
PhD thesis, National University of Ireland Maynooth.
Abstract
Modern racing and high performance road motorcycles have begun to use ever
more sophisticated control systems to improve performance and safety. Traction
control, anti-wheelie control, engine brake control and in the case of road bikes,
anti-lock braking are now ubiquitous. Electronically adjustable suspension damping
is becoming ever more common. At the time of writing, no manufacturer uses
a high fidelity real time model of the motorcycle and tyres in their control strategies.
The use of such a model would assist in integrating separate strategies into
an overall vehicle stability strategy. Furthermore, the development of racing and
high performance road motorcycles has traditionally depended more on experience
and testing than on modelling and simulation. One reason for this has been
the lack of availability of a high fidelity motorcycle model suitable for the task.
The development of general multibody simulation software such as MSC Adams
has been driven primarily by the four wheel world and is much more suited to cars
than motorcycles. Simplified or over-linearised models lack the required fidelity.
A new high fidelity multibody motorcycle model for use in real time is proposed.
It is an eleven degree of freedom model and the equations of motion are
formulated using Kane's equations. Kane's method has been chosen over other
methodologies as it scales well to complex systems and lends itself to automated
numerical computation in a way that other methods do not. There are few linear
relationships in the mechanism of a motorcycle, but many relationships are very
nearly linear. This fact is used to simplify the model while maintaining fidelity
and this contributes to lowering the computation cost. The tyre model is the
widely used Magic Formula model, developed by Pacejka and others. The motorcycle
model estimates data which is not directly measurable, such as tyre shear forces and slip angles.
A motorcycle was instrumented and data was recorded during various tests,
including coast-down testing and some very competitive laps of a race circuit by
a professional motorcycle racer and test rider. The data from the coast-down
tests was used to estimate aerodynamic and engine drag parameters. The model
was validated against the race track test data with satisfactory results. Tyre
model parameters were not available for the tyres used in testing, so a method
was developed to estimate the tyre parameters which predict lateral force. The
behaviour of the model was analysed by applying various test functions and root
locus analysis was carried out to investigate the system modes.
The utility of the model for motorcycle development and set-up was investigated
and a method was developed whereby motorcycle parameters may be
optimised with respect to certain performance criteria. This method may be
used to explore directions for future development and also to optimise settings
for racing.
| Item Type: |
Thesis
(PhD)
|
| Keywords: |
High Fidelity Modelling;
Motorcycle Dynamics; |
| Academic Unit: |
Faculty of Science and Engineering > Electronic Engineering |
| Item ID: |
12555 |
| Depositing User: |
IR eTheses
|
| Date Deposited: |
09 Mar 2020 16:39 |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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