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Introduction 17
shows good correlation between MSC.ADAMS and test measurements
when comparing yaw rate for an 80 kph lane change manoeuvre. It is also
stated, however, that this model had over 200 DOF and used the Pacejka
tyre model that required up to 50 parameters. Pilling (1995) also gives
information about the work at Lotus in the field of vehicle dynamics and
simulation with an emphasis on the role of the tyre.
1.8 Commercial computer packages
General purpose programs such as MSC.ADAMS have been developed
with a view to commercial gain and as such are able to address a much
larger set of problems across a wide range of engineering industries. In
addition to the automotive industry MSC.ADAMS is an established tool
within the aerospace, large construction, electro-mechanical and the general
mechanical engineering industries. The general nature of the program
means that within any one industry the class of applications may develop
and extend over a broad range.
The MSC.ADAMS program is typical of the range of multibody analysis
programs described as numeric where the user is concerned with assembling
a physical description of the problem rather than writing equations of
motion. A comprehensive overview of MSC.ADAMS is provided by Ryan
(1990), although since the date of that publication the development of the
software has moved on considerably, particularly in the area of graphical
pre- and post-processing.
Blundell (1999; 2000a,b) published a series of four IMechE papers with the
aim of summarizing typical processes involved with using MSC.ADAMS
to simulate full vehicle handling manoeuvres. The first paper provided an
overview of the usage of multibody systems analysis in vehicle dynamics.
The second paper described suspension modelling and analysis methodologies.
The third paper covered tyre modelling and provided example routines
used with MSC.ADAMS for different tyre models and data. The
fourth and final paper brought the series together with a comparative study
of full vehicle models, of varying complexity, simulating a double lane
change manoeuvre. Results from the simulation models were compared
with measured test data from the proving ground. The overall emphasis of
the series of papers was to demonstrate the accuracy of simple efficient
models based on parameters amenable to design sensitivity study variations
rather than blindly modelling the vehicle ‘as is’.
Before the evolution of programs like MSC.ADAMS, engineers analysed
the behaviour of mechanisms such as cam-followers and four bar linkages
on the basis of pure kinematic behaviour. Graphical methods were often
used to obtain solutions. Chace (1985) summarizes the early programs that
led to the development of the MSC.ADAMS program. One of the first programs
(Cooper et al., 1965) was KAM (Kinematic Analysis Method) capable
of performing displacement, velocity and acceleration analysis and
solving reaction forces for a limited set of linkages and suspension models.
Another early program (Knappe, 1965) was COMMEND (Computer-
Orientated Mechanical Engineering Design) which was used for planar
problems.