DOI: https://doi.org/10.15368/theses.2015.37
Available at: https://digitalcommons.calpoly.edu/theses/1360
Date of Award
5-2015
Degree Name
MS in Mechanical Engineering
Department/Program
Mechanical Engineering
Advisor
Charles Birdsong
Abstract
This research focuses on the development of an eight degree of freedom vehicle model in the MATLAB computing language. Its purpose is to provide flexibility in the modeling and implementation of signal inputs and crash avoidance logic while maintaining accuracy in the physics of the vehicle’s motion. Firstly, the equations of motion for the bodies involved under a reasonable set of assumptions were developed. Next the model was translated to computer code. By writing the model in SimuLink with *.m files, the modularity of the code is enhanced. To validate the model, several well defined tests were simulated.
To establish some form of credibility, the solutions from this model were compared against three independent solution sets. Three different visual correlates were noted: dynamic response, steady state accuracy, and tendency to oscillate in the high frequency domain. The dynamic response of the model was shown to agree with the empirically measured results. Some steady state accuracy arguments were presented, with focus on further development of the tire model. Future research into other finite difference methods were also given.
Regarding three dimensional kinematics, it should be mentioned that this model uses the simplest approximation to a set of partial differential equations allowable, which gives it some form of presentability in the classroom. The method is comprehensible to even the most amateur computational physicist. For the tests presented, this approximation is convergent, and highlights the efficacy of residual methodologies.