State observers based on detailed multibody models applied to an automobile

Abstract

A multibody system is a set of rigid or flexible bodies that are linked via joints. Mulltibody dynamics is a discipline in which efficient computational methods are studied to solve the equations of the dynamics of these systems. If the calculation of dynamics runs faster than the motion of the mechanism, the resulting simulation can be synchronized with real external elements, opening a range of new possibilities, such as its use in simulators, or in state observers. A state observer is a mathematical tool in whieh the dynamic model of a system is combined with information from sensors to obtain more and/or bettcr information about the system. Thcy are used when the desired magnitude cannot be directly measured due to economical or tcchnical reasons. In this thesis, multibody-based state observers are developed and tested. They are tested first in simulation with simple models of flat mechanisms, studying their achieved accuracy and computational costo Finally, the method which has a better relationship between accuracy and computational cost is implemented for an automobile.