An Efficient Equation Generation Mechanism for a Component-based Modeling Scheme
Barve, Aparna A
:
2008-04-14
Abstract
Fault diagnosis mechanisms for continuous dynamic systems involve
building observers that can track system behavior. Continuous
dynamic systems can be modeled using bond graphs which are a
domain independent graphical description of dynamic behavior of
physical systems. The observer plays an important part in
diagnosing faults in such systems by comparing the system output
with the estimated output and monitoring the observer residual for
possible faults. The steps involved in building an observer from a
bond graph model involve transforming the bond graph model of the
physical system to its corresponding block diagram model,
generating the state space equations and the output equations and
then implementing the observer that uses the mathematical
equations and other parameters including the output generated by
the system.
The thesis provides an efficient equation generation mechanism for
a component based modeling scheme. Assigning causalities to the
bonds captures the cause effect relationship between the bond
graph elements and considering these causalities in the equation
generation algorithm significantly optimizes the process of
deriving the state space or the process model and the measurement
model. These models have also been used to construct a Kalman
filter based observer, which is used to track the system behavior.
A mechanism for extending the modeling paradigm to include n-port
elements that play an important part in the modeling on
multi-domain physical systems has also been given. The
implementation has been verified by running the system for a
hydraulic actuator and a two tank system.