Abstract

A wide range of modeling techniques is available to the engineer. The objective of this paper is to compare some
typical modeling techniques for the simulation of a multidomain mechatronic system. Usual dynamic modeling
methods, such as block diagrams and iconic diagrams, can cause problems for the engineer. Differential algebraic
equations (DAEs) and algebraic loops can significantly increase simulation times and cause numeric errors. Bond
graphs are less common in industry, and are presented here as a method which allows the engineer to easily identify causal loops and elements in differential causality. These can indicate DAEs in the underlying equations. An aircraft landing gear is given as an example of a multi-domain system, and is modeled as a block diagram, an iconic diagram and as a bond graph. The time to construct the model, time to solve and problems faced by the analyst are presented. Bond graphs offer distinct advantages in terms of the ease of implementing algebraic equations and visibility of causality. The time taken to model a system can be significantly reduced and the results appear free from computational errors. Bond graphs are therefore recommended for this type of multi-domain systems analysis