  We develop a method for systematically constructing Lagrangian functions for
dissipative mechanical, electrical and, mechatronic systems. We derive the
equations of motion for some typical mechatronic systems using deterministic
principles that are strictly variational. We do not use any ad hoc features
that are added on after the analysis has been completed, such as the Rayleigh
dissipation function. We generalise the concept of potential, and define
generalised potentials for dissipative lumped system elements. Our innovation
offers a unified approach to the analysis of mechatronic systems where there
are energy and power terms in both the mechanical and electrical parts of the
system. Using our novel technique, we can take advantage of the analytic
approach from mechanics, and we can apply these pow- erful analytical methods
to electrical and to mechatronic systems. We can analyse systems that include
non-conservative forces. Our methodology is deterministic and does does require
any special intuition, and is thus suitable for automation via a computer-based
algebra package.
