Design and Simulation of Heterogeneous
Control Systems Using Ptolemy II
Johan Eker, Chamberlain Fong, Joern W. Janneck, and Jie Liu
IFAC Conference on New Technologies for Computer Control (NTCC’01),
Hong Kong, China, Nov. 2001
ABSTRACT
Complex control systems are heterogeneous from both an implementation
and a modeling perspective. Design and simulation environments for such
systems need to integrate different component interaction styles, like differential
equations, discrete events, state machines, dataflow networks, and real-time
scheduling. This paper motivates the use of Ptolemy II software environment for
modeling and simulation of heterogeneous control systems. Ptolemy II advocates a
component-based design methodology, and hierarchically integrates multiple models
of computation, which can be used to capture different design perspectives. A
Furuta pendulum control system is used as a motivating example. After designing
a three-mode hybrid controller under idealized assumptions, implementation effects,
like real-time scheduling and network protocols, are taken into consideration
to achieve a more realistic simulation. The 3D animation package in Ptolemy II
helps designers to visualize the control results. In this process of refining the
design, components modeled in early phases can be reused.