Design and Simulation of Heterogeneous Control Systems Using Ptolemy Ii

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. Copyright 2001 IFAC