DES Control of Concurrent Hybrid Systems
Systems & control · 2006
This chapter extends the DES framework toward the description of concurrency in hybrid systems. Concurrency could arise in various ways in hybrid systems. A possible paradigm is presented in Figures 9.1 and 9.2. Fig. 9.1 presents n subsystems operating in parallel. Fig. 9.2 presents a two-level control architecture. The lower level consists of the controllers C 1, C 2, ..., Cn . The role of the controllers is to govern the hybrid dynamics of the subsystems. The lower level design generates the controllers C 1, C 2, ..., Cn and obtains a logical model for each closed loop of a controller and a subsystem. The logical models are composed to form the global logical model of the system. This global model of the system is used when the supervisor is generated at the higher level design step. In Fig. 9.2 the global model is implemented (for instance, as a computer program), and the variables of the global model are updated (according to the rules of the global model) when a subsystem generates an event. The supervisor uses the global model variables in order to decide which controller inputs are appropriate. The control input of a controller Ci dictates the region where the state of the controlled subsystem should be. Given a state of the system, the supervisor may have more than one choice in selecting the inputs of the controllers, and so an operator (for instance, another computer program) can select a specific input according to some optimization criteria. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.