This category contains all control problems for which the underlying mathematical model contains differential as well as algebraic variables.
If the model includes algebraic constraints and variables, for example from conversation laws, a problem will be categorized as a DAE model. The model equations for will then include both differential equations and algebraic constraints that determine the algebraic states in dependence of the differential states and the controls. A more detailed classification includes the index of the algebraic equations.
- The differential equations might depend on state-dependent switches.
- The variables may include boolean variables.
- The underlying process might be a multistage process.
- The dynamics might be unstable.
- There might be an underlying network topology.
- The integer control functions might have been (re)formulated by means of an outer convexification.