Many realistic contexts in which planning can be applied feature a mixture of discrete and continuous behaviours. For example, the management of a refinery [Boddy JohnsonBoddy Johnson2004], the start-up procedure of a chemical plant [Aylett, Soutter, Petley, Chung, EdwardsAylett
et al.2001], the control of an autonomous vehicle [Léauté WilliamsLéauté Williams2005] and the coordination of the activities of a planetary lander (Blake et al., 2004) are problems for which reasoning about continuous change is fundamental to the planning process. These problems also contain discrete change which can be modelled through traditional planning formalisms. Such situations motivate the need to model mixed discrete-continuous domains as planning problems.
We present two motivating examples to demonstrate how discrete and continuous behaviours can interact to yield interesting planning problems. These are Boddy and Johnson's petroleum refinery domain and the battery power model of Beagle 2.