This paper is an exploration into the relationship between the operating environment and the mode-structure of supervisory control systems. Based on a field-study describing operators' (e.g., pilots, controllers, technicians) interaction with modal systems, we developed several hypotheses about why and how operators transition among modes. We used these hypotheses to develop a framework of the complete environment-human-machine relationship. The framework, called 'OFAN,' is based on Statecharts and Operator-Function models - both modern extensions to the finite-state-machine theory. Using the OFAN framework, we describe two examples of moding problems and identify the system's features that induce such problems. In the first example, a moding problem in a display, it was the product of dual transitions into a state: one consistent with the layout of the controls/displays (and therefore intuitive), the other dependent upon some internal state (and therefore unintuitive). In the second example, a moding problem in an automatic flight control system, it was a default entry into a state (of the machine) which was inconsistent with the state of the environment. For both examples, the underlying approach and methods used to highlight these moding problems are briefly discussed.
|Original language||English (US)|
|Number of pages||8|
|Journal||Proceedings of the IEEE International Conference on Systems, Man and Cybernetics|
|State||Published - 1995|
ASJC Scopus subject areas
- Hardware and Architecture
- Control and Systems Engineering