Bond graph and external modeling for FDI design of smart actuators

External model leads on concepts of services and user operating modes and requires information from fault detection and isolation algorithms to propose to the operator various modes and explains how to go from one to another. The bond graph methodology as a graphical modelling language becomes a complementary tool for those purposes. In this way, by adding a bond graph methodology, it becomes possible to obtain physical knowledge of the actuators, and to improve their monitoring, and consequently to insure the best safety using its causal properties. The methodology is applied to an intelligent industrial actuator used as a benchmark in the EU FP5 grant DAMADICS project.