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Adding random disturbances to Modelica models is necessary to represent stochastic fluctuations like sensor noise, air gusts and road irregularities. In this paper, we present a library to specify a pseudo random noise for continuous-time simulations. The random number generator, a probability density function and a frequency spectrum can be defined independently. A new random number generator is proposed to generate a continuous random signal, which is proven to be highly suitable for continuous models. The performance of the noise models is tested in two benchmarks using an academic as well as a realistic model both showing a remarkable increase in simulation speed.

Moving towards the more electric aircraft to be able to replace mechanic, hydraulic and pneumatic components of an aircraft, the aircraft industry calls for new technologies able to support this trend. One of these technologies is the development of advanced electro-mechanical actuators for aircraft control surfaces. Step by step hydraulic actuators are replaced by their electro-mechanical alternatives featuring weight and cost savings. As hydraulic actuators are used for decades by the aircraft industry, they are augmented with advanced signal and model based fault detection and diagnosis systems able to monitor the actuator and initiate adaptations in case of failures. For electromechanical actuators such advanced monitoring systems are still in the initial stages. In this paper, fault detection and isolation filters are designed by applying advanced residual filter synthesis algorithms to be able to monitor the sensor of electro-mechanical actuators. This paves the way for possible adaptations in electromechanical actuator systems in case of failures.

The object of this paper is to present an universal model that describes the gear contact between two gears in a planar environment. The model includes elastic effects between the gear wheels. Using this model it is possible to create arbitrary spur gear connections as well as all kinds of epicyclic gearing configurations by supplying the proper external constraints. The presented model is implementated in the Modelica language and Dymola is used for the simulations.

The implementation of faults in Modelica is currently not standardized, which leads to many noncompatible implementations. To support the standardization of fault implementations, a new standard for fault implementation and triggering is proposed. The proposed standard can handle parameter faults as well as variable faults during a time simulation to cover all common fault possibilities. Using instance modifiers as well as an inner-outer broadcasting method, the faults can be triggered in a central block. Furthermore, care was taken so that the simulation of the models in a fault-free condition can be guaranteed. A library using the proposed standard was developed. In this library, the fault implementation as well as the triggering of these faults was modeled with the end user in mind. An example implementation is presented which shows the capabilities of the library.General fault triggering architecture to trigger model faults in Modelica using a standardized blockset 430