Malfunctions and failures within the adaption process are harmful for the overall load-bearing structure or compromise functioning for the user and have to be avoided or rather detected in time. Therefore, if a failure occurs it may not have fatal consequences.
For this reason project B03 examines uncertainties, disturbances, faults and failure possibilities. An integrated monitoring and fault detection informs about the occurrence of faults. A subsequent fault diagnosis allows conclusions about the fault location, which is used for their isolation and detection at an early stage. To design the system less susceptible to interferences and more robust against disturbances, the disturbances are considered in the fault diagnosis design. For a more sustainable construction, the safety and reliability-oriented design of adaptive load-bearing structures is important. The more precisely the expected operating load is known and considered in the reliability model, the more accurately the load-bearing structure is designed. Uncertainties caused by failures of the adaptive function must be avoided by a functionally safe system, in which diagnostics in turn play an important role.
Summarized this yields to the following essential questions:
- Which fauls and loads are characteristic for adaptive structures and how can they be modelled?
- Which load spectra lead to failure-critical states and what is the relationship to serviceability and ultimate limit state of adaptive structures?
- How can this relationship be modelled considering failures in the adaptation process?
- How can faults be distinguished from unknown loads and reliably detected and isolated?
- Which methods are suitable for fault detection and diagnosis in adaptive structures?
- Which failure reactions are necessary to avoid fatal faults?
- How do safety, reliability and sustainability of adaptive structures influence each other and how can a comprehensive design method include these central aspects?
- What are relevant measurement signals for the detection of faults?
The basic objective of the failure detection is the diagnosis of faults in actuators and sensors of adaptive structures which are influenced by stochastic and non measurable loads.
For fault diagnosis, it must be ensured that the faults are detectable and distinguishable from the loads. For this purpose, criteria are developed which allow the disinguishability between faults and loads as well as the isolation of faults. Model-based and data-based methods are investigated for the detection and isolation of the faults.
The results of the fault diagnosis is passed to the projects B02 and B04 for reconfiguring the observer and controller. C02 is provided with reliability requirements for choosing an actuator concept optimized regarding reliability. For a reliable power supply of the electro active polymers an investigation is handed to C03.
In the further course of the project, the influence of the topology and the position of the actuators on the serviceability and load-bearing capacity will be identified and technical concepts will be developed to ensure stability in the event of total failure of the actuators. Furthermore, concepts for actuator and sensor placement with regard to detectability and fault tolerance are developed in cooperation with other subprojects.
The concepts for actuator and sensor placement form the basis for the development of model and data-based approaches for fault diagnosis and generalization to different types of adaptive structures. This will be supplemented by an active fault diagnosis in the actuator system. Furthermore, a Prognostics and Health Management for reliability and sustainability improvement with influence on the actuators is developed.
- Prof. Dr.-Ing. Bernd Bertsche, Institute of Machine Components
- Prof. Dr.-Ing. Cristina Tarín, Institute for System Dynamics