A model-based design can significantly help reduce development time and minimize risks. The central element of such a layout should be a continuous simulation model. The level of details for this simulation model should be selected with respect to the current development phase. This can be used for the clarification of the tasks on the comparative assessment of different solutions, the provision of data for the design components and for the virtual testing of control loop algorithms.
While often analytically determined, for first assessments, sub models are used. That progresses concretization of the system as the sub models are defined numerically or determined experimentally. This can, for example, from domain-specific simulation tools (e.g. an FE program), be identified from measurement results imported into the system or simulation. These basic modeling approaches must be combined with each other and should be interchangeable. Therefore, essential prerequisites for effective development are
- a modular, hierarchical model structure,
- defined interfaces between the individual sub models
- and suitable approaches for describing the sub models.
Our MATLAB®/Simulink® libraries see a description of the system behavior based on alternating impedance and admittance description and thereby defined interfaces between the individual models. Through impedance description, for physical fluxes (such as mechanical speed differences or electric currents) potential sizes such as mechanical forces and momentum or electrical voltages are calculated. Sub models in an admittance formulation calculate field variables of corresponding potential variables. The outputs of a sub model in an impedance formulation are then in turn the inputs on a sub model in admittance description. The blocks may also contain non-linear formulations in which the impedance or admittance description refers only to the inputs and outputs.
The picture shows the model of an elastically mounted plate. The plate is simulated by the process forces which are calculated in the sub model stimulation. It measures the accelerations which are established at another location on the disk. The admittance model of the disk can be imported, for example, from an upstream FE calculation to system simulation. For the storage elements standardized sub models in an impedance formulation are available.
AdaptroSim® Structure and Vibration combines proven and standardized sub models for the hierarchical and modular description of passive mechanical systems. AdaptroSim® Smart Structures contains standard sub models of different levels of details for actuators and sensors as well as several algorithms for control of electromechanical systems. It allows, among other things, the easy modeling of semi-active and active systems for vibration reduction.
AdaptroSim® ANSYS®-MATLAB® Interface includes various functions for model reduction of FE models and provides a powerful interface between upstream numerical tools and system simulation. All part-models and functions have extensive documentation that is included in the MATLAB® Help.