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U·Sim (Usage-Simulation) is the central tool within the process of deriving customer-oriented load distributions and design loads. Similarly, it can be applied to the analysis of energy efficiency (consumption and emission).
It combines a model for:
An example for a factor model is
An operating state is a combination of one level for each factor. The operating states are used to decompose the operation of a vehicle. The separation between vehicle usage, expressed in terms of frequencies of operating states, and vehicle loads, covered by a set of measurements within each operating state, is an effective approach to limit the effort of measuring to the statistically necessary amount and being able to simulate different groups of users by varying the usage model.
A large number of virtual customers is generated by a Monte Carlo simulation, which varies the frequencies of the operating states as well as the loads within an operating state across a large number of virtual vehicles. This results in empirical distributions for each measurement channel. A high quantile (e.g., 99 percent) may be extracted as a design load for further processing (component optimisation, mapping to the proving ground, or deriving test loads). Special manoeuvres (e.g., curb crossings) maybe added on request.
The software is easy to use. The usage model as well as the load data are defined via Excel sheets. The usage model parameters may be defined in a manual way based on rough assumptions about the vehicle’s usage (for instance from the sales department) or based on a more elaborate investigation (see VMS usage modelling). The Excel sheet for the load data has been automatically generated by VMC GeoLDA in advance. Both are imported and the empirical load distributions are generated with a few clicks. In particular, the following features are provided:
Once the load distributions and design loads have been generated, the software U·SimOpt may be used to map the design load to a schedule on the proving ground. Additionally safety factors and rig tests can be defined in Jurojin with respect to the simulated load distributions
Fraunhofer Institute for Industrial Mathematics ITWM