Fuzzy modelling of wagon wheel unloading due to longitudinal impact forces

In this paper a fuzzy model is developed to predict wagon wheel unloading due to wagon body and bogie pitch modes induced by longitudinal impact forces. Data was obtained using the wagon dynamics simulation package, VAMPIRE/spl reg/, with a wagon model typical of wagons in Australian freight service. Simulations were completed for 31 states of wagon body mass from empty to maximum load, 8 to 62 tonne and 31 states of longitudinal force were applied making 961 scenarios. Four 2-input 1-output fuzzy systems were developed to predict wheel unloading for each axle using wagon mass and the impact force magnitude as inputs. A cooperative co-evolutionary algorithm was used to determine a complete set fuzzy rules for this system together with defining fuzzy set definitions. The fuzzy model produced was then evaluated for its suitability as a predictive model.