MODELING AND SIMULATION OF HYDRAULIC ACTUATOR WITH VISCOUS FRICTION

Many second order mechanical systems have components subjected to viscous friction. The prediction of dynamic characteristics of such systems involves inclusion of a force term due to friction. When the velocity of sliding is high and constant, the standard models of fluid film lubrication can be employed for this purpose. However, when the sliding velocity is low, and also variable, such standard models cannot be employed. In such situations the behaviour of the mechanical system becomes uncertain due to presence of friction. For a particular system one has to identify a particular model, which gives the best analytical results, as compared to practical observations. In the present work the dynamics of a hydraulic actuator is obtained by simulation by the Lugre friction. The mechanical system used for such simulation is a one-degree-of-freedom second order system. This study is useful in understanding the relative discrepancies, which may arise due to use of different friction models. One can compare the experimental data for a particular application with these results, in order to determine which particular model is in best agreement with the experimental results.