Physical Table Identification for Nominal Hydraulic Cylinders and its Application to Pressure Estimation

The paper provides the first completed version of our identification approach as an intersection of two existing approaches: the physical model approach and the data table approach, for a set of valve flow blocks in nominal hydraulic cylinder dynamics. As one of the well-known physical models, the standard Bernoulli equation needs more accuracy in some cases owing to the steady flow assumption, whereas many data tables often need an expensive flow measurement. The proposed identification approach gives a new matrix representation that resembles the table representation but does not need any flow measurement as well as the steady flow assumption. In particular, unlike the conventional valve flow blocks, the updated valve flow blocks have no empty components via the projection guaranteeing the optimization. The effectiveness is confirmed experimentally by an application to the pressure estimation. The proposed identification approach will be applicable to other blocks including nonlinear friction blocks.