Abstract: At present, the hydrostatic bearing system, usually considered as the linear system, is mostly researched on the dynamic performance. But the error via linearization transform hasn’t yet analyzed. Take the open-type hydrostatic worktable based on the multi-head pump for instance, the nonlinear differential equations systems on the pressure and the flow are derived. On the one hand, the hydrostatic bearing system is linearized, and the transfer function via Laplace transform is obtained. The stability is discriminated with Routh criteria, and then the step response curves and the pulse response curves are plotted. On the other hand, the system block diagram of the worktable bearing system is built with fourth-order Runge-Kutta method using Simulink tool box, and the step response curves are plotted. Comparing the response curves obtained separately from two different methods, the difference between the curves is very small, and the precision can meet the demand of the practical engineering, then the linear treatment is valid for the open-type hydrostatic worktable based on the multi-head pump. So the dynamic performance on the worktable is analyzed, and the amplitude-frequency curves, the phase-frequency curves, and the dynamic stiffness-frequency curves are present. The proposed research contrasts the response results of the hydrostatic worktable with two different methods, and provides a basis for the practical engineering.

Key words: Dynamic stiffness, Fourth-order Runge-Kutta method, Laplace transform, Multi-head pump, Nonlinear differential equations systems, Open-type hydrostatic worktable, Big data, Intelligent fault diagnosis, Mechanical equipment