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Hardware-in-the-loop simulation on controllable hydrostatic thrust bearing

In the hydrostatic thrust bearing with open-loop quantity oil supply system for the heavy NC machine tool, the time-variable oil viscosity and the loads will cause the lubricant film thickness deviating from the optimum value, which reduce the bearing film rigidity and affect the machine tool precision. This paper proposed a controllable hydrostatic thrust bearing, which combined the constant flow chambers and the controllable flow chambers. The chamber flow can be adjusted automatically according to the load, the cutting force, and the thermal results of thrust bearing. The controllable chamber flow was adjusted by the electro-hydraulic servo variable mechanism. The oil film thickness error was measured in real time to maintain the most optimum film thickness. The models of controllable chamber flow and servo variable mechanism were established, and the model identification experiments for servo variable mechanism were carried on. The hardware-in-loop simulation results show that the controllable bearings assure the stability and rapidity of system, compensate effectively the effect of load parameter on oil film thickness, and improve the position tracking performance, and validate the creditability of the identification model.