Open-loop control of elliptical shaft center orbit

Abstract

In order to realize the machining of elliptical holes, the article researches control simulation of shaft center movement orbit using Eulerian method. A new hydrostatic bearing and a hydraulic control system are proposed, and quantitative relation between the expected shaft center coordinates and spool displacement of electro-hydraulic servo valve is studied. With the Eulerian method, open-loop control orbit of shaft center is simulated. And the simulation results indicate that open-loop control method not only controls shaft center movement to form ellipse orbits but also has strong robustness against dynamic disturbing force or instantaneous static disturbing force. This article lays theoretical basis for machining of elliptical holes.

Optimal control simulation of elliptical shaft center orbit with the hydraulic servo system

“…Figure 1 shows the hydraulic control system of shaft center movement orbit. Compared to previous hydraulic control system with four servo valves in literature, 15 the new system in the present research has only two servo valves. The new scheme not only simplifies the control system but also decreases the cost of the system.…”

“…There is a big deviation between the black line segments and blue ellipse. In the previous research, 15 with a large number of collocation points, Eulerian control method can be used to control shaft and make the shaft center orbit get close to the expected ellipse. But the control precision of Eulerian method becomes obviously worse with fewer collocation points, and the Eulerian method is not suitable for this situation in the present research.…”

“…Based on preliminary work, 14,15,28,29 the present research researches the hydraulic control scheme to bore elliptical hole and uses optimal control method based on GPM to realize control simulation of shaft center movement orbit. The present research not only discusses the feasibility of realizing new boring method 14 with hydrostatic bearing system but also provides a reference for rotor vibration abatement with the optimal control mechanism of shaft center.…”

“…Based on similarity between the movement orbit of shaft center and the satellite movement orbit, the present research applies the optimal control approach based on GPM in aerospace field to shaft center orbit control. Compared to Eulerian control method, 15 optimal control method can control the shaft center orbit with very few collocation points, which can decrease the frequency response requirements of electro-hydraulic servo valve and system cost. And the comparison results also show better feasibility and more advantages of optimal control method in the application of the new machining method.…”

“…So, as long as the orbit of shaft center is an expected ellipse, elliptical hole is able to be processed. In the previous research, literature 15 adopted Eulerian method to control shaft center orbit and made the orbit approach the expected ellipse. Though the control precision of Eulerian method is good, the number of collocation points (i.e.…”