Linear motion control with a low-power hydraulic switching converter - Part II: Flatness-based control. (October 2015)

• Record Type: Journal Article
• Authors: Kogler, Helmut; Scheidl, Rudolf
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 229:Number 9(2015)
• Page Start: 818
• Page End: 828
• Publication Date: 2015-10
• Subjects: Hydraulics -- buck converter -- flatness-based control -- switching control; Mechanical engineering -- Periodicals; Automatic control -- Periodicals; Systems engineering -- Periodicals; 621.3
• DOI: 10.1177/0959651815589668
• Languages: English
• ISSNs: 0959-6518

Abstract

Hydraulic switching control is an opportunity for economic, robust and energy efficient hydraulic motion control. The hydraulic buck converter represents a promising concept, which meets these requirements. Part I of this publication has shown that for a convenient control performance a model-based control should be applied. In this paper a flatness-based controller for linear hydraulic motion control with a sub-kilowatt hydraulic buck converter is presented. A simple model-based on an averaging of the switching converter is employed to derive a flatness-based controller combined with a nonlinear observer to estimate all system states only from a position signal. Its performance is studied by simulations and experiments for large ramp type and sinusoidal motions of a heavy mass. Comparison of motion quality and energy consumption are made between the converter and a standard hydraulic proportional drive using a servo-valve instead of the switching converter. With this flatness-based controller a tracking performance as good as of a proportional drive can be achieved, yet at much better efficiency. Proportional control for the switching converter, however, leads to inferior results for this type of intended motions.