A dead-band model and its online detection for the pilot stage of a two-stage directional flow control valve. (March 2016)

• Record Type: Journal Article
• Authors: Xu, Bing; Su, Qi; Zhang, Junhui; Lu, Zhenyu
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 230:Number 4(2016)
• Page Start: 639
• Page End: 654
• Publication Date: 2016-03
• Subjects: Dead-band model -- pilot stage -- two-stage directional flow control valve -- cascade controller -- trajectory tracking; Mechanical engineering -- Periodicals; 621.05
• DOI: 10.1177/0954406215578158
• Languages: English
• ISSNs: 0954-4062

Abstract

The dead-band in the electro-hydraulic proportional control valve is one of the main factors that affect its dynamic performance. Especially in the pilot stages of two-stage directional flow control valves, the insistent dead-band will result in a conservative valve controller design. In this paper, a detailed dead-band model describing the relationship between pilot valve spool and the flow rate of the pilot control valve is proposed. And an improved dead-band description involved with the housing clearance of the valve spool is developed to prove the dead-band uncertainty for a single valve system. Then a simple and effective method is proposed to detect the varying dead-band values in the pilot stage. This method is specially designed with a limited main spool displacement and short time interval so that it can be used for online detection without affecting the hydraulic system where the two-stage valve is involved. With the regular dead-band inverse function, comparative experimental results show that this method is effective to attenuate the large trajectory tracking error caused by the varying dead-band. This dead-band detection also can be applied to other electro-hydraulic proportional valve-controlled position control systems with unknown dead-bands.