Affordable Access

Access to the full text

New method to improve dynamic stiffness of electro-hydraulic servo systems

Authors
  • Bai, Yanhong1, 2
  • Quan, Long1
  • 1 Taiyuan University of Technology, Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education, Taiyuan, 030024, China , Taiyuan (China)
  • 2 Taiyuan University of Science and Technology, School of Electronics Information Engineering, Taiyuan, 030024, China , Taiyuan (China)
Type
Published Article
Journal
Chinese Journal of Mechanical Engineering
Publisher
Springer Berlin Heidelberg
Publication Date
Sep 28, 2013
Volume
26
Issue
5
Pages
997–1005
Identifiers
DOI: 10.3901/CJME.2013.05.997
Source
Springer Nature
Keywords
License
Yellow

Abstract

Most current researches working on improving stiffness focus on the application of control theories. But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated, so the control action is lagged. Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms. In this paper, the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed. On this basis, the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward. And a scheme using double servo valves to realize flow feedforward compensation is presented, in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time. The two valves are arranged in parallel to control the cylinder jointly. Furthermore, the model of flow compensation is derived, by which the product of the amplitude and width of the valve’s pulse command signal can be calculated. And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations. Using the proposed scheme, simulations and experiments at different positions with different force changes are conducted. The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time. That is, system dynamic load stiffness is evidently raised. This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

Report this publication

Statistics

Seen <100 times