Mathematical Problems in Engineering
Volume 2011 (2011), Article ID 287565, 14 pages
Research Article

Fractional-Order Control of Pneumatic Position Servosystems

State Key Laboratory for Manufacturing Systems Engineering, Research Institute of Diagnostics and Cybernetics, Xi'an Jiaotong University, Xi'an 710049, China

Received 24 January 2011; Revised 3 April 2011; Accepted 30 April 2011

Academic Editor: Mohammad Younis

Copyright © 2011 Cao Junyi and Cao Binggang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A fractional-order control strategy for pneumatic position servosystem is presented in this paper. The idea of the fractional calculus application to control theory was introduced in many works, and its advantages were proved. However, the realization of fractional-order controllers for pneumatic position servosystems has not been investigated. Based on the relationship between the pressure in cylinder and the rate of mass flow into the cylinder, the dynamic model of pneumatic position servo system is established. The fractional-order controller for pneumatic position servo and its implementation in industrial computer is designed. The experiments with fractional-order controller are carried out under various conditions, which include sine position signal with different frequency and amplitude, step position signal, and variety inertial load. The results show the effectiveness of the proposed scheme and verify their fine control performance for pneumatic position servo system.