Model-based trajectory tracking control for an electrohydraulic lifting system with valve compensation strategy
来源期刊：中南大学学报(英文版)2012年第11期
论文作者：ZHOU Hua(周华) HOU Jiao-yi(侯交义) ZHAO Yong-gang(赵勇刚) CHEN Ying-long(陈英龙)
文章页码：3110 - 3117
Key words：electrohydraulic system; trajectory tracking control; valve compensation; dead zone compensation; mobile machinery
Abstract: The natural frequency of the electrohydraulic system in mobile machinery is always very low, which brings difficulties to the controller design. To improve the tracking performance of the hydraulic system, mathematical modeling of the electrohydraulic lifting system and the rubber hose was accomplished according to an electrohydraulic lifting test rig built in the laboratory. Then, valve compensation strategy, including spool opening compensation (SOC) and dead zone compensation (DZC), was designed based on the flow-pressure characteristic of a closed-centered proportional valve. Comparative experiments on point-to-point trajectory tracking between a proportional controller with the proposed compensations and a traditional PI controller were conducted. Experiment results show that the maximal absolute values of the tracking error are reduced from 0.039 m to 0.019 m for the slow point-to-point motion trajectory and from 0.085 m to 0.054 m for the fast point-to-point motion trajectory with the proposed compensations. Moreover, tracking error of the proposed controller was analyzed and corresponding suggestions to reduce the tracking error were put forward.
ZHOU Hua(周华)1, HOU Jiao-yi(侯交义)1, ZHAO Yong-gang(赵勇刚)2, CHEN Ying-long(陈英龙)1
(1. State Key Laboratory of Fluid Power Transmission and Control (Zhejiang University), Hangzhou 310027, China;
2. 707 Institute of CSIC, Jiujiang 332007, China)
Abstract:The natural frequency of the electrohydraulic system in mobile machinery is always very low, which brings difficulties to the controller design. To improve the tracking performance of the hydraulic system, mathematical modeling of the electrohydraulic lifting system and the rubber hose was accomplished according to an electrohydraulic lifting test rig built in the laboratory. Then, valve compensation strategy, including spool opening compensation (SOC) and dead zone compensation (DZC), was designed based on the flow-pressure characteristic of a closed-centered proportional valve. Comparative experiments on point-to-point trajectory tracking between a proportional controller with the proposed compensations and a traditional PI controller were conducted. Experiment results show that the maximal absolute values of the tracking error are reduced from 0.039 m to 0.019 m for the slow point-to-point motion trajectory and from 0.085 m to 0.054 m for the fast point-to-point motion trajectory with the proposed compensations. Moreover, tracking error of the proposed controller was analyzed and corresponding suggestions to reduce the tracking error were put forward.
Key words:electrohydraulic system; trajectory tracking control; valve compensation; dead zone compensation; mobile machinery
