Robust hydraulic actuator force control through relief discharge. (April 2015)

• Record Type: Journal Article
• Authors: Nourizadeh, Reza; Rezaei, S Mehdi; Zareinejad, Mohammad; Baghestan, Keivan; Tivay, Ali; Saadat, Mozafar
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 229:Number 4(2015)
• Page Start: 308
• Page End: 318
• Publication Date: 2015-04
• Subjects: Servo-hydraulic systems -- mechanical control systems -- control system implementation -- dynamic modeling -- control system design; Mechanical engineering -- Periodicals; Automatic control -- Periodicals; Systems engineering -- Periodicals; 621.3
• DOI: 10.1177/0959651814564480
• Languages: English
• ISSNs: 0959-6518

Abstract

Actuator force control in servo-hydraulic systems has numerous applications in machinery and industrial settings. The prevalent hydraulic configuration for force control utilizes a proportional directional control valve to properly route the supplied hydraulic fluid toward the chambers of the actuator. It is well known that this configuration imposes certain physical limitations on force-tracking performance. In this article, a different configuration is utilized to improve the hydraulic force control performance. This is done by replacing the proportional directional control valve with a proportional double-stage relief valve. It is shown that this new setting is superior in its achievable force-tracking performance. This comes at the cost of a more challenging control problem compared to the proportional directional control valve case, due to the presence of un-modeled dynamics and unknown parameters. A robustH ∞ control approach has been followed as the main solution to address uncertainty problems. However, conservative robust design imposes its own limitations on force-tracking performance. To address this issue, a combination of additional switched-proportional–integral–derivative and Prandtl–Ishlinskii hysteresis compensation control loops is proposed. Conditions are derived under which the additional loops improve the performance of the robustH ∞ controller. The effectiveness of the proposed configuration and control method is demonstrated by the experimental results.