Numerical simulation and analysis of nonlinear state-space control design for hydraulic actuator control

Summary In order to investigate the dynamic behavior of complex structural systems experimental testing is indispensable and real-time pseudodynamic (PSD) and real-time hybrid simulation (RTHS) are versatile testing methods to address this need. Accurate control of hydraulic actuators is essential for the accuracy and stability of these methods. This paper introduces a nonlinear state-space controller to control hydraulic actuators under displacement control, specifically for real-time testing applications. The proposed control design process uses the nonlinear state-space model of the system, and utilizes state feedback linearization through a transformation of the state variables. As such, it can efficiently handle the nonlinearities associated with the servo-hydraulic system and the test structure. Comparisons of numerical simulation results for linear state-space and nonlinear state-space controllers are provided. The improved tracking performance of the proposed controller will contribute to more accurate real-time test results, which in turn will enable a more accurate assessment of dynamic characteristics of complex structural systems. Copyright © 2015 John Wiley & Sons, Ltd.