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Summary Servo‐hydraulic actuators are typically employed in real‐time hybrid simulation (RTHS) to impose dynamic loads on a specimen. The success and reliability of an RTHS depend on the accurate tracking of the command displacements by the actuators. This paper introduces a new adaptive compensation approach, adaptive discrete feedforward (ADF) controller, based on the principles of model‐based feedforward and feedback (MFF) controller. While the MFF controller relies on an accurate model of the controlled system obtained through system identification, the ADF controller updates its parameters to adapt to the changing dynamics of the controlled system during the test. This paper presents an experimental parametric investigation that determines the parameters required for implementing the ADF controller, such as the buffer size and the controller updating frequency. The performance of the ADF controller was compared with two other compensation methods: MFF controller and adaptive time series compensator in a series of predefined displacement tracking tests and RTHSs considering both linear and nonlinear specimens. The results are discussed in detail, where the ADF controller was shown to considerably improve the capability of the servo‐hydraulic actuator in tracking the command displacements.

The numerical substructure of a real-time hybrid simulation (RTHS) has been considerably simplified through condensation methods to relieve the burden incurred by computation. However, this simplification severely limits the application of RTHS to structures whose numerical parts are complex and require a large number of degrees of freedom (DOFs) to model. Thus, in this study, a vector form intrinsic finite element (VFIFE) analysis is introduced to RTHS with numerical substructures containing a large number of DOFs. A field programmable gate array (FPGA) is also employed to speed-up the numerical simulation of the VFIFE through parallel computing in RTHS. The characteristics of this parallel RTHS platform using VFIFE and FPGA are discussed in detail in this paper. A simple RTHS was carried out to verify the feasibility of this new platform, followed by a complex virtual RTHS to show its powerful computational capability. KEYWORDS degree of freedom, field programmable gate array, parallel computing, real-time hybrid simulation, vector form intrinsic finite element

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