Real time hybrid simulation (RTHS) has increasingly been recognized as a powerful testing methodology to evaluate structural components and systems under realistic operating conditions. RTHS is a cost effective approach compared with large scale shake table testing. Furthermore it can maximally preserve rate dependency and nonlinear characteristics of physically tested (non) structural components. Although conceptually very attractive, challenges do exist that require comprehensive validation before RTHS should be employed to assess complicated physical phenomena. One of the most important issues that governs the stability and accuracy of a RTHS is the ability to achieve synchronization of boundary conditions between the computational and physical elements. The objective of this study is to propose and validate an H-infinity design for actuator motion control in RTHS. Controller performance is evaluated in the laboratory using a worst-case substructure proportioning scheme. A modular, one-bay, one-story steel moment resisting frame specimen is tested experimentally. Its deformation is kept within linear range for ready comparison with the reference analytical solution. Both system analysis and experimental results show that the proposed H-infinity-controller can significantly improve both the stability limit and test accuracy compared to several existing strategies. Another key feature of the proposed controller is ts robust performance in terms of unmodeled dynamics and uncertainties, which inevitably exist in all physical systems. This characteristic is essential to enhance test quality for specimens with nonlinear dynamic behavior, thus ensuring the validity of proposed approach for more complex RTHS implementations.
This work was supported in part by the U.S. National Science Foundation under Grant CNS-1028668 (MRI), CMMI-1011534 (NEESR), and by the Purdue University Cyber-Center Special Incentive Research Grant and the School of Mechanical Engineering at Purdue University.
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Researchers should cite this work as follows:
X. Gao, N. Castaneda and S. J. Dyke (2011). Development and Validation of a Robust Actuator Motion Controller for Real-time Hybrid Testing Applications, Report IISL-001, Purdue University, December 2011.