Shake table testing is an important tool to challenge integrity of structural and non-structural specimens by imposing excitations at their base. When shake tables are loaded with specimens, the interaction between the tables and specimens influences the system dynamics that may result in undesired performance. In order to compensate the effects of the interaction, open loop feedforward compensation methods have been widely used successfully in current practice of table controls, assuming that the specimens remain linear. On the contrary, unsatisfactory signal performances during shake table testing were observed when flexible and heavy specimens experience nonlinear behavior. While lack of high fidelity might be acceptable for the purpose of exploration research of specimens subjected to random excitations, a high fidelity of signal reproduction is necessary for shake table qualification testing where specific target motion is required to challenge the specimens. In this study, a nonlinear tracking control scheme based on the feedback linearization method is proposed for the control of shake tables to simulate target motions at specific locations of test structures, having nonlinear hysteretic behavior. Additionally, a real-time estimator using the extended Kalman filter is adopted and combined with the controller in order to account for the changes and uncertainties in system models due to nonlinearities and yielding caused by extreme excitations. The proposed adaptive tracking control method has been applied to a realistic shake table-structure test setup by means of numerical simulations, and the results show good tracking and estimation performance. Copyright (C) 2016 John Wiley & Sons, Ltd.
