Sigmoid function-based hysteresis modeling of magnetorheological pin joints

![CDATA[The magnetorheological (MR) pin joint is a semi-active control device which can be installed in the column-beam structures for structural vibration control. Nevertheless, the nonlinear response of the MR pin joint together with its unique rheological nature makes the device modeling difficult and impedes its engineering application. Although many complicated phenomenal models have been proposed to illustrate the dynamic behaviour of MR devices, a large number of model parameters and differential equations bring the challenges for model identification and controller design. In this study, we try to predict the dynamic response of a MR pin joint using a novel and simple phenomenal model, which is comprised of a rotary spring, a rotary damper and a sigmoid function-based hysteresis component. Then, the model parameters are identified using trust-region-reflective least squares algorithm in MATLAB optimization toolbox. Finally, the experimental results under various loading conditions are used to validate the performance of the proposed model.]]