A Calibration Technique for Bi-axial Shake Tables with Stepper Motor

Shaking tables are frequently used to determine the dynamic behavior of structures in the laboratory environment. In order to obtain realistic results in experimental studies, table response and performance should be consistent with the desired motion. In this multidisciplinary study, an application of a new method for determining and calibrating the mechanical response of a developed bi-axial displacement controlled shake table according to the desired motion data is presented. The bi-axial shake table's electro-mechanical components consist of stepper motors, ball screw sets, linear ball bearings, and linear potentiometers positioned on both axes for displacement measurements. For the control and data acquisition (DAQ) unit of the shake table, an open-source electronic prototyping platform Arduino was used. From several experimental results, it was seen that, with the presented calibration method, harmonic and earthquake simulations could be achieved with a relative root mean square error (relative RMS error) of less than 5% for desired displacement-time histories.