Experimental assessment of PID control for a uniaxial shake table

Abstract

Accurate actuator displacement tracking is essential in the seismic verification of structures on shake tables. This paper summarises an experimental study on the effects of proportional, integral, derivative and delta pressure gain on the transfer functio n of a uniaxial shake table. The study shows that the correct proportional gain component can deliver excellent response in the 0 - 10 Hz frequency range. The delta pressure gain can simultaneously limit response in the 10 - 30 Hz frequency range to give a tab le transfer function closest to unity. The derivative and in particular integral gains have minimal influence on the transfer function. The study concludes that optimal gain settings alone are insufficient to ensure the desired accelerations are achieved. The command excitation should be iteratively updated using the transfer function to minimise error in the single degree of freedom (SDOF) response spectra.