Experimental active control: bench tests on controller units

Abstract Preliminary results of bench tests on off-the-shelf industrial PID general purpose programmable logic controllers, and dedicated PID controllers implemented on the latest generation microprocessors, are reported. The responses of both full size and reduced scale structures were simulated and controller response performance investigated in the frequency ranges of significance for structural engineering. Criteria for programming controllers to protect structures against horizontal random disturbances, and preliminary criteria for evaluating delays in the various stages of the control system closed loop are discussed. The numerical values obtained may be used to improve mathematical modelling and guide sizing and choice of control equipment. An FFT microprocessor-based spectral analyser was considered for the realization of on line strategies for the adaptive resetting of controller parameters according to building response.