Experimental digital control of structures

The. formulation of a predictive control law and its implementation in a computer control system for the seismic response of an experimental model structure is presented. Two main characteristics of the control system are emphasized: (1) The discrete-time nature imposed by the presence of a computer in the closed loop; and (2) the existence of a time delay between the measurement and the control action. The most common way to take into account both characteristics has been to formulate a continuous-time control law with a compensation for the time delay. In that case a discrete approximation has to be made a posteriori for computer programming. Alternatively, the predictive control proposed herein is a digital control strategy which directly yields a simple discrete-time control algorithm for computer control of systems with time delay. Experimental results are presented to illustrate the capability of this predictive control. Its robustness in the presence of errors in the true time delay is discussed based on a comparison between experimental and numerical simulation results.