On-Line Control of Nonlinear Flexible Structures

A simple yet efficient method is presented for the on-line control of nonlinear, multidegree-of-freedom systems responding to arbitrary dynamic environments. The control procedure uses pulse generators located at selected positions throughout a given system. The degree of system oscillation near each controller determines the controller’s activation time and pulse amplitude. The direct method of Liapunov is used to establish that the response of the controlled nonlinear system is Lagrange stable. Simulation studies of three example systems (conducted with digital and analog computers) demonstrate the feasibility, reliability, and robustness of the proposed active-control method. These systems, which include one with a hysteretic nonlinearity, are structures representative of modern tall buildings; they are subjected to nonstationary random excitation representative of earthquake ground motions.