Active control of ALP with improved performance function

Abstract

Conventional optimal control theories usually deal with performance function that involves only structural displacement and velocity. This paper presents an algorithm for the linear active control by considering also the structural acceleration in the performance function without bringing in the actuator dynamics. The linear optimal control law, thus achieved, is implemented to control the peak displacement response of a 180.5 m tall articulated leg platform (ALP) under the random sea state. Both controlled and uncontrolled responses of the ALP are obtained by an iterative frequency domain technique which duly considers all the nonlinearities present in the system. The controlled responses are compared with those obtained by the conventional linear feedback control strategy in order to investigate the efficiency of the proposed algorithm. Numerical results indicate that the proposed algorithm performs better than the conventional control strategy.