Robust wave compensation controller design for an active hexapod platform with time-varying input delays

In this paper, we address the problem of wave motion compensation for a Stewart platform with gangway. The kinematics and dynamics of the Stewart-Gangway system are established by employing the Kane's method. Building on the derived model, a robust controller is designed to guarantee that the Stewart top platform keeps motionless in the presence of external disturbance and time-varying input delays. A pre-compensation for the input delays is integrated in the devised controller, achieving uniformly ultimate boundedness (UUB). In order to ensure that the designed actuation signals are bounded with respect to position and attitude errors, a saturation function is used. A smooth projection operator is introduced to ensure that the estimated disturbance remains within a prescribed bound. Simulation results are presented and analyzed, validating the efficacy and performance of the proposed controller.