Ship-mounted cranes are widely used in transportation and installation of heavy loads to the seabed. To minimize adverse effect caused by harsh environment, the cranes are equipped with compensation equipment for the motion. When we design the compensation equipment for the cranes, anti-sway control algorithms in the equipment should be included. To test the feasibility of the algorithms effectively at the early design stage, the hardware-in-the-loop simulation (HILS) framework can be used as one of alternatives. The proposed method consists of several components: virtual mechanical system based on multibody system dynamics, virtual actuator and sensor, and hardware controller. In this study, it is applied to an example of the anti-sway control of the crane on an offshore supply vessel (OSV) during the installation operation of a subsea equipment using the proposed HILS framework.
Cranes on the offshore supply vessel are used for offshore construction including transportation and installation heavy loads in a marine environment. During the transfer operations, the swing problem is inevitable, in addition, harsh and changeable sea condition can be regarded as a persistent external disturbance and be further intensified the swing motion. Meanwhile, waves induce the motion of the OSV. The OSV induces similar effects on the subsea equipment suspended by the OSV. For the safety, the transfer operation by the crane should be paused in harsh environment conditions to avoid collisions between the load and hull of the vessel which was attributed to insufficient capability of the controller. Therefore, in order to improve safety and increase transportation efficiency, controller with suitable anti-sway control algorithm should be developed, which make it possible to reduce residual swing motion significantly by controlling the angles of the knuckle boom. When we design the compensation system for the cranes, suitable control algorithm should be included. For this reasons, some literatures (Xu, et al., 2012, Gjelstenli, 2012, Chu et al., 2015) are recently focused on the control of cranes. In this study, we considered anti-sway control for the crane on the OSV, which is shown in Fig. 1. Since the controller performance should be evaluated in advance of operation, the Hardware-In-the-Loop Simulation concept used as an effective method to test the controller. Therefore, this study proposes the HILS framework which consists of several components: virtual mechanical system based on multibody system dynamics, virtual actuator, virtual sensor, and hardware controller. At first, the configuration of the simulation framework aforementioned was introduced. Then, the application of the simulation for anti-sway of the OSV crane was presented. Finally, conclusion and future work discussion were summarized in the remainder of this paper.
