An offshore container crane is expected to realize high productivity and economic feasibility in the maritime logistics due to its versatile functions for container transportation. However, severe working conditions resulting from the oceanic environment may cause difficulty in its accurate and safe cargo transfer. Specifically, the presence of ship-motion-induced disturbances, wind disturbances and parameter uncertainties in the payload mass and rope length result in positioning errors and large swings during ship-to-ship transportation. For efficient cargo transportation, such control problems should be solved with consideration of physical constraints like control input saturation. Therefore, a continuous integral sliding mode control is developed in this study using a 4-degrees-of-freedom (4-DOFs) dynamic model with input saturation. The control scheme consists of two parts: i) A super-twisting control for disturbance rejection, and ii) a nominal control to drive the state vector to the desired equilibrium point. Therein, the nonlinear integral-type sliding surface is decoupled into two sub-systems, so that the control laws for the lateral and longitudinal trolley dynamics are independently developed. The asymptotic stability of the closed-loop system in consideration of the input saturation is assured by the Lyapunov method. Moreover, simulation results are provided to demonstrate the effectiveness of the proposed control strategy compared with the conventional sliding mode control.

中文翻译：

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具有输入饱和度的海上集装箱起重机的连续积分滑模控制

海上集装箱起重机由于其多功能的集装箱运输功能，有望在海上物流中实现高生产率和经济可行性。然而，海洋环境导致的恶劣工作条件可能会导致其准确和安全的货物转运存在困难。具体而言，船舶运动引起的扰动、风扰动以及有效载荷质量和绳索长度的参数不确定性的存在会导致船对船运输过程中的定位误差和大摆动。对于有效的货物运输，应考虑控制输入饱和等物理约束来解决此类控制问题。因此，本研究使用具有输入饱和度的 4 自由度 (4-DOF) 动态模型开发了连续积分滑模控制。控制方案由两部分组成：i) 用于抑制干扰的超扭曲控制，以及 ii) 将状态向量驱动到所需平衡点的标称控制。其中，非线性积分型滑动面被解耦为两个子系统，从而独立开发了横向和纵向小车动力学的控制规律。Lyapunov 方法保证了考虑输入饱和的闭环系统的渐近稳定性。此外，仿真结果证明了所提出的控制策略与传统滑模控制相比的有效性。非线性积分型滑动面解耦为两个子系统，独立开发横向和纵向小车动力学控制律。Lyapunov 方法保证了考虑输入饱和的闭环系统的渐近稳定性。此外，仿真结果证明了所提出的控制策略与传统滑模控制相比的有效性。非线性积分型滑动面解耦为两个子系统，独立开发横向和纵向小车动力学控制律。Lyapunov 方法保证了考虑输入饱和的闭环系统的渐近稳定性。此外，仿真结果证明了所提出的控制策略与传统滑模控制相比的有效性。