Abstract: Heave compensation systems are widely applied in offshore drilling, marine hoisting and subsea installation. To improve the operational performance and safety of heave compensation systems, an investigation was performed on compensation schemes and control methods. To address the limitations of existing systems, a novel direct-acting heave compensation scheme based on a triple-piston accumulator is proposed. The system integrates passive and active compensation modes with mode-switching functionality, along with seawater pressure compensation and variable hydraulic damping. Based on the technical specifications of a 100 t load capacity under Sea State 6 conditions, the system was designed. The proposed system offers multifunctional integration, strong adaptability to diverse operational environments and working conditions, and excellent bidirectional active compensation performance. A closed-loop control structure for active compensation was then designed, and the effects of nonlinear factors, including time delay, friction, and hydraulic circuit stiffness, on compensation performance were analyzed, providing a basis for system optimization. Furthermore, a switching control method for multiple operating states was developed. To eliminate impact and instability during the startup and shutdown of the active compensation mode, a flexible switching strategy based on trajectory planning of the closed-loop system command signal was proposed, enabling smooth startup, operation, and shutdown of the compensation function. To address the saturation of active compensation capability under harsh sea conditions, a bounded switching scheme based on cylinder position thresholds and hyperbolic tangent trajectory planning was proposed to ensure that the compensation cylinder operates within its stroke limits, thereby preventing safety accidents. Finally, a prototype of the compensation system and its test platform were developed. The test results demonstrate that the system operates stably, the switching processes are smooth, and the compensation performance is satisfactory, thereby validating the effectiveness of the proposed compensation scheme and control methods.

Key words: offshore operations, heave compensation, hydrostatic pressure compensation, switching control, test system

摘要： 为提高海工升沉补偿系统作业能力与安全性，开展了升沉补偿方案及控制方法研究。针对现有补偿系统的不足，提出一种基于三活塞式蓄能器、集成了被动和主动补偿等作业模式及切换功能、具备海水压力补偿和变阻尼调节功能的新型直接作用式补偿方案，基于载荷100 t、六级海况的技术指标完成了系统设计，该系统具有多功能集成、对作业场合和工况适应性强、双向主动补偿性能好等优点；设计了主动补偿闭环控制结构，分析了时滞、摩阻、液压回路刚度等非线性因素对补偿性能的影响，为系统优化提供了依据；进一步开展了系统多状态之间的切换控制方法研究，针对主动补偿模式启停过程的冲击和失稳现象，提出了基于闭环系统指令信号轨迹规划的柔性切换方案，实现了补偿功能的平稳启动、运行及停止；针对恶劣海况下主动补偿能力饱和的问题，提出了基于补偿缸位置门限与双曲正切函数轨迹规划的有界切换方案，保证补偿缸的运动不会越过行程边界；并开发了原理样机及试验系统。测试结果表明，系统运行状态及切换过程稳定，补偿性能良好，验证了补偿方案及控制方法的有效性。

关键词: 海工作业, 升沉补偿, 水压补偿, 切换控制, 试验系统