水面舰船动力定位系统ESO输入饱和控制

Dynamic positioning system of marine surface vessel with ESO and input saturation control

为解决现实服役海洋环境下,模型参数未知的水面舰船动力定位系统的控制问题,考虑执行器输入有界、舰船运动状态信号难测量等工程因素的限制,提出一种动力定位的状态观测饱和控制算法。首先,对非线性扩张状态观测器(extended state observer,ESO)在含有未知饱和控制输入结构下的状态观测能力进行分析,在原有假设条件的基础上制定一条附加假设条件,并分析该观测系统的合理性。接下来,将非线性ESO的特例(即线性ESO)应用于对舰船运动状态变量的实时观测,设计自适应律对模型的阻尼项和执行器不确定增益进行在线估计,进而得到各个执行器可变螺距形式的控制输入,引入动态辅助系统处理执行器的输入饱和限制。仿真结果表明:相比于传统的动力定位系统控制策略,所提出的控制策略在保证高定位精度和合理收敛速度要求的同时,更符合工程实际。

To control the dynamic positioning system of marine surface vessels with unknown model para- meters in the real sea environment, and taking into account the limitation of actuators’ saturation and states unavailability etc., a state-observing saturation control scheme for dynamic positioning is proposed. First, the ability of the nonlinear extended state observer (ESO) including the unknown saturated control inputs is analyzed. Based on the existing assumptions, a new one is established and the reasonability of the ESO is proved. Then, the linear ESO as the special case is adopted to observe the kinetic states of the ship. Adaptive laws are devised to estimate the damping term of the model and the uncertain gains of actuators, the control input in the form of pitch rate is further derived, and an auxiliary system is introduced to tackle the actuator saturation. The simulation shows that the proposed scheme much more fits engineering reality than previous schemes, while a high precision of positioning and rational convergence speed are promised.