基于零空间的船舶自主靠泊自抗扰控制分配

Null-space-based active disturbance rejection control allocation for ship autonomous berthing

[目的]针对船舶自主靠泊过程中遇到的环境载荷、岸壁效应、模型不确定以及控制分配误差等多源干扰的影响,提出一种基于零空间的自抗扰控制(ADRC)分配方法。[方法]首先,建立船舶靠泊运动数学模型、多源干扰模型和控制分配模型,并据此设计神经网络扩张状态观测器(NNESO)实时估计船舶运动及其所受到的多源干扰;然后,引入零空间技术设计控制分配算法,并基于该方法实现先泊位外镇定再平行靠泊方案;最后,证明船舶自主靠泊系统在所提方法下所有误差信号一致最终有界,保证船舶自主靠泊过程的安全性。[结果]仿真对比结果表明,所提方法在轨迹跟踪效果与二次规划(QP)法近似的情况下,求解所需时间为其1.3%,艏向最大分配误差为伪逆法(PI)的36.51%。[结论]所提方法在满足靠泊运动控制精度的同时,求解所需时间明显缩短,最大分配误差显著降低,保证了控制分配的实时性与精确性。

[Objective]This paper proposes a null-space-based active disturbance rejection control(ADRC)allocation method to analyze the influence of multi-source disturbances encountered during the autonomous berthing of ships,such as environmental loads,bank effects,model uncertainties and control allocation errors.[Methods]First,a ship berthing motion model,multi-source disturbance model and control allocation model are established,and a neural network extended state observer(NNESO)is designed to estimate ship states and multi-source disturbances in real time.Second,null-space technology is introduced to design the control allocation algorithm.Based on this method,a scheme for stabilization control outside the berth and parallel berthing is realized.Finally,it is proven that all error signals of the autonomous berthing system under the proposed method remain uniformly ultimately bounded,ensuring the safety of the autonomous berthing process.[Results]The comparative simulation results show that the proposed method has a trajectory tracking effect similar to that of the quadratic programming(QP)method,with a solution time of about 1.3%and a yaw maximum allocation error of 36.51%of the pseudo inverse(PI)method.[Conclusion]The proposed method not only ensures the accuracy of berthing motion control,but also significantly reduces the solution time and maximum allocation error,thereby ensuring real-time control allocation with high accuracy.