基于RBFNNMLP和有限时间滑模的欠驱动船舶路径跟踪与避障控制

Path Following and Obstacle Avoidance Control of Underactuated Ships Based on RBFNNMLP and Finite Time Sliding Mode

  • 摘要: 【目的】针对存在模型不确定性和外界环境干扰的欠驱动船舶路径跟踪与避障问题,结合指令滤波技术、最小学习参数(minimal learning parameter,MLP)算法以及模拟退火(simulated annealing,SA)算法,提出一种基于径向基函数神经网络最小学习参数算法(radial basis function neural network minimal learning parameter,RBFNNMLP)的自适应有限时间滑模控制律和改进的人工势场(improved artificial potential field,IAPF)。【方法】首先在虚拟船制导的基础上根据跟踪误差和方位角设计虚拟控制律,引入指令滤波技术对虚拟控制律的导数进行估计,降低计算复杂度。对控制输入设计有限时间滑模面,结合RBFNNMLP算法,以单参数在线学习代替所有权值在线学习,避免出现维数爆炸问题,并设计控制律和自适应律。Lyapunov稳定性分析证明了系统在有限时间内稳定。对静态、动态障碍物分别改进人工势场斥力函数,并引入模拟退火算法,克服局部极小值问题以及未考虑船舶和障碍物的位置、相对速度关系问题。【结果】仿真对比结果表明,在海浪干扰下,所设计控制器的收敛精度更高,收敛时间更短,且船舶在陷入局部极小值时能有效实现避障,验证了所提控制算法的有效性和鲁棒性。【结论】所提控制算法可以为欠驱动船舶路径跟踪与避障问题提供参考。

     

    Abstract: ObjectiveAiming at the path following and obstacle avoidance problems of underactuated ships with model uncertainty and external environmental disturbance, an adaptive finite time sliding mode control law based on radial basis function neural network minimum learning parameter (RBFNNMLP) algorithm and an improved artificial potential field are proposed by combining command filter technology, minimum learning parameter (MLP), and simulated annealing algorithm.MethodsFirstly, based on the guidance of the virtual ship, a virtual control law is designed according to the following error and azimuth angle. The command filter technique is introduced to estimate the derivative of the virtual control law, reducing the computational complexity. Combining algorithm of RBFNNMLP, a finite time sliding surface is designed for control input, and single parameter online learning is used instead of ownership value online learning to avoid the problem of dimensionality explosion. Control law and adaptive law are also designed. Lyapunov Stability analysis proves that the system is stable in finite time. Improve the repulsion function of artificial potential field for static and dynamic obstacles separately, and introduce simulated annealing algorithm to overcome the local minimum problem and the problem of not considering the position and relative velocity relationship between ships and obstacles.ResultsThe simulation comparison results show that under wave interference, the designed controller has higher convergence accuracy, shorter convergence time, and can effectively avoid obstacles when the ship falls into local minima, verifying the effectiveness and robustness of the proposed control algorithm.ConclusionsThe proposed algorithm can provide reference for underactuated ship path following and obstacle avoidance problems.

     

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