基于最优控制的双喷推无人艇路径跟踪方法

针对双喷推无人艇自主航行时的路径跟踪问题,采用最优控制的方法进行求解。根据双喷推无人艇的动力学特性建立双喷推无人艇三自由度运动方程,并由任务需求设定目标函数;在此基础上,根据航行实况建立约束条件,从而得到求解双喷推无人艇路径跟踪问题的数学模型。通过建立含有拉格朗日松弛项的哈密顿函数,将带有复杂约束的优化问题转化为无约束优化问题,采用粒子群优化算法求解最优拉格朗日乘子,并将其代入哈密顿函数;采用广义梯度下降法对数学模型进行求解,得到最优的喷泵电机转速,从而实现对双喷推无人艇的路径跟踪控制。设计实船试验验证方法的有效性,双喷推无人艇路径跟踪试验结果表明,双喷推无人艇实测的轨迹与设定轨迹的最大偏差不超过3m,该方法具有可行性和实用性。

Research on Path Tracking Method of Double Propelled Unmanned Boat Based on Optimal Control

Aiming at the path tracking problem of water-jet-propelled unmanned surface vehicle(USV) in autonomous navigation, the optimal control method is used to solve the problem. Firstly, according to the dynamic characteristics of the USV, a three-degree-of-freedom equation of motion for the USV is established, in addition the objective function is set by the task demand, and then the constraints are established according to the navigation practice, so as to obtain the mathematical model of the path of the USV path tracking; secondly, by establishing the Hamiltonian with the Lagrangian relaxation term ,the function transforms the optimization problem with complex constraints into an unconstrained optimization problem, furthermore using the particle swarm optimization algorithm to solve the optimal Lagrangian multiplier, substituting it into the Hamiltonian function, thereby solving the mathematical model by the generalized gradient descent method. The optimal speed of the jet pump motor is obtained, so as to realize the path tracking control of the USV. Finally, the effectiveness of the actual ship experimental verification method is designed. The USV path tracking experiment results show that the maximum deviation between the measured trajectory of the unmanned boat and the set trajectory does not exceed 3m,this method is feasible and practical.