海流建模及其在路径规划中的应用

Method of Designing Optimal Smooth Way for Vehicle

对水下航行器进行路径规划时,除了要考虑所规划的路径长度外,还需要考虑所规划路径满足航行器能量消耗约束,其中海流是影响航行器能量消耗的重要因素,为考虑海流对路径规划的影响,这里提出了一种利用B样条曲面对动态海流环境进行建模的方法,并将海流对航行器能量消耗的影响作为约束函数应用到路径规划算法中,使航行器能够在路径的搜索过程中,综合考虑全局路径消耗和能量消耗,寻找能够实现目标函数最优的路径;另外考虑到海流各向异性、时变的特性,对路径规划算法进行改进,使航行器规划路径能够利用海流模型,避开局部湍流,并根据动态海流信息实时对所设计路径进行修正。通过仿真验证,将建立的海流模型应用到路径规划算法后,改进的路径规划算法可以利用海流减少航行器的能源消耗,根据海流的实时变化调整航行路径,航行器满足安全运动条件,并实现在满足能源消耗前提下的路径长度最优。

In the field of path planning for autonomous underwater vehicle,the factors to be considered are not only the length of the path,but also the limits of the resource consumed by the vehicle which the ocean current has great influence on. With respect to the influence of ocean current on path planning,a method of constructing the model for the dynamic ocean current with B-spline surface was introduced. Besides of that,the influence of ocean current is regarded as the constraint function implemented into path planning,so when searching for the path,the vehicle could take the path length and energy expense into account in the heuristic function and find the optimal path. On the other hand,as the ocean current has the property of anisotropy and time varying,the modification is made to the algorithm of path planning and the vehicle could avoid running into the rip current and make improvement in the designed path based on the dynamic information with the model of ocean current. Throughout the simulation,these methods could utilize the ocean current to reduce the cost of energy and change the path according to the dynamic ocean current,which could also satisfy the restriction on safety running,the limits of resource and the optimization in length of path.