Abstract:

The traditional Deep Learning （DL）-based multi-objective solvers have the problems of low model utilization and being easy to fall into the local optimum. Aiming at these problems， a Multi-objective Optimization model for Unmanned aerial vehicles Trajectory based on Decomposition and Trajectory search （DTMO-UT） was proposed. The proposed model consists of the encoding and decoding parts. First， a Device encoder （Dencoder） and a Weight encoder （Wencoder） were contained in the encoding part， which were used to extract the state information of the Internet of Things （IoT） devices and the features of the weight vectors. And the scalar optimization sub-problems that were decomposed from the Multi-objective Optimization Problem （MOP） were represented by the weight vectors. Hence， the MOP was able to be solved by solving all the sub-problems. The Wencoder was able to encode all sub-problems， which improved the utilization of the model. Then， the decoding part containing the Trajectory decoder （Tdecoder） was used to decode the encoding features to generate the Pareto optimal solutions. Finally， to alleviate the phenomenon of greedy strategy falling into the local optimum， the trajectory search technology was added in trajectory decoder， that was generating multiple candidate trajectories and selecting the one with the best scalar value as the Pareto optimal solution. In this way， the exploration ability of the trajectory decoder was enhanced during trajectory planning， and a better-quality Pareto set was found. The results of simulation experiments show that compared with the mainstream DL MOP solvers， under the condition of 98.93% model parameter quantities decreasing， the proposed model reduces the distribution of MOP solutions by 0.076%， improves the ductility of the solutions by 0.014% and increases the overall performance by 1.23%， showing strong ability of practical trajectory planning of DTMO-UT model.

Key words: trajectory planning, Deep Learning (DL), multi-objective optimization, decomposition, Pareto set

摘要：

基于深度学习（DL）的传统多目标求解器存在模型利用率低以及容易陷入局部最优的问题。针对这些问题，提出了基于分解法与轨迹搜索的无人机群轨迹多目标优化模型（DTMO-UT）。所提模型包含编码与解码部分。首先，编码部分由设备编码器（Dencoder）和权重编码器（Wencoder）组成，用于提取物联网（IoT）设备的状态信息与权重向量的特征，其中权重向量代表分解多目标优化问题（MOP）的标量优化子问题，因此解决所有子问题即可解决该MOP。权重编码器可以实现对所有子问题的编码，从而提高了模型的利用率。然后，使用包含轨迹解码器（Tdecoder）的解码部分对编码特征进行解码，以生成帕累托最优解。最后，为了减少贪婪策略陷入局部最优的现象，为轨迹解码器设计轨迹搜索技术，即通过生成多个候选轨迹选标量值最优的轨迹作为帕累托最优解，从而增强了轨迹解码器在轨迹规划时的探索能力，并获得质量更好的帕累托集。仿真实验结果表明，所提模型相较于主流的基于DL的MOP求解器，在模型参数量降低98.93%的情况下，MOP解的分布性提高了0.076%，延展性提高了0.014%，平均综合性提高了1.23%，表现出较强的实用性路径规划能力。

关键词: 轨迹规划, 深度学习, 多目标优化, 分解法, 帕累托集