| الملخص: | The path following mechanism of fixed-wing Unmanned Aerial Vehicles (UAVs) is crucial in the UAV domain. In the field of six-Degrees of Freedom (DOF) dynamics, the fixed-wing UAV is presented as a nonlinear system, wherein the high dimensions of its continuous state and action spaces make it challenging to control and guide. A novel hierarchical reinforcement learning framework is proposed to address the complex issues in fixed-wing UAV path following. The basis of this framework is to decompose path following into separate control and guidance problems. For the control problem, a Proximal Policy Optimization with Differential Compensator (PPO-DC) algorithm is introduced by incorporating a differential compensator, which demonstrates a faster convergence speed and control stability. Experimental results reveal that the proposed PPO-DC algorithm improves convergence speed by approximately 2.5 times compared to the standard PPO algorithm and achieves better control accuracy. Moreover, models trained for specific control tasks exhibit strong adaptability when handling other control tasks. For the guidance problem, the fixed-wing UAV guidance is modeled, and an effective guidance strategy is proposed. Additionally, a cumulative reward design is proposed to address the sequential learning of multiple objectives in reinforcement learning tasks, ensuring effective convergence of training. Experimental results show that the proposed hierarchical reinforcement learning framework performs exceptionally well in various complex path-following scenarios, maintaining an average path-following error of less than 20 meters for fixed-wing UAVs.
|