论文标题
使用不确定性耐受性计划器和推力调节栖息在移动倾斜的表面上
Perching on Moving Inclined Surfaces using Uncertainty Tolerant Planner and Thrust Regulation
论文作者
论文摘要
具有栖息倾斜表面的二次旋转能力可以通过利用地面车辆来节省能量并延长其行进距离。在SE(3)中,实现动态栖息地对轨迹规划和终端状态准确性的性能的需求很高。但是,在栖息过程中,目标表面预测,跟踪控制和外部干扰的不确定性可能导致轨迹计划故障或导致不可接受的终端错误。为了应对这些挑战,我们首先提出了一个轨迹规划师,该规划师认为对目标预测和跟踪控制中的不确定性进行了适应。为了促进这项工作,首先分析了四肢状态。可达集合的状态具有不确定性目标的最大覆盖率概率,被定义为最佳航路点。随后,提出了一种寻求局部最佳路点的方法,以实现静态和移动的不确定性目标。相应地开发了基于优化航路点的实时轨迹规划师。其次,在终端态度跟踪阶段还实施了推力法规,以处理外部干扰。当命令四摩托器的态度与目标表面保持一致时,对推力进行了优化以最大程度地减少终端错误。这使得末端位置和速度以闭环方式控制。因此,提高了对干扰和终端精度的抵抗力。广泛的仿真实验表明,我们的方法可以提高不确定性下末端状态的准确性。与没有推力法规的两端计划者相比,成功率大约提高了$ 50 \%$。使用我们提出的异质合作系统在户外,还可以在汽车后窗上栖息。这验证了我们方法的可行性和实用性。
Quadrotors with the ability to perch on moving inclined surfaces can save energy and extend their travel distance by leveraging ground vehicles. Achieving dynamic perching places high demands on the performance of trajectory planning and terminal state accuracy in SE(3). However, in the perching process, uncertainties in target surface prediction, tracking control and external disturbances may cause trajectory planning failure or lead to unacceptable terminal errors. To address these challenges, we first propose a trajectory planner that considers adaptation to uncertainties in target prediction and tracking control. To facilitate this work, the reachable set of quadrotors' states is first analyzed. The states whose reachable sets possess the largest coverage probability for uncertainty targets, are defined as optimal waypoints. Subsequently, an approach to seek local optimal waypoints for static and moving uncertainty targets is proposed. A real-time trajectory planner based on optimized waypoints is developed accordingly. Secondly, thrust regulation is also implemented in the terminal attitude tracking stage to handle external disturbances. When a quadrotor's attitude is commanded to align with target surfaces, the thrust is optimized to minimize terminal errors. This makes the terminal position and velocity be controlled in closed-loop manner. Therefore, the resistance to disturbances and terminal accuracy is improved. Extensive simulation experiments demonstrate that our methods can improve the accuracy of terminal states under uncertainties. The success rate is approximately increased by $50\%$ compared to the two-end planner without thrust regulation. Perching on the rear window of a car is also achieved using our proposed heterogeneous cooperation system outdoors. This validates the feasibility and practicality of our methods.