为加快末端物流配送的效率,提出一种配送无人机的航迹规划问题。针对传统快速搜索随机树(rapidlysearch random tree,RRT)算法在航迹规划中存在的盲目性和路径不平滑等问题,将人工势场法(artificial potential field,APF)与Informed-RRT...为加快末端物流配送的效率,提出一种配送无人机的航迹规划问题。针对传统快速搜索随机树(rapidlysearch random tree,RRT)算法在航迹规划中存在的盲目性和路径不平滑等问题,将人工势场法(artificial potential field,APF)与Informed-RRT^(*)算法融合,提出一种自适应步长增长策略的改进APF-Informed-RRT^(*)算法。首先在选择新节点时,考虑到障碍物和目标点的影响,提出一种自适应步长增长策略来解决采样的盲目性;其次采用三次B样条对拐点处进行平滑处理;最后分别采用RRT^(*)算法、Informed-RRT^(*)算法和改进APF-Informed-RRT^(*)算法在两种环境中进行仿真实验。结果表明,改进APF-Informed-RRT^(*)算法相较于RRT^(*)算法和Informed-RRT^(*)算法,在运行时间、迭代次数以及路径平滑上都得到提升。展开更多
针对六自由度工业机器人在复杂的分拣环境中分拣速度慢、避障效果差等问题,提出了一种融合人工势场(Artificial Potential Field,APF)算法的快速扩展随机树(Rapidly-exploring Random Tree,RRT)改进算法。传统RRT算法路径规划随机性强...针对六自由度工业机器人在复杂的分拣环境中分拣速度慢、避障效果差等问题,提出了一种融合人工势场(Artificial Potential Field,APF)算法的快速扩展随机树(Rapidly-exploring Random Tree,RRT)改进算法。传统RRT算法路径规划随机性强、收敛速度慢,在该算法中引入APF机制引导其向目标点进行有效扩展,减少路径搜索过程中的无效分支,提高搜索效率;优化对父系节点的选择策略,对原路径局部节点进行优化重连,提高路径质量及平滑性。根据实际分拣中可能出现的状况,在MATLAB软件中建立了3个不同的仿真场景,并将所提出的改进APF-RRT算法与传统RRT算法、APF-RRT算法进行对比仿真实验。结果表明,改进APF-RRT算法于不同分拣环境中,在路径长度、搜索时间、节点个数和迭代次数4个指标上均有一定提升,能以更高的效率搜索到更高质量的路径。展开更多
Frequent flood disasters caused by climate change may lead to tremendous economic and human losses along inland waterways.Emergency response and rescue vessels(ERRVs)play an essential role in minimizing losses and pro...Frequent flood disasters caused by climate change may lead to tremendous economic and human losses along inland waterways.Emergency response and rescue vessels(ERRVs)play an essential role in minimizing losses and protecting lives and property.However,the path planning of ERRVs has mainly depended on expert experiences instead of rational decision making.This paper proposes an improved artificial potential field(APF)algorithm to optimize the shortest path for ERRVs in the rescue process.To verify the feasibility of the proposed model,eight tests were carried out in two water areas of the Yangtze River.The results showed that the improved APF algorithm was efficient with fewer iterations and that the response time of path planning was reduced to around eight seconds.The improved APF algorithm performed better in the ERRV’s goal achievement,compared with the traditional algorithm.The path planning method for ERRVs proposed in this paper has theoretical and practical value in flood relief.It can be applied in the emergency management of ERRVs to accelerate flood management efficiency and improve capacity to prevent,mitigate,and relieve flood disasters.展开更多
在有源电力滤波器(Active Power Filter,APF)的低信噪比(Signal Noise Ratio,SNR)环境下,为了提高变步长最小均方(Least Mean Square,LMS)自适应算法对谐波电流检测的跟踪速度及精度,提出改进的变步长LMS算法。该算法在MVSS-LMS算法的...在有源电力滤波器(Active Power Filter,APF)的低信噪比(Signal Noise Ratio,SNR)环境下,为了提高变步长最小均方(Least Mean Square,LMS)自适应算法对谐波电流检测的跟踪速度及精度,提出改进的变步长LMS算法。该算法在MVSS-LMS算法的基础上,增加历史误差的遗忘加权和估计并控制步长更新,动态控制步长更新范围,采用滑动窗遗忘加权减小了计算复杂度。同时,对改进算法性能进行稳定性分析。实验结果表明,该算法不仅具有较快的动态响应速度,而且在APF的低信噪比情况下,稳态误差有所减小,具有较高的抗干扰能力,谐波电流检测效果较好。展开更多
文摘为加快末端物流配送的效率,提出一种配送无人机的航迹规划问题。针对传统快速搜索随机树(rapidlysearch random tree,RRT)算法在航迹规划中存在的盲目性和路径不平滑等问题,将人工势场法(artificial potential field,APF)与Informed-RRT^(*)算法融合,提出一种自适应步长增长策略的改进APF-Informed-RRT^(*)算法。首先在选择新节点时,考虑到障碍物和目标点的影响,提出一种自适应步长增长策略来解决采样的盲目性;其次采用三次B样条对拐点处进行平滑处理;最后分别采用RRT^(*)算法、Informed-RRT^(*)算法和改进APF-Informed-RRT^(*)算法在两种环境中进行仿真实验。结果表明,改进APF-Informed-RRT^(*)算法相较于RRT^(*)算法和Informed-RRT^(*)算法,在运行时间、迭代次数以及路径平滑上都得到提升。
文摘针对六自由度工业机器人在复杂的分拣环境中分拣速度慢、避障效果差等问题,提出了一种融合人工势场(Artificial Potential Field,APF)算法的快速扩展随机树(Rapidly-exploring Random Tree,RRT)改进算法。传统RRT算法路径规划随机性强、收敛速度慢,在该算法中引入APF机制引导其向目标点进行有效扩展,减少路径搜索过程中的无效分支,提高搜索效率;优化对父系节点的选择策略,对原路径局部节点进行优化重连,提高路径质量及平滑性。根据实际分拣中可能出现的状况,在MATLAB软件中建立了3个不同的仿真场景,并将所提出的改进APF-RRT算法与传统RRT算法、APF-RRT算法进行对比仿真实验。结果表明,改进APF-RRT算法于不同分拣环境中,在路径长度、搜索时间、节点个数和迭代次数4个指标上均有一定提升,能以更高的效率搜索到更高质量的路径。
基金The National Natural Science Foundation of China(Grant No.72274052)the National Natural Science Foundation of China(Grant No.72174173).
文摘Frequent flood disasters caused by climate change may lead to tremendous economic and human losses along inland waterways.Emergency response and rescue vessels(ERRVs)play an essential role in minimizing losses and protecting lives and property.However,the path planning of ERRVs has mainly depended on expert experiences instead of rational decision making.This paper proposes an improved artificial potential field(APF)algorithm to optimize the shortest path for ERRVs in the rescue process.To verify the feasibility of the proposed model,eight tests were carried out in two water areas of the Yangtze River.The results showed that the improved APF algorithm was efficient with fewer iterations and that the response time of path planning was reduced to around eight seconds.The improved APF algorithm performed better in the ERRV’s goal achievement,compared with the traditional algorithm.The path planning method for ERRVs proposed in this paper has theoretical and practical value in flood relief.It can be applied in the emergency management of ERRVs to accelerate flood management efficiency and improve capacity to prevent,mitigate,and relieve flood disasters.
文摘在有源电力滤波器(Active Power Filter,APF)的低信噪比(Signal Noise Ratio,SNR)环境下,为了提高变步长最小均方(Least Mean Square,LMS)自适应算法对谐波电流检测的跟踪速度及精度,提出改进的变步长LMS算法。该算法在MVSS-LMS算法的基础上,增加历史误差的遗忘加权和估计并控制步长更新,动态控制步长更新范围,采用滑动窗遗忘加权减小了计算复杂度。同时,对改进算法性能进行稳定性分析。实验结果表明,该算法不仅具有较快的动态响应速度,而且在APF的低信噪比情况下,稳态误差有所减小,具有较高的抗干扰能力,谐波电流检测效果较好。
