A new particle filter is presented for nonlinear tracking problems. Inpractice, maneuvering target-tracking systems are usually nonlinear and incompletely observed, andthe main difficulty of maneuvering target-trackin...A new particle filter is presented for nonlinear tracking problems. Inpractice, maneuvering target-tracking systems are usually nonlinear and incompletely observed, andthe main difficulty of maneuvering target-tracking problem lies in the fact that the maneuverabilityat every step is of high uncertainties. Here a new smoothing particle filter algorithm is proposed,which combines the particle filter to tackle the non-linear and non-Gaussian peculiarities of theproblem, together with smoothing of the PDF of system modes and thus settles the estimate problem ofthe target maneuverability. The simulation comparison with the auxiliary particle filters showsthat the approach has superiority and yields performance improvements in solving nonlinear trackingproblems.展开更多
Recently, lots of smoothing techniques have been presented for maneuvering target tracking. Interacting multiple model-probabilistic data association （IMM-PDA） fixed-lag smoothing algorithm provides an efficient sol...Recently, lots of smoothing techniques have been presented for maneuvering target tracking. Interacting multiple model-probabilistic data association （IMM-PDA） fixed-lag smoothing algorithm provides an efficient solution to track a maneuvering target in a cluttered environment. Whereas, the smoothing lag of each model in a model set is a fixed constant in traditional algorithms. A new approach is developed in this paper. Although this method is still based on IMM-PDA approach to a state augmented system, it adopts different smoothing lag according to diverse degrees of complexity of each model. As a result, the application is more flexible and the computational load is reduced greatly. Some simulations were conducted to track a highly maneuvering target in a cluttered environment using two sensors. The results illustrate the superiority of the proposed algorithm over comparative schemes, both in accuracy of track estimation and the computational load.展开更多
Focus is laid on the adaptive practical output-tracking problem of a class of nonlinear systems with high-order lower-triangular structure and uncontrollable unstable linearization. Using the modified adaptive additio...Focus is laid on the adaptive practical output-tracking problem of a class of nonlinear systems with high-order lower-triangular structure and uncontrollable unstable linearization. Using the modified adaptive addition of a power integrator technique as a basic tool, a new smooth adaptive state feedback controller is designed. This controller can ensure all signals of the closed-loop systems are globally bounded and output tracking error is arbitrary small.展开更多
针对无人机复杂环境下的全局航迹规划问题,将人工势场法与双向RRTs(Rapidly-exploring random trees)算法结合,提出一种改进双向RRTs算法。首先,目标偏置策略引导采样点以一定概率顺着目标点生成,同时随机树新节点受到障碍物斥力和目标...针对无人机复杂环境下的全局航迹规划问题,将人工势场法与双向RRTs(Rapidly-exploring random trees)算法结合,提出一种改进双向RRTs算法。首先,目标偏置策略引导采样点以一定概率顺着目标点生成,同时随机树新节点受到障碍物斥力和目标点引力的合力影响有效避开障碍物生长,提高航迹搜寻效率,其次对随机树的节点扩展考虑了无人机飞行性能约束条件,最后采用3阶贝塞尔函数进一步航迹优化。仿真结果表明:二维和三维复杂环境中改进双向RRTs算法相比传统RRT、双向RRTs算法航迹搜索耗时减少了71.3%、24.7%和41.0%、18.6%,验证了改进算法全局搜索能力的快速性和有效性,能很好的应用于无人机离线全局航迹规划场合。展开更多
针对快速扩展随机树(rapidly-exploring random tree,RRT)算法在无人机路径规划过程中采样次数多、生成路径曲折等问题,提出了一种将路径重规划策略和平滑度优化相结合的路径规划算法。首先,通过重新构造采样区域降低RRT算法采样次数,...针对快速扩展随机树(rapidly-exploring random tree,RRT)算法在无人机路径规划过程中采样次数多、生成路径曲折等问题,提出了一种将路径重规划策略和平滑度优化相结合的路径规划算法。首先,通过重新构造采样区域降低RRT算法采样次数,利用目标偏向寻优策略为RRT算法添加导向性;其次,在筛选初始航迹点的同时引入无人机性能约束;然后,利用B样条对重规划路径进行平滑处理;最后,利用Matlab对所提出的算法进行仿真实验。实验结果为平均采样次数为386次,平均运行时间为0.43 s,平均航迹距离为1392.16(无量纲),表明了算法可有效降低采样次数并改善路径平滑性。展开更多
大规模分布式电源的存在允许配电网通过网络重构改变供电方式,实现部分区域在必要时刻以异步孤岛形式运行。但配电网运行方式的改变必然伴随着关键换流器控制模式的切换和参数的调整,如何平稳地实现配电分区在并网和孤岛之间的转换是实...大规模分布式电源的存在允许配电网通过网络重构改变供电方式,实现部分区域在必要时刻以异步孤岛形式运行。但配电网运行方式的改变必然伴随着关键换流器控制模式的切换和参数的调整,如何平稳地实现配电分区在并网和孤岛之间的转换是实现有源配电网安全可靠运行的重要内容。针对通过软开关(soft open point,SOP)实现柔性互联的配电分区,分析了该系统由并网转为异步孤岛运行的暂态特性,提出了基于参考功率自适应的改进下垂控制策略,并采用状态跟踪方法降低了配电网运行状态切换时刻的暂态波动,实现了配电网运行方式的平滑切换。在PSCAD/EMTDC环境下搭建了仿真模型进行验证,结果表明,所提控制方法可有效提升分区互联有源配电网运行的灵活性。展开更多
文摘A new particle filter is presented for nonlinear tracking problems. Inpractice, maneuvering target-tracking systems are usually nonlinear and incompletely observed, andthe main difficulty of maneuvering target-tracking problem lies in the fact that the maneuverabilityat every step is of high uncertainties. Here a new smoothing particle filter algorithm is proposed,which combines the particle filter to tackle the non-linear and non-Gaussian peculiarities of theproblem, together with smoothing of the PDF of system modes and thus settles the estimate problem ofthe target maneuverability. The simulation comparison with the auxiliary particle filters showsthat the approach has superiority and yields performance improvements in solving nonlinear trackingproblems.
基金This work is supported by the Projects of the State Key Fundamental Research (No. 2001CB309403)
文摘Recently, lots of smoothing techniques have been presented for maneuvering target tracking. Interacting multiple model-probabilistic data association （IMM-PDA） fixed-lag smoothing algorithm provides an efficient solution to track a maneuvering target in a cluttered environment. Whereas, the smoothing lag of each model in a model set is a fixed constant in traditional algorithms. A new approach is developed in this paper. Although this method is still based on IMM-PDA approach to a state augmented system, it adopts different smoothing lag according to diverse degrees of complexity of each model. As a result, the application is more flexible and the computational load is reduced greatly. Some simulations were conducted to track a highly maneuvering target in a cluttered environment using two sensors. The results illustrate the superiority of the proposed algorithm over comparative schemes, both in accuracy of track estimation and the computational load.
基金This work was supported by the National Natural Sdence Foundation of China (No. 60304003)the National Sdence Foundation of Shandong Province (No. Q2002G02)
文摘Focus is laid on the adaptive practical output-tracking problem of a class of nonlinear systems with high-order lower-triangular structure and uncontrollable unstable linearization. Using the modified adaptive addition of a power integrator technique as a basic tool, a new smooth adaptive state feedback controller is designed. This controller can ensure all signals of the closed-loop systems are globally bounded and output tracking error is arbitrary small.
文摘针对无人机复杂环境下的全局航迹规划问题,将人工势场法与双向RRTs(Rapidly-exploring random trees)算法结合,提出一种改进双向RRTs算法。首先,目标偏置策略引导采样点以一定概率顺着目标点生成,同时随机树新节点受到障碍物斥力和目标点引力的合力影响有效避开障碍物生长,提高航迹搜寻效率,其次对随机树的节点扩展考虑了无人机飞行性能约束条件,最后采用3阶贝塞尔函数进一步航迹优化。仿真结果表明:二维和三维复杂环境中改进双向RRTs算法相比传统RRT、双向RRTs算法航迹搜索耗时减少了71.3%、24.7%和41.0%、18.6%,验证了改进算法全局搜索能力的快速性和有效性,能很好的应用于无人机离线全局航迹规划场合。
文摘针对快速扩展随机树(rapidly-exploring random tree,RRT)算法在无人机路径规划过程中采样次数多、生成路径曲折等问题,提出了一种将路径重规划策略和平滑度优化相结合的路径规划算法。首先,通过重新构造采样区域降低RRT算法采样次数,利用目标偏向寻优策略为RRT算法添加导向性;其次,在筛选初始航迹点的同时引入无人机性能约束;然后,利用B样条对重规划路径进行平滑处理;最后,利用Matlab对所提出的算法进行仿真实验。实验结果为平均采样次数为386次,平均运行时间为0.43 s,平均航迹距离为1392.16(无量纲),表明了算法可有效降低采样次数并改善路径平滑性。
文摘大规模分布式电源的存在允许配电网通过网络重构改变供电方式,实现部分区域在必要时刻以异步孤岛形式运行。但配电网运行方式的改变必然伴随着关键换流器控制模式的切换和参数的调整,如何平稳地实现配电分区在并网和孤岛之间的转换是实现有源配电网安全可靠运行的重要内容。针对通过软开关(soft open point,SOP)实现柔性互联的配电分区,分析了该系统由并网转为异步孤岛运行的暂态特性,提出了基于参考功率自适应的改进下垂控制策略,并采用状态跟踪方法降低了配电网运行状态切换时刻的暂态波动,实现了配电网运行方式的平滑切换。在PSCAD/EMTDC环境下搭建了仿真模型进行验证,结果表明,所提控制方法可有效提升分区互联有源配电网运行的灵活性。
