针对标准快速扩展随机树(Rapidly Exploring Random Tree,RRT)算法在复杂环境下存在盲目扩展、陷入局部搜索易导致规划失败、采样成功率低、路径冗长等问题,提出一种自适应目标导向策略结合区域采样备选策略以及贪婪剪枝策略的改进RRT...针对标准快速扩展随机树(Rapidly Exploring Random Tree,RRT)算法在复杂环境下存在盲目扩展、陷入局部搜索易导致规划失败、采样成功率低、路径冗长等问题,提出一种自适应目标导向策略结合区域采样备选策略以及贪婪剪枝策略的改进RRT算法。在机械臂运动学基础上,用包络简化机械臂模型来提高碰撞检测的效率;自适应目标导向策略解决了复杂环境中RRT算法盲目搜索、搜索成功率低、不易收敛的问题;区域采样备选策略解决了RRT算法易陷入局部搜索、采样成功率低以及采样时间长的问题;贪婪剪枝策略剔除了冗余节点,缩短了路径,提升了路径质量,增强了算法的鲁棒性。在Matlab软件和机器人操作系统(Robot Operating System,ROS)中对不同场景进行了避障仿真规划。结果表明,改进RRT算法平均搜索成功率提高了82.4%,平均采样成功率提高了67.5%,平均路径规划成功率提高了70%,平均时间效率提高了81.9%,平均路径长度缩短了63.05%。最后,对实体机械臂进行轨迹规划,进一步验证了算法的实用性与有效性。展开更多
Recent investigations have shown that with varying the amplitude of the external force, the deterministic ratchets exhibit multiple current reversals, which are undesirable in certain circumstances. To control the mul...Recent investigations have shown that with varying the amplitude of the external force, the deterministic ratchets exhibit multiple current reversals, which are undesirable in certain circumstances. To control the multiple reverse current to unidirectional current, an adaptive control law is presented inspired from the relation between multiple reversaJs current and the chaos-periodic/quasiperiodic transition of the transport velocity. The designed controller can stabilize the transport velocity of ratchets to steady state and suppress any chaos-periodic/quasiperiodic transition, namely, the stable transport in ratchets is achieved, which makes the current sign unchanged.展开更多
We propose a self-adaptive process （SAP） that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-...We propose a self-adaptive process （SAP） that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-oriented meth- odologies due to its explicitly defined inputs and outputs. To this aim, the proposed SAP is integrated with the service-oriented modeling and application （SOMA） methodology in a two-layered structure to create a novel methodology, named self-adaptive service-oriented architecture methodology （SASOAM）, which provides a semi-automatic self-aware method by the composition of architectural tactics. Moreover, the maintenance activity of SOMA is improved using architectural and adaptive patterns, which results in controlling the software architecture quality. The improvement in the maintainability of SOMA is demonstrated by an analytic hierarchy process （AHP） based evaluation method. Furthermore, the proposed method is applied to a case study to represent the feasibility and practicality of SASOAM.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10862001 and 10947011the Construction of Key Laboratories in Universities of Guangxi under Grant No. 200912
文摘Recent investigations have shown that with varying the amplitude of the external force, the deterministic ratchets exhibit multiple current reversals, which are undesirable in certain circumstances. To control the multiple reverse current to unidirectional current, an adaptive control law is presented inspired from the relation between multiple reversaJs current and the chaos-periodic/quasiperiodic transition of the transport velocity. The designed controller can stabilize the transport velocity of ratchets to steady state and suppress any chaos-periodic/quasiperiodic transition, namely, the stable transport in ratchets is achieved, which makes the current sign unchanged.
文摘We propose a self-adaptive process （SAP） that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-oriented meth- odologies due to its explicitly defined inputs and outputs. To this aim, the proposed SAP is integrated with the service-oriented modeling and application （SOMA） methodology in a two-layered structure to create a novel methodology, named self-adaptive service-oriented architecture methodology （SASOAM）, which provides a semi-automatic self-aware method by the composition of architectural tactics. Moreover, the maintenance activity of SOMA is improved using architectural and adaptive patterns, which results in controlling the software architecture quality. The improvement in the maintainability of SOMA is demonstrated by an analytic hierarchy process （AHP） based evaluation method. Furthermore, the proposed method is applied to a case study to represent the feasibility and practicality of SASOAM.
