移动机器人导航功能的实现需要同时定位与建图(simultaneous localization and mapping,SLAM)和路径规划这两方面的技术,其中由SLAM技术生成的栅格地图是移动机器人运用路径规划算法的前提。2D激光SLAM由于其建图精度较高、性能稳定且...移动机器人导航功能的实现需要同时定位与建图(simultaneous localization and mapping,SLAM)和路径规划这两方面的技术,其中由SLAM技术生成的栅格地图是移动机器人运用路径规划算法的前提。2D激光SLAM由于其建图精度较高、性能稳定且价格便宜,在室内移动机器人中应用十分广泛。2D激光SLAM是指移动机器人在自身所处环境及位置先验信息未知的情况下,以2D激光雷达为主要传感器,感知周围环境信息,从而实现自身位姿的估计和地图的构建。将2D激光SLAM分为两部分,第一部分从激光测距原理入手,对三角法和飞行时间法进行了详细介绍和优缺点比较。第二部分从前端扫描匹配、后端优化、回环检测和地图构建这四个方面分别详细阐述了2D激光SLAM系统框架。同时对主流2D激光SLAM算法进行了深入分析和优缺点比较,并对激光SLAM未来的发展进行了展望。展开更多
We perform an experimental study of two-dimensional（2D） electron density profiles of the laser-induced plasma plumes in air by ordinarily laboratorial interferometry. The electron density distributions measured show...We perform an experimental study of two-dimensional（2D） electron density profiles of the laser-induced plasma plumes in air by ordinarily laboratorial interferometry. The electron density distributions measured show a feature of hollow core. To illustrate the feature, we present a theoretical investigation by using dynamics analysis. In the simulation, the propagation of laser pulse with the evolution of electron density is utilized to evaluate ionization of air target for the plasma-formation stage. In the plasma-expansion stage, a simple adiabatic fluid dynamics is used to calculate the evolution of plasma outward expansion. The simulations show good agreements with experimental results, and demonstrate an effective way of determining 2D density profiles of the laser-induced plasma plume in gas.展开更多
A novel theoretical model of thermal diffusion has been established to study thermal interaction between two neighboring diodes in semiconductor laser arrays. The main cause of the ocurrence of the thermal interaction...A novel theoretical model of thermal diffusion has been established to study thermal interaction between two neighboring diodes in semiconductor laser arrays. The main cause of the ocurrence of the thermal interaction between two neighboring diodes in array devices is the heat conduction through heat sink. We hold that as the devices must have heat sink to diffuse heat, this kind of interaction in the array would always exist. However, when the pitch between two neighboring diodes in the array is reasonably defined, this troublesome thermal interaction can be simply reduced by using our model. Based on the individual diodes with leaky waveguide structure, we experimentally succeeded in fabricating 2D 4 ×4 arrays. The thermal interaction between upper and lower diodes in the 2D array is also considered as well as the function of the heat sink. The measured results show that the pulse peak output powor of the 2D 4 ×4 array is high up to 11 W.展开更多
文摘移动机器人导航功能的实现需要同时定位与建图(simultaneous localization and mapping,SLAM)和路径规划这两方面的技术,其中由SLAM技术生成的栅格地图是移动机器人运用路径规划算法的前提。2D激光SLAM由于其建图精度较高、性能稳定且价格便宜,在室内移动机器人中应用十分广泛。2D激光SLAM是指移动机器人在自身所处环境及位置先验信息未知的情况下,以2D激光雷达为主要传感器,感知周围环境信息,从而实现自身位姿的估计和地图的构建。将2D激光SLAM分为两部分,第一部分从激光测距原理入手,对三角法和飞行时间法进行了详细介绍和优缺点比较。第二部分从前端扫描匹配、后端优化、回环检测和地图构建这四个方面分别详细阐述了2D激光SLAM系统框架。同时对主流2D激光SLAM算法进行了深入分析和优缺点比较,并对激光SLAM未来的发展进行了展望。
基金supported by National Natural Science Foundation of China(Nos.11264036,11465016 and 11364038)
文摘We perform an experimental study of two-dimensional（2D） electron density profiles of the laser-induced plasma plumes in air by ordinarily laboratorial interferometry. The electron density distributions measured show a feature of hollow core. To illustrate the feature, we present a theoretical investigation by using dynamics analysis. In the simulation, the propagation of laser pulse with the evolution of electron density is utilized to evaluate ionization of air target for the plasma-formation stage. In the plasma-expansion stage, a simple adiabatic fluid dynamics is used to calculate the evolution of plasma outward expansion. The simulations show good agreements with experimental results, and demonstrate an effective way of determining 2D density profiles of the laser-induced plasma plume in gas.
文摘A novel theoretical model of thermal diffusion has been established to study thermal interaction between two neighboring diodes in semiconductor laser arrays. The main cause of the ocurrence of the thermal interaction between two neighboring diodes in array devices is the heat conduction through heat sink. We hold that as the devices must have heat sink to diffuse heat, this kind of interaction in the array would always exist. However, when the pitch between two neighboring diodes in the array is reasonably defined, this troublesome thermal interaction can be simply reduced by using our model. Based on the individual diodes with leaky waveguide structure, we experimentally succeeded in fabricating 2D 4 ×4 arrays. The thermal interaction between upper and lower diodes in the 2D array is also considered as well as the function of the heat sink. The measured results show that the pulse peak output powor of the 2D 4 ×4 array is high up to 11 W.
