Mobile manipulators are used in a variety of fields because of their flexibility and maneuverability.The path planning capability of the mobile manipulator is one of the important indicators to evaluate the performanc...Mobile manipulators are used in a variety of fields because of their flexibility and maneuverability.The path planning capability of the mobile manipulator is one of the important indicators to evaluate the performance of the manipulator,but it is greatly challenged in the face of maps with narrow channel.To address the problem,an improved hierarchical motion planner(IHMP)is proposed,which consists of a two-dimensional(2D)path planner for the mobile base,and a three-dimensional(3D)trajectory planner for the on-board manipulator.Firstly,a hybrid sampling strategy is proposed,which can reduce invalid nodes of the generated probabilistic roadmap.Bridge test is used to locate the narrow channel areas,and a Gaussian sampler is deployed in these areas and the boundaries.Meanwhile,a random sampler is deployed in the rest areas.Trajectory planner for on-board manipulator is to generate a collision-free and safe trajectory in the narrow channel with collaboration of the 2D path planner.The experimental results show that IHMP is effective for mobile manipulator motion planning in complex static environments,especially in narrow channel.展开更多
Turbulence represents an essential aspect in atmospheric and oceanic circulations.In particu- lar,it is a preponderant factor in the dispersion of pollutants of artificial or natural origin.The vertical turbulent jets...Turbulence represents an essential aspect in atmospheric and oceanic circulations.In particu- lar,it is a preponderant factor in the dispersion of pollutants of artificial or natural origin.The vertical turbulent jets,plumes and buoyant jets discharging into static environment is one of the most important and basic flow patterns related with the environment pollution.These flows have numerous important applications,for example,thrust augmentors,waste disposal plumes from stacks and combustion systems,and significant problems of turbulent diffusion.展开更多
文摘Mobile manipulators are used in a variety of fields because of their flexibility and maneuverability.The path planning capability of the mobile manipulator is one of the important indicators to evaluate the performance of the manipulator,but it is greatly challenged in the face of maps with narrow channel.To address the problem,an improved hierarchical motion planner(IHMP)is proposed,which consists of a two-dimensional(2D)path planner for the mobile base,and a three-dimensional(3D)trajectory planner for the on-board manipulator.Firstly,a hybrid sampling strategy is proposed,which can reduce invalid nodes of the generated probabilistic roadmap.Bridge test is used to locate the narrow channel areas,and a Gaussian sampler is deployed in these areas and the boundaries.Meanwhile,a random sampler is deployed in the rest areas.Trajectory planner for on-board manipulator is to generate a collision-free and safe trajectory in the narrow channel with collaboration of the 2D path planner.The experimental results show that IHMP is effective for mobile manipulator motion planning in complex static environments,especially in narrow channel.
文摘Turbulence represents an essential aspect in atmospheric and oceanic circulations.In particu- lar,it is a preponderant factor in the dispersion of pollutants of artificial or natural origin.The vertical turbulent jets,plumes and buoyant jets discharging into static environment is one of the most important and basic flow patterns related with the environment pollution.These flows have numerous important applications,for example,thrust augmentors,waste disposal plumes from stacks and combustion systems,and significant problems of turbulent diffusion.
