Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the ch...Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer dimension can cause counter-steering behavior. The simulator can be used to improve the automatic flight control. It can also be used for the hydrodynamic design optimization of the devices.展开更多
Hazard prevention in mission plans requires careful analysis and appropriate tools to support the design of preventive and/or corrective measures.It is most challenging in systems with large sets of states and complex...Hazard prevention in mission plans requires careful analysis and appropriate tools to support the design of preventive and/or corrective measures.It is most challenging in systems with large sets of states and complex state relations.In the case of sociotechnical systems,hazard prevention becomes even more dicult given that the behaviour of human centric components can at best be partially predictable.In the present article we focus on a specic class of sociotechnical systems-namely air spaces containing pilot controlled as well as autonomous aircrafts and introduce the notion of relevant hazards.We also introduce soft institutions as an appropriate basis for analysis,with the aim of addressing relevant hazards.The concept of soft institutions is drawn from specication languages for interaction between agents in multi-agent systems but,in our case,is adapted for use in systems that combine human and automated actors.展开更多
This paper proposed an improved artificial physics(AP)method to solve the autonomous navigation problem for multiple unmanned aerial vehicles(UAVs)/unmanned ground vehicles(UGVs)heterogeneous coordination in the three...This paper proposed an improved artificial physics(AP)method to solve the autonomous navigation problem for multiple unmanned aerial vehicles(UAVs)/unmanned ground vehicles(UGVs)heterogeneous coordination in the three-dimensional space.The basic AP method has a shortcoming of easily plunging into a local optimal solution,which can result in navigation fails.To avoid the local optimum,we improved the AP method with a random scheme.In the improved AP method,random forces are used to make heterogeneous multi-UAVs/UGVs escape from local optimum and achieve global optimum.Experimental results showed that the improved AP method can achieve smoother trajectories and smaller time consumption than the basic AP method and basic potential field method(PFM).展开更多
文摘Underwater gliders are recent innovative types of autonomous underwater vehicles （AUVs） used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer dimension can cause counter-steering behavior. The simulator can be used to improve the automatic flight control. It can also be used for the hydrodynamic design optimization of the devices.
基金partially supported by FAPESP-Brazil and by the EPSRCUK
文摘Hazard prevention in mission plans requires careful analysis and appropriate tools to support the design of preventive and/or corrective measures.It is most challenging in systems with large sets of states and complex state relations.In the case of sociotechnical systems,hazard prevention becomes even more dicult given that the behaviour of human centric components can at best be partially predictable.In the present article we focus on a specic class of sociotechnical systems-namely air spaces containing pilot controlled as well as autonomous aircrafts and introduce the notion of relevant hazards.We also introduce soft institutions as an appropriate basis for analysis,with the aim of addressing relevant hazards.The concept of soft institutions is drawn from specication languages for interaction between agents in multi-agent systems but,in our case,is adapted for use in systems that combine human and automated actors.
基金supported by the National Natural Science Foundation of China(Grant Nos.61273054,60975072)the National Basic Research Program of China("973" Project)(Grant No.2013CB035503)+3 种基金the Program for New Century Excellent Talents in University of China(Grant No.NCET-10-0021)the Top-Notch Young Talents Program of Chinathe Fundamental Research Funds for the Central Universities of Chinathe Aeronautical Foundation of China(Grant No.20115151019)
文摘This paper proposed an improved artificial physics(AP)method to solve the autonomous navigation problem for multiple unmanned aerial vehicles(UAVs)/unmanned ground vehicles(UGVs)heterogeneous coordination in the three-dimensional space.The basic AP method has a shortcoming of easily plunging into a local optimal solution,which can result in navigation fails.To avoid the local optimum,we improved the AP method with a random scheme.In the improved AP method,random forces are used to make heterogeneous multi-UAVs/UGVs escape from local optimum and achieve global optimum.Experimental results showed that the improved AP method can achieve smoother trajectories and smaller time consumption than the basic AP method and basic potential field method(PFM).
