In order to ensure the safety and efficiency of planetary exploration rovers,path planning and tracking control of a planetary rover are expected to consider factors such as complex 3D terrain features,the motion cons...In order to ensure the safety and efficiency of planetary exploration rovers,path planning and tracking control of a planetary rover are expected to consider factors such as complex 3D terrain features,the motion constraints of the rover,traversability,etc.An improved path planning and tracking control method is proposed for planetary exploration rovers on rough terrain in this paper.Firstly,the kinematic model of the planetary rover is established.A 3D motion primitives library adapted to various terrains and the rover’s orientations is generated.The state expansion process and heuristic function of the A*algorithm are improved using the motion primitives and terrain features.Global path is generated by improved A*-based algorithm that satisfies the planetary rover’s kinematic constraints and the 3D terrain restrictions.Subsequently,an optional arc path set is designed based on the traversable capabilities of the planetary rover.Each arc path corresponds to a specific motion that determines the linear and angular velocities of the planetary rover.The optimal path is selected through the multi-objective evaluation function.The planetary rover is driven to accurately track the global path by sending optimal commands that corresponds to the optimal path for real-time obstacle avoidance.Finally,the path planning and tracking control method is effectively validated during a given mission through two simulation tests.The experiment results show that the improved A*-based algorithm reduces planning time by 30.05% and generates smoother paths than the classic A^(*) algorithm.The multi-objective arc-based method improves the rover’s motion efficiency,ensuring safer and quicker mission completion along the global path.展开更多
A concert of powers has become a new institutional arrangement for building a new-type major powers relationship in East Asia.In view of standardization,the consistency,legitimacy,accountability,inclusiveness,and self...A concert of powers has become a new institutional arrangement for building a new-type major powers relationship in East Asia.In view of standardization,the consistency,legitimacy,accountability,inclusiveness,and self-restraint,etc.enjoyed by a concert of powers are very suitable for the East Asian multilateral security mechanism featuring"cooperative security"concept,"ASEAN Way"of decision-making as well as"open regionalism"approach.In view of the practical conditions,major powers peculiarities and effectively solving hot issues highlighted by the East Asia geopolitical ecology require a concert of powers while a relative equilibrium of the East Asian regional major powers is in favor of a concert of powers.In terms of experience,the peaceful settlement of the Cambodian issue and the Six-party Talks on the DPRK nuclear issue provide a feasible path to initiate a concert of powers in sub-regions regarding the traditional security matter related indirectly with major powers.A new concert of powers in East Asia has three options,namely"soft security"-oriented multilateral coordination,"comprehensive security"-oriented"bilateral coordination"and"multilateral coordination".East Asia Summit and the existing major powers’bilateral strategic dialogue mechanisms are available institutional assets to be used by above-mentioned first two paths.The ideal state of third path is an independent security mechanism,designed to respond to major regional conflicts and crises.In practice,these three kinds of path can overlap,and be in parallel operation,and constitute"a concert of powers network"with bilateral and multilateral interactions,thus,providing a solid and effective mechanism for the East Asian regional security governance.展开更多
基金funded by the State Key Laboratory,China(KJW6142210210308)the National Natural Science Founda-tion of China(61806183).
文摘In order to ensure the safety and efficiency of planetary exploration rovers,path planning and tracking control of a planetary rover are expected to consider factors such as complex 3D terrain features,the motion constraints of the rover,traversability,etc.An improved path planning and tracking control method is proposed for planetary exploration rovers on rough terrain in this paper.Firstly,the kinematic model of the planetary rover is established.A 3D motion primitives library adapted to various terrains and the rover’s orientations is generated.The state expansion process and heuristic function of the A*algorithm are improved using the motion primitives and terrain features.Global path is generated by improved A*-based algorithm that satisfies the planetary rover’s kinematic constraints and the 3D terrain restrictions.Subsequently,an optional arc path set is designed based on the traversable capabilities of the planetary rover.Each arc path corresponds to a specific motion that determines the linear and angular velocities of the planetary rover.The optimal path is selected through the multi-objective evaluation function.The planetary rover is driven to accurately track the global path by sending optimal commands that corresponds to the optimal path for real-time obstacle avoidance.Finally,the path planning and tracking control method is effectively validated during a given mission through two simulation tests.The experiment results show that the improved A*-based algorithm reduces planning time by 30.05% and generates smoother paths than the classic A^(*) algorithm.The multi-objective arc-based method improves the rover’s motion efficiency,ensuring safer and quicker mission completion along the global path.
文摘A concert of powers has become a new institutional arrangement for building a new-type major powers relationship in East Asia.In view of standardization,the consistency,legitimacy,accountability,inclusiveness,and self-restraint,etc.enjoyed by a concert of powers are very suitable for the East Asian multilateral security mechanism featuring"cooperative security"concept,"ASEAN Way"of decision-making as well as"open regionalism"approach.In view of the practical conditions,major powers peculiarities and effectively solving hot issues highlighted by the East Asia geopolitical ecology require a concert of powers while a relative equilibrium of the East Asian regional major powers is in favor of a concert of powers.In terms of experience,the peaceful settlement of the Cambodian issue and the Six-party Talks on the DPRK nuclear issue provide a feasible path to initiate a concert of powers in sub-regions regarding the traditional security matter related indirectly with major powers.A new concert of powers in East Asia has three options,namely"soft security"-oriented multilateral coordination,"comprehensive security"-oriented"bilateral coordination"and"multilateral coordination".East Asia Summit and the existing major powers’bilateral strategic dialogue mechanisms are available institutional assets to be used by above-mentioned first two paths.The ideal state of third path is an independent security mechanism,designed to respond to major regional conflicts and crises.In practice,these three kinds of path can overlap,and be in parallel operation,and constitute"a concert of powers network"with bilateral and multilateral interactions,thus,providing a solid and effective mechanism for the East Asian regional security governance.
