Walking robots use leg structures to overcome obstacles or move on complicated terrains. Most robots of current researches are equipped with legs of simple structure. The specific design method of walking robot legs i...Walking robots use leg structures to overcome obstacles or move on complicated terrains. Most robots of current researches are equipped with legs of simple structure. The specific design method of walking robot legs is seldom studied. Based on the generalized-function(GF) set theory, a systematic type synthesis process of designing robot legs is introduced. The specific mobility of robot legs is analyzed to obtain two main leg types as the goal of design.Number synthesis problem is decomposed into two stages, actuation and constraint synthesis by name,corresponding to the combinatorics results of linear Diophantine equations. Additional restrictions are discussed to narrow the search range to propose practical limb expressions and kinematic-pair designs. Finally, all the fifty-one leg structures of four subtypes are carried out, some of which are chosen to make up robot prototypes, demonstrating the validity of the method. This paper proposed a novel type synthesis methodology, which could be used to systematically design various practical robot legs and the derived robots.展开更多
探求鞭腿技术击打不同类型目标时因动作运用不当可能引发膝关节运动损伤的危险时刻。运用VICON System 3D运动采集系统,对10名优秀散打运动员鞭腿技术进行空击、击打脚靶、沙包时的运动轨迹进行采集,依据鞭打动作特点和下肢关节运动特征...探求鞭腿技术击打不同类型目标时因动作运用不当可能引发膝关节运动损伤的危险时刻。运用VICON System 3D运动采集系统,对10名优秀散打运动员鞭腿技术进行空击、击打脚靶、沙包时的运动轨迹进行采集,依据鞭打动作特点和下肢关节运动特征,将鞭腿动作划分为3个时刻、2个时段,对其在各时刻的动作速度、作用腿膝关节角度、角速度、力矩等运用VICON Nexus和Polygon分析软件进行处理。研究结果表明:作用腿膝关节屈伸、内收外展、回旋角度和角速度以及关节力矩等各方面均存在着显著性差异(P<0.05);鞭腿空击技术类型的动作速度相对较慢,击打时段膝关节角速度相对较快、伸展时段膝关节呈外旋、加速并过度伸展状态;击打脚靶类型的动作速度相对较快,伸展时段膝关节呈外旋伸展运动状态;击打沙包类型膝关节的各项力矩相对较大,伸展时段膝关节呈反方向运动状态。鞭腿的3种击打类型均存在引发膝关节运动损伤的危险时刻,建议运动员在训练和实战时遵循鞭腿技术动作的运动规律。展开更多
The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters.As the most pivotal component of the jack-up unit,the leg system can directly affect the global ...The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters.As the most pivotal component of the jack-up unit,the leg system can directly affect the global performance of a jack-up unit.Investigation shows that there are three kinds of leg structure forms in the world now:the reverse K,X,and mixing types.In order to clarify the advantage and defects of each one,as well as their effect on the global performance of the jack-up unit,this paper commenced to study performance targets ofa deepwater jack-up unit with different leg systems(X type,reverse K type,and mixing type).In this paper a typical leg scantling dimension and identical external loads were selected,detailed finite element snalysis(FEA)models were built to simulate the jack-up unit's structural behavior,and the multi-point constraint(MPC)element together with the spring element was used to deal with the boundary condition.Finally,the above problems were solved by comparative analysis of their main performance targets(including ultimate static strength,dynamic response,and weight).展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.U1613208,51335007)National Basic Research Program of China(973 Program,Grant No.2013CB035501)+1 种基金Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51421092)Science and Technology Commission of Shanghai-based "Innovation Action Plan" Project(Grant No.16DZ1201001)
文摘Walking robots use leg structures to overcome obstacles or move on complicated terrains. Most robots of current researches are equipped with legs of simple structure. The specific design method of walking robot legs is seldom studied. Based on the generalized-function(GF) set theory, a systematic type synthesis process of designing robot legs is introduced. The specific mobility of robot legs is analyzed to obtain two main leg types as the goal of design.Number synthesis problem is decomposed into two stages, actuation and constraint synthesis by name,corresponding to the combinatorics results of linear Diophantine equations. Additional restrictions are discussed to narrow the search range to propose practical limb expressions and kinematic-pair designs. Finally, all the fifty-one leg structures of four subtypes are carried out, some of which are chosen to make up robot prototypes, demonstrating the validity of the method. This paper proposed a novel type synthesis methodology, which could be used to systematically design various practical robot legs and the derived robots.
文摘探求鞭腿技术击打不同类型目标时因动作运用不当可能引发膝关节运动损伤的危险时刻。运用VICON System 3D运动采集系统,对10名优秀散打运动员鞭腿技术进行空击、击打脚靶、沙包时的运动轨迹进行采集,依据鞭打动作特点和下肢关节运动特征,将鞭腿动作划分为3个时刻、2个时段,对其在各时刻的动作速度、作用腿膝关节角度、角速度、力矩等运用VICON Nexus和Polygon分析软件进行处理。研究结果表明:作用腿膝关节屈伸、内收外展、回旋角度和角速度以及关节力矩等各方面均存在着显著性差异(P<0.05);鞭腿空击技术类型的动作速度相对较慢,击打时段膝关节角速度相对较快、伸展时段膝关节呈外旋、加速并过度伸展状态;击打脚靶类型的动作速度相对较快,伸展时段膝关节呈外旋伸展运动状态;击打沙包类型膝关节的各项力矩相对较大,伸展时段膝关节呈反方向运动状态。鞭腿的3种击打类型均存在引发膝关节运动损伤的危险时刻,建议运动员在训练和实战时遵循鞭腿技术动作的运动规律。
文摘The jack-up unit is one of the best drilling platforms in offshore oil fields with water depth shallower than 150 meters.As the most pivotal component of the jack-up unit,the leg system can directly affect the global performance of a jack-up unit.Investigation shows that there are three kinds of leg structure forms in the world now:the reverse K,X,and mixing types.In order to clarify the advantage and defects of each one,as well as their effect on the global performance of the jack-up unit,this paper commenced to study performance targets ofa deepwater jack-up unit with different leg systems(X type,reverse K type,and mixing type).In this paper a typical leg scantling dimension and identical external loads were selected,detailed finite element snalysis(FEA)models were built to simulate the jack-up unit's structural behavior,and the multi-point constraint(MPC)element together with the spring element was used to deal with the boundary condition.Finally,the above problems were solved by comparative analysis of their main performance targets(including ultimate static strength,dynamic response,and weight).
