In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-u...In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-uniform motion is developed. The structural properties of the system are investigated by means of the theory of Hamiltonian systems. A relationship between the parameters of the system and the parameters of the proposed decentralized PD controller is shown to ensure local stability and tracking performance. Simulation results are included to show the obtained non-uniform motion.展开更多
虚拟管道宽度直接影响了管道内无人机的流速,但目前虚拟管道规划的方法并不能保证管道宽度,容易造成堵塞,严重影响无人机通行效率。对此,提出一种虚拟管道空间满足规划方法,可以在包含障碍物的环境中得到一条满足虚拟管道空间要求的管...虚拟管道宽度直接影响了管道内无人机的流速,但目前虚拟管道规划的方法并不能保证管道宽度,容易造成堵塞,严重影响无人机通行效率。对此,提出一种虚拟管道空间满足规划方法,可以在包含障碍物的环境中得到一条满足虚拟管道空间要求的管道生成线。主要包括路径搜索和轨迹优化,基于快速探索随机树*(rapidly exploring random tree*,RRT*)搜索,通过空间检测判断每段路径周围是否有足够空间,若无足够空间则重新拓展搜索,替换掉空间不足的路径段。在轨迹优化过程中,使用均匀B样条参数化轨迹,并设计碰撞代价函数和光滑代价函数,使轨迹远离障碍物,为虚拟管道规划提供足够空间。仿真测试验证了所提方法在大规模集群中的优越性和鲁棒性。在仿真测试中,15架无人机集群通行时间平均降低20%。展开更多
A magneto-electric field appearing in a laboratory due to moving charges has unusual properties. In particular, such a field of kinematical origin does not obey the wave equation with a non-relativistic velocity inste...A magneto-electric field appearing in a laboratory due to moving charges has unusual properties. In particular, such a field of kinematical origin does not obey the wave equation with a non-relativistic velocity instead of light speed;so, its movement resembles that of a rigid body. In this paper the field of a uniformly charged sphere moving at constant velocity is considered. Relativistic axiom, implicitly used in the derivation of formulas describing a kinematic deformation for the proper spherical field from the point of view of a fixed observer, is revealed. A discrepancy was found between the generally accepted idea of the configuration of a deformed field and its real geometry. It is shown that the correct interpretation of known formulas leads to a logical contradiction, which cannot be eliminated within the framework of the theory of relativity. A scheme of a decisive experiment is proposed.展开更多
A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients...A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients in the formula have been obtained.The formula has been verified with prototype observation data, flumes data of both nature and lightweight sand.The computed results fully reflect the characteristics of thresh- old motion of non-uniform sediment.The result have been used in some physical mo...展开更多
以传统式张力腿平台(Tension Leg Platform)为对象,采用数值模拟与水池实验相结合的方法研究TLP涡激运动问题,以及张力腿和立管涡激振动特性;采用计算流体力学的方法,建立TLP涡激运动数值分析模型,分析均匀流作用下不同流速、来流方向...以传统式张力腿平台(Tension Leg Platform)为对象,采用数值模拟与水池实验相结合的方法研究TLP涡激运动问题,以及张力腿和立管涡激振动特性;采用计算流体力学的方法,建立TLP涡激运动数值分析模型,分析均匀流作用下不同流速、来流方向、以及规则波波流联合下TLP涡激运动规律,对张力腿、立管的涡激振动特性进行分析;将数值模拟计算结果与拖曳水池、全水深系泊水池试验结果对比,验证数值模拟与水池试验的一致性。分析结果表明,当流的折合速度在5.5~8.5之间时,TLP涡激运动出现锁频现象,系泊有减小平台横向涡激运动的作用,规则波对于流致涡激运动横荡方向运动有减小作用,而对纵荡的影响是其响应随规则波波高的增加而增加。本文得到的结论可为TLP的运动性能研究和工程设计提供参考。展开更多
文摘In this paper, a decentralized proportional-derivative （PD） controller design for non-uniform motion of a Hamiltonian hybrid system is considered. A Hamiltonian hybrid system with the capability of producing a non-uniform motion is developed. The structural properties of the system are investigated by means of the theory of Hamiltonian systems. A relationship between the parameters of the system and the parameters of the proposed decentralized PD controller is shown to ensure local stability and tracking performance. Simulation results are included to show the obtained non-uniform motion.
文摘虚拟管道宽度直接影响了管道内无人机的流速,但目前虚拟管道规划的方法并不能保证管道宽度,容易造成堵塞,严重影响无人机通行效率。对此,提出一种虚拟管道空间满足规划方法,可以在包含障碍物的环境中得到一条满足虚拟管道空间要求的管道生成线。主要包括路径搜索和轨迹优化,基于快速探索随机树*(rapidly exploring random tree*,RRT*)搜索,通过空间检测判断每段路径周围是否有足够空间,若无足够空间则重新拓展搜索,替换掉空间不足的路径段。在轨迹优化过程中,使用均匀B样条参数化轨迹,并设计碰撞代价函数和光滑代价函数,使轨迹远离障碍物,为虚拟管道规划提供足够空间。仿真测试验证了所提方法在大规模集群中的优越性和鲁棒性。在仿真测试中,15架无人机集群通行时间平均降低20%。
文摘A magneto-electric field appearing in a laboratory due to moving charges has unusual properties. In particular, such a field of kinematical origin does not obey the wave equation with a non-relativistic velocity instead of light speed;so, its movement resembles that of a rigid body. In this paper the field of a uniformly charged sphere moving at constant velocity is considered. Relativistic axiom, implicitly used in the derivation of formulas describing a kinematic deformation for the proper spherical field from the point of view of a fixed observer, is revealed. A discrepancy was found between the generally accepted idea of the configuration of a deformed field and its real geometry. It is shown that the correct interpretation of known formulas leads to a logical contradiction, which cannot be eliminated within the framework of the theory of relativity. A scheme of a decisive experiment is proposed.
基金Supported by Doctorial Fund of Ministry of Education (2002-173) and (2003-172)
文摘A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients in the formula have been obtained.The formula has been verified with prototype observation data, flumes data of both nature and lightweight sand.The computed results fully reflect the characteristics of thresh- old motion of non-uniform sediment.The result have been used in some physical mo...
文摘以传统式张力腿平台(Tension Leg Platform)为对象,采用数值模拟与水池实验相结合的方法研究TLP涡激运动问题,以及张力腿和立管涡激振动特性;采用计算流体力学的方法,建立TLP涡激运动数值分析模型,分析均匀流作用下不同流速、来流方向、以及规则波波流联合下TLP涡激运动规律,对张力腿、立管的涡激振动特性进行分析;将数值模拟计算结果与拖曳水池、全水深系泊水池试验结果对比,验证数值模拟与水池试验的一致性。分析结果表明,当流的折合速度在5.5~8.5之间时,TLP涡激运动出现锁频现象,系泊有减小平台横向涡激运动的作用,规则波对于流致涡激运动横荡方向运动有减小作用,而对纵荡的影响是其响应随规则波波高的增加而增加。本文得到的结论可为TLP的运动性能研究和工程设计提供参考。
