Robot-based remanufacturing system can scan the worn parts and develop the corresponding models, compare them with the standard model, calculate the weld deposit, implement welding path planning, and repair the worn p...Robot-based remanufacturing system can scan the worn parts and develop the corresponding models, compare them with the standard model, calculate the weld deposit, implement welding path planning, and repair the worn parts with MIG surfacing automatically. This paper investigates the welding path planning after calibrating, scanning and model rebuilding. The following aspects are contained： introducing the planning principle, selecting the suitable welding process based on welding parameters （current and speed）, calculating welding overlap quantity by the superposition method. Also, it has been verified that good weld profile can be obtained with the optimized parameters.展开更多
This paper presents a singularity robust path planning for space manipulator to achieve base （satellite） attitude adjustment and end-effector task. The base attitude adjustment by the movement of manipulator will sa...This paper presents a singularity robust path planning for space manipulator to achieve base （satellite） attitude adjustment and end-effector task. The base attitude adjustment by the movement of manipulator will save propellant compared with conventional attitude control system. A task-priority reaction null-space control method is applied to achieve the primary task of adjusting attitude and secondary task of accomplishing end-effector task. Furthermore, the algorithm singularity is eliminated in the proposed algorithm compared with conventional reaction null-space algorithm. And the singular value filtering decomposition is introduced to dispose the dynamic singularity, the unit quaternion is also introduced to overcome representation singularity. Hence, a singularity robust path planning algorithm of space robot for base attitude adjustment is derived. A real time simulation system of the space robot under Linux/RTAl （realtime application interface） is developed to verify and test the feasibility and reliability of the method. The experimental results demonstrate the feasibility of online base attitude adjustment of space robot by the proposed algorithm.展开更多
Characteristic towns as a characteristic industry are one of the important measures of China's new urbanization strategy. The construction of characteristic towns in different regions needs to pay attention to reg...Characteristic towns as a characteristic industry are one of the important measures of China's new urbanization strategy. The construction of characteristic towns in different regions needs to pay attention to regional differentiation. At present, the research on characteristic towns focuses on the developed the developed central and eastern regions. There are still few studies on characteristics towns in underdeveloped areas. Starting from the analysis of the concept of the characteristic town, this paper sorted out the general situation of the construction of characteristic towns in China based on the existing research literature, selected Ganzhou City for research, pointed out there were "two restrictions and two singles" in the construction of characteristic towns in Ganzhou City, and clarified that the characteristic towns of Ganzhou City should adhere to the construction path of "two characteristics and two integrations", with a view to providing a useful reference for in Ganzhou City the construction of characteristic towns, industrial transformation and upgrading, and poverty alleviation in such underdeveloped, resource-based cities.展开更多
To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coa...To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection.展开更多
The path planning problem for intelligent mobile robots involves two main problems:the represent of task environment including obstacles and the development of a strategy to determine a collision-free route.In this pa...The path planning problem for intelligent mobile robots involves two main problems:the represent of task environment including obstacles and the development of a strategy to determine a collision-free route.In this paper, new approaches have been developed to solve these problems.The first problem was solved using the fuzzy system approach,which represent obstacles with a circle.The other problem was overcome through the use of a strategy selector,which chooses the best strategy between velocity control strategy and direction control strategy.展开更多
This paper presents an FBCRI(feedback based compositional rule of inference)based novel path planning method to satisfy the requirements of real-time navigation,smoothness optimization and probabilistic obstacle avoid...This paper presents an FBCRI(feedback based compositional rule of inference)based novel path planning method to satisfy the requirements of real-time navigation,smoothness optimization and probabilistic obstacle avoidance.With local path-searching behaviors in regional ranges and global goal-seeking behaviors in holistic ranges,the method infers behavior weights using fuzzy reasoning embedded with feedback,and then coordinates the behaviors to generate new reference waypoints.In view of the deterministic decisions and the uncertain states of a UAV(unmanned air vehicle),chance constraints are adopted to probabilistically guarantee the UAV’s safety at a required level.Simulation results in representative scenes prove that the method is able to rapidly generate convergent paths in obstacle-rich environments,as well as highly improve the path quality with respect to smoothness and probabilistic safety.展开更多
The effect of lamellar orientation on crack paths in PST crystals of y-TiAl based alloys was investigated by in-situ SEM technique. The results indicate that the crack paths in PST crystals of y-TiAl based alloys are ...The effect of lamellar orientation on crack paths in PST crystals of y-TiAl based alloys was investigated by in-situ SEM technique. The results indicate that the crack paths in PST crystals of y-TiAl based alloys are strongly dependent on lamellar orientation ofPST crystals, and the differently oriented PST crystals show different nucleation and propagation mechanisms of crack, resulting in different levels of fracture toughness.展开更多
In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The...In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The traits of the parents (30 plants), F1 (30 plants) and F2 generations (492 individuals) were evaluated at the Rice Research Institute of Iran (RRII) during 2007. Heritabilities of the number of panicles per plant, plant height, days to heading and panicle exsertion were greater than that of grain yield. The selection indices were developed using the results of multivariate analysis. To evaluate selection strategies to maximize grain yield, 14 selection indices were calculated based on two methods (optimum and base) and combinations of 12 traits with various economic weights. Results of selection indices showed that selection for grain weight, number of panicles per plant and panicle length by using their phenotypic and/or genotypic direct effects (path coefficient) as economic weights should serve as an effective selection criterion for using either the optimum or base index.展开更多
A new novel function materials, structure self-monitoring asphalt-based composite was introduced. The results show that the output resistance of electrically conductive asphalt-based composites would change under cycl...A new novel function materials, structure self-monitoring asphalt-based composite was introduced. The results show that the output resistance of electrically conductive asphalt-based composites would change under cyclic loading and vehicle loading action. The resistance change of conductive asphalt-based composites was aroused by the variation of its interior structure. When the fatigue failure was studied, the larger cracks cut the continuous electrically conductive path and the electron is difficult to overcome the potential barrier of gap. In the early period, the slight deformation and microcrack may be recovered due to the viscoelasticity character of asphalt, which leads to some cracks close again, the output resistance changes a little. But with the shear process performs continuously, the cracks become larger and larger, which would cut the conductive path and block off the transition of electrons, and if the cracks are large enough, the pitch-matrix composites containing carbon fillers will lose electrically conductive function. When the rutting failure was studied, the flowage of conductive substance results in the decrease of substance due to electrically conducting and conductive path decreasing. The decrease of electron volume contribute to electrically conducting and large stone aggregate prevent the electron from transiting. In a word, the variation of output resistance is aroused by the variation of interior structure completely.展开更多
针对多自主水下航行器(Autonomous Underwater Vehicle,AUV)的全覆盖路径规划问题,提出了一种考虑随机初始位置约束的多AUV覆盖路径规划方法(Dividing Areas based on Robots Initial Positions CPP,DARIP-CPP)。根据多自主水下机器人...针对多自主水下航行器(Autonomous Underwater Vehicle,AUV)的全覆盖路径规划问题,提出了一种考虑随机初始位置约束的多AUV覆盖路径规划方法(Dividing Areas based on Robots Initial Positions CPP,DARIP-CPP)。根据多自主水下机器人的随机初始位置对工作海域进行均衡区域划分,将划分所得的不重叠区域分配给多AUV进行独立覆盖路径规划,每台AUV利用生物启发神经网络(Bio-inspired Neural Network)优化各个区域的全覆盖路径。为了克服传统全覆盖路径规划中的“死区”问题,采用A^(*)路径规划算法进行“死区”逃离,沿着较短的路径快速到达未覆盖区域点。仿真结果表明,所提出的DARIPCPP方法可有效提高多AUV全覆盖目标区域的工作效率。展开更多
文摘Robot-based remanufacturing system can scan the worn parts and develop the corresponding models, compare them with the standard model, calculate the weld deposit, implement welding path planning, and repair the worn parts with MIG surfacing automatically. This paper investigates the welding path planning after calibrating, scanning and model rebuilding. The following aspects are contained： introducing the planning principle, selecting the suitable welding process based on welding parameters （current and speed）, calculating welding overlap quantity by the superposition method. Also, it has been verified that good weld profile can be obtained with the optimized parameters.
基金supported by National Program on Key Basic Research Project(973 Program,No.2013CB733103)the Program for New Century Excellent Talents in University(No.NCET-10-0058)
文摘This paper presents a singularity robust path planning for space manipulator to achieve base （satellite） attitude adjustment and end-effector task. The base attitude adjustment by the movement of manipulator will save propellant compared with conventional attitude control system. A task-priority reaction null-space control method is applied to achieve the primary task of adjusting attitude and secondary task of accomplishing end-effector task. Furthermore, the algorithm singularity is eliminated in the proposed algorithm compared with conventional reaction null-space algorithm. And the singular value filtering decomposition is introduced to dispose the dynamic singularity, the unit quaternion is also introduced to overcome representation singularity. Hence, a singularity robust path planning algorithm of space robot for base attitude adjustment is derived. A real time simulation system of the space robot under Linux/RTAl （realtime application interface） is developed to verify and test the feasibility and reliability of the method. The experimental results demonstrate the feasibility of online base attitude adjustment of space robot by the proposed algorithm.
文摘Characteristic towns as a characteristic industry are one of the important measures of China's new urbanization strategy. The construction of characteristic towns in different regions needs to pay attention to regional differentiation. At present, the research on characteristic towns focuses on the developed the developed central and eastern regions. There are still few studies on characteristics towns in underdeveloped areas. Starting from the analysis of the concept of the characteristic town, this paper sorted out the general situation of the construction of characteristic towns in China based on the existing research literature, selected Ganzhou City for research, pointed out there were "two restrictions and two singles" in the construction of characteristic towns in Ganzhou City, and clarified that the characteristic towns of Ganzhou City should adhere to the construction path of "two characteristics and two integrations", with a view to providing a useful reference for in Ganzhou City the construction of characteristic towns, industrial transformation and upgrading, and poverty alleviation in such underdeveloped, resource-based cities.
基金Supported by the National Basic Research Program of China under Grant No 2014CB340102
文摘To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection.
文摘The path planning problem for intelligent mobile robots involves two main problems:the represent of task environment including obstacles and the development of a strategy to determine a collision-free route.In this paper, new approaches have been developed to solve these problems.The first problem was solved using the fuzzy system approach,which represent obstacles with a circle.The other problem was overcome through the use of a strategy selector,which chooses the best strategy between velocity control strategy and direction control strategy.
基金National Nature Science Foundation of China(60904066)
文摘This paper presents an FBCRI(feedback based compositional rule of inference)based novel path planning method to satisfy the requirements of real-time navigation,smoothness optimization and probabilistic obstacle avoidance.With local path-searching behaviors in regional ranges and global goal-seeking behaviors in holistic ranges,the method infers behavior weights using fuzzy reasoning embedded with feedback,and then coordinates the behaviors to generate new reference waypoints.In view of the deterministic decisions and the uncertain states of a UAV(unmanned air vehicle),chance constraints are adopted to probabilistically guarantee the UAV’s safety at a required level.Simulation results in representative scenes prove that the method is able to rapidly generate convergent paths in obstacle-rich environments,as well as highly improve the path quality with respect to smoothness and probabilistic safety.
文摘The effect of lamellar orientation on crack paths in PST crystals of y-TiAl based alloys was investigated by in-situ SEM technique. The results indicate that the crack paths in PST crystals of y-TiAl based alloys are strongly dependent on lamellar orientation ofPST crystals, and the differently oriented PST crystals show different nucleation and propagation mechanisms of crack, resulting in different levels of fracture toughness.
文摘In order to study selection indices for improving rice grain yield, a cross was made between an Iranian traditional rice (Oryza sativa L.) variety, Tarommahalli and an improved indica rice variety, Khazar in 2006. The traits of the parents (30 plants), F1 (30 plants) and F2 generations (492 individuals) were evaluated at the Rice Research Institute of Iran (RRII) during 2007. Heritabilities of the number of panicles per plant, plant height, days to heading and panicle exsertion were greater than that of grain yield. The selection indices were developed using the results of multivariate analysis. To evaluate selection strategies to maximize grain yield, 14 selection indices were calculated based on two methods (optimum and base) and combinations of 12 traits with various economic weights. Results of selection indices showed that selection for grain weight, number of panicles per plant and panicle length by using their phenotypic and/or genotypic direct effects (path coefficient) as economic weights should serve as an effective selection criterion for using either the optimum or base index.
基金Project (2004ABB019) supported by the Outstanding Youth Foundation of Hubei Province, China project (NCET-05-0656) supported by the New Century Excellent Talents in Wuhan University
文摘A new novel function materials, structure self-monitoring asphalt-based composite was introduced. The results show that the output resistance of electrically conductive asphalt-based composites would change under cyclic loading and vehicle loading action. The resistance change of conductive asphalt-based composites was aroused by the variation of its interior structure. When the fatigue failure was studied, the larger cracks cut the continuous electrically conductive path and the electron is difficult to overcome the potential barrier of gap. In the early period, the slight deformation and microcrack may be recovered due to the viscoelasticity character of asphalt, which leads to some cracks close again, the output resistance changes a little. But with the shear process performs continuously, the cracks become larger and larger, which would cut the conductive path and block off the transition of electrons, and if the cracks are large enough, the pitch-matrix composites containing carbon fillers will lose electrically conductive function. When the rutting failure was studied, the flowage of conductive substance results in the decrease of substance due to electrically conducting and conductive path decreasing. The decrease of electron volume contribute to electrically conducting and large stone aggregate prevent the electron from transiting. In a word, the variation of output resistance is aroused by the variation of interior structure completely.
文摘针对多自主水下航行器(Autonomous Underwater Vehicle,AUV)的全覆盖路径规划问题,提出了一种考虑随机初始位置约束的多AUV覆盖路径规划方法(Dividing Areas based on Robots Initial Positions CPP,DARIP-CPP)。根据多自主水下机器人的随机初始位置对工作海域进行均衡区域划分,将划分所得的不重叠区域分配给多AUV进行独立覆盖路径规划,每台AUV利用生物启发神经网络(Bio-inspired Neural Network)优化各个区域的全覆盖路径。为了克服传统全覆盖路径规划中的“死区”问题,采用A^(*)路径规划算法进行“死区”逃离,沿着较短的路径快速到达未覆盖区域点。仿真结果表明,所提出的DARIPCPP方法可有效提高多AUV全覆盖目标区域的工作效率。
