为了减小 CO2 焊接过程中的飞溅和改善焊缝成型 ,实现焊接参数的最佳匹配。介绍了一种在波形控制基础上 ,采用电弧自身传感的协同式模糊控制方法对焊接过程参数进行实时控制的逆变式 CO2 焊机控制系统。它通过电弧自身传感对 CO2 焊接...为了减小 CO2 焊接过程中的飞溅和改善焊缝成型 ,实现焊接参数的最佳匹配。介绍了一种在波形控制基础上 ,采用电弧自身传感的协同式模糊控制方法对焊接过程参数进行实时控制的逆变式 CO2 焊机控制系统。它通过电弧自身传感对 CO2 焊接过程有重要影响的短路过渡频率的检测 ,通过模糊处理和模糊判决之后 ,实时的对电弧电压进行控制 ,以保持焊接过程中规范参数的协同匹配关系。实验结果表明 ,采用该控制系统的焊机 ,实现了焊接规范参数的自动匹配和自动调节 ,同时明显改善了焊缝成型和降低了焊接过程中的飞溅。展开更多
Interacting with digital contents in 3 D is an essential task in various applications such as modeling packages, gaming, virtual reality, etc. Traditional interfaces using keyboard and mouse or trackball usually requi...Interacting with digital contents in 3 D is an essential task in various applications such as modeling packages, gaming, virtual reality, etc. Traditional interfaces using keyboard and mouse or trackball usually require a non-trivial amount of working space as well as a learning process. We present the design of EZ-Manipulator, a new 3 D manipulation interface using smartphones that supports mobile, fast, and ambiguity-free interaction with 3 D objects. Our system leverages the built-in multi-touch input and gyroscope sensor of smartphones to achieve 9 degrees-of-freedom axis-constrained manipulation and free-form rotation.Using EZ-Manipulator to manipulate objects in 3 D is easy. The user merely has to perform intuitive singleor two-finger gestures and rotate the hand-held device to perform manipulations at fine-grained and coarse levels respectively. We further investigate the ambiguity in manipulation introduced by indirect manipulations using a multi-touch interface, and propose a dynamic virtual camera adjustment to effectively resolve the ambiguity. A preliminary study shows that our system has significant lower task completion time compared to conventional use of a keyboard–mouse interface, and provides a positive user experience to both novices and experts.展开更多
Flexible strain sensors are essential components of wearable electronic skins.Here we report a new kind of flexible strain sensor by filling conductive nanowires in elastomers featuring a concentration gradient.The fa...Flexible strain sensors are essential components of wearable electronic skins.Here we report a new kind of flexible strain sensor by filling conductive nanowires in elastomers featuring a concentration gradient.The fabrication method involves a fast photo-induced copolymerization of acrylates in the presence of gradient deposited polypyrrole(PPy)nanowires,which is facile and cost-effective in steadily doping PPy into elastomeric films.The combination of delicately selected polyacrylates as the matrix filled with entangled,nano-sized PPy endows the sensor good stretchability,sensitive deformation-electrical signal conversion and high fatigue resistance,which can be used repeatedly without scarifying the sensitivity of electrical signal.Besides,the lower side of the composite films exhibits high light absorption(>98%)in a wide spectral range(250—2400 nm).Systematic characterizations of the sensors support that the excellent strain sensing and light-heat conversion performances are essentially dependent on the gradient filling of PPy nanowires.Moreover,the applications of this flexible strain sensor for human motion monitoring and wearable thermotherapy are demonstrated,manifesting a promising option for wearable electronics and personalized healthcare.展开更多
文摘为了减小 CO2 焊接过程中的飞溅和改善焊缝成型 ,实现焊接参数的最佳匹配。介绍了一种在波形控制基础上 ,采用电弧自身传感的协同式模糊控制方法对焊接过程参数进行实时控制的逆变式 CO2 焊机控制系统。它通过电弧自身传感对 CO2 焊接过程有重要影响的短路过渡频率的检测 ,通过模糊处理和模糊判决之后 ,实时的对电弧电压进行控制 ,以保持焊接过程中规范参数的协同匹配关系。实验结果表明 ,采用该控制系统的焊机 ,实现了焊接规范参数的自动匹配和自动调节 ,同时明显改善了焊缝成型和降低了焊接过程中的飞溅。
文摘Interacting with digital contents in 3 D is an essential task in various applications such as modeling packages, gaming, virtual reality, etc. Traditional interfaces using keyboard and mouse or trackball usually require a non-trivial amount of working space as well as a learning process. We present the design of EZ-Manipulator, a new 3 D manipulation interface using smartphones that supports mobile, fast, and ambiguity-free interaction with 3 D objects. Our system leverages the built-in multi-touch input and gyroscope sensor of smartphones to achieve 9 degrees-of-freedom axis-constrained manipulation and free-form rotation.Using EZ-Manipulator to manipulate objects in 3 D is easy. The user merely has to perform intuitive singleor two-finger gestures and rotate the hand-held device to perform manipulations at fine-grained and coarse levels respectively. We further investigate the ambiguity in manipulation introduced by indirect manipulations using a multi-touch interface, and propose a dynamic virtual camera adjustment to effectively resolve the ambiguity. A preliminary study shows that our system has significant lower task completion time compared to conventional use of a keyboard–mouse interface, and provides a positive user experience to both novices and experts.
基金Financial support by the National Key Research and Development Programof China(Grants 2017YFA0207800and 2017YFA0204503)the National Natural Science Foundation of China(Grants 21734006 and 21975178)is gratefully acknowledged.
文摘Flexible strain sensors are essential components of wearable electronic skins.Here we report a new kind of flexible strain sensor by filling conductive nanowires in elastomers featuring a concentration gradient.The fabrication method involves a fast photo-induced copolymerization of acrylates in the presence of gradient deposited polypyrrole(PPy)nanowires,which is facile and cost-effective in steadily doping PPy into elastomeric films.The combination of delicately selected polyacrylates as the matrix filled with entangled,nano-sized PPy endows the sensor good stretchability,sensitive deformation-electrical signal conversion and high fatigue resistance,which can be used repeatedly without scarifying the sensitivity of electrical signal.Besides,the lower side of the composite films exhibits high light absorption(>98%)in a wide spectral range(250—2400 nm).Systematic characterizations of the sensors support that the excellent strain sensing and light-heat conversion performances are essentially dependent on the gradient filling of PPy nanowires.Moreover,the applications of this flexible strain sensor for human motion monitoring and wearable thermotherapy are demonstrated,manifesting a promising option for wearable electronics and personalized healthcare.
