直线音圈电机驱动定位平台可避免机械耦合环节的引入,但其产生的振动将引起末端平台的响应,从而影响末端定位平台的定位精度.文中采用一种被动减振结构——浮动定子,与传统直线电机相比,浮动定子音圈电机可有效抑制惯性反冲力引起的振动...直线音圈电机驱动定位平台可避免机械耦合环节的引入,但其产生的振动将引起末端平台的响应,从而影响末端定位平台的定位精度.文中采用一种被动减振结构——浮动定子,与传统直线电机相比,浮动定子音圈电机可有效抑制惯性反冲力引起的振动,从而削弱前端振动对末端定位平台的影响.采用数字信号处理(programmable multi axis controller,PMAC)运动控制卡实现平台的运动控制,通过切换控制(PID与模糊控制的切换)实现运动平台的精密定位.实验结果表明:浮动定子类末端平台的振动相对减小,同时切换控制的应用提高了直线平台的定位精度.展开更多
The combination of ipsilateral humeral fractures at three different levels namely proximal, shaft and supracondyle has been rarely defined in the literature. We present a case report on such a complex injury in a 10-y...The combination of ipsilateral humeral fractures at three different levels namely proximal, shaft and supracondyle has been rarely defined in the literature. We present a case report on such a complex injury in a 10-year- old child after falling down from the second floor of his house while playing. To the best of our knowledge, no such case report exists in the English literature. We define it as ＂double floating arm＂ injury. Firstly, shaft of humerus was open reduced and fixed with 4.5 mm narrow dynamic com- pression plate. Then closed reduction and pinning of the supracondylar humerus under an image intensifier was obtained. Open reduction using deltopectoral approach to the proximal humerus was done and the fracture was fixed with three K-wires. Ipsilateral multiple fractures in children often result from high energy trauma. Immediate reduction and fixation is required. Usually surgeons need to treat simple fractures firstly, which makes the subsequent treat- ment of complex fractures easier.展开更多
文摘直线音圈电机驱动定位平台可避免机械耦合环节的引入,但其产生的振动将引起末端平台的响应,从而影响末端定位平台的定位精度.文中采用一种被动减振结构——浮动定子,与传统直线电机相比,浮动定子音圈电机可有效抑制惯性反冲力引起的振动,从而削弱前端振动对末端定位平台的影响.采用数字信号处理(programmable multi axis controller,PMAC)运动控制卡实现平台的运动控制,通过切换控制(PID与模糊控制的切换)实现运动平台的精密定位.实验结果表明:浮动定子类末端平台的振动相对减小,同时切换控制的应用提高了直线平台的定位精度.
文摘The combination of ipsilateral humeral fractures at three different levels namely proximal, shaft and supracondyle has been rarely defined in the literature. We present a case report on such a complex injury in a 10-year- old child after falling down from the second floor of his house while playing. To the best of our knowledge, no such case report exists in the English literature. We define it as ＂double floating arm＂ injury. Firstly, shaft of humerus was open reduced and fixed with 4.5 mm narrow dynamic com- pression plate. Then closed reduction and pinning of the supracondylar humerus under an image intensifier was obtained. Open reduction using deltopectoral approach to the proximal humerus was done and the fracture was fixed with three K-wires. Ipsilateral multiple fractures in children often result from high energy trauma. Immediate reduction and fixation is required. Usually surgeons need to treat simple fractures firstly, which makes the subsequent treat- ment of complex fractures easier.
