Because of its characteristics of simple algorithm and hardware, optical flow-based motion estimation has become a hot research field, especially in GPS-denied environment. Optical flow could be used to obtain the air...Because of its characteristics of simple algorithm and hardware, optical flow-based motion estimation has become a hot research field, especially in GPS-denied environment. Optical flow could be used to obtain the aircraft motion information, but the six-(degree of freedom)(6-DOF) motion still couldn't be accurately estimated by existing methods. The purpose of this work is to provide a motion estimation method based on optical flow from forward and down looking cameras, which doesn't rely on the assumption of level flight. First, the distribution and decoupling method of optical flow from forward camera are utilized to get attitude. Then, the resulted angular velocities are utilized to obtain the translational optical flow of the down camera, which can eliminate the influence of rotational motion on velocity estimation. Besides, the translational motion estimation equation is simplified by establishing the relation between the depths of feature points and the aircraft altitude. Finally, simulation results show that the method presented is accurate and robust.展开更多
针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运...针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运动磁场共用定、转子磁路。永磁体设置在定子上,动子上既无绕组也无永磁体,动子结构简单坚固,重量轻,具有转矩惯量比高、动态响应速度快、可靠性高等特点;定子同时设置有直线与旋转两套绕组,直线和旋转运动控制独立,降低两自由度驱动控制的复杂度。分析该类电机的运行原理和结构特点,探讨混合磁路特征,构建该类SEHMC-LRPM电机的解耦等效磁路模型,实现该类电机的磁路设计。在此基础上,基于3D有限元方法分析混合磁路与两自由度耦合磁场,揭示两自由度磁场与电机磁场分布、空载和负载特性的关系。最后,加工制造样机,并进行实验研究,验证该电机结构的有效性和理论分析的正确性。展开更多
基金Project(2012CB720003)supported by the National Basic Research Program of ChinaProjects(61320106010,61127007,61121003,61573019)supported by the National Natural Science Foundation of ChinaProject(2013DFE13040)supported by the Special Program for International Science and Technology Cooperation from Ministry of Science and Technology of China
文摘Because of its characteristics of simple algorithm and hardware, optical flow-based motion estimation has become a hot research field, especially in GPS-denied environment. Optical flow could be used to obtain the aircraft motion information, but the six-(degree of freedom)(6-DOF) motion still couldn't be accurately estimated by existing methods. The purpose of this work is to provide a motion estimation method based on optical flow from forward and down looking cameras, which doesn't rely on the assumption of level flight. First, the distribution and decoupling method of optical flow from forward camera are utilized to get attitude. Then, the resulted angular velocities are utilized to obtain the translational optical flow of the down camera, which can eliminate the influence of rotational motion on velocity estimation. Besides, the translational motion estimation equation is simplified by establishing the relation between the depths of feature points and the aircraft altitude. Finally, simulation results show that the method presented is accurate and robust.
文摘针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运动磁场共用定、转子磁路。永磁体设置在定子上,动子上既无绕组也无永磁体,动子结构简单坚固,重量轻,具有转矩惯量比高、动态响应速度快、可靠性高等特点;定子同时设置有直线与旋转两套绕组,直线和旋转运动控制独立,降低两自由度驱动控制的复杂度。分析该类电机的运行原理和结构特点,探讨混合磁路特征,构建该类SEHMC-LRPM电机的解耦等效磁路模型,实现该类电机的磁路设计。在此基础上,基于3D有限元方法分析混合磁路与两自由度耦合磁场,揭示两自由度磁场与电机磁场分布、空载和负载特性的关系。最后,加工制造样机,并进行实验研究,验证该电机结构的有效性和理论分析的正确性。
