Traversing the singularity hypersurface by applying the input disturbances to 6-SPS parallel manipulator

The singular points of a 6-SPS Stewart platform are distributed on the multi-dimensional singularity hypersurface in the task-space, which divides the workspace of the manipulator into several singularity-free regions. Because of the motion un- certainty at singular points, while the manipulator traverses this kind of hypersurface from one singularity-free region to another, its motion cannot be predetermined. In this paper, a detailed approach for the manipulator to traverse the singularity hypersurface with its non-persistent configuration is presented. First, the singular point transfer disturbance and the pose disturbance, which make the perturbed singular point transfer horizontally and vertically, respectively, are constructed. Through applying these disturbances into the input parameters within the maximum loss control domain, the perturbed persistent configuration is transformed into its corresponding non-persistent one. Under the action of the disturbances, the manipulator can traverse the singularity hypersurface from one singularity-flee region to another with a desired configuration.

论动态影像中的静止

本文通过分析电影—装置的影像运行机制,发现在电影中存在着三个时刻:拍摄时刻、放映时刻与观看时刻,而发生在拍摄时刻与放映时刻之间的机械移行(具体移行),最终转换为放映时刻与观看时刻重叠中的画面移行(抽象移行)。机械—画面移行概念纠正了我们从单一运动的视角看待画面的静止,而赋予静止画面以双项取值(x,y)。从这一影像函数中我们最终得以揭示的,是电影——或者作为更大范畴的动态影像中,所孕育的运动与静止的共在性。动态影像的静止视域不仅召唤出潜藏在影像背后的运动——摄影机—放映机的机械运动,还富有洞见地揭示了“缓行电影”中所蕴含的纯粹物质世界的“静止美学”。而这些都是在叙事影像晓畅的运动中被遮蔽的。