因为肩端是多轴性关节，可多方向自由运动，所以特定某个方向是困难的。
Because the shoulder end is a multi axis joint, it can move freely in many directions, so it is difficult to be specific in one direction.
对多轴膝关节进行了分析，提出了承重稳定裕度角、全伸展位绝对瞬心距和相对瞬心距的概念，用于评价下肢假肢的稳定性和相对稳定性。
Based on analyzing the knee joints of the four bar linkage, this paper presents the concepts of the stable well off angle, absolute and relative instantaneous distance.
结合生物医学人体关节研究成果，研究了一种四连杆封闭链仿生关节；给出了一种由四连杆机构组成、智能MR阻尼器控制的多轴仿生膝关节机构；
Combining with the achievement of study on human-body joint of biologic medical science, a kind of four-bar link close-chained bionic joint was studied.
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