本研究對多模式空間7R機構作位置分析探討其運動特性。多模式空間7R是利用兩個任意的Bennett機構，重合其中一個接頭所組成。用意是將Bennett機構的構形保留於7R機構中，使7R含有Bennett機構的運動型態。
本論文利用Raghavan和Roth分析開放6R機械臂的解析解，解決閉迴路7R機構的逆向位置關係。對此多模式7R機構進行位置分析，使輸入桿繞行一周，得到所有可能的可行範圍內，各接頭對輸入角的運動曲線。
多模式7R機構的運動曲線明顯表現此種機構有三種運動模式，兩組Bennett機構的過拘束運動及一般7R模式。機構可於交會構形藉著接頭鎖住或轉動作模式間的轉換，到達其他分支。
藉著模式轉換，一般7R經由Bennett機構單調連續的運動，避開原本無法越過的奇異構形，而毋須將整個連桿拆解重組。由於Bennett機構的運動特性，將7R的運動版圖放大至360 所有可能的可行範圍。

This thesis deals with the position analysis of a single-DOF single-loop 7R mechanism with multiple motion modes. The 7R mechanism is constructed by combining two Bennett 4R linkages with a common joint. The common joint is taken as the input joint of the 7R linkage. As a result, the 7R linkage features three motion modes: two Bennett modes and a 7R mode.
By employing the closed-form solution to the inverse kinematics of 6R manipulators, all feasible configurations of the 7R linkage can be obtained as the driving crank makes a full rotation. And the result of the position analysis is presented in six plots, which give six joint angles against the driving joint angle.
According to the result of the position analysis, the multiple-mode linkage can undergo three operation modes, including two Bennett modes and a general 7R mode. These modes can be switched by locking or triggering joints at connecting configurations. As a result, singularity configurations of the 7R mechanism can avoided via the simple motion of Bennett mechanism without disconnecting and reassembling the 7R mechanism.

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