A planar parallel 3-RRR robot with synchronously driven cranks

作者：Can Engin^*; Stachel Hellmuth

来源：Mechanism and Machine Theory, 2014, 79: 29-45.

DOI：10.1016/j.mechmachtheory.2014.04.001

• Planar mechanism
• F-mechanism
• Planar parallel 3-RRR-robot
• Velocity analysis
• Acceleration analysis
• Completely turnable

This paper focuses on the analysis and synthesis of F-mechanisms, i.e., of planar parallel 3-RRR robots with three synchronously driven cranks. These are high-speed planar mechanisms, which allow modifying the periodical constrained motion by phase shifting during operation. There is a broad variety of obtainable constrained motions - including a permanent stillstand. %26lt;br%26gt;The velocity analysis reveals that there are poses with either no pole configuration or an infinite number of pole configurations. These singular resp. twofold singular poses can be geometrically characterized. It turns out that in general the singular poses are those where the cranks need to reverse the rotation in order to perform the full motion. At twofold singular poses bifurcations can take place. The constrained motions are algebraic of degree 6. The question of whether the active bars of a given F-mechanism are completely turnable can only be cleared from case to case by a numerical analysis. Here a particular diagram which indicates reverse poses as well as bifurcations is useful.

• 出版日期2014-9