Analysis of Rotational Axes of 2-UPR-SPR Parallel Mechanism
Analysis of Rotational Axes of 2-UPR-SPR Parallel Mechanism
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DOI：
10.3901/jme.2013.21.062
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发表时间：
2013
影响因子：
--
通讯作者：
Qinchuan Li
中科院分区：
文献类型：
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作者：
Qinchuan Li
2 R1 T并联机构具有一个平移自由度和两个转动自由度。它包含两种旋转轴：连续旋转轴和瞬时旋转轴。对于具有高定向能力的并联机构，如五轴并联机床（PKM），其转动轴的性质和空间几何分布对机构的轨迹规划和运动学标定具有重要意义。Exechon五自由度混联加工中心在先进制造业中得到了广泛的应用。它由属于2 R1 T PM的2-UPR-SPR PM和RR串联机构组成。利用旋量理论，建立了2-UPR-SPR PM在初始位形和1、2自由度连续旋转位形时的肢体扭转系统和肢体约束系统。根据转动轴与刚体约束力的关系，识别出动平台的两个连续转动轴。这两个连续旋转轴取决于2-UPR-SPR PM的配置，并穿过参考系的原点和球形接头的中心。
2R1T Parallel mechanism(PM) can undergo one translational degree of freedom(DOF) and two rotational DOFs. It contains two kinds of rotational axes: continuous rotational axis and instantaneous rotational axis. The property and geometrical distribution of rotational axes in space are important to trajectory planning and kinematic calibration of parallel mechanisms in which high orientation ability is required, such as five axes parallel kinematic machine(PKM). The 5-DOF Exechon hybrid machining center has been widely used in the advanced manufacturing. It consists of a 2-UPR-SPR PM which belongs to 2R1T PM and a RR serial mechanism. Using screw theory, limb twist system and limb constraint system were established when the 2-UPR-SPR PM is at the initial configuration and configurations after continuous rotation of 1 DOF and 2 DOFs. Based on the relation of rotation axis and constraint force of rigid body, two continuous rotational axes of the moving platform have been identified. These two continuous rotational axes is dependent on the configuration of the 2-UPR-SPR PM and pass through the origin of the reference frame and the center of the spherical joint.