一种类球面并联腕部机构及其运动学分析

A Spheroid Parallel Wrist Mechanism and Its Kinematic Analysis

  • 摘要: 采用构型演变法将2自由度球面并联机构Omni-Wrist V演变为一种3自由度2R1T(2转动1移动)的类球面并联机构,并对其运动学特性进行了系统的分析.首先,采用基于约束理论的图谱法对该机构的自由度进行了分析;其次,建立了其等效运动学模型,推导了解析形式的正、逆运动学方程,并讨论了其奇异性;最后,采用蒙特卡洛法求得机构的工作空间,并提出一种3维切片法分析其特性.在工作空间分析中,选择水平切片的面积和形状来衡量机构的旋转性能,采用定偏转角切片形成的扇形片径向位移量来表征其平移性能.该并联机构可作为腕部串接于SCARA(选择顺应性装配机械手)或Delta机器人末端,组成混联机器人,应用于需要同时大转角改变姿态和位置的电子或轻工生产等场合.

     

    Abstract: Based on the 2-DOF (degree of freedom) spherical parallel Omni-Wrist V, a 3-DOF 2R1T (2 rotational and 1 translational) spheroid parallel mechanism is proposed by the configuration evolution method, and its kinematic analysis is systematically carried out. The DOF of the proposed mechanism is first analyzed with an atlas method based on constraint theory. An equivalent kinematic model is then established, the forward and inverse kinematic equations are derived in an analytical form, and its singularity is discussed. Finally, the workspace is generated by Monte Carlo method, and a 3D cutting method is proposed to analyze its characteristics. In the workspace analysis, the slice area and shape generated by level cutting are used to measure the rotational manipulability, and the radial displacement of sector piece generated by cutting slice with a fixed tilt angle is defined to evaluate the translational manipulability. The presented parallel mechanism can be used as a wrist at the end of Delta or SCARA (selective compliance assembly robot arm) robots, to form hybrid robots for electronic and light industries where large change of the object configuration (orientation and position) is to be performed.

     

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