ANSYS®-Based Gear Stress Analysis of a Lightweight 3-DOF Wrist Mechanism for a Parallel Robot with Expanded Workspace

Although a parallel robot is operated at high speed, its work space is relatively narrow, compared to that of a SCARA (Selective Compliance Assembly Robot Arm) robot or an articulated robot. It is anticipated that if a 3-DOF (Degrees Of Freedom) wrist mechanism is added to a pick-and-place 3-DOF parallel robot with the increased workspace by using an additional straight axis at its top, then the overall 6-DOF parallel robot has an increased degrees of freedom as well as a high velocity within wider workspace. Thus this kind of parallel robot has a wider workspace so that the application of the robot to the assembly of small-sized mechanical components and electronic components or the processing process will increase. This paper aims to offer a way of testing stability when selecting gears, in order to reduce the weight of a 3-DOF wrist mechanism for a pick-and-place 3-DOF parallel robot with the increased workspace by using an additional straight axis at its top. We will perform SolidWorks
^®
modeling- and ANSYS
^®
-based structural analysis of a pinion gear, which is most vulnerable to the force from a 3-DOF wrist mechanism, in order to lighten the robot weight for various tasks to perform. Although there is no need to get equal theoretical values and analysis results, because individual gears have different forms of teeth, somewhat approximate values should be obtained when there is no mistake in analysis conditions. If initial analysis results considerably differ from theoretical values that are calculated in advance, we will check if there is something wrong with contact conditions or input values. Ultimately, it is anticipated that this methodology presented in this paper will help in mitigating mistakes during analysis and looking for accurate values for a lightweight 3-DOF wrist mechanism for a parallel robot with expanded workspace.