Movement Simulation and Analysis of a Compliant Parallel Robot Under Cryogenic Working Conditions

In recent years, compliant mechanisms have increasingly found their way into parallel kinematic robot systems, replacing traditional rigid swivel joints. While swivel joints have positive characteristics, such as high structural stiffness and large rotation angles, they are susceptible to contamination, wear, and jamming. The motion concept of compliant mechanisms is based on the inherent elastic, reversible deformability of individual monolithically manufactured joints (solid-state joints). Since compliant mechanisms rely on the deformation of individual components, it is challenging to solve and model their motion behavior analytically. This paper presents the FEM modeling of a 3 DOF parallel robot with passive universal joints made of monolithic solid joints in ANSYS. Since typical FEM simulations can only adequately represent small deformations and displacements, a framework was developed to address the problems arising from non-linearities, meshing errors, and large deflections. We examine the simulation environment for accuracy and accuracy plausibility. From the simulation data, we generated a model in form of multiple regressions to describe the motion behavior of the parallel robot in the workspace to derive conclusions about the positioning accuracy of the robot under cryogenic working conditions. The results obtained can then be used for optimized calibration and as a basis for feed forward control of the parallel robot.