A Decoupled 6-DOF Compliant Parallel Mechanism with Optimized Dynamic Characteristics Using Cellular Structure

Abstract

This paper presents a novel six degrees-of-freedom (DOF) compliant parallel mechanism (CPM) with decoupled output motions, large workspace of ≥6 mm for translations and ≥12° for rotations, optimized stiffness, and dynamic properties. The working range and the motion decoupling capability of the six-DOF CPM are experimentally verified, and the mechanical properties are shown to be predictable. The proposed CPM is synthesized by applying the beam-based structural optimization method together with the criteria for achieving motion decoupling capability. In order to improve the dynamic behaviors for the CPM, cellular structure is used to design its end effector. The obtained results show that the dynamic performance of the CPM with cellular end effector is significantly enhanced with the increase of 33% of the first resonance frequency as compared to the initial design. Performances of the three-dimensional (3D)-printed prototype are experimentally evaluated in terms of mechanical characteristics and decoupled motions. The obtained results show that the actual stiffness and dynamic properties agree with the predictions with the highest deviation of ~10.5%. The motion decoupling capability of the CPM is also demonstrated since almost input energy (>99.5%) generates the desired output motions while the energy causes parasitic motions is only minor (<0.5%).