Reconfigurable Parallel Mechanism with Metamorphic Diamond-like Chain: Design and Mode Switching

Abstract Current research on reconfigurable parallel mechanisms (RPMs) primarily focuses on achieving limited configuration changes, while mechanisms capable of extensive mode switching with distinct motion branches remain challenging to design. Conventional kinematotropic chains offer limited reconfigurability, underscoring the need for novel designs that enable broader operational adaptability. In this research, a novel diamond-like chain (DLC) with metamorphic units is proposed developed from generalized diamond kinematotropic chains. By altering the axes of the metamorphic units, the DLC realizes three distinct configurations, each corresponding to one of five motion branches characterized by bifurcation and metamorphic transitions. This DLC serves as the fundamental building block for constructing a reconfigurable hybrid limb. Using screw theory, the constraint properties of the limb in its five phases are analyzed and classified into three types: unconstrained limbs, limbs applying constraint forces, and limbs applying constraint couples. Based on this analysis, a RPM consisting of three reconfigurable limbs is developed. Its reconfigurability stems from the inherent bifurcation and metamorphic capabilities of the DLC-based limbs. This research introduces a RPM capable of controlled switching among ten distinct motion modes, with mobility ranging from three to six degrees of freedom. The proposed mechanism demonstrates high versatility and practical feasibility, offering a promising solution for applications requiring variable motion characteristics and adaptive performance.