Design, modeling, and workspace analysis of an extensible rod-driven Parallel Continuum Robot

Abstract

Rod-driven Parallel Continuum Robots (PCR) are a class of continuum robots (CR) that possess the potential to combine advantages of parallel structure into CRs. However, rod-driven PCRs usually have a limited workspace due to the designed constraints, which restrict the exploitation of their potentials. This paper presents the design, statics modeling, and workspace analysis of a rod-driven PCR for extending its motion range. The proposed design has 5 degrees of freedom (DoFs) for manipulation by reasonably arranging constraints and kinematic pairs. We employ a known modeling method based on the Cosserat equations and a variant of the Levenberg-Marquardt method to solve the model, making the PCR with multi-intermediate constraints approach real-time applications. The design's feasibility is experimentally verified on a developed prototype. We then present a numerical procedure for analyzing partial workspace efficiently. Our results highlight the design's feature to enlarge workspace, of which a set of configurations can reach about 64% of the cube volume of max arm length, and an average of 4 s solving spatial paths, with max errors of 2.5% of max arm length.