Comparison Analysis of Bio-Inspired Tendon-Driven Manipulators Based on Their Tension-Feasible Workspace

Abstract

Bio-inspiration can be used in the development of novel dextrous and energy efficient manipulators. This paper focuses on planar manipulators inspired by the bird neck built upon stacking a series of tensegrity X-joints. The manipulators are actuated with four tendons, have different numbers of modules, with or without offsets. The objective of this work is to study the influence of offsets, number of modules, geometry of the joints, configuration at rest of the manipulators and actuation scheme on the size of the wrench-feasible workspace (WFW). The spring constants of the X-joints are determined so that the configuration at rest features a desired end-effector pose with a minimal stiffness to ensure stability. Our study demonstrates that increasing the number of modules results in a larger WFW, although the number of active tendons is fixed. We find that the WFW can be maximized with appropriate modification of the joint geometry. Additionally, we explore the influence of bio-inspired approaches on the manipulator configuration at rest and actuation scheme in relation to the WFW.