Novel planar continuum robot with spiral pulley actuation and gear synced body

Abstract

Continuum robots are an attractive solution for navigation in complex and restrictive environments. However, with the existing technology, only two approaches are possible for development of high dexterity continuum robots with low compliance: (i) utilizing a fully articulated body with high number of individually actuated rigid links; (ii) employing a body consisting of flexible sections and strong spring elements. While the former requires numerous actuators, thus a heavy and expensive actuator-pack, the latter necessitates larger and costlier actuators to overcome the spring force. Moreover, the latter approach cannot achieve as low compliance due to its flexible nature. This paper introduces a novel planar continuum robot design that benefits from a fully articulated body divided into individually actuated sections of synchronized links. The kinematic modelling and motion planning of the robot arm are presented and utilized for evaluation of the proposed design. A six-section prototype, consisting of 30 links, validates the proposed designs and demonstrates its performance in both simulation and real experiments on four different paths. The validation is based on distal deviation of individual links from the intended paths. Evaluation verifies that the concepts lead to lower compliance, higher dexterity and actuator-pack size reduction (i.e. one actuator per section), as compared to existing approaches.