Modeling, analysis and design of an extensible planar parallel tendon actuated continuum robot

In this paper, we introduce a novel design for a compressible/extensible planar continuum parallel manipulator, characterized by fixed joints and tendon-based actuation with parallel routing. The goal of this design is to generate a planar workspace without adding any rigid translational actuators by considering compressible legs. To optimize the robot’s design, its static behavior is first modeled using a Jacobian-based geometric variable strain approach, providing a foundation for performance analysis. We then explore key performance metrics, including workspace, stability, and payload capacity, in relation to critical design parameters: the distance between the robot’s legs and the bending-to-compression stiffness ratio. While the leg distance is a well-studied factor in parallel architectures, the influence of the stiffness ratio, despite its significant impact on performance, has received limited attention. Our work investigates the effects of these parameters, culminating in the development of a new modular prototype that leverages these insights to obtain optimal robot performances.