Limiting-case Analysis of Continuum Trunk Kinematics

Continuum robotic manipulators, termed trunks, mimic the astounding capabilities of elephant trunks and octopus arms by bending in smooth arcs. Several approaches to kinematic analysis of continuum trunks complement a wide variety of available continuum robots. However, these kinematics exhibit singularity-like conditions when the trunk assumes a straight posture, which is essential to complete many tasks. The novel limiting-case analysis presented in this paper eliminates these problems, demonstrating that the unique causes of the problem are rooted in the continuum formulation and cannot be solved by traditional rigid-link singularity analysis. Three practical examples demonstrate the necessity of this analysis presented, enabling the trunk to successfully perform each task.