Practical Stability of Under-Constrained Cable-Suspended Parallel Robots
This paper, motivated by the development of a novel gait rehabilitation system, presents a mechanical approach for the dynamic modelling and analysis of equilibrium stability of under-constrained cable suspended parallel robots. These types of cable robots exhibit interesting characteristics of self-motion in the Jacobian null-space. Modelling and understanding of this motion is essential for their applications. It is demonstrated that both a wrench consistency test and proof of stability conditions, derived for real robots with a pulley mechanism, play a crucial role for practical equilibrium stability assessment. Thereby dynamic simulation of the null-space motion help to analyse robustness of the equilibrium against perturbations. Several examples with a 4-4 type robots illustrate the theoretical analysis.
Keywordscable-driven parallel robots under-constrained cable suspended structures equilibrium stability analysis gait rehabilitation
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