Mechanistic Analysis of Cable Tension Effects on the Stiffness of Cable-Driven Serpentine Manipulators
Yicheng Dai, Sheng Wang, Xin Wang, HAN YUAN
AI summary
Problem
Prior stiffness models for cable-driven serpentine manipulators often treat driving cables as ideal springs, overlooking their inherent nonlinear stiffness and creating a gap in understanding how cable tension specifically influences overall robot stiffness.
Approach
The authors derive an analytical stiffness model that explicitly couples cable tension with the nonlinear tensile stiffness of multi-strand cables, validating the framework through numerical simulations and physical experiments.
Key results
- Analytical stiffness model integrating cable tension and nonlinear cable stiffness
- Characterization of tension-dependent tensile stiffness in multi-strand cables
- Quantification of cable tension’s coupled effect on overall robot stiffness
- Experimental validation confirming simulation predictions across varying configurations
Why it matters
Provides critical insights for accurate stiffness control and design optimization of cable-driven manipulators used in minimally invasive surgery and industrial maintenance.
Abstract
This paper presents a mechanistic analysis of stiff- ness in cable-driven serpentine manipulators (CDSMs), incorpo- rating both cable tension and cable stiffness. First, we derive an analytical stiffness model based on robot statics, identifying cable tension and stiffness as the dominant factors governing robot stiffness at a given configuration. Crucially, we characterize a previously overlooked tension-stiffness coupling effect: cable tension induces nonlinear stiffness variations in driving cables, significantly altering the overall robot stiffness. Due to this interdependence, quantifying cable tension’s specific influence on stiffness remains a challenging research gap. To address this, simulations and experiments validate the model and quantify their coupled effects on robotic stiffness. Results demonstrate that for CDSMs using multi-strand cables with nonlinear stiffness, robot stiffness increases sharply with rising tension. Conversely, when cable elasticity is constant, robot stiffness decreases with increasing tension. These findings provide critical insights for advancing stiffness control accuracy in CDSMs.