Dynamics modeling and analysis of cable-driven segmented manipulator considering friction effects

In this paper, a new cable-driven segmented manipulator is studied, which maintains a nearly piecewise constant curvature under the constraint of a cable-constrained synchronous rotating mechanism. The main purpose of this paper is to present a refined dynamics model for the cable-driven segmented manipulator system considering friction effects and deformation of the cables. First, the arbitrary-Lagrangian-Eulerian method is introduced for the modeling of the driving cables, and the friction between the cables and the manipulator is described by the LuGre model. Second, the dynamics model and algorithm for the 2D segmented manipulator system considering friction effects and deformation of the cables is established using Lagrange's equation of the first kind and Baumgarte's stabilization method. Finally, a single-segment manipulator and a multi-segment manipulator are simulated successively, and an example of the manipulator circumventing an obstacle is simulated. The control errors caused by friction and deformation of the cables are analyzed, and the influences of the joint angle and the cable pre-tightening force on the control errors are discussed. In addition, the control errors of different segments are compared and analyzed, and reduced by adjusting the pre-tightening force of the cables.