Geometric Determination of the Interference-Free Constant-Orientation Workspace of Parallel Cable-Driven Mechanisms

Abstract

The increasing use of parallel cable-driven mechanisms calls for a better understanding of their behavior and highly efficient algorithms to attenuate their drawbacks at the design stage. One of these drawbacks is the high probability of mechanical interferences between the moving parts of the mechanism. In this paper, the phenomenon is described under the assumption that a cable is a line segment in space. When a mechanical contact occurs between two cables or between a cable and an edge of the end effector, these entities necessarily lie in the same plane, and then the three-dimensional problem becomes two-dimensional. This fact is used to simplify the equations, and leads to exhaustive descriptions of the associated interference loci in the constant-orientation workspace of a cable-driven mechanism. These results provide a fast method to graphically represent all interference regions in the manipulator workspace, given its geometry and the orientation of its end effector.

Optimal Force Generation for an Underconstrained Planar Cable Robot

“…Another study allows the wrench feasibility of a particular pose to be checked geometrically without iteration (Bouchard et al, 2010). With cable robots, there is also a concern of cable interference, as studied in Perrault et al (2010).…”

Dynamic trajectory planning study of planar two-dof redundantly actuated cable-suspended parallel robots

“…Some techniques can be found in the literature for the determination of potential interferences on cable-driven robots (the reader is referred to [19] for more details). However, for the robots considered in this paper, interferences along certain trajectories are obvious and hence two distinct cases are considered to avoid them.…”

Dynamic trajectory planning of planar two-dof redundantly actuated cable-suspended parallel robots

“…Some techniques can be found in the literature for the determination of potential interferences (see for instance [16]). However, for the robots considered in this paper, interferences are obvious and hence two distinct cases are considered to avoid them.…”