Kinematic Modeling of Cable-Driven Parallel Robots with Unlimited Rotational Axis

Endless rotation about an axis is widespread among manipulators for industrial use. Manipulators, such as articulated robots, Delta, or SCARA robots, provide endless rotation about at least one axis to arbitrarily change the orientation of the workpiece handled. It is quite uncommon, on the other hand, for parallel manipulators to be capable of such operations, yet alone for cable-driven parallel robots for which this capability is yet to be explored. Due to their intrinsic properties, these systems offer key benefits over other kinematic manipulators, combination of which with an endless rotation about an arbitrary axis will beckon new applications for cable-driven parallel robots in production.The first record of a particular design of a cable-driven parallel robot with an endless rotation about one axis has been given in preparatory works to this proposal done by the proposer. However, generalization of this approach to a broader selection of applications is yet to be completed as methods for describing and specifying such robots are lacking existence.Endless rotation about an arbitrary axis may mechanically be described by means of a passive kinematic chain resulting in an increase in the number of internal degrees of freedom in the already redundant cable-driven parallel robots. This physically extended model indeed requires a significantly extended kinematic specification to capture the interaction of all kinematic chains and the cable drive trains. This method of specification has not been explored but is essential to the investigation of generalized designs of cable-driven parallel robots with an endless rotation about an arbitrary axis. In the proposer’s preparatory work, the description is based on an application-specific extension of the structural equation, which provides a solution for the example given. However, it is not possible to generalize this approach such that it also covers other mechanical means of generating rotations.Within the scope of this project, extension of modeling and synthesizing methods of cable-driven parallel robots shall be explored, by means of which endless rotation about an arbitrary axis can be consistently integrated into such existing methods. The aim of this work is to find generalized designs for such cable-driven parallel robots types based on the extended description of the kinematic and geometric properties. Besides the theoretical description, experimental validation will show that there are implementable designs with an endless rotation about an arbitrary axis.