On the modelling and control of fully constrained cable driven robots with flexible cables

In this paper modelling and control of cable-driven redundant parallel manipulators (CDRPM) with flexible cables are studied in detail. In this type of manipulators the cables should remain in tension in the whole workspace. New research results have shown that in fully constrained CDRPM cable can be modelled as an axial spring. Based on this fact a new model of this type of robot is studied. Furthermore, internal forces are introduced and incorporated in the proposed control algorithm. This control algorithm is formed in cable length coordinates in which the internal forces play an important role. Finally, the closed loop system is proved to be stable, through Lyapunov analysis, and the performance of the proposed algorithm is studied through simulation.