Analysis of reachable workspace of a wire driven parallel robot and its stiffness estimation

The feed cable-supporting system of the large radio telescope(LT) can be regarded as a wire driven parallel robot(WDPR).Based on the nonlinear mechanics model of this system,the reachable workspace of the WDPR is confirmed to be subject to the restrictions on the cable tensions,spherical joints,and cable lengths.Furthermore,the static stiffness matrix of the WDPR is established by the finite element analysis to estimate the stiffness characteristics utilizing the minimum eigenvalue of the matrix.Through the kinematic numerical simulation,the stiffness curved surface and the three-dimensional reachable workspace of the 50 meter scaled model of the WDPR are drawn respectively.Results show that the restriction on the cable tensions has the most prominent effect on the reachable workspace,and that the differences of the stiffness characteristics are obvious between the WDPR and Stewart platform.