Simulation of effect of cable robot configuration on natural frequency

Cable-driven parallel robots consist of non-rigid cables which are different from traditional serial robots. The lightweight of the cables allows them to have higher payload and larger workspace. However, the cables may cause significant vibration during operation because the cables are inevitably flexible. Increasing natural frequencies is one of the solutions to reduce the vibration of the cable robots. We propose that relationship between the shape of end-effector and the shape of frame can affect natural frequencies of planar cable driven parallel robots. To investigate the relationship, equations of motion for a planar cable robot is developed using Lagrange approach. Equations of motion are linearized for vibration analysis. Through mode analysis with different shapes of end-effector, it is verified that different combinations of end-effector shape and frame shape can cause different natural frequencies. Thus, it is possible to design a planar cable robot by utilizing the relationship between the shapes.