Static and dynamic stiffness analyses of cable-driven parallel robots with non-negligible cable mass and elasticity

• Stiffness analysis of cable-driven parallel robots
• Dynamic stiffness model based on the Dynamic Stiffness Matrix method is proposed.
• Study of the effect of both cable mass and elasticity on the end-effector pose error
• Identification of natural frequencies through the dynamic response functions
• Discussion about each cable model, on the task and user requirements topics

This paper focuses on the stiffness analysis of cable-driven parallel robots (CDPRs), including the static stiffness and the dynamic stiffness analyses. Static and dynamic cable models are introduced considering the effect of both cable mass and elasticity. Based on these models, the static stiffness of CDPRs is evaluated by the variation of the end-effector pose error, and the dynamic stiffness of CDPRs is analyzed by identifying the robot natural frequencies. Simulations and experiments are made on a 6-DOF prototype to validate the theoretical models. Comparison with other methods available in literature is presented. Results show the important effect of cable mass and elasticity on the static and dynamic stiffness of CDPRs.