Static and dynamic characterization of the 6-Dofs parallel robot 3CRS

• The 3CRS parallel robot in the research has 6 degrees of freedom with 3 limbs.
• The analytical method takes into account all robot structural parameters.
• The analytical model shows a good agreement with the solid FE model.
• The robot stiffness and the modal frequencies are evaluated overall the workspace.

The prediction of the mechanical behaviour of a robot, depending on its mechanism configuration, is required for the robot design and optimal exploitation. To this end, an analytical model can be used. It offers a fast computational time, which is appropriate for design optimisation as well as for model based control. This paper presents a static and dynamic modelling and characterization of a parallel robot manipulator, 3CRS, with 6 degrees of freedom (6-Dofs) and only 3 limbs. Model derivation is based on analytical approach, called matrix structure analysis (MSA). Robot passive joints are considered separately as connection constraints. In order to deal with the static and modal analysis under kinematic constraint conditions, the Lagrange equations with multipliers are used. The results are compared with a finite element analysis (FEA) in ANSYS software, in which structural components are built by solid elements. Moreover, the influence of the deformable platform on robot stiffness is analysed. Finally, the stiffness and modal frequency of the robot are identified and mapped in its Cartesian workspace.