Modeling and Experimental Evaluation of Stiffness of a Linear Decoupled 3 Degree of Freedom Parallel Robot

Parallel robots have a lot of compared to their counterparts, serial robots, such as higher accuracy, more load to weight ratio, and higher stiffness, which contribute to their various, and precise applications. Stiffness of the robot, as one of the most crucial parameters which should be considered in of the robot, the desired application. In this paper, an experimental study is investigated on evaluation of the robot’s stiffness and the errors corresponding to of the mechanism, which indicate the displacement of -effector of the robot with respect to external imposed forces. The aim of this paper is to evaluate the stiffness and the errors due to the softness behavior of the mechanism of a 3 degree of freedom (3-DoF) parallel robot; for this end, the amount of transfer of the final executor to the applied load is simulated. First, the 3-DoF decoupled robot is introduced and its features are expressed and the stiffness of the mechanism is modeled using Finite Element Method (FEM). Then, of the mechanism is determined in different positions of the end-effector by considering predefined boundary conditions. In order to evaluate the obtained model of the robots’ stiffness, a novel experimental setup is developed to measure the stiffness of the mechanism. By employing the setup, of the robot is measured in different conditions. Finally, the output results of the stiffness model are compared to the experimental tests. The results reveal that the 3-DoF decoupled parallel robot shows a proper stiffness behavior. Hence, it can be employed in various applications with high precision.