Analysis of the stiffness of modular reconfigurable parallel robot with four configurations

Abstract

This paper studies the static stiffness of a kind of Modular Reconfigurable Parallel robot (MRP robot for short). The MRP robot can be reconstituted to four different configurations. The 3D entity models of the MRP robot of all configurations are established by UG software, according to the modular modeling method and certain simplified rules. The stiffness model of the MRP robot is established. The factors affecting stiffness of the MRP robot are obtained. The static stiffness and stress distribution of the MRP robot are obtained with different forces in the initial position of various configurations by using ANSYS. The static stiffness in z direction (perpendicular to the static base) of each configuration is larger than the static stiffness in x and y directions (in the static base). This shows that the main stiffness is located in z direction. While the stiffness in x, y directions are close to each other. The main stiffness of four kinds of configurations is different. The main stiffness of 6-SPS configuration is significantly greater than that of other three kinds of configurations. The weaker links of the MRP robot are related to the position of the hinges and the connecting position of the moving platform and the screw. The overall stiffness of the MRP robot can be obviously improved by increasing the stiffness of the module which has great influence on the stiffness. The results provide a theoretical basis for the design of the MRP robot.