Analysis and Verification of Dynamic Characteristics of Flexible Spatial Parallel Robot

To study the dynamic characteristics of the flexible 3-RRRU spatial parallel robot, the coupling dynamic model of the 3-RRRU spatial parallel robot with both rigid and spatial flexible links in the kinematic chain was established by Adams software. In order to verify the correctness of the established coupling model, the positive kinematic results of the fully rigid 3-RRRU spatial parallel robot and the flexible 3-RRRU spatial parallel robot are compared and analyzed. Based on the coupling model, the driving torque, elastic modulus, and stress are discussed. And the effect of stress distribution on the flexible 3-RRRU spatial parallel robot. The results show that under the same conditions, the trajectory of the geometric center of the end-effector in the two types of models is basically the same, but due to the elastic deformation generated by the spatial flexible link, the trajectory of the end-effector in the coupled model in the x, y, and z directions will fluctuate. The maximum floating values are 3.57 mm, 2.96 mm and 2.05 mm; respectively, therefore, a reasonable modeling of rigid-flexible coupling spatial parallel robots is essential. It can be seen from the coupling model that the maximum stress of the system is mainly concentrated on the geometric center of the spatial flexible link and the joint connected to the rigid link, and the driving torque is asymmetry, which provides a data reference for structural optimization; the greater the elastic modulus, the more obvious the coupling effects, which leads to the enhanced system oscillation.