Flexible planetary gear drives in robotics

A method of modeling and computation of industrial robots with rigid-link flexible joints actuated by flexible planetary gear drives is presented. Joint flexibility, as a predominant source of resource, often results in inaccurate tracking of prescribed robot trajectories. The authors consider an n-link industrial robot modeled by rigid-body linkage members interconnected by flexible joints, actuated by DC servomotors and a flexible planetary gear system. The single-link joint model with one flexible planetary gear unit has six degrees of freedom (DOFs). In the gears the periodical time-dependent tooth stiffness represents an essential excitation source and was incorporated into a dynamic model of a robot system. The dynamic model of the robot with flexible joints for the case of elastic planetary gear is presented on example of the SCARA robot´s basic configuration for two DOFs