Analysis of the Position-dependent Vibration behaviour of an Industrial 6-axis Robot and Combined FE-based Modelling of the Mechanical Frequency Responses

Abstract

Industrial robots (IR) are a cost-effective and highly flexible alternative to machining centres. Nevertheless, their use for separating processes in production technology is limited because of their low structural rigidity, which results in comparatively low accuracies. The vibration behaviour of the robots is a major challenge to increasing accuracy, as it can vary significantly depending on the position of the tool centre point (TCP) in the workspace. To apply vibration compensation, it is necessary to be able to describe the vibration behaviour of the robot with sufficient accuracy. This article presents a new approach, utilising parametric FEM simulation to generate a state space description of the robot. The simulation captures the pose-dependent vibration behaviour of each axis, which is then integrated into a downstream system simulation, resulting in a comprehensive description of the robot's vibration behaviour. After being finely tuned, the model demonstrates excellent alignment with the experimentally determined behaviour. Hence, the robot's vibration behaviour in the workspace can be holistically described, which is a decisive advantage over the limited possibilities of experimental identification.

Keywords

• fem simulation
• dynamic behaviour
• frequency response
• industrial robot.