Dynamic Modeling and Digital Twin of a Harmonic Drive Based Collaborative Robot Joint

Collaborative robots are gradually taking over the leading position in automating the production and manufacturing of the SMEs, where the human-robot collaboration is highly emphasized. Therefore, estimating the force and simulating the performance of robots are of great importance. As a newly introduced technology, digital twin, has gained more attentions for simulation, process evaluation, real-time monitoring, etc. However, the current state-of-the-art of digital twin for robots still remains on the kinematic level, and the integrated robot system dynamics is too complex to be incorporated into the digital twin. Therefore, this research starts with the perspective of harmonic drive based robot joint, and proposes a dynamic model of robot joint by analyzing the composition, transmission principle, and internal interactions. Then the experimental parameter identification is performed to obtain the inherent parameters, which can reflect the system performance characteristics. Finally, a preliminary digital twin of robot joint integrated with dynamic model is established with Gazebo and MATLAB. The proposed approach could be used to simulate the dynamic behavior of robot joint in real time and make contributions to the state of the art for digital twin.