Modeling a harmonic drive gear transmission

In order to capture the dynamic behavior of harmonic drives, dynamic models must include accurate representations of transmission friction, compliance, and kinematic error. Experimental observations are used to guide the development of a model to describe harmonic-drive operation. This model is able to replicate many of the features observed in actual harmonic-drive dynamic response. Valuable insights are gained about the factors which govern harmonic-drive dynamic response. Using these insights to guide the gradual development of a harmonic-drive model, the tradeoffs between model accuracy and complexity are exposed. In particular, despite careful measurement and characterization of transmission friction, compliance, and kinematic error, model performance cannot be improved without acknowledging gear-tooth rubbing losses as well. When a model incorporating gear-tooth behavior is implemented, predicted results reproduce many of the complexities of the experimental dynamic response