Analytical Backlash Model for 3K-type Planetary Gear Train with Flexure-Based Anti-backlash Carrier

The 3K-type Planetary Gear Train (PGT) with a high reduction ratio and high backdrivability is suitable for enhancing the human-robot interaction performance of collaborative robots. However, the low accuracy of 3K-type PGT is an urgent problem. The backlash analysis of the 3K-type PGT is critical to evaluate its transmission accuracy. To calculate the backlash of 3K-type PGT directly based on the design parameters, an analytical backlash model is established based on an equivalent pinion-rack model. Moreover, the analytical backlash model is modified further for a novel 3K-type PGT with a flexure-based anti-backlash carrier to analyze the effects of the opening angle of the flexure-based carrier on the backlash. Through the simulations and experiments on the prototypes, the effectiveness and accuracy of the established analytical backlash model are verified.