Effect of Wave Generator Misalignment on the Strain Wave Gear Hysteretic Behavior in a Rotary Electro-Mechanical Actuator

Urban Air Mobility (UAM) is a rapidly growing field focused on transforming urban transportation using electric Vertical Take-Off and Landing (eVTOL) aircraft. Rotary Electro-Mechanical flight control Actuators play a crucial role in this technology, with the Strain Wave Gear (SWG) being a key component for power transfer. Reliability and safety are paramount in UAM, necessitating the monitoring of SWG health and estimation of Remaining Useful Life (RUL) through Prognostics and Health Management (PHM) techniques. This work presents a two-dimensional planar equivalent model of an SWG, assessing its performance under various operating conditions and accounting for wave generator misalignment and flexspline hysteresis. Wave generator misalignment can lead to uneven loading and premature wear, compromising the gear's load-carrying capacity. After the model description a simulation campaign results were proposed and analyzed.