Multi-rotor eVTOL Safety Interval Assessment Based on Improved Event Model

The rapid development of electric vertical take-off and landing vehicles (eVTOL) is a response to the increasingly congested urban ground traffic, low positioning accuracy, and the many hidden risks of traversing flight. Therefore, the safety interval standard is of great significance in ensuring the safe operation of these vehicles. To investigate the safety interval of multi-rotor eVTOL in low-altitude airspace, we have improved the Event collision model for lateral, longitudinal, and vertical collisions by modifying the shape characteristics. Specifically, we have replaced the original rectangular collision box with a round table body collision box, which reduces computational redundancy. We have also calculated the relative velocity and overlap probability while considering the error distribution. Finally, this text presents an arithmetic analysis using the EH 216-S model as an example to calculate the safety interval under different safety target levels and navigation accuracy. When the safety target level is 1 × 10–7 times/flight hour and the navigation accuracy is high, the minimum longitudinal, lateral, and vertical safety intervals are 42.1 m, 24.5 m, and 14.4 m, respectively. The improved model reduced the longitudinal, lateral, and vertical collision risks by 43.4%, 23%, and 58.4%, respectively, compared to the original model. The study results can serve as a reference for developing eVTOL interval standards for multi-rotor types. If a vehicle smaller than the safety interval standard is detected, it can be promptly displayed on the human-computer interface to alert the supervisors.