Abstract: Deflection of a rotor of a motor, such as a brushless motor, of an unmanned aerial vehicle (“UAV”) during operation may cause the magnets coupled to the interior surface of the rotor to move or walk down the surface, imbalancing the motor and potentially creating an unsafe flying condition for the UAV. The described methods and apparatus monitor rotor deflection of the motor during operation and alter one or more flight characteristics of the UAV if the deflection exceeds a tolerance range. By altering flight characteristics, external forces acting on the motor may be reduced, thereby reducing the deflection of the rotor.

Abstract: This disclosure describes systems, methods, and apparatus for automating the verification of aerial vehicle sensors as part of a pre-flight, flight departure, in-transit flight, and/or delivery destination calibration verification process. At different stages, aerial vehicle sensors may obtain sensor measurements about objects within an environment, the obtained measurements may be processed to determine information about the object, as presented in the measurements, and the processed information may be compared with the actual information about the object to determine a variation or difference between the information. If the variation is within a tolerance range, the sensor may be auto adjusted and operation of the aerial vehicle may continue. If the variation exceeds a correction range, flight of the aerial vehicle may be aborted and the aerial vehicle routed for a full sensor calibration.

Abstract: This disclosure describes systems and methods for visually tracking a position of an unmanned aerial vehicle (“UAV”) using reflected light. A light source at an origin location, such as the location of an operator of the UAV, is aligned and emitted toward the position of the UAV. The emitted light source reflects off a reflector coupled to the UAV toward a location of the operator or a visual observer working with the operator. The reflected light increases the visibility of the UAV, thereby extending the distance from an operator at which the UAV can be operated while maintaining visible contact between the operator and/or a visual observer working with the operator and the UAV.

Abstract: This disclosure describes an unmanned aerial vehicle (“UAV”) and system that may perform one or more techniques for protecting objects from damage resulting from an unintended or uncontrolled impact by a UAV. As described herein, various implementations utilize a damage avoidance system that detects a risk of damage to an object caused by an impact from a UAV that has lost control and takes steps to reduce or eliminate that risk. For example, the damage avoidance system may detect that the UAV has lost power and/or is falling at a rapid rate of descent such that, upon impact, there is a risk of damage to an object with which the UAV may collide. Upon detecting the risk of damage and prior to impact, the damage avoidance system activates a damage avoidance system having one or more protection elements that work in concert to reduce or prevent damage to the object upon impact by the UAV.