Blade pitch detection for an aerial vehicle
A blade pitch detection apparatus for an aircraft having a lower rotor hub assembly and an upper rotor hub assembly, the upper rotor hub assembly including a blade pitch adjustment linkage configured to maintain the rotor blades at a first blade pitch while a rotational velocity of the upper rotor hub assembly is below a threshold and to maintain the rotor blades at a second blade pitch while the rotational velocity is above a threshold. The pitch detection apparatus includes a magnet coupled to a component of the blade pitch adjustment linkage and a sensor coupled to a component of the lower rotor hub assembly and configured to generate a signal in the presence of the magnet. Processing circuitry in communication with the sensor can determine whether the plurality of rotor blades are at the first blade pitch or the second blade pitch based on the signals.
1 . A rotor blade pitch detection apparatus for an aircraft, the rotor blade pitch detection apparatus comprising:
a magnet coupled to a movable component of a blade pitch adjustment linkage for a plurality of rotor blades of a rotor of the aircraft, the movable component having a first orientation while the plurality of rotor blades are at a first blade pitch and a second orientation while the plurality of rotor blades are at a second blade pitch;
a sensor coupled to the aircraft and configured to generate a signal in the presence of the magnet, wherein:
when the movable component is in the first orientation, the magnet repeatedly triggers the sensor to generate the signal while the rotor is rotating, and
when the movable component is in the second orientation, the magnet does not trigger the sensor while the rotor is rotating; and
processing circuitry in communication with the sensor and configured to determine whether the plurality of rotor blades are at the first blade pitch or the second blade pitch based on signals received from the sensor.
2 . The rotor blade pitch detection apparatus of claim 1 , wherein the sensor comprises a hall effect sensor.
3 . The rotor blade pitch detection apparatus of claim 1 , wherein the movable component is a synchronization pivot arm configured to at least partially synchronize individual blade pitches of the plurality of rotor blades.
4 . The rotor blade pitch detection apparatus of claim 1 , wherein the processing circuitry is further configured to determine a rotational speed of the upper rotor hub assembly, based on the signals, while the blade pitch adjustment linkage is in the first orientation.
5 . The rotor blade pitch detection apparatus of claim 4 , wherein the processing circuitry is further configured to determine, based on the determined rotational speed, a pitch transition rotational speed at which the blade pitch begins to transition from the first blade pitch to the second blade pitch.
6 . The rotor blade pitch detection apparatus of claim 5 , wherein the processing circuitry is further configured to determine an operational status of a biasing element of the blade pitch adjustment linkage by comparing the pitch transition rotational speed to an intended transition speed, a range of intended transition speeds, or one or more previously determined pitch transitional rotational speeds.
7 . The rotor blade pitch detection apparatus of claim 1 , further comprising a rotational speed detection apparatus comprising:
a second magnet coupled to a component of the rotor; and
a second sensor in communication with the processing circuitry, the second sensor coupled to a component of the lower rotor hub assembly and configured to generate a second signal in the presence of the second magnet.
8 . The rotor blade pitch detection apparatus of claim 7 , wherein the component of the rotor is rotationally fixed to the rotor.
9 . The rotor blade pitch detection apparatus of claim 7 , wherein the second magnet repeatedly triggers the second sensor to generate the second signal while the rotor is rotating and the plurality of rotor blades are at the first blade pitch and while the rotor is rotating and the plurality of rotor blades are at the second blade pitch.
10 . The rotor blade pitch detection apparatus of claim 7 , wherein the processing circuitry is configured to determine that the plurality of rotor blades are at the first blade pitch in response to a similarity between a first rotational speed calculated based on the signals from the sensor and a second rotational speed calculated based on the second signals from the second sensor.
11 . The rotor blade pitch detection apparatus of claim 7 , wherein the processing circuitry is configured to determine that the plurality of rotor blades are at the second blade pitch in response to a discrepancy between a first rotational speed calculated based on the signals from the sensor and a second rotational speed calculated based on the second signals from the second sensor.
12 . The rotor blade pitch detection apparatus of claim 1 , wherein the processing circuitry is configured to determine that the plurality of rotor blades are at the first blade pitch in response to repeatedly receiving the signals from the sensor.
13 . The rotor blade pitch detection apparatus of claim 1 , wherein the processing circuitry is configured to determine that the plurality of rotor blades are at the second blade pitch in response to failing to receive at least a threshold number of signals from the sensor over a predetermined time period.
14 . The rotor blade pitch detection apparatus of claim 1 , wherein the magnet is disposed radially outward from an axis of rotation of the rotor such that the magnet moves repeatedly along a circular path while the rotor is rotating.