System and method for airspeed determination
A method for determining airspeed of an aircraft that includes determining a rotor model relating a power coefficient of a propeller of the aircraft to an axial inflow velocity through the propeller as a function of a set of rotor operating parameters; determining the set of rotor operating parameters by sampling an electronic control signal associated with an electric motor actuating the propeller; computing the axial inflow velocity through the propeller based on the set of rotor operating parameters using the rotor model; and determining the airspeed based on the axial inflow velocity.
1. A method for an aircraft comprising:
determining a set of propeller operating parameters based on an electronic control signal controlling actuation of a propeller;
determining an inflow velocity through the propeller based on the set of propeller operating parameters and a propeller model relating a power coefficient of the propeller of the aircraft to the inflow velocity through the propeller; and
determining a vehicle state parameter of the aircraft based on the inflow velocity through the propeller.
2. The method of claim 1 , wherein the inflow velocity comprises an axial inflow velocity.
3. The method of claim 1 , wherein the set of rotor operating parameters further comprises a tilt angle of the propeller, wherein determining the vehicle state parameter further comprises modifying at least one of the inflow velocity by a correction factor relating the tilt angle of the propeller to the inflow velocity.
4. The method of claim 1 , wherein vehicle state parameter comprises an airspeed of the aircraft.
5. The method of claim 4 , wherein the airspeed of the aircraft is not determined by an airflow sensor unless a trigger condition is satisfied.
6. The method of claim 5 , wherein the trigger condition comprises an inflow velocity exceeding a threshold.
7. The method of claim 6 , wherein the threshold comprises a slipstream velocity value behind the propeller.
8. The method of claim 5 , wherein the set of rotor operating parameters further comprises a tilt angle of the propeller, wherein the trigger condition comprises the tilt angle outside of a threshold range.
9. The method of claim 1 , wherein vehicle state parameter comprises at least one of a force on the aircraft or moment on the aircraft.
10. The method of claim 1 , further comprising: measuring the vehicle state parameter using an auxiliary measurement device to generate a second determined vehicle state parameter; comparing the determined vehicle state parameter to the second determined vehicle state parameter to generate a validation metric; and validating the second determined vehicle state parameter based on the validation metric.
11. The method of claim 1 , wherein the propeller comprises a fixed-pitch propeller.
12. A method for an aircraft comprising:
determining a first measurement with an air data sensor, the first measurement associated with a vehicle state parameter of the aircraft;
determining a set of operating parameters based on an electronic control signal associated with an aerodynamic actuator;
calculating a first value of an airflow parameter based on the set of operating parameters using a model relating a power coefficient of the aerodynamic actuator to an airflow parameter; and
determining the vehicle state parameter of the aircraft based on the first measurement and the first value.
13. The method of claim 12 , wherein the aerodynamic actuator comprises a rotary aerodynamic actuator.
14. The method of claim 12 , wherein the airflow parameter comprises an axial inflow velocity.
15. The method of claim 12 , wherein vehicle state parameter comprises an airspeed of the aircraft.
16. The method of claim 12 , wherein vehicle state parameter comprises at least one of a force on the aircraft or moment on the aircraft.
17. The method of claim 12 , further comprising:
determining a second set of operating parameters based on a second electronic control signal associated with a second aerodynamic actuator; and
calculating a second value of the airflow parameter based on the second set of operating parameters using a second model relating a second power coefficient of the second aerodynamic actuator to the airflow parameter;
wherein the vehicle state parameter of the aircraft is further determined based on the second value.
18. The method of claim 17 , wherein determining the vehicle state parameter comprises: fusing the first measurement, first value, and second value within a Kalman filter.
19. The method of claim 12 , wherein the aerodynamic actuator comprises a rotor, wherein the electronic control signal controls the actuation of an electric motor, the electric motor mechanically coupled to a rotor of the aircraft.
20. The method of claim 12 , wherein the set of operating parameters comprises a pitch angle of the aerodynamic actuator.
21. The method of claim 12 , wherein determining the vehicle state parameter of the aircraft comprises a cross-validation of the first measurement against the first value.