Inbound transition control for a tail-sitting vertical take off and landing aircraft
View Patent ↗A system for controlling inbound transition of an aircraft includes a fuselage and first and second freewings pivotably mounted on opposing sides thereof. The system includes an airspeed sensor that outputs an airspeed indication signal. The system includes a controller for increasing aircraft engine thrust to substantially maximum for inbound transition, and for generating pitch and freewing control signals. The system includes actuators for actuating aircraft control surfaces in response to the pitch control signal to rapidly increase pitch of the fuselage to decelerate the aircraft, and for actuating freewing control surfaces in response to the freewing control signal to adjust lift produced by the freewings to oppose climbing of the aircraft due to the increase in engine thrust and the increase in the fuselage pitch. The controller is configured to decrease the engine thrust as the aircraft decelerates until the aircraft is in a hover mode.
1. A system for controlling inbound transition of a tail-sitting vertical takeoff and landing (VTOL) aircraft, comprising:
a fuselage;
a first freewing and a second freewing pivotably mounted on opposing sides of the fuselage;
an airspeed sensor,
wherein the airspeed sensor determines an airspeed of the aircraft and outputs an airspeed indication signal;
a controller in communication with the airspeed sensor, wherein the controller receives the airspeed indication signal,
wherein the controller increases thrust of an engine of the aircraft to substantially maximum during inbound transition, and
wherein the controller generates a pitch control signal and a freewing control signal in response to the airspeed indication signal; and
at least one actuator in communication with the controller,
wherein the at least one actuator actuates control surfaces of the aircraft in response to the pitch control signal, rapidly increases a pitch of the fuselage and decelerates the aircraft,
wherein the at least one actuator actuates control surfaces of the first and second freewings in response to the freewing control signal to adjust lift produced by the first and second freewings to oppose climbing of the aircraft due to the increase in the thrust of the engine and the increase in the pitch of the fuselage, and
wherein the controller decreases the thrust of the engine as the aircraft decelerates until the aircraft is in a hover mode.
2. The system of claim 1 , wherein the controller determines a flight path of the aircraft for inbound transition.
3. The system of claim 2 , comprising:
an inertial sensor in communication with the controller,
wherein the inertial sensor generates inertial guidance signals, and
wherein the controller controls the at least one actuator to actuate the control surfaces of the first and second freewings in response to the inertial guidance signals to maintain the determined flight path.
4. The system of claim 1 , wherein the controller decreases the thrust of the engine to land the aircraft from the hover mode.
5. The system of claim 1 , wherein the controller controls the at least one actuator to actuate the control surfaces of the first and second freewings to adjust the lift produced by the first and second freewings to be negative to oppose climbing by the aircraft due to the increase in the thrust of the engine and the increase in the pitch of the fuselage.
6. The system of claim 1 , wherein the controller controls the at least one actuator to actuate the control surfaces of the aircraft to increase the pitch of the fuselage greater than perpendicular with respect to ground to further assist in deceleration of the aircraft.
7. The system of claim 1 , wherein the controller causes the aircraft to descend as the pitch of the fuselage is increased.
8. The system of claim 1 , wherein the airspeed sensor comprises:
a pitot tube mounted on a boom on a fore portion of at least one of the first freewing and the second freewing.
9. The system of claim 8 , wherein the pitot tube balances a weight of the at least one of the first freewing and the second freewing.
10. The system of claim 1 , wherein the controller controls the at least one actuator to actuate the control surfaces of the first and second freewings to alter an angle of attack of the first and second freewings to produce substantially zero lift in the hover mode.
11. The system of claim 1 , wherein the controller controls the at least one actuator to actuate the control surfaces of the first and second freewings to alter an angle of attack of the first and second freewings to produce a positive lift to increase performance of the aircraft.
12. The system of claim 1 , wherein the aircraft comprises a ducted fan VTOL aircraft.
13. The system of claim 1 , wherein the first and second freewings are each independently pivotably mounted on the opposing sides of the fuselage.
14. A system for controlling inbound transition of a tail-sitting vertical takeoff and landing (VTOL) aircraft, comprising:
a sensor circuit,
wherein the sensor circuit determines an airspeed of the aircraft and to output an airspeed indication signal, and
wherein the aircraft includes a first freewing and a second freewing pivotably mounted on opposing sides of a fuselage of the aircraft;
a control circuit in communication with the sensor circuit to receive the airspeed indication signal,
wherein the control circuit increases a throttle of an engine of the aircraft to substantially maximum for inbound transition, and
wherein the control circuit generates a pitch control signal and a freewing control signal in response to the airspeed indication signal; and
a control surface actuator in communication with the control circuit,
wherein the control surface actuator actuates control surfaces of the aircraft in response to the pitch control signal to rapidly increase a pitch of the fuselage to decelerate the aircraft,
wherein the control surface actuator actuates control surfaces of the first and second freewings in response to the freewing control signal to adjust lift produced by the first and second freewings to oppose climbing of the aircraft due to the increase in the throttle of the engine and the increase in the pitch of the fuselage, and
wherein the control circuit decreases the throttle of the engine as the aircraft decelerates until the aircraft is in a hover mode.
15. A method of controlling inbound transition of a tail-sitting vertical takeoff and landing (VTOL) aircraft, comprising:
a.) increasing a throttle of an engine of the aircraft to substantially maximum,
wherein the aircraft includes a first freewing and a second freewing pivotably mounted on opposing sides of a fuselage of the aircraft;
b.) rapidly increasing a pitch of the fuselage of the aircraft, in response to an airspeed of the aircraft, to decelerate the aircraft;
c.) adjusting lift produced by the first freewing and second freewing to oppose climbing of the aircraft due to the increase in the throttle of the engine and the increase in the pitch of the fuselage; and
d.) decreasing the throttle of the engine as the aircraft decelerates until the aircraft is in a hover mode.
16. The method of claim 15 , comprising the step of:
e.) determining a flight path of the aircraft for inbound transition.
17. The method of claim 16 , comprising the steps of:
f.) generating inertial guidance signals; and
g.) adjusting the first and second freewings in response to the inertial guidance signals to maintain the determined flight path.
18. The method of claim 15 , wherein step (d) comprises the step of:
e.) further decreasing the throttle of the engine to land the aircraft from the hover mode.
19. The method of claim 15 , wherein step (c) comprises the step of:
e.) adjusting the lift produced by the first and second freewings to be negative to oppose climbing by the aircraft due to the increase in the throttle of the engine and the increase in the pitch of the fuselage.
20. The method of claim 15 , wherein step (b) comprises the step of:
e.) increasing the pitch of the fuselage greater than perpendicular with respect to ground to further assist in deceleration of the aircraft.
21. The method of claim 15 , comprising the step of:
e.) descending the aircraft as the pitch of the fuselage is increased.
22. The method of claim 15 , wherein a pitot tube is mounted on a boom on a fore portion of at least one of the first freewing and the second freewing for measuring the airspeed of the aircraft.
23. The method of claim 22 , wherein the pitot tube is configured to balance a weight of the at least one of the first freewing and the second freewing.
24. The method of claim 15 , comprising the step of:
e.) altering an angle of attack of the first and second freewings to produce substantially zero lift in the hover mode.
25. The method of claim 15 , comprising the step of:
e.) altering an angle of attack of the first and second freewings to produce a positive lift to increase performance of the aircraft.
26. The method of claim 15 , wherein the aircraft comprises a ducted fan VTOL aircraft.
27. The method of claim 15 , wherein the first and second freewings are each independently pivotably mounted on the opposing sides of the fuselage.