Online optimization-based flight control system
Techniques to control flight of an aircraft are disclosed. In various embodiments, a set of inputs associated with a requested set of forces and moments to be applied to the aircraft is received. An optimal mix of actuators and associated actuator parameters to achieve to an extent practical the requested forces and moments is determined, including by minimizing a weighted set of costs that includes costs associated with one or more errors each corresponding to a difference between a requested force or moment and a corresponding force or moment achieved by the computed solution.
1. An aircraft comprising:
an airframe;
actuators coupled with the airframe, wherein the actuators comprise lift fans;
sensors via which sensor data is generated, wherein the sensor data is indicative of whether each of a plurality of the lift fans has a failure induced reduced capacity;
a flight controller configured to:
receive flight control inputs corresponding to a set of forces and moments to be applied to the aircraft via operation of the actuators;
monitor the sensor data to detect whether any one of a plurality of lift fans has a failure induced reduced capacity to generate lift;
determine, for an instance in which at least one of the lift fans has a failure induced reduced capacity to generate lift, a solution space based on current capabilities of the actuators; and
determine, within the solution space, a combination of the actuators and associated actuator parameters to apply the set of forces and moments to the aircraft to an extent practicable with the failure induced reduced capacity of the at least one of the lift fans.
2. The aircraft of claim 1 , wherein the failure induced reduced capacity is measured, detected and/or inferred from indirect indications.
3. The aircraft of claim 2 , wherein the indirect indications comprise a temperature of one of the lift fans, an air temperature and/or airspeed.
4. The aircraft of claim 1 , wherein the solution space is defined at least partially by one or more constraints.
5. The aircraft of claim 4 , wherein the one or more constraints comprise one or more of minimum and/or maximum rotation speed or torque, minimum and/or maximum deflection angle and minimum and/or maximum rate of change.
6. The aircraft of claim 4 , wherein the one or more constraints includes a maximum power constraint.
7. The aircraft of claim 1 , wherein the combination of the actuators and associated actuator parameters are determined so as to minimize combined thrust of the lift fans.
8. The aircraft of claim 1 , wherein the combination of the actuators and associated actuator parameters are determined so as to minimize variation in thrust generated by each of the lift fans while accounting for the failure induced reduced capacity of the at least one of the lift fans.
9. The aircraft of claim 1 , wherein the actuators comprise seven or more independent actuators.
10. The aircraft of claim 1 , wherein:
the airframe comprises a fuselage, a left wing attached to the fuselage and a right wing attached to the fuselage;
a first plurality of the lift fans is attached to the left wing; and
a second plurality of the lift fans is attached to the right wing.
11. The aircraft of claim 1 , wherein:
the airframe comprises a fuselage, a left wing attached to the fuselage and a right wing attached to the fuselage;
the left wing comprises a first left wing pylon, a second left wing pylon and a third left wing pylon;
the right wing comprises a first right wing pylon, a second right wing pylon and a third right wing pylon;
two of the lift fans are attached to the first left wing pylon;
two of the lift fans are attached to the second left wing pylon;
two of the lift fans are attached to the third left wing pylon;
two of the lift fans are attached to the first right wing pylon;
two of the lift fans are attached to the second right wing pylon; and
two of the lift fans are attached to the third right wing pylon.
12. The aircraft of claim 1 , wherein the flight control inputs are associated with a set of inceptor outputs.
13. The aircraft of claim 1 , wherein the flight control inputs are provided by an autopilot or other automated flight computer.
14. The aircraft of claim 1 , wherein the flight controller is configured to map the flight control inputs to the set of forces and moments to be applied to the aircraft via operation of the actuators.
15. The aircraft of claim 1 , wherein flight controller determines the combination of the actuators and associated actuator parameters in real time.
16. The aircraft of claim 1 , wherein the flight controller determines the combination of the actuators and associated actuator parameters using a linear model of the aircraft.
17. The aircraft of claim 1 , wherein the flight controller determines the combination of the actuators and associated actuator parameters by using a quadratic optimization approach.
18. The aircraft of claim 1 , wherein the flight controller determines the combination of the actuators and associated actuator parameters so as to prioritize moments associated with stability of the aircraft in a plane defined in a transverse axis and a longitudinal axis of the aircraft over one or more of the other of the set of forces and moments.
19. The aircraft of claim 1 , wherein the flight controller determines the combination of the actuators and associated actuator parameters so as to prioritize one or more of the set of forces and moments over the other forces and/or moments of the set of forces and moments.