Supplemental attitude with engaged and disengaged input device modes

1. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

receive an input attitude controlled by an input device of an aircraft;

determine a state of the input device, wherein the state includes one of: engaged or disengaged;

generate a supplemental attitude based at least in part on the state of the input device, including by:

selecting a position-based supplemental attitude to be the supplemental attitude in the event the input device is in a disengaged state; and

selecting a velocity-based supplemental attitude to be the supplemental attitude in the event the input device is in an engaged state;

combine, using an adder, the input attitude and the supplemental attitude in order to obtain a combined attitude; and

control the aircraft using the combined attitude including by instructing control surfaces of the aircraft to actuate.

2. The system recited in claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a desired velocity which includes a desired direction of movement;

obtain a measured velocity; and

generate the velocity-based supplemental attitude, including by:

determining a difference between the desired velocity and the measured velocity; and

determining a portion of the difference that is perpendicular to the desired direction of movement.

3. The system recited in claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

compare a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, decide that the input device is engaged;

compare the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, decide that the input device is disengaged.

4. The system recited in claim 3 , wherein the input device includes a joystick and the displacement includes a radial displacement.

5. The system recited in claim 1 , wherein the instructions for generating the supplemental attitude include instructions for:

in the event the input device switches from the engaged state to the disengaged state, gradually transition from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transition from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

6. The system recited in claim 1 , wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

compare a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, decide that the input device is engaged;

compare the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, decide that the input device is disengaged; and

the instructions for generating the supplemental attitude include instructions for:

in the event the input device switches from the engaged state to the disengaged state, gradually transition from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transition from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

7. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

receive an input attitude controlled by an input device of an aircraft;

determine a state of the input device, wherein the state includes one of: engaged or disengaged;

generate a supplemental attitude based at least in part on the state of the input device, including by selecting a position-based supplemental attitude to be the supplemental attitude in the event the input device is in a disengaged state and selecting a velocity-based supplemental attitude to be the supplemental attitude in the event the input device is in an engaged state;

combine the input attitude and the supplemental attitude in order to obtain a combined attitude; and

control the aircraft using the combined attitude including by instructing control surfaces of the aircraft to actuate.

8. The system recited in claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a desired velocity which includes a desired direction of movement;

obtain a measured velocity; and

generate the velocity-based supplemental attitude, including by:

determining a difference between the desired velocity and the measured velocity; and

determining a portion of the difference that is perpendicular to the desired direction of movement.

9. The system recited in claim 1 , wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

compare a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, decide that the input device is engaged;

compare the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, decide that the input device is disengaged.

10. The system recited in claim 9 , wherein the input device includes a joystick and the displacement includes a radial displacement.

11. The system recited in claim 7 , wherein the instructions for generating the supplemental attitude include instructions for:

in the event the input device switches from the engaged state to the disengaged state, gradually transition from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transition from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

12. The system recited in claim 7 , wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

compare a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, decide that the input device is engaged;

compare the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, decide that the input device is disengaged; and

the instructions for generating the supplemental attitude include instructions for:

in the event the input device switches from the engaged state to the disengaged state, gradually transition from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transition from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

13. A method, comprising:

receiving an input attitude controlled by an input device of an aircraft;

determining a state of the input device, wherein the state includes one of: engaged or disengaged;

generating a supplemental attitude based at least in part on the state of the input device, including by:

selecting a position-based supplemental attitude to be the supplemental attitude in the event the input device is in a disengaged state; and

selecting a velocity-based supplemental attitude to be the supplemental attitude in the event the input device is in an engaged state;

combining the input attitude and the supplemental attitude in order to obtain a combined attitude; and

controlling the aircraft using the combined attitude including by instructing control surfaces of the aircraft to actuate.

14. The method recited in claim 13 further comprising:

obtaining a desired velocity which includes a desired direction of movement;

obtaining a measured velocity; and

generating the velocity-based supplemental attitude, including by:

determining a difference between the desired velocity and the measured velocity; and

determining a portion of the difference that is perpendicular to the desired direction of movement.

15. The method recited in claim 13 further comprising:

comparing a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, deciding that the input device is engaged;

comparing the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, deciding that the input device is disengaged.

16. The method recited in claim 15 , wherein the input device includes a joystick and the displacement includes a radial displacement.

17. The method recited in claim 13 , wherein generating the supplemental attitude includes:

in the event the input device switches from the engaged state to the disengaged state, gradually transitioning from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transitioning from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

18. The method recited in claim 13 , wherein:

the method further includes:

comparing a displacement, of the input device from a spring-centered position, against a first threshold;

in the event the displacement exceeds the first threshold, deciding that the input device is engaged;

comparing the displacement against a second threshold, wherein the second threshold is less than the first threshold; and

in the event the displacement does not exceed the second threshold, deciding that the input device is disengaged; and

generating the supplemental attitude includes:

in the event the input device switches from the engaged state to the disengaged state, gradually transitioning from the velocity-based supplemental attitude to the position-based supplemental attitude as the supplemental attitude; and

in the event the input device switches from the disengaged state to the engaged state, gradually transitioning from the position-based supplemental attitude to the velocity-based supplemental attitude as the supplemental attitude.

19. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

receiving an input attitude controlled by an input device of an aircraft;

determining a state of the input device, wherein the state includes one of: engaged or disengaged;

generating a supplemental attitude based at least in part on the state of the input device, including by:

selecting a position-based supplemental attitude to be the supplemental attitude in the event the input device is in a disengaged state; and

selecting a velocity-based supplemental attitude to be the supplemental attitude in the event the input device is in an engaged state;

combining the input attitude and the supplemental attitude in order to obtain a combined attitude; and

controlling the aircraft using the combined attitude including by instructing control surfaces of the aircraft to actuate.