Damping unit as a secondary load path for a movable element with actuator

1 . A method comprising:

controlling, by a control system, an actuator to actuate to cause a tilting motion of a tiltable propulsion system relative to a support structure, wherein the actuator is coupled to the tiltable propulsion system and coupled to the support structure, a damping unit is coupled to the tiltable propulsion system and coupled to the support structure, and the damping unit is configured to provide a damping force that opposes the tilting motion of the tiltable propulsion system;

determining, by the control system, a load on the actuator during the tilting motion of the tiltable propulsion system, wherein the damping unit, when operational, causes an increase in the load on the actuator by opposing the tilting motion of the tiltable propulsion system being caused by the actuator;

comparing, by the control system, the load on the actuator to a predetermined threshold value; and

determining, by the control system, that the damping unit is operational when the load on the actuator exceeds the predetermined threshold value, wherein exceeding the predetermined threshold value indicates the load on the actuator has been increased as a result of the damping unit applying the damping force to the tiltable propulsion system.

2 . The method of claim 1 , wherein the determining the load on the actuator during the tilting motion of the tiltable propulsion system includes:

receiving, from a load measurement device, a measured parameter; and

calculating, based on the measured parameter, the load on the actuator.

3 . The method of claim 2 , wherein the load measurement device is a current meter, and the measured parameter is an amount of electric current being drawn by the actuator.

4 . The method of claim 1 , wherein a magnitude of the damping force is based on a speed of the tilting motion of the tiltable propulsion system, where an increase in speed causes a corresponding increase in magnitude.

5 . The method of claim 1 , wherein the predetermined threshold value is based on a previous load on the actuator during a previous motion of the tiltable propulsion system when the damping unit was disengaged.

6 . The method of claim 1 , wherein the actuator actuates linearly between an extended position and a retracted position, the damping unit is configured to passively extend or retract linearly, the damping unit is configured to resist an extension or a retraction, and the tilting motion of the tiltable propulsion system causes the extension or the retraction of the damping unit.

7 . The method of claim 1 , wherein the actuator provides a primary load path between the tiltable propulsion system and the support structure, the damping unit provides a secondary load path between the tiltable propulsion system and the support structure, the secondary load path opposes the primary load path, and the determining that the damping unit is operational includes determining that the secondary load path is functioning.

8 . The method of claim 7 , wherein the tilting motion of the tiltable propulsion system is a first tilting motion of the tiltable propulsion system, and wherein, upon a failure of the primary load path, the secondary load path slows a second tilting motion of the tiltable propulsion system.

9 . The method of claim 1 , wherein the tiltable propulsion system is coupled to an aircraft, and the controlling the actuator to actuate is performed while the aircraft is at rest on a surface, and further comprising:

after the determining that the damping unit is operational, initiating a flight process.

10 . The method of claim 1 , wherein the actuator is coupled to the support structure and the tiltable propulsion system such that actuating of the actuator between an extended position and a retracted position causes the tilting motion of the tiltable propulsion system between a first position and a second position, and the damping unit is coupled to the support structure and the tiltable propulsion system such that the tilting motion of the tiltable propulsion system causes extension or retraction of the damping unit.

11 . The method of claim 10 , wherein the tiltable propulsion system is coupled to an aircraft, and the support structure is coupled to the aircraft.

12 . The method of claim 11 , wherein the first position is a vertical flight configuration, and the second position is a forward flight configuration.

13 . A control system comprising:

a processor;

a computer readable medium comprising instructions that, when executed by the processor, cause the processor to execute a method comprising:

controlling an actuator to actuate to cause a tilting motion of a tiltable propulsion system relative to a support structure, wherein the actuator is coupled to the tiltable propulsion system and coupled to the support structure, a damping unit is coupled to the tiltable propulsion system and coupled to the support structure, and the damping unit is configured to provide a damping force that opposes the tilting motion of the tiltable propulsion system;

determining a load on the actuator during the tilting motion of the tiltable propulsion system, wherein the damping unit, when operational, causes an increase in the load on the actuator by opposing the tilting motion of the tiltable propulsion system being caused by the actuator;

comparing the load on the actuator to a predetermined threshold value; and

determining that the damping unit is operational when the load on the actuator exceeds the predetermined threshold value, wherein exceeding the predetermined threshold value indicates the load on the actuator has been increased as a result of the damping unit applying the damping force to the tiltable propulsion system.

14 . The control system of claim 13 , wherein the determining the load on the actuator during the tilting motion of the tiltable propulsion system includes:

receiving, from a load measurement device, a measured parameter; and

calculating, based on the measured parameter, the load on the actuator.

15 . The control system of claim 13 , wherein the predetermined threshold value is based on a previous load on the actuator during a previous motion of the tiltable propulsion system when the damping unit was disengaged.

16 . The control system of claim 13 , wherein the tiltable propulsion system is coupled to an aircraft.

17 . An aircraft comprising:

a tiltable propulsion system;

a support structure;

an actuator coupled to the tiltable propulsion system and coupled to the support structure, and configured to cause a tilting motion of the tiltable propulsion system relative to the support structure;

a damping unit coupled to the tiltable propulsion system and coupled to the support structure, and configured to provide a damping force to the tiltable propulsion system that opposes the tilting motion of the tiltable propulsion system; and

a control system configured to:

control the actuator to actuate to cause the tilting motion of the tiltable propulsion system;

determine a load on the actuator during the tilting motion of the tiltable propulsion system, wherein the damping unit, when operational, causes an increase in the load on the actuator by opposing the tilting motion of the tiltable propulsion system;

compare the load on the actuator to a predetermined threshold value; and

determine that the damping unit is operational when the load on the actuator exceeds the predetermined threshold value, wherein exceeding the predetermined threshold value indicates the load on the actuator has been increased as a result of the damping unit applying the damping force to the tiltable propulsion system.

18 . The aircraft of claim 17 , further comprising:

a fuselage; and

a pair of wings coupled to opposite sides the fuselage,

wherein the support structure is coupled to one of the pair of wings.

19 . The aircraft of claim 17 , wherein the tilting motion of the tiltable propulsion system is a first tilting motion of the tiltable propulsion system, and wherein, upon a failure of the actuator, the damping unit slows a second tilting motion of the tiltable propulsion system.