Method and apparatus for controlled force deployment of user interface devices

1. A method for driving a deployable user interface device onboard an aircraft comprising the steps of:

receiving motion information from the deployable device, regarding motion of the deployable device;

wherein said deployable device comprises an inflight passenger electronic user interface apparatus, which is configured to be deployed from a stowed position to a position from which the electronic user interface apparatus is configured to provide enhanced utility;

applying power to an actuator in order to cause the deployable device to begin deployment;

reversing power to the actuator if deployment of the deployable device has been physically retarded which is indicated if the rate of motion as indicated by the motion information is less than a first pre-established rate threshold;

increasing the power applied to the actuator if the rate of motion as indicated by the motion information has exceeded a second pre-established rate threshold for a set period of time; and

decreasing the power applied to the actuator to a holding level if the full-deployment indicator becomes active.

2. The method of claim 1 further comprising the step of reversing power to the actuator if the motion information indicates that the deployable device has receded from the fully deployed position by a pre-established recession threshold.

3. The method of claim 1 further comprising the step of reversing power to the actuator if the rate of motion as indicated by the motion information falls below a third rate of motion threshold after power has been increased to the actuator and the full-deployment signal is not received.

4. The method of claim 1 wherein the step of applying power to the actuator in order to cause the device to begin deployment comprises the steps of:

applying substantially full power to the actuator until the deployable device has cleared a latch assembly; and

applying a reduced power level to the actuator device.

5. The method of claim 1 wherein the step of applying power to the actuator in order to cause the device to begin deployment comprises the step of cyclically applying power for a first time period and then removing the power for a second time period to the actuator in order to limit the force applied by the actuator to the deployable device to a pre-established force threshold.

6. The method of claim 1 wherein the actuator is an electric device and the step of applying power to the actuator in order to cause the device to begin deployment comprises the step of reducing the electrical current delivered to the actuator in order to limit the force applied by the actuator to the deployable device to a pre-established force threshold.

7. The method of claim 1 wherein the step of decreasing the power applied to the actuator to a holding level comprises the step of cyclically applying power for a first time period and then removing the power for a second time period to the actuator in order to maintain contact with a deployment stop.

8. The method of claim 1 wherein the actuator is an electrical device that comprises an electrical coil contained within a magnetic field and wherein the step of decreasing the power applied to the actuator to a holding level comprises the steps of:

causing the electrical coil to resist changes in the magnetic field for a pre-established braking period; and

cyclically applying power for a first time period and then removing the power for a second time period to the actuator in order to maintain contact with a deployment stop.

9. A deployable user interface device onboard an aircraft comprising:

base structure for mounting the user interface device;

inflight user interface assembly that is moveably mounted to the base structure;

motion sensor that is coupled to the user interface assembly and provides motion information according to the motion of said user interface assembly;

full-deployment sensor coupled to the user interface assembly that generates a full-deployment signal when the user interface assembly is fully deployed;

actuator that, when it receives power, minimally causes the user interface assembly to move from a stowed position to a deployed position; and

actuator control unit that:

applies power to the actuator in order to cause the user interface assembly to begin moving out of the stowed position;

reverses the power applied to the actuator if the rate of motion as indicated by the motion sensor is less than a first pre-established rate threshold;

increases the power applied to the actuator if the rate of motion as indicated by the motion sensor exceeds a second pre-established rate threshold for a set period of time; and

decreases the power applied to the actuator to a holding level if the full-deployment signal is received.

10. The deployable user interface of claim 9 wherein the actuator control unit further reverses power to the actuator if the motion information received from the motion sensors indicates that the user interface assembly has receded from the fully deployed position by a pre-established recession threshold.

11. The deployable user interface of claim 9 wherein the actuator control unit further reverses power to the actuator if the rate of motion as indicated by the motion sensor is less than a third pre-established rate threshold after power applied to the actuator has been increased and the full-deployment signal has not been received.

12. The deployable user interface of claim 9 wherein the actuator control unit applies power to the actuator in order to cause the user interface assembly to begin moving out of the stowed position by applying substantially full power to the actuator for a pre-established latch clearance time and reducing the power level applied to the actuator in order to reduce the force applied by the actuator to the user interface assembly.

13. The deployable user interface of claim 9 wherein the actuator control unit further comprises a pulse-width-modulated power controller that cyclically applies power to the actuator for a first time period and then removes power from the actuator for a second time period in order to limit the force applied to the user interface assembly to a pre-established safety force threshold.

14. The deployable user interface of claim 9 wherein the actuator is an electrical device and wherein the actuator control unit further comprises a current regulator that reduces the electrical current delivered to the actuator in order to limit the force applied to the user interface assembly to a pre-established force threshold.

15. The deployable user interface of claim 9 wherein the actuator control unit further comprises a pulse-width-modulated power controller that cyclically applies power to the actuator for a first time period and then removes power from the actuator for a second time period in order to limit the force applied to the user interface assembly to a pre-established holding force threshold.

16. The deployable user interface of claim 9 wherein the actuator is an electrical device that comprises an electrical coil having a plurality of input leads contained in a magnetic field and wherein the actuator control unit further comprises:

electrical braking circuit; and

pulse-width-modulated power controller and wherein the actuator control unit decreases the power applied to the actuator to a holding level by causing the electrical braking circuit to connect the input leads of the actuator to each other for a pre-established braking period and then causing the pulse-width-modulator to cyclically apply power to the actuator for a first period of time and then remove power from the actuator for a second period of time.

17. A deployable overhead display unit comprising:

base structure for mounting the overhead display unit onboard an aircraft;

display screen that is pivotally mounted to the base structure to provide an inflight interface;

motion sensor that is coupled to the display screen and provides motion information according to the motion of said display screen;

full-deployment sensor coupled to the display screen that generates a full-deployment signal when the display screen is fully deployed; actuator that, when it receives power, causes the display screen to pivot about its mounting; and

actuator control unit that:

applies power to the actuator in order to cause the display screen to begin moving out of a stowed position;

reverses the power applied to the actuator if the rate of motion as indicated by the motion sensor is less than a first pre-established rate threshold;

increases the power applied to the actuator if the rate of motion as indicated by the motion sensor exceeds a second pre-established rate threshold for a set period of time; and

decreases the power applied to the actuator to a holding level if the full-deployment signal is received.

18. The deployable overhead display unit of claim 17 wherein the actuator control unit further reverses power to the actuator if the motion information received from the motion sensors indicates that the display screen has receded from the fully deployed position by a pre-established recession threshold.

19. The deployable user interface of claim 17 wherein the actuator control unit further reverses power to the actuator if the rate of motion as indicated by the motion sensor is less than a third pre-established rate threshold after power applied to the actuator has been increased and the full-deployment signal has not been received.

20. The deployable overhead display unit of claim 17 wherein the actuator control unit applies power to the actuator in order to cause the user interface assembly to begin moving out of a stowed position by applying substantially full power to the actuator for a pre-established latch clearance time and reducing the power level applied to the actuator in order to reduce the force applied by the actuator to the display screen.

21. The deployable overhead display unit of claim 17 wherein the actuator control unit further comprises a pulse-width-modulated power controller that cyclically applies power to the actuator for a first time period and then removes power from the actuator for a second time period in order to limit the force applied to the display screen to a pre-established safety force threshold.

22. The deployable overhead display unit of claim 17 wherein the actuator is an electrical device that comprises an electrical coil having a plurality of input leads and which is contained in a magnetic field and wherein the actuator control unit further comprises:

electrical braking circuit; and

pulse-width-modulated power controller and wherein the actuator control unit decreases the power applied to the actuator to a holding level by causing the electrical braking circuit to connect the input leads of the actuator to each other for a pre-established braking period and then causing the pulse-width-modulator to cyclically apply power to the actuator for a first period of time and then remove power from the actuator for a second period of time.