Power lever tactile cueing system

• US 20030094539A1
• Filed: 11/12/2002
• Published: 05/22/2003
• Est. Priority Date: 05/16/2000
• Status: Active Grant

• Current Assignee: Textron Innovations Incorporated (Textron Inc)
• Original Assignee: Textron Innovations Incorporated (Textron Inc)
• Inventors: King, David W., Schaeffer, Joseph M., Mehra, Anil
• Granted Patent: US 6,695,264 B2
• Time in Patent Office: Days
• US Class Current: 244/17.13
• CPC Class Codes: B64C 29/0033 the propellers being tiltable relative to the fuselage
• CPC Class Codes: B64D 31/04 actuated personally
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

The present invention is a power lever tactile cueing system for providing tactile alerts to pilots as operational limits of an aircraft are approached. The cueing system generates a tactile cue comprising a variable dive rate and a variable friction force on a power lever of an aircraft. The cueing system provides spring-like tactile cues when power commands reach a predetermined operating limit, without the use of mechanical springs. The cueing system trims down the power lever position and provides the additional friction force based upon aircraft and engine state. The cueing system remains activated until the aircraft is again operated within its operational limits. The pilot may override the cueing system in certain situations.

Claims

1. A tiltrotor aircraft comprising:

a fuselage;

at least one wing member coupled to the fuselage;

a tiltrotor assembly pivotally coupled to the at least one wing member;

at least one flight control computer;

a power lever for controlling the operations of the tiltrotor aircraft, the power lever being electrically coupled to the at least one flight control computer; and

a springless cueing system electrically coupled to the power lever and to the at least one flight control computer for generating tactile cues to the power lever in response to a tactile cue command generated by the at least one flight control computer.

2. The tiltrotor aircraft according to claim 1, wherein the springless cueing system comprises:

control electronics electrically coupled to the at least one flight control computer;

an electric motor electrically coupled to the control electronics;

a variable friction magnetic particle clutch electrically coupled to the control electronics; and

a position sensor coupled to the control electronics for sensing the position of the power lever;

wherein the electric motor and the variable friction magnetic particle clutch generate the tactile cues to the power lever without the use of mechanical springs.

3. The tiltrotor aircraft according to claim 2, wherein the springless cueing system is activated when the position of the power lever approaches a position which represents an operational limit of the tiltrotor aircraft as detected by the position sensor.

4. The tiltrotor aircraft according to claim 1, wherein the tactile cues comprise:

a variable drive rate on the power lever; and

a variable friction force on the power lever;

wherein the variable drive rate and the variable friction force resist movement of the power lever.

5. The tiltrotor aircraft according to claim 4, wherein the variable drive rate is between about 0.08 inches per second and about 0.8 inches per second.

6. The tiltrotor aircraft according to claim 4, wherein the variable friction force is between about zero pounds and about 3.0 pounds.

7. The tiltrotor aircraft according to claim 4, further comprising:

a means for producing a pilot adjustable friction force on the power lever;

wherein the variable friction force is added to the pilot adjustable friction force.

8. The tiltrotor aircraft according to claim 4, further comprising:

a plurality of sensors for generating sensor signals corresponding to selected operating conditions of the tiltrotor aircraft;

a plurality of red line limit algorithms for generating red line signals corresponding to selected operating conditions of the tiltrotor aircraft;

a backdrive command algorithm for comparing the sensor signals to the red line signals and for generating an error signal;

wherein the magnitudes of the tactile cues are determined by the backdrive command algorithm.

9. The tiltrotor aircraft according to claim 8, wherein the variable drive rate is proportional to the error signal.

10. The tiltrotor aircraft according to claim 1, further comprising:

a one engine inoperative switch electrically coupled to the power lever;

a plurality of sensors disposed throughout the tiltrotor aircraft for sensing data for measured gas temperature, engine torque, transmission torque, the status of the one engine inoperative switch, and nacelle angle which is defined as the angle between a longitudinal axis of the tiltrotor assembly and the at least one wing member, the plurality of sensors generating signals corresponding to the sensed data;

a first backdrive command which is a function of the sensed data for the measured gas temperature, the status of the one engine inoperative switch, and the nacelle angle;

a second backdrive command which is a function of the sensed data for the engine torque and the nacelle angle; and

a third backdrive command which is a function of the sensed data for the transmission torque and the nacelle angle;

wherein the tactile cue command is the most critical of the first backdrive command, the second backdrive command, or the third backdrive command, as determined by the at least one flight control computer, depending upon the operational state of the tiltrotor aircraft.

11. A tactile cueing system for use in an aircraft, the tactile cueing system comprising:

at least one flight control computer;

a power lever electrically coupled to the at least one flight control computer;

a plurality of sensors for generating signals corresponding to selected operating conditions of the aircraft;

a plurality of operational limits of the aircraft generated by the at least one flight control computer;

a means for generating tactile cues to the power lever;

wherein the magnitudes of the tactile cues are determined by the at least one flight control computer.

12. The tactile cueing system according to claim 11, wherein the means for generating tactile cues comprises:

an electric motor electrically coupled to the at least one flight control computer;

a variable friction magnetic particle clutch coupled to the electric motor and the power lever;

control electronics electrically coupled to the electric motor and the variable friction magnetic particle clutch; and

a position sensor coupled to the control electronics for sensing the position of the power lever;

wherein the electric motor and the variable friction magnetic particle clutch generate the tactile cues to the power lever without the use of mechanical springs.

13. The tactile cueing system according to claim 11, wherein the plurality of sensors for generating signals corresponding to selected operating conditions of the aircraft comprises:

a first sensor for sensing measured gas temperature;

a second sensor for sensing engine torque;

a third sensor for sensing transmission torque

a fourth sensor for sensing nacelle angle which is the angle between a longitudinal axis of the tiltrotor assembly and the at least one wing member; and

a fifth sensor for sensing the status of a one engine inoperative switch.

14. The tactile cueing system according to claim 11, wherein the tactile cues comprise:

a variable drive rate on the power lever; and

a variable friction force on the power lever;

wherein the variable drive rate and the variable friction force resist movement of the power lever.

15. The tactile cueing system according to claim 14, wherein the variable drive rate is between about 0.08 inches per second and about 0.8 inches per second.

16. The tactile cueing system according to claim 14, wherein the variable friction force is between about zero pounds and about 3.0 pounds.

17. A method of reducing pilot workload in an aircraft, the method comprising the steps of:

providing a flight control computer;

coupling a power lever to the flight control computer;

providing a means for generating tactile cues on the power lever in response to selected operating conditions of the aircraft;

generating the tactile cues on the power lever without the use of mechanical springs as the power lever approaches a position which represents operational limits of the aircraft, thereby reducing pilot workload.

18. The method according to claim 17, wherein the step of providing a means for generating tactile cues on the power lever comprises:

electrically coupling control electronics to the flight control computer;

electrically coupling an electric motor to the control electronics;

electrically coupling a variable friction magnetic particle clutch to the control electronics;

electrically coupling a position sensor to the control electronics;

coupling the position sensor to the power lever;

disposing a plurality of sensors on the aircraft;

sensing selected operational conditions of the aircraft with the plurality of sensors;

sensing the position of the power lever with the position sensor;

calculating with the flight control computer whether the position of the power lever would cause the aircraft to approach the operational limits of the aircraft; and

generating the tactile cues to the power lever with the electric motor and the variable friction magnetic particle clutch if the position of the power lever would cause the aircraft to approach the operational limits of the aircraft.

19. The method according to claim 18, wherein the step of generating the tactile cues to the power lever comprises the step of:

imparting a variable drive rate of between about 0.08 inches per second and about 0.8 inches per second to the power lever.

20. The method according to claim 18, wherein the step of generating the tactile cues to the power lever comprises the step of:

imparting a variable friction force of between about zero pounds and about 3.0 pounds to the power lever.