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EP-4339580-B1 - SYSTEM AND METHOD FOR MEASURING THE AMOUNT OF BACKLASH IN AN ACTUATOR ASSEMBLY

EP4339580B1EP 4339580 B1EP4339580 B1EP 4339580B1EP-4339580-B1

Inventors

  • PODOLA, David
  • NOZKA, MICHAL
  • HEDL, RADEK
  • MIKAN, ALBERT

Dates

Publication Date
20260506
Application Date
20230825

Claims (13)

  1. A system for measuring an amount of backlash in an actuator assembly, comprising: a housing assembly (102) having a retract end stop (116) and an extend end stop (118) mounted therein; an actuator (104) disposed at least partially in the housing, the actuator coupled to receive a drive force and configured, in response to the drive force, to move to an actuator position between and including (i) a fully-retracted position, in which the actuator contacts the retract end stop, and (ii) a fully-extended position, in which the actuator contacts the extend end stop; a drive source (106) coupled to receive actuator commands and configured, upon receipt of the actuator commands, to supply the drive force to the actuator; an actuator position sensor (108) configured to sense an actuator position; a drive source position sensor (112) configured to sense a drive source position; and a controller (114) in operable communication with the drive source, the actuator position sensor, and the drive source position sensor, the controller configured to selectively implement a built-in test during which the controller is configured to: (i) command the drive source to move the actuator to the fully-extended position, and then command the drive source to move the actuator to a first predetermined position that is past the fully-extended position, (ii) while commanding the drive source to move the actuator to the first predetermined position, read a first actuator position from the actuator position sensor and a first drive source position from the drive source position sensor, (iii) command the drive source to move the actuator to the fully-retracted position, and then command the drive source to move the actuator to a second predetermined position that is past the fully-retracted position, (iv) while commanding the drive source to move the actuator to the second predetermined position, read a second actuator position from the actuator position sensor and a second drive source position from the drive source position sensor, (v) determine a first travel distance from the first and second actuator positions, (vi) determine a second travel distance from the first and second drive source positions, and (vii) determine the amount of backlash from the first and second travel distances by subtracting the first travel distance from the second travel distance.
  2. The system of claim 1, wherein: the first travel distance is determined by subtracting the second actuator position from the first actuator position; and the second travel distance is determined by subtracting the second drive source position from the first drive source position.
  3. The system of claim 1, wherein the drive force supplied by the drive source is a rotational drive force, and wherein the actuator comprises: an actuator shaft (202) rotationally mounted in the housing assembly, the actuator shaft adapted to receive the rotational drive force and configured, upon receipt thereof, to rotate; and an actuation member (204) mounted on the actuator shaft and is configured to translate in response to rotation of the actuator shaft.
  4. The system of claim 3, further comprising: a gear box (214) mounted in the housing assembly and disposed between the drive source and the actuator shaft, the gear box having a gear assembly (216) disposed therein that transfers the rotational drive force from the drive source to the actuator shaft.
  5. The system of claim 4, further comprising: a bearing assembly (206) mounted within the gear box and having the actuator shaft mounted thereon.
  6. The system of claim 1, wherein: the actuator comprises an electromechanical actuator; and the drive source comprises an electric motor.
  7. The system of claim 1, wherein the actuator is selected from the group consisting of a linear actuator and a rotary actuator.
  8. The system of claim 1, wherein the actuator is selected from the group consisting of an electromechanical actuator, a hydraulic actuator, and a pneumatic actuator.
  9. A method for measuring an amount of backlash in an actuator assembly, comprising the steps of: commanding (302), with a controller, a drive source to move the actuator assembly to a fully-extended position; commanding (304), with the controller, the drive source to move the actuator assembly to a first predetermined position that is past the fully-extended position; while commanding the drive source to move the actuator assembly to the first predetermined position, reading (306, 308), with the controller, a first actuator position from an actuator position sensor and a first drive source position from a drive source position sensor; commanding (312), with the controller, the drive source to move the actuator assembly to a fully-retracted position; commanding (314), with the controller, the drive source to move the actuator to a second predetermined position that is past the fully-retracted position; while commanding the drive source to move the actuator to the second predetermined position, reading (316, 318), with the controller, a second actuator position from the actuator position sensor and a second drive source position from the drive source position sensor; determining (322), with the controller, a first travel distance from the first and second actuator positions; determining (324), with the controller, a second travel distance from the first and second drive source positions; and determining (326), with the controller, the amount of backlash from the first and second travel distances by subtracting the first travel distance from the second travel distance.
  10. The method of claim 9, wherein: the first travel distance is determined by subtracting the second actuator position from the first actuator position; and the second travel distance is determined by subtracting the second drive source position from the first drive source position.
  11. The method of claim 9, wherein: the actuator comprises an electromechanical actuator; and the drive source comprises an electric motor.
  12. The method of claim 9, wherein the actuator is selected from the group consisting of a linear actuator and a rotary actuator.
  13. The method of claim 9, wherein the actuator is selected from the group consisting of an electromechanical actuator, a hydraulic actuator, and a pneumatic actuator.

Description

TECHNICAL FIELD The present disclosure generally relates to actuator assemblies, and more particularly relates to systems and methods for measuring the amount of backlash in actuator assemblies. BACKGROUND Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to move various control surfaces or components. In many applications, such as, for example, aircraft flight surface control systems and thrust reverser actuation control systems, the actuators that are used may be subject to relatively severe environmental conditions, as well as relatively high magnitude shock and vibration. However, even normal environmental and operational conditions can lead to progressive degradation of the actuators, which in turn can cause unscheduled operation interruptions. One of the most significant progressive degradations in actuators is backlash, which can, in some instances, result in sudden and unexpected failure. Unfortunately, backlash is often delimited by external loads or the actuator controller function, making it difficult to detect and monitor in-situ. Current approaches to detecting backlash have several limitations that prevent using them for regular backlash detection and monitoring. These limitations include: the necessity to remove the actuator from the aircraft (or other vehicle or system) to inspect it for presence of backlash; and/or the need for special tooling and fixtures to do the inspection. Therefore, the inspection can be effectively done only after actuator repair and overhaul or during the vehicle heavy maintenance checks. Hence, there is a need for an effective solution for regular and in-situ monitoring of actuator backlash. The present disclosure addresses at least this need. Documents cited during prosecution include WO 2016/087891 A1. BRIEF SUMMARY This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. A first aspect of the invention is defined in appended Claim 1. A second aspect of the invention is defined in appended Claim 9. Embodiments of the invention are defined in the other appended claims. Furthermore, other desirable features and characteristics of the system and method will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein: FIG. 1 depicts a simplified functional block diagram of a system for measuring an amount of backlash in an actuator assembly;FIG. 2 depicts an embodiment of an electromechanical actuator that may be used in the system of FIG. 1;FIG. 3 depicts a built-in test, in flowchart form, that may be implemented in the system of FIG. 1;FIGS. 4 and 5 depict the actuator of FIG. 2 in the fully-extended and fully-retracted positions, respectively;FIG. 6 graphically illustrates position commands and actuator positions during the built-in test of FIG. 3; andFIG. 7 graphically depicts the travel distances sensed and determined during the built-in test. DETAILED DESCRIPTION The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Thus, any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description. Referring to FIG. 1, a simplified functional block diagram of a system for measuring an amount of backlash in an actuator assembly is depicted. The system 100 includes a housing assembly 102, an actuator 104, a drive source 106, an actuator position sensor 108, a drive source position sensor 112, and a controller 114. The housing 102 includes at least a retract end stop 116 mounted therein and an extend end stop 118 mounted therein. The actuator 104 is disposed at least partially in the housing 102 and is coupled to receive a drive force from the drive source 106. The actuator 104 is configur