ACTUATOR MECHANISM FOR CONTROL SURFACE MASS BALANCE ALLEVIATION

Abstract

Installation of powered actuators in the leading edge of a control surface in order to have a better weight distribution. The systems described herein propose an actuation system with a static ground structure used to move a control surface of an aircraft. The actuation system, and the ground structure are aligned with the center of rotation of the control surface, providing the aircraft with flutter suppression. This proposal is an approach to use the actuator in a place favorable to the mass balancing and reducing or even dismissing the usage of mass balancing, saving weight and cost.

Claims

1. A control surface actuation system comprising: a) an actuator installed inside a control surface located in a leading edge of the control surface; and b) a ground structure, coupled to the actuator, aligned with a center of rotation of the control surface; c) wherein the actuator comprises an electromechanical actuator.

2. The system of claim 1, wherein the actuation system is coupled to a control surface fixation.

3. The system of claim 1, wherein the electromechanical actuator comprises a linear or rotary actuator.

4. The system of claim 1, wherein the actuator is configured to move the control surface proportionally to an amount the actuator moves.

5. Actuator installation in the leading edge of a control surface, comprising: an actuator providing for a better mass distribution of a control surface; wherein the actuator translates with control surface rotation.

6. An aircraft comprising: a control surface having a leading edge and a center of rotation; an electromechanical actuator installed inside the control surface and disposed in the leading edge of the control surface; and a ground structure, mechanically coupled to the actuator, aligned with the center of rotation of the control surface.

7. The aircraft of claim 6, wherein the actuation system is coupled to a control surface fixation.

8. The aircraft of claim 6, wherein the electromechanical actuator comprises a linear or rotary actuator.

9. The aircraft of claim 6, wherein the actuator is configured to move the control surface proportionally to an amount the actuator moves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following detailed description of exemplary non-limiting illustrative embodiments is to be read in conjunction with the drawings of which:

[0021] FIG. 1 shows an example aircraft including control surfaces.

[0022] FIG. 2 shows an example fly-by-wire control system.

[0023] FIG. 3 is a non-limiting embodiment of an example four bar control surface actuation system.

[0024] FIG. 4 illustrates the FIG. 3 mechanism arrangement after actuation.

[0025] FIG. 5 shows a rack and pinion arrangement between the actuator pinion (2) and the ground structure rack (1). This solution has its own challenges, such as the exposure of the mechanism could easily lead to a jam.

[0026] FIG. 6 shows a direct connection from the actuator (2) and the vertical empennage (1) through the rod (3). This solution eliminates the need for a ground structure overrunning inside the control surface.

[0027] FIG. 7 shows use of a linear actuator (2) directly connected on the ground structure (1).

DETAILED DESCRIPTION OF EXAMPLE NON-LIMITING EMBODIMENTS

[0028] A typical aircraft as shown in FIG. 1 includes a fly-by-wire (FBW) system as shown in FIG. 2. In such an example system 100, the flight control module processor (FCM) 102 receives inputs from cockpit control systems 112 (e.g., including the yoke or other inceptor) and other aircraft systems 106 such as sensor outputs including calibrated air speed and stored values such as load factor, and provides outputs to a fly-by-wire (FBW) system including HS-ACE (horizontal stabilizer actuator control electronics) 108. The FCM 102 executes program code instructions stored in a non-transitory memory that generate, in response to such inputs, electronic control signals that the FCM provides via HS-ACE 108 to an actuator 104 such as an electric motor and/or a hydraulic actuator. In this particular example, the cockpit control systems 112 may also provide inputs directly to HS-ACE 104. When active, the actuator 104 changes the position of controls surfaces 110 based on the control signals it receives from the FCM processor 102 via the HS-ACE 108. As the inputs change, the FCM 102 uses a control law to update the control signals which causes the actuators 104 to change the position of the flight control surfaces 110, thereby adapting the pitch of the aircraft to the changing inputs including pilot control inputs 112 and other inputs relating to the aircraft flight environment, the current state of the aircraft (including weight amount and distribution) and the like.

[0029] Aircraft control surfaces such as flaps, ailerons, elevators, rudders, trim tabs, horizontal stabilizers, etc. (see FIG. 1) demand a design that provides a high level of integrity over the flutter suppression. A balanced control surface has the advantage of being a passive solution, where the position of its center of gravity (CG) is a stable structure for flutter conditions. Moreover, this solution has much less dormant failure than a damped design. In the proposed solution, the actuator is located in the leading edge of the control surface. This configuration is favorable for mass balance of the control surface.

[0030] In one embodiment, the control actuation system of FIG. 3 is comprised of a rotary actuator (2), a surface fixation or anchor (4), and a rod (3) which connects the actuator to a tube fixed in the hinge line and grounded to a vertical empennage (1). In this arrangement, the relation from actuator rotation to surface rotation is one-to-one (i.e., each angle degree of rotation of the actuator (2) causes the control surface to rotate by one degree in the same direction), but the bars can be dimensioned as desired to provide different proportionality to achieve project requirements. In one embodiment, the actuator (2) mechanism will control only the control surface and there is no dynamic on the proposal that the mechanism will control the CG. The way we are proposing to install the actuator (2) and other associated part(s) such as linkages, is prone to bringing the CG of the control surface on the way to the leading edge of the control surface.

[0031] In one embodiment, actuator (2) may comprise one or more linear electromechanical actuators. One type of such linear electromechanical actuators typically uses one or two electric motors to drive a linear screw or a rotary arm that is capable of moving the applicable control surface and holding the required position. Such electromechanical actuators can be controlled using control currents to provide a desired degree of damping.

[0032] FIG. 4 illustrates how the load is transmitted when the actuator (2) rotates its arm which compresses the rod (3). The rod (3) transmits, through the ball bearings (5) or other pivot points, the load to the grounded structure (1) which leads to surface rotation and actuator translation.

[0033] FIG. 5 shows an example rotary actuator including a rack and pinion arrangement between the actuator pinion (2) and the ground structure rack (1). In one embodiment, the pinion is directly on the axis of rotary actuator. Rotary actuators are not limited to the 90° pivot arc typical of cylinders; they can achieve arc lengths of 180°, 360°, or even 720° or more, depending on the configuration. This solution has its own challenges (for example, such a mechanism could easily lead to a jam) but it may be successful in some implementations.

[0034] FIG. 6 shows a direct connection from the actuator (2) and the vertical empennage (1) through the rod (3). This solution eliminates the need for a ground structure overrunning inside the control surface.

[0035] FIG. 7 shows a use of a linear actuator (2) directly connected on the ground structure (1).

Acronyms and Abbreviations

[0036] CG Center of Gravity [0037] EHSV Electro-Hydraulic Servo Valve [0038] EMF Electromotive Force [0039] FBW Fly-By-Wire [0040] MSV Mode Select Valve