Actuator system and method for controlling a control surface of an aircraft

Abstract

The present application discloses an actuator system for controlling a control surface of an aircraft and a method for controlling a control surface of an aircraft. The actuator system includes a control structure defining a control surface, and the control structure has a rotation axis, and the control structure can rotate relative to the aircraft around the rotation axis. A first actuator assembly has a first actuator arm, and a second actuator assembly has a second actuator arm. The first actuator assembly and the second actuator assembly are spaced apart from each other along the rotation axis. The first actuator arm is connected to a first belt member and the first belt member is connected to the control structure on a first side of the rotation axis, and the second actuator arm is connected to a second belt member and the second belt member is connected to the control structure on a second opposite side of the rotation axis.

Description

Technical Field

[0001] The present disclosure relates to a hydraulic actuator system, and more particularly, to a hydraulic actuator system that provides rotation of a control surface. Background Art

[0002] Control surfaces are used to steer an aircraft in motion. Control surfaces typically rotate about hinge joints. Rotation of control surfaces has been achieved by a variety of actuator systems, including, for example, rack and pinion actuators. Rack and pinion actuators include a meshing of a rotary gear and a linear gear. In operation, the meshing of the rotary gear and the linear gear includes impact and friction between the rotary gear and the linear gear during operation.

[0003] Impact and frictional contact between gear parts cause gear wear. Wear on gears causes the interaction between gears to be less precise. Control surfaces rely on precise movement of control surfaces and once a control surface position for the desired operation of an aircraft has been achieved, that position is maintained. Wear on gears reduces the precise meshing between gears. Therefore, frictional wear on drive systems, such as rack and pinion drive systems, requires frequent inspection, maintenance, and replacement of actuation systems, such as rack and pinion actuators, over time.

[0004] Additionally, actuator systems for thinner wing aircraft, for example, need to operate in smaller spaces. Actuator systems such as rack and pinion actuator systems require size reduction relative to rotary and linear gears in order to operate in more confined spaces within thinner wing structures. As the pinion diameter decreases, a conflict arises between close tolerance manufacturing and designing for high gear tooth loads. It would be desirable to provide an actuator system that controls the motion of a control surface and maintains its position without encountering the design and operational challenges of maintaining close tolerances and handling high gear tooth loads and operating within the confined spaces of thinner wing aircraft.

[0005] Therefore, there is a need for an actuation system that does not experience undesirable frictional wear in operation and achieves smooth precise operation and reliability in maintaining the desired position of the control surface. Since there is less frictional wear within the actuation system, the costs associated with the inspection, maintenance and replacement of the actuation system will be saved. In addition, there is a need for an actuation system that will operate within smaller space constraints, such as within thinner wing aircraft, without encountering conflicts such as reduction in pinion diameter, which conflicts with close tolerance manufacturing and design for high gear tooth loads. Summary of the invention

[0006] One example includes an actuator system for controlling a control surface of an aircraft, the actuator system including a control structure defining the control surface, wherein the control structure has an axis of rotation and the control structure is rotatable relative to the aircraft about the axis of rotation. A first actuator assembly has a first actuator arm and a second actuator assembly has a second actuator arm. The first actuator assembly and the second actuator assembly are spaced apart from each other along the axis of rotation. The first actuator arm is connected to a first strap member, and the first strap member is connected to the control structure on a first side of the axis of rotation, and the second actuator arm is connected to a second strap member, and the second strap member is connected to the control structure on a second opposite side of the axis of rotation.

[0007] One example includes a method for controlling a control surface of an aircraft, comprising applying a first force to a first actuator arm of a first actuator assembly, and applying a second force to a second actuator arm of a second actuator assembly. A control structure defines the control surface, and the control structure has an axis of rotation, and the control structure is rotatable relative to the aircraft about the axis of rotation. The first actuator arm is connected to a first strap member, and the first strap member is connected to the control structure on a first side of the axis of rotation, and the second actuator arm is connected to a second strap member, and the second strap member is connected to the control structure on a second opposite side of the axis of rotation. The first actuator assembly and the second actuator assembly are spaced apart from each other along the axis of rotation.

[0008] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view of the aircraft;

[0010] Figure 2 is along Figure 1 A perspective cross-sectional view of line 2-2;

[0011] Figure 3 It is used to control Figure 1 A schematic plan view of a first actuator assembly and a second actuator assembly of a control surface of an aircraft, wherein the first actuator assembly and the second actuator assembly are energized by an accumulator and further controlled by a four-way servo valve;

[0012] Figure 4A is along Figure 3 A cross-sectional view of line 4A-4A of the aircraft, wherein the control surface is aligned with an adjacent surface of the aircraft;

[0013] Figure 4B is along Figure 3 A cross-sectional view taken along line 4B-4B of the vehicle, wherein the control surface is aligned with an adjacent surface of the vehicle;

[0014] Figure 5A is along Figure 3 A cross-sectional view of the control surface taken along line 4A-4A of the aircraft, wherein the control surface is not aligned with the adjacent surface of the aircraft and is positioned at an angle on one side of an extension of the adjacent surface of the aircraft;

[0015] Figure 5B is along Figure 3 A cross-sectional view of line 4B-4B of the aircraft, wherein the control surface is not aligned with the adjacent surface of the aircraft and is positioned at an angle on a first side of an extension of the adjacent surface of the aircraft;

[0016] Fig. 6A is along Figure 3 A cross-sectional view of line 4A-4A of the aircraft, wherein the control surface is not aligned with the adjacent surface of the aircraft and is positioned at an angle on a second side of an extension of the adjacent surface of the aircraft;

[0017] Figure 6B is along Figure 3 a cross-sectional view taken along line 4B-4B, wherein the control surface is not aligned with the adjacent surface of the aircraft and is positioned at an angle on a second side of an extension of the adjacent surface of the aircraft; and

[0018] Figure 7 is a flow chart of a method for controlling an aircraft control surface. DETAILED DESCRIPTION

[0019] As previously mentioned, there is a need for an actuation system for controlling a control surface of an aircraft such that the actuation system does not experience undesirable frictional wear during operation, such as that found in a rack and pinion actuation system. This wear is caused by the application of forces in the meshing of the linear gear and the rotary gear during the operation of the rack and pinion, resulting in friction experienced relative to the gears. The wear applied to the rack and pinion actuator system affects the smooth and precise operation of the control surface and the maintenance of the control surface in the desired position. Since less frictional wear occurs within the actuator system, the costs of inspection, maintenance and replacement associated with the actuator system will be saved. In addition, there is a need for an actuator system that operates within smaller space constraints, such as within an aircraft with thinner wings, without encountering conflicts such as the reduction of the pinion diameter, which conflicts with the design of close tolerance manufacturing and high gear tooth loads.

[0020] refer to Figure 1 , shows an example of an aircraft 10 having various control surfaces for maneuvering the aircraft 10 in operation. The control surfaces are located on the aircraft 10 depending on the type and configuration of the aircraft 10. Some of these control surfaces include, for example, aileron control surfaces 12 on wings 14 (also on Figure 2), elevator control surfaces 16 on horizontal stabilizers 18, rudder control surfaces 20 on vertical stabilizers 22, and trim control surfaces 24 positioned on wings 14 of aircraft 10. All of these control surfaces have corresponding control structures that define the control surfaces, and each control structure is rotatable about an axis of rotation.

[0021] refer to Figures 3 to 6B , an actuator system 26 for controlling a control surface 28 of an aircraft 10 is shown. A control structure 30 defines the control surface 28, wherein the control structure 30 has a rotation axis 32 about which the control structure 30 can rotate relative to the aircraft 10. A first actuator assembly 34 has a first actuator arm 36, and a second actuator assembly 38 has a second actuator arm 40. Figure 2 and Figure 3 As shown, the first actuator assembly 34 and the second actuator assembly 38 are spaced apart from each other along the rotation axis 32. The first actuator arm 36 is connected to the first band member 42, and the first band member 42 is connected to the control structure 30 on a first side 44 of the rotation axis 32, and the second actuator arm 40 is connected to the second band member 46, and the second band member 46 is connected to the control structure 30 on a second opposite side 48 of the rotation axis 32. The first band member 42 and the second band member 46 can be constructed of a variety of materials, such as metal or carbon fiber composite materials or materials having appropriate properties.

[0022] like Figure 4A , Figure 5A and Fig. 6A As shown, the first band member 42 has a first end 50 fixed to the control structure 30 and a second end 52 fixed to the first actuator arm 36. At least a portion 54 of the first band member 42 located between the first end 50 and the second end 52 is positioned to contact the curved surface 56 of the control structure 30. The first actuator arm 36 is connected to a first cylinder member 58, and the first cylinder member 58 includes a first side wall 60 and a first end wall 62. The first side wall 60 defines a first cylinder opening 64, which is positioned within the first cylinder member 58 and extends along the first cylinder member 58. The first cylinder opening 64 contains a first piston 66, and a first sealing member 68 is positioned around the first piston 66 so that a seal is formed between the first side wall 60 and the first piston 66. The first volume 70 is located within the first cylinder member 58 and includes the boundaries of the first piston 66, the boundaries of the first end wall 62, the boundaries of the first side wall 60, and the boundaries of the first sealing member 68 within the first cylinder member 58. The first sidewall 60 of the first cylinder member 58 defines a first opening 72 that extends through the first sidewall 60 and is in fluid communication with the first volume 70 providing hydraulic fluid that can enter or exit the first volume 70 through the first opening 72 .

[0023] The first opening 72 is in fluid communication with a direct-actuated four-way servo valve 74, which provides that hydraulic fluid can pass between the first opening 72 and the direct-actuated four-way servo valve 74. The direct-actuated four-way servo valve 74 is in fluid communication with an accumulator 76 for containing pressurized hydraulic fluid, and as a result, hydraulic pressure can flow between the first volume 70 and the accumulator 76. The first piston 66 has a first connecting member 78 that engages a rotating shaft member 80, wherein the rotating shaft member 80 extends along the rotating shaft 32. The rotating shaft member 80 and the control structure 30 rotate together relative to the first connecting member 78.

[0024] like Figure 4A As shown, when the first piston 66 is positioned in the first position 82 relative to the first end wall 62 and the first band member 42 (in this example, the first end 50) is connected to the control structure 30 on the first side 44 of the rotation axis 32, the first distance D1 from the rotation axis 32, the control surface 28 is aligned with the adjacent surface 86 of the aircraft 10. In this example, the control surface 28 and the adjacent surface 86 of the aircraft 10 are aligned.

[0025] like Figure 5A 8. As shown, when the first piston 66 is positioned in the second position 88 relative to the first end wall 62, wherein, in this example, the first piston 66 is positioned closer to the first end wall 62 than when the first piston 66 is in the first position 82 described above. The first strap member 42 is positioned to be connected to the control structure 30 on the first side 44 of the rotation axis 32, a second distance D2 from the rotation axis 32, and the control surface 28 is not aligned with the adjacent surface 86 of the aircraft 10, and is angularly positioned on a side 90 of an extension 92 of the adjacent surface 86 of the aircraft 10, as shown by the angle mark "A". In this example, the control surface 28 is in an angular relationship relative to the adjacent surface 86 of the aircraft 10.

[0026] like Fig. 6A 8. As shown, when the first piston 66 is positioned in the third position 94 relative to the first end wall 62, wherein in this embodiment, the first piston 66 is positioned further away from the first end wall 62 than when the first piston 66 is in the first position 82 described above. The first strap member 42 (in this example, the first end 50) is positioned to be connected to the control structure 30 on the first side 44 of the rotation axis 32, a third distance D3 from the rotation axis 32, and the control surface 28 is not aligned with the adjacent surface 86 of the aircraft 10, and is angularly positioned on a second opposite side 96 of the extension 92 of the adjacent surface 86 of the aircraft 10, as shown by the angle mark "B". In this example, the control surface 28 is in an angular relationship relative to the adjacent surface 86 of the aircraft 10.

[0027] Regarding the second actuator assembly 38, as shown in FIG. Figure 4B , Figure 5B and Figure 6BAs shown, the second band member 46 has a first end 98 fixed to the control structure 30 and a second end 100 fixed to the second actuator arm 40. At least a portion 102 of the second band member 46 located between the first end 98 and the second end 100 is positioned to contact the curved surface 104 of the control structure 30. The second actuator arm 40 is connected to a second piston 106. The second piston 106 is positioned within a second cylinder member 108, and the second cylinder member 108 includes a second side wall 110 and a second end wall 112 of the second cylinder member 108. The second side wall 110 of the second cylinder member 108 defines a second cylinder opening 114, which is positioned within and extends along the second cylinder member 108. A second sealing member 116 is positioned around the second piston 106 so that a seal is formed between the second side wall 110 of the second cylinder member 108 and the second piston 106. The second volume 118 is located within the second cylinder member 108 , and the second volume 118 includes the boundary of the second piston 106 , the boundary of the second end wall 112 , the boundary of the second side wall 110 , and the boundary of the second sealing member 116 .

[0028] The second side wall 110 of the second cylinder member 108 defines a second opening 120 that extends through the second side wall 110 and is in fluid communication with the second volume 118 such that hydraulic fluid can enter or exit the second volume 118 through the second opening 120. Figure 3 As shown, the second opening 120 is in fluid communication with the direct-actuated four-way servo valve 74, which is in fluid communication with the accumulator 76 for containing pressurized hydraulic fluid. The second cylinder member 108 has a second connecting member 122 that engages with the rotating shaft member 80. The rotating shaft member 80 extends along the rotating shaft 32, and the rotating shaft member 80 and the control structure 30 rotate together relative to the second connecting member 122.

[0029] like Figure 4B 1, when the second piston 106 is positioned in the fourth position 124 relative to the second end wall 112, and the second band member 46 is connected to the control structure 30 on the second opposite side 48 of the rotation axis 32, the fourth distance D4 from the rotation axis 32. The control surface 28 is aligned with the adjacent surface 86 of the aircraft 10, as previously discussed with respect to the Figure 4A The structure of the first actuator assembly 34 with respect to the control structure 30 and the control surface 28 is shown in FIG.

[0030] like Figure 5BAs shown, when second piston 106 is positioned in fifth position 126 relative to second end wall 112 and second band member 46 (in this example first end 98) is connected to control structure 30 on second opposite side 96 of rotation axis 32 at a fifth distance D5 from rotation axis 32, control surface 28 is not aligned with adjacent surface 86 of aircraft 10 and control surface 28 is angularly positioned on side 90 of extension 92 of adjacent surface 86 of aircraft 10, as shown. Figure 5A Similarly illustrated, indicated by the angle marker “A” positioned on one side 90 of the extension 92 of the adjacent surface 86 of the aircraft 10 , the control surface 28 is at an angled relationship relative to the adjacent surface 86 of the aircraft 10 in this example.

[0031] like Figure 6B As shown, when the second piston 106 is positioned in the sixth position 128 relative to the second end wall 112 and the second band member 46 (in this example, the first end 98) is connected to the control structure 30 on the second opposite side 96 of the rotation axis 32, the sixth distance D6 from the rotation axis 32, the control surface 28 is not aligned with the adjacent surface 86 of the aircraft 10, as shown. Fig. 6A Similarly shown, indicated by angle label “B”, the control surface is angularly positioned on a second opposing side 96 of the extension 92 of the adjacent surface 86 of the aircraft 10 . In this example, the control surface 28 is in an angled relationship relative to the adjacent surface 86 of the aircraft 10 .

[0032] refer to Figure 7 , a method 130 for controlling a control surface 28 of an aircraft 10 includes applying a first force to a first actuator arm 36 of a first actuator assembly 34, and applying a second force to a second actuator arm 40 of a second actuator assembly 38. As will be further understood herein, the first force and the second force are of the same magnitude when maintaining the control structure 30 and the control surface 28 in a static position, and they are different when used to rotate the control structure 30 and the control surface 28 in a desired direction. The control structure 30 defines the control surface 28, and the control structure 30 has an axis of rotation 32 about which the control structure 30 rotates relative to the aircraft 10. The first actuator arm 36 is connected to a first strap member 42, and the first strap member 42 (in this example a first end 50) is connected to the control structure 30 on a first side 44 of the axis of rotation 32, and the second actuator arm 40 is connected to a second strap member 46, and the second strap member (in this example a first end 98) is connected to the control structure 30 on a second opposite side 48 of the axis of rotation 32. The first actuator assembly 34 and the second actuator assembly 38 are spaced apart from each other along the rotation axis 32 .

[0033] As previously described, the first actuator arm 36 is connected to the first cylinder member 58, which includes a first sidewall 60 and a first end wall 62, the first sidewall 60 defining a first cylinder opening 64 positioned within and extending along the first cylinder member 58. The first cylinder opening 64 contains a first piston 66, and a first sealing member 68 is positioned around the first piston 66 so that a seal is formed between the first sidewall 60 and the first piston 66. Within the first cylinder member 58, a first volume 70 includes the boundaries of the first piston 66, the boundaries of the first end wall 62, the boundaries of the first sidewall 60, and the boundaries of the first sealing member 68.

[0034] As previously described, the second actuator arm 40 is connected to the second piston 106, and the second piston 106 is positioned within the second cylinder member 108, which includes a second side wall 110 and a second end wall 112 of the second cylinder member 108. The second side wall 110 of the second cylinder member 108 defines a second cylinder opening 114, which is positioned within and extends along the second cylinder member 108. The second sealing member 116 is positioned around the second piston 106 so that a seal is formed between the second side wall 110 of the second cylinder member 108 and the second piston 106. Within the second cylinder member 108, a second volume 118 includes the boundaries of the second piston 106, the boundaries of the second end wall 112, the boundaries of the second side wall 110, and the boundaries of the second sealing member 116.

[0035] In method 130 , control structure 30 and control surface 28 are maintained in a static position, such as Figure 4A and Figure 4B As shown, the method includes maintaining equal fluid hydraulic pressures within the first volume 70 and the second volume 118 such that a first force applied to the first actuator arm 36 by the fluid hydraulic pressure within the first volume 70 and a second force applied to the second actuator arm 40 by the fluid hydraulic pressure within the second volume 118 provide equal tensions on the first band member 42 and the second band member 46, respectively. The equal tensions applied to the first band member 42 and the second band member 46 maintain the control structure 30 and the control surface 28 in a desired static position.

[0036] like Figure 5A and Figure 5B As shown, the control structure 30 and the control surface 28 rotate about the rotation axis 32 in a first direction 136, from Figure 4A and Figure 4B to the position shown in e.g. Figure 5A and Figure 5B. Rotation of the control structure 30 and the control surface 28 in the first direction 136 is achieved by providing a first fluid hydraulic pressure in the first volume 70 to apply a first force to the first actuator arm 36 and a second fluid hydraulic pressure in the second volume 118 to apply a second force to the second actuator arm 40. In this example, the hydraulic fluid pressure circuit is positioned between the accumulator 76 and the first actuator assembly 34 and the second actuator assembly 38. Figure 3 As shown, the pressurized hydraulic fluid enters the inlet port 138 and then enters the direct-actuated four-way servo valve 74. The direct-actuated four-way servo valve 74 directs different pressurized hydraulic fluids to the first volume 70 and the second volume 118 of the first actuator assembly 34 and the second actuator assembly 38, respectively, as needed. The pressurized hydraulic fluid can return to the accumulator 76 from the first volume 70 and the second volume 118 of the first actuator assembly 34 and the second actuator assembly 38, respectively, through the direct-actuated four-way servo valve 74 and the outlet port 140.

[0037] For example, as the control structure 30 and the control surface 28 move in the first direction 136, the direct-actuated four-way servo-valve 74 pressurizes the first volume 70 and the second volume 118 as needed. In this example, the pressurized hydraulic fluid enters through the first opening 72 and applies a hydraulic pressure within the first volume 70 that is lower than the hydraulic pressure of the pressurized hydraulic fluid within the second volume 118 hydraulically communicated from the direct-actuated four-way servo-valve 74 through the second opening 120. As a result of the first force applied to the first actuator arm 36 and the second force applied to the second actuator arm 40, the tension applied to the first band member 42 is lower than the tension applied to the second band member 46.

[0038] As a result, the control structure 30 rotates in the first direction 136, as shown in FIG. Figure 5A and Figure 5B 4, wherein the second actuator arm 40 extends outwardly away from the rotation axis 32 toward the first side 44, and the first actuator arm 36 follows the second actuator arm 40 to extend toward the first side 44, while maintaining tension on the first band member 42. When the first band member 42 is wound or unwound on the curved surface 56 of the control structure 30 and the second band member 46 is wound or unwound on the curved surface 104 of the control structure 30, the operation does not cause impact or friction wear to the first band member 42 or the second band member 46. When the desired position of the control structure 30 and the control surface 28 is reached, the direct-actuated four-way servo valve 74 provides equal pressure to the first volume 70 and the second volume 118 to maintain the position of the control structure 30 and the control surface 28.

[0039] Or, if Fig. 6A and Figure 6BAs shown, the control structure 30 and the control surface 28 rotate about the rotation axis 32 in the second direction 142. For example, the direct-actuated four-way servo valve 74 pressurizes the first volume 70 and the second volume 118. In this example, the pressurized hydraulic fluid enters through the first opening 72 and applies a third fluid hydraulic pressure within the first volume 70, which is greater than the fourth fluid hydraulic pressure applied from the direct-actuated four-way servo valve 74 through the second opening 120 to the second volume 118. The third hydraulic pressure applies a first force to the first actuator arm 36, and the fourth fluid hydraulic pressure applies a second force to the second actuator arm 40, wherein the third fluid hydraulic pressure is higher than the fourth fluid hydraulic pressure, so that the tension applied to the first band member 42 is higher than the tension applied to the second band member 46.

[0040] As a result, the control structure 30 rotates in the second direction 142, such as Fig. 6A and Figure 6B 4, wherein the first actuator arm 36 is retracted away from the rotation axis 32 in the direction of the second opposite side 48 and the second actuator arm follows the first actuator arm 36 toward the second opposite side 48, while maintaining tension on the second belt member 46. When winding or unwinding the first belt member 42 on the curved surface 56 of the control structure 30 and winding or unwinding the second belt member 46 on the curved surface 104, the operation does not cause impact or friction wear to the first belt member 42 or the second belt member 46. When the desired position of the control structure 30 and the control surface 28 is reached, the direct-acting four-way servo valve 74 provides equal hydraulic pressure to the first volume 70 and the second volume 118 to maintain the position of the control structure 30 and the control surface 28.

[0041] Although various embodiments are described above, the present disclosure is not limited thereto. Modifications may be made to the disclosed embodiments, and the modifications are still within the scope of the attached technical solutions.

Claims

1. An actuator system for controlling a control surface of an aircraft, the actuator system comprising: a control structure defining the control surface, wherein the control structure has an axis of rotation about which the control structure is rotatable relative to the aircraft; a first actuator assembly having a first actuator arm; A second actuator assembly having a second actuator arm, wherein: The first actuator assembly and the second actuator assembly are spaced apart from each other along the rotational axis; and The first actuator arm is connected to a first strap member, wherein The first strap member has a first end secured to the control structure and has a second end secured to the first actuator arm; and at least a portion of the first strap member positioned between the first end and the second end is positioned in contact with a curved surface of the control structure; the first strap member being connected to the control structure on a first side of the rotational axis, The second actuator arm is connected to the second strap member, and The second strap member is connected to the control structure on a second opposite side of the rotational axis.

2. The actuator system according to claim 1, wherein: The first actuator arm is connected to a first cylinder member including a first side wall and a first end wall.

3. The actuator system of claim 2, wherein: the first sidewall defining a first cylinder opening positioned within and extending along the first cylinder member; The first cylinder opening includes a first piston, a first sealing member positioned around the first piston such that a seal is formed between the first sidewall and the first piston; and Within the first cylinder member, a first volume includes a boundary of the first piston, a boundary of the first end wall, a boundary of the first side wall, and a boundary of the first sealing member.

4. The actuator system of claim 3, the first sidewall of the first cylinder member defining a first opening extending through the first sidewall and in fluid communication with the first volume such that hydraulic fluid can enter or exit the first volume through the first opening.

5. The actuator system according to claim 4, wherein: The first opening is in fluid communication with a direct-actuated four-way servo valve, which is in fluid communication with an accumulator for containing pressurized hydraulic fluid.

6. The actuator system of claim 3, wherein: The first piston has a first connecting member that engages with a rotating shaft member, wherein the rotating shaft member extends along the rotating shaft; and The rotational axis member and the control structure rotate together relative to the first connection member.

7. The actuator system of claim 3, wherein: the control surface being aligned with an adjacent surface of the aircraft when the first piston is positioned in a first position relative to the first end wall and the first band member is coupled to the control structure on the first side of the rotational axis at a first distance from the rotational axis; or when the first piston is positioned in a second position relative to the first end wall and the first band member is connected to the control structure on the first side of the rotational axis at a second distance from the rotational axis, the control surface is misaligned with the adjacent surface of the vehicle and is angularly positioned on one side of an extension of the adjacent surface of the vehicle; or When the first piston is positioned in a third position relative to the first end wall and the first band member is connected to the control structure on the first side of the rotational axis at a third distance from the rotational axis, the control surface is misaligned with the adjacent surface of the aircraft and is angularly positioned on a second opposite side of the extension of the adjacent surface of the aircraft.

8. The actuator system of claim 1, wherein: the second strap member having a first end secured to the control structure and having a second end secured to the second actuator arm; and At least a portion of the second strap member positioned between the first end and the second end is positioned in contact with the curved surface of the control structure.

9. The actuator system of claim 1, wherein: The second actuator arm is connected to a second piston.

10. The actuator system of claim 9, wherein: the second piston being positioned within a second cylinder member, the second cylinder member including a second side wall and a second end wall of the second cylinder member; the second sidewall of the second cylinder member defining a second cylinder opening positioned within and extending along the second cylinder member; a second sealing member positioned around the second piston so that a seal is formed between the second side wall of the second cylinder member and the second piston; and A second volume is located within the second cylinder member, the second volume including a boundary of the second piston, a boundary of the second end wall, a boundary of the second side wall, and a boundary of the second sealing member.

11. The actuator system of claim 10, wherein: The second sidewall of the second cylinder member defines a second opening extending through the second sidewall and in fluid communication with the second volume such that hydraulic fluid can enter or exit the second volume through the second opening.

12. The actuator system of claim 11, wherein: The second port is in fluid communication with a direct-actuated four-way servo valve, which is in fluid communication with an accumulator for containing pressurized hydraulic fluid.

13. The actuator system of claim 11, wherein: The second cylinder member has a second connecting member engaged with the rotating shaft member; The rotation axis member extends along the rotation axis; and The rotational axis member and the control structure rotate together relative to the second connection member.

14. The actuator system of claim 10, wherein: the control surface is aligned with an adjacent surface of the aircraft when the second piston is positioned in a fourth position relative to the second end wall and the second band member is coupled to the control structure on a second opposite side of the rotational axis at a fourth distance from the rotational axis; or when the second piston is positioned in a fifth position relative to the second end wall and the second band member is coupled to the control structure on a second opposite side of the rotational axis at a fifth distance from the rotational axis, the control surface is not aligned with the adjacent surface of the vehicle and the control surface is angularly positioned on one side of an extension of the adjacent surface of the vehicle; or When the second piston is positioned in a sixth position relative to the second end wall and the second band member is connected to the control structure on a second opposite side of the rotational axis at a sixth distance from the rotational axis, the control surface is misaligned with the adjacent surface of the vehicle and is angularly positioned on a second opposite side of the extension of the adjacent surface of the vehicle.

15. A method for controlling a control surface of an aircraft, comprising: applying a first force to a first actuator arm of a first actuator assembly; and applying a second force to a second actuator arm of a second actuator assembly, wherein: a control structure defining the control surface, and the control structure having an axis of rotation about which the control structure is rotatable relative to the aircraft; The first actuator arm is connected to a first strap member, wherein The first strap member has a first end secured to the control structure and has a second end secured to the first actuator arm; and at least a portion of the first strap member positioned between the first end and the second end is positioned in contact with a curved surface of the control structure; the first strap member being connected to the control structure on a first side of the rotational axis, The second actuator arm is connected to a second strap member; and the second strap member is connected to the control structure on a second opposite side of the rotational axis; and The first actuator assembly and the second actuator assembly are spaced apart from each other along a rotational axis.

16. The method of claim 15, wherein: the first actuator arm being connected to a first cylinder member, the first cylinder member comprising a first sidewall and a first end wall, wherein the first sidewall defines a first cylinder opening, the first cylinder opening being positioned within and extending along the first cylinder member; The first cylinder opening includes a first piston, a first sealing member positioned around the first piston such that a seal is formed between the first sidewall and the first piston; and Within the first cylinder member, a first volume includes a boundary of the first piston, a boundary of the first end wall, a boundary of the first side wall, and a boundary of the first sealing member.

17. The method of claim 16, wherein: The second actuator arm is connected to a second piston; the second piston being positioned within a second cylinder member, the second cylinder member including a second side wall and a second end wall of the second cylinder member; the second sidewall of the second cylinder member defining a second cylinder opening positioned within and extending along the second cylinder member; a second sealing member positioned around the second piston so that a seal is formed between the second side wall of the second cylinder member and the second piston; and Within the second cylinder member, a second volume includes a boundary of the second piston, a boundary of the second end wall, a boundary of the second side wall of the second cylinder member, and a boundary of the second sealing member.

18. The method according to claim 17, wherein: Maintaining the control structure and the control surface in the static position includes maintaining equal fluid hydraulic pressures in the first volume and the second volume such that the first force applied to the first actuator arm and the second force applied to the second actuator arm provide equal tension on the first band member and the second band member, respectively.

19. The method of claim 17, wherein: the control structure and the control surface rotate about the rotation axis in a first direction, wherein a first fluid hydraulic pressure is provided in the first volume, the first fluid hydraulic pressure exerting the first force on the first actuator arm, and a second fluid hydraulic pressure is provided in the second volume, the second fluid hydraulic pressure exerting the second force on the second actuator arm, wherein the first fluid hydraulic pressure is lower than the second fluid hydraulic pressure such that a tension applied to the first band member is lower than a tension applied to the second band member; or The control structure and the control surface rotate in a second direction about the rotation axis, wherein a third fluid hydraulic pressure is provided in the first volume, the third fluid hydraulic pressure exerting the first force on the first actuator arm, and a fourth fluid hydraulic pressure is provided in the second volume, the fourth fluid hydraulic pressure exerting the second force on the second actuator arm, wherein the third fluid hydraulic pressure is higher than the fourth fluid hydraulic pressure such that a tension applied to the first band member is higher than a tension applied to the second band member.

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