阅读说明：本技术 双独立混合致动器系统 (Dual independent hybrid actuator system ) 是由 戴维·E·布兰丁 杰弗里·C·科夫曼 吉米·M·基安鲍 于 2021-03-19 设计创作，主要内容包括：一种双独立混合致动器系统,包括限定液压室的致动器主体。致动器系统包括液压活塞组件,该液压活塞组件包括液压活塞,该液压活塞设置在液压室内并将液压室分成与第一液压流体通道流体连通的第一子液压室和与第二液压流体通道流体连通的第二子液压室。致动器系统还包括安装到液压活塞的活塞杆,该活塞杆穿过第二子液压室,其中远端从致动器主体向外伸出。致动器系统还包括安装到致动器主体的电机、以及机械地联接到电机的电机轴的螺纹轴。螺纹轴穿过第一子液压室并与形成在液压活塞组件中的螺纹端口接合。(A dual independent hybrid actuator system includes an actuator body defining a hydraulic chamber. The actuator system includes a hydraulic piston assembly including a hydraulic piston disposed within the hydraulic chamber and dividing the hydraulic chamber into a first sub-hydraulic chamber in fluid communication with the first hydraulic fluid passage and a second sub-hydraulic chamber in fluid communication with the second hydraulic fluid passage. The actuator system further includes a piston rod mounted to the hydraulic piston, the piston rod passing through the second sub-hydraulic chamber with the distal end extending outwardly from the actuator body. The actuator system also includes a motor mounted to the actuator body, and a threaded shaft mechanically coupled to a motor shaft of the motor. The threaded shaft passes through the first sub-hydraulic chamber and engages a threaded port formed in the hydraulic piston assembly.)

1. A dual independent hybrid actuator system, wherein the dual independent hybrid actuator system comprises:

an actuator body defining a hydraulic chamber within an interior of the actuator body, the actuator body further defining a first hydraulic fluid passage and a second hydraulic fluid passage in fluid communication with the hydraulic chamber;

a hydraulic piston assembly, said hydraulic piston assembly comprising:

a hydraulic piston disposed within the hydraulic chamber and dividing the hydraulic chamber into a first sub-hydraulic chamber in fluid communication with the first hydraulic fluid passage and a second sub-hydraulic chamber in fluid communication with the second hydraulic fluid passage, an

A piston rod mounted to the hydraulic piston and passing through the second sub-hydraulic chamber,

the piston rod has a distal end projecting outwardly from the actuator body;

a motor mounted to the actuator body, the motor having a motor shaft; and

a threaded shaft mechanically coupled to the motor shaft of the motor, the threaded shaft passing through the first sub-hydraulic chamber and engaging a threaded port formed in the hydraulic piston assembly.

2. The dual independent hybrid actuator system of claim 1, wherein rotation of the motor shaft of the motor in a first rotational direction urges the hydraulic piston to move within the hydraulic chamber in a first translational direction such that the distal end of the piston rod extends outwardly from the actuator body; and is

Wherein rotation of the motor shaft of the motor in a second rotational direction opposite the first rotational direction urges the hydraulic piston to move within the hydraulic chamber in a second translational direction opposite the first translational direction to retract the piston rod inwardly toward the actuator body.

3. A dual independent hybrid actuator system according to claim 2, wherein a first pressure differential between the first sub hydraulic chamber and the second sub hydraulic chamber urges the hydraulic piston to move in the first translational direction, wherein the first sub hydraulic chamber has a higher hydraulic pressure than the second sub hydraulic chamber; and is

Wherein a second pressure difference between the first sub-hydraulic chamber and the second sub-hydraulic chamber, which has a higher hydraulic pressure than the first sub-hydraulic chamber, urges the hydraulic piston to move in the second translational direction opposite to the first translational direction.

4. The dual independent hybrid actuator system of claim 3, further comprising:

a hydraulic system in communication with the first and second hydraulic fluid passages of the actuator body; and

a control system configured to coordinate operation of the electric machine and an electro-hydraulic servo valve of the hydraulic system to:

increasing the hydraulic pressure in the first sub-hydraulic chamber relative to the second sub-hydraulic chamber to achieve the first pressure differential while operating the motor to rotate in the first rotational direction; and

increasing the hydraulic pressure in the second sub-hydraulic chamber relative to the first sub-hydraulic chamber to achieve the second pressure differential while operating the motor to rotate in the second rotational direction.

5. A dual independent hybrid actuator system according to claim 1, wherein the threaded shaft is coaxial with the piston rod or with a translation axis of the piston rod.

6. The dual independent hybrid actuator system of claim 5, wherein the motor shaft is coaxial with the piston rod or with a translation axis of the piston rod.

7. The dual independent hybrid actuator system of claim 1, wherein the hydraulic piston assembly further comprises a ball screw nut defining the threaded port; and is

Wherein the threaded shaft forms a ball screw shaft.

8. The dual independent hybrid actuator system of claim 1, wherein the hydraulic piston assembly defines an internal chamber within the body of the hydraulic piston and/or the piston rod, the internal chamber housing a portion of the threaded shaft protruding through the threaded port;

wherein the body of the hydraulic piston and/or piston rod defines a fluid passage between the internal chamber and the first sub-hydraulic chamber, the fluid passage being independent of the threaded port; and is

Wherein the hydraulic piston assembly further includes an inline check valve positioned along the fluid passageway that provides a greater resistance to hydraulic fluid flow through the inline check valve toward the internal chamber than hydraulic fluid flow through the inline check valve from the internal chamber.

9. The dual independent hybrid actuator system of claim 1, further comprising a drive train;

wherein the threaded shaft is mechanically coupled to the motor shaft of the motor via the drive train; and is

Wherein the drive train provides a non-coordinated effective gear ratio between the motor shaft and the threaded shaft.

10. The dual independent hybrid actuator system of claim 9, wherein the non-coordinated effective gear ratio provides a reduced rate of rotation of the threaded shaft relative to a rate of rotation of the motor shaft.

11. The dual independent hybrid actuator system of claim 9, wherein the drive train comprises a planetary gear system.

12. The dual independent hybrid actuator system of claim 1, wherein the actuator body and the piston rod in combination form a linkage comprising:

a first bearing attachment point at the distal end of the piston rod, an

A second bearing attachment point at a distal end of the actuator body opposite the first bearing attachment point.

13. A method of controlling a dual independent hybrid actuator system, wherein the method comprises:

controlling operation of an electro-hydraulic servo valve of a hydraulic system to create a first hydraulic pressure differential between opposing sides of a hydraulic piston that urges a piston rod mounted to the hydraulic piston to move in a first translational direction;

controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft during movement of the piston rod in the first translational direction,

wherein controlling operation of the motor comprises providing power to the motor to rotate the motor shaft in a first rotational direction such that:

urging the piston rod to move in the first translational direction in coordination with the force exerted by the first hydraulic pressure difference, or

Reducing a resistance of the motor to movement of the piston rod in the first translational direction.

14. The method of claim 13, further comprising:

in response to the hydraulic system being unable to generate the first hydraulic pressure difference between the opposing sides of the hydraulic piston, increasing the power provided to the motor to rotate the motor shaft in the first rotational direction, which urges the piston rod to move in the first translational direction to a target position.

15. The method of claim 13, further comprising:

controlling operation of the electro-hydraulic servo valve of the hydraulic system to create a second hydraulic pressure differential between opposite sides of the hydraulic piston that urges the piston rod to move in a second translational direction opposite the first translational direction;

controlling operation of the motor by providing power to the motor to rotate the motor shaft in a second rotational direction opposite the first rotational direction during movement of the piston rod in the second translational direction: such that:

pushing the piston rod to move in the second translational direction in coordination with the force exerted by the second hydraulic pressure difference, or

Reducing a resistance of the motor to movement of the piston rod in the second translational direction.

16. The method of claim 15, further comprising:

in response to the hydraulic system being unable to generate the second hydraulic pressure differential between the opposing sides of the hydraulic piston, increasing power provided to the motor to rotate the motor shaft in the second rotational direction, which urges the piston rod to move in the second translational direction to a target position.

17. The method of claim 13, wherein controlling operation of the motor includes providing power to the motor to rotate the motor shaft in a first rotational direction that eliminates resistance of the motor to movement of the piston rod in the first translational direction.

18. A method of controlling a dual independent hybrid actuator system, wherein the method comprises:

during a first control operation, controlling operation of an electro-hydraulic servo valve of a hydraulic system to generate a first hydraulic pressure difference between opposite sides of a hydraulic piston, the first hydraulic pressure difference urging a piston rod mounted to the hydraulic piston to move in a first translational direction; and

during a second control operation, controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft to rotate the motor shaft in a first rotational direction, which urges the piston rod to move in the first translational direction.

19. The method of claim 18, wherein the second control operation is performed in response to the hydraulic system failing to produce the first hydraulic pressure difference between opposite sides of the hydraulic piston during the first control operation.

20. The method of claim 18, wherein the second control operation is performed simultaneously with the first control operation.

Technical Field

The disclosed invention generally relates to an actuator that is independently operable by a hydraulic system and an electric motor.

Background

Aircraft utilize flight control surfaces, such as flaps and rudders, manipulated by actuators to change the orientation and/or position of the flight control surfaces relative to the fuselage. Hydraulic actuators commonly used in commercial aircraft are controlled by electro-hydraulic servo valves of a hydraulic system in communication with the hydraulic actuators. Other types of mechanical systems besides aircraft also utilize hydraulic actuators to manipulate mechanical components. In some cases, a backup system may be used in conjunction with the hydraulic actuator to enable flight control surfaces or other mechanical components to be manipulated by the backup system in the event that the hydraulic system is unable to provide sufficient control.

Disclosure of Invention

According to one example of the present disclosure, a dual independent hybrid actuator system includes an actuator body defining a hydraulic chamber within an interior of the actuator body. The actuator body also defines a first hydraulic fluid passage and a second hydraulic fluid passage in fluid communication with the hydraulic chamber. The actuator system includes a hydraulic piston assembly including a hydraulic piston disposed within the hydraulic chamber and dividing the hydraulic chamber into a first sub-hydraulic chamber in fluid communication with the first hydraulic fluid passage and a second sub-hydraulic chamber in fluid communication with the second hydraulic fluid passage. The actuator system further includes a piston rod mounted to the hydraulic piston, the piston rod passing through the second sub-hydraulic chamber with the distal end extending outwardly from the actuator body. The actuator system also includes a motor mounted to the actuator body, and a threaded shaft mechanically coupled to a motor shaft of the motor. The threaded shaft passes through the first sub-hydraulic chamber and engages a threaded port formed in the hydraulic piston assembly.

According to another example of the present disclosure, a method of controlling a dual independent hybrid actuator system includes controlling operation of an electro-hydraulic servo valve of a hydraulic system to create a first hydraulic pressure differential between opposing sides of a hydraulic piston that urges a piston rod mounted to the hydraulic piston to move in a first translational direction. The method also includes controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft during movement of the piston rod in the first translational direction. Controlling operation of the motor includes providing power to the motor to rotate the motor shaft in a first rotational direction, which urges the piston rod to move in a first translational direction in coordination with a force applied by the first hydraulic pressure differential, or reducing resistance of the motor to movement of the piston rod in the first translational direction.

According to another example of the present disclosure, a method of controlling a dual independent hybrid actuator system includes, during a first control operation, controlling operation of an electro-hydraulic servo valve of a hydraulic system to create a first hydraulic pressure difference between opposite sides of a hydraulic piston, which urges a piston rod mounted to the hydraulic piston to move in a first translational direction; and during a second control operation, controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft to rotate the motor shaft in a first rotational direction, which urges the piston rod to move in a first translational direction.

The features and techniques discussed in this summary may be provided independently in various examples or may be combined in yet other examples, further details of which are described with reference to the following description and drawings.

Drawings

Fig. 1 illustrates an example of a dual independent hybrid actuator system according to the present disclosure.

Fig. 2A and 2B illustrate an example electric brake that may be used with the actuator system of fig. 1.

FIG. 3A illustrates a detailed view of the actuator system of FIG. 1, including an example interface between a threaded shaft and a threaded port.

FIG. 3B illustrates a detailed view of the actuator system of FIG. 1, including an example in-line check valve.

FIG. 4 is a flow chart illustrating an example method for controlling a dual independent hybrid actuator system including the actuator system of FIG. 1.

FIG. 5 schematically illustrates an example control architecture for a dual independent hybrid actuator system including the actuator system of FIG. 1.

FIG. 6 illustrates an example planetary gear system that may be included in the drive train of the actuator system of FIG. 1.

FIG. 7 illustrates an example computing system in which the method of FIG. 4 may be implemented in conjunction with the control architecture of FIG. 5 for a dual independent hybrid actuator system including the actuator system of FIG. 1.

Detailed Description

Disclosed herein are dual independent hybrid actuator systems and methods of operating the same that enable mechanical components, such as flight control surfaces, to be independently controlled by hydraulic pressure provided by a hydraulic system and mechanical force provided by an electric motor. In a disclosed example, an actuator system incorporates an electric motor into an actuator body and mechanically couples the electric motor to a hydraulic piston assembly via a threaded shaft. The hydraulic piston assemblies may be independently operated by an electric motor via a threaded shaft and/or by a hydraulic system that provides a hydraulic pressure differential to opposite sides of the hydraulic piston. In one example, an electro-hydraulic servo valve of a hydraulic system, also known as an electro-hydraulic servo actuator (EHSA), may be used for primary control of actuator position, and an electric motor mechanically coupled to a hydraulic piston assembly may be used for alternative or additional control of actuator position.

Fig. 1 shows an example of a dual independent hybrid actuator system 100. The actuator system 100 includes an actuator body 110 that defines a hydraulic chamber 112 within an interior of the actuator body. In fig. 1, aspects of an actuator system 100 are shown in cross-section to illustrate internal components contained within an actuator body 100. The actuator body 110 also defines a first hydraulic fluid passage 114 and a second hydraulic fluid passage 116 in fluid communication with different areas of the hydraulic chamber 112.

The actuator system 100 also includes a hydraulic piston assembly 118 that includes a hydraulic piston 120 disposed within the hydraulic chamber 112. The hydraulic piston 120 divides the hydraulic chamber 112 into a first sub-hydraulic chamber 112A that is in fluid communication with the first hydraulic fluid passage 114 and a second sub-hydraulic chamber 112B that is in fluid communication with the second hydraulic fluid passage 116. The hydraulic piston 120 may include one or more seals and/or bearings, schematically indicated at 121 and 123, that engage the inner surface of the hydraulic chamber 112 to seal the first sub-hydraulic chamber 112A from the second sub-hydraulic chamber 112B and/or reduce friction against movement of the hydraulic piston relative to the actuator body.

Hydraulic piston assembly 118 also includes a piston rod 122 mounted to hydraulic piston 120. The piston rod 122 passes through the second sub-hydraulic chamber 112B through an opening 111 formed in the actuator body 110, and has a distal end 124 that projects outwardly from the actuator body. The actuator body 110 may include one or more seals and/or bearings, schematically indicated at 113, connected with the piston rod 122 to seal the second sub-hydraulic chamber 112B and/or reduce friction against movement of the piston rod.

Actuator body 110 in combination with piston rod 122 forms a linkage 126 that includes a first bearing attachment point 128 at distal end 124 of piston rod 122, and a second bearing attachment point 130 at another distal end 132 of the actuator body opposite first bearing attachment point 128. As used herein, the term "actuator position" may refer to the length of the link 126 formed between the first bearing attachment point 128 of the piston rod 122 and the second bearing attachment point 130 of the actuator body. In one example, the first bearing attachment point 128 may be mechanically coupled to a controlled mechanical component 127 (e.g., a flight control surface) schematically illustrated in fig. 1, the controlled mechanical component 127 may include or be associated with a positioning sensor 129 by which the electronic control system 170 may measure and determine the position and/or orientation of the mechanical component 127, such that the electronic control system can move the hydraulic piston assembly 118 to achieve a target position and/or orientation of the mechanical component 127.

The actuator system 100 includes a hydraulic system 134 in communication with the first and second hydraulic fluid passages 114, 116 of the actuator body 110. The hydraulic system 134 is schematically illustrated in fig. 1 as including one or more hydraulic pumps 136 and one or more electro-hydraulic servo valves 138. The one or more hydraulic pumps 136 are selectively operable by the electronic control system 170 to generate hydraulic pressure within the hydraulic system 134, and the one or more servo valves 138 are selectively operable by the electronic control system to each independently control the supply of hydraulic fluid to the first sub-hydraulic chamber 112A via the first hydraulic fluid passage 114 and to the second sub-hydraulic chamber 112B via the second hydraulic fluid passage 116 to generate a target pressure differential between the first and second sub-hydraulic chambers. However, in at least some examples, one or more bi-directional hydraulic pumps (e.g., of pump 136) or hydraulic motors of the hydraulic system 134 may be used to control the hydraulic pressure differential between the first and second sub-hydraulic chambers 112A, 112B.

According to an example operation of the actuator system 100, a first pressure differential may be created between the first and second sub-hydraulic chambers 112A, 112B, wherein the first sub-hydraulic chamber has a higher hydraulic pressure than the second sub-hydraulic chamber to urge the hydraulic piston 120 and the piston rod 122 of the hydraulic piston assembly 118 to move in the first translational direction 102 (i.e., the extension direction) along the translational axis 125, thereby increasing the length of the connecting rod 126 between the bearing attachment points 128 and 130. A second pressure differential between the first and second sub-hydraulic chambers 112A, 112B may be generated by the hydraulic system 134, wherein the second sub-hydraulic chamber has a higher hydraulic pressure than the first sub-hydraulic chamber to urge the hydraulic piston 120 and the piston rod 122 of the hydraulic piston assembly 118 to move along the translation axis 125 in a second translation direction 104 (i.e., a retraction direction) opposite the first translation direction 102, thereby reducing the length of the connecting rod 126 between the attachment points 128 and 130.

The actuator system 100 also includes a motor 140 mounted to the actuator body 110. In the example shown in fig. 1, the motor 140 is housed in a separate sub-chamber of the actuator body 110 that is partially defined by the cover 110A. The motor 140 includes a motor shaft 142 that rotates about an axis (e.g., 125) when power is applied by the electronic control system 170. According to one embodiment, the motor 140 may take the form of a direct current motor or an alternating current motor. The electronic control system 170 can selectively vary the power and/or phase supplied to the motor 140 to control the direction of rotation and rate of rotation of the motor shaft 142.

The motor shaft 142 may be mounted on one or more axial bearings, examples of which are schematically indicated at 145A and 145B. The axial bearing may be disposed at other suitable amounts and/or positions relative to the motor shaft 142. The axial bearings 145A and 145B may take the form of thrust bearings that support the load of the motor shaft in an axial or transverse direction (e.g., along the axis 125).

The actuator system 100 also includes a threaded shaft 150 mechanically coupled to the motor shaft 142 of the motor 140. In the example shown in fig. 1, a threaded shaft 150 passes through the first sub-hydraulic chamber 112A and engages a threaded port 152 formed in the hydraulic piston assembly 118. As one example, the hydraulic piston assembly 118 includes a ball screw nut (shown at 310 in fig. 3A) that defines the threaded port 152, and the threaded shaft 150 forms a ball screw shaft (shown at 312 in fig. 3A).

In at least some examples, the hydraulic piston assembly 118 defines an internal chamber 154 within the hydraulic piston 120 and/or the piston rod 122 that receives a portion of the threaded shaft 150 that protrudes through the threaded port 152. In the example shown in fig. 1, the threaded shaft 150 is coaxial with the piston rod 122 and the piston rod's translation axis 125. However, in other examples, the threaded shaft 150 may be parallel to, but not coaxial with, either the piston rod 122 or the translation axis 125. Also in the example shown in fig. 1, the motor shaft 142 is coaxial with the piston rod 122 and the piston rod's translation axis 125. However, in other examples, the motor shaft 142 may be oriented at an angle relative to the piston rod 112 and the translation axis 125, or the motor shaft 142 may be parallel to, but not coaxial with, either the piston rod 122 or the translation axis 125. For example, the motor shaft 142 may be mechanically coupled to the threaded shaft 150 via a drive train that enables the motor shaft 142 to be offset and/or angled relative to the threaded shaft 150.

The actuator system 100 may include a drive train 160 through which the threaded shaft 150 is mechanically coupled to the motor shaft 142 of the motor 140. In at least some examples, the drive train 160 provides a non-coordinated (e.g., greater than or less than 1:1) effective gear ratio between the motor shaft 142 and the threaded shaft 150. As one example, the non-coordinated effective gear ratio of the drive train 160 provides a reduced rate of rotation of the threaded shaft 150 relative to the rate of rotation of the motor shaft 142, thereby providing a mechanical advantage to the motor 140 that increases the motor torque provided to the threaded shaft 150 and the piston assembly 118. In the example shown in fig. 6, the drive train 160 includes a planetary gear system. However, other suitable drive trains may be used. Fig. 1 also shows a drive train 160 that includes an output shaft 162 and an axial bearing 164 by which the threaded shaft 150 is mounted or otherwise mechanically coupled to the threaded shaft 150. The axial bearing 164 may take the form of a thrust bearing that supports the load of the output shaft 162 in an axial or transverse direction (e.g., along the axis 125).

In at least some examples, the motor 140 can take the form of a stepper motor that enables the electronic control system 170 to measure and determine the rotational position and rate of rotation of the motor shaft 142. Additionally or alternatively, one or more position sensors 148A, 148B, etc. may be included that enable the electronic control system 170 to measure and determine the rotational position and rate of rotation of the motor shaft 142. The position sensor may include a resolver mounted on the motor shaft 142, the output shaft 162, and/or the threaded shaft 150 to measure rotation of the motor shaft 142 and/or the threaded shaft 150. As one example, the position sensor may also include an encoder and a hall effect sensor to determine the rotational position of the shaft. In at least some examples, a position sensor may be used to detect backlash between the threaded shaft 150 and the hydraulic piston 120. The position sensor may be disposed in other suitable amounts and/or positions relative to the motor shaft 142, the output shaft 162, and/or the threaded shaft 150. In at least some examples, the actuator position may be determined by the electronic control system 170 from sensor data received from the position sensors 148A and 148B, or by the motor 140 in the case of a stepper motor that reports its rotational position.

According to an example operation of the actuator system 100, rotation of the motor shaft 142 of the motor 140 in a first rotational direction (e.g., 144 or 146) urges the hydraulic piston 120 and the piston rod 122 of the hydraulic piston assembly 118 to move in the first translational direction 102 such that the distal end 124 of the piston rod 122 extends outwardly from the actuator body 110, thereby increasing the length of the connecting rod 126 between the attachment points 128 and 130. Rotation of the motor shaft 142 of the motor 140 in a second rotational direction opposite the first rotational direction forces the hydraulic piston 120 and the piston rod 122 of the hydraulic piston assembly 118 to move in a second translational direction 104 opposite the first translational direction 102 to retract the distal end 124 of the piston rod 122 inwardly toward the actuator body 110, thereby reducing the length of the connecting rod 126 between the attachment points 128 and 130.

The control system 170 may coordinate operation of the electric machine 140 and operation of one or more electro-hydraulic servo valves 138 of the hydraulic system 134 during at least some operating conditions. For example, the control system 170 may increase the hydraulic pressure in the first sub-hydraulic chamber 112A relative to the second sub-hydraulic chamber 112B to achieve a first pressure differential that urges the piston rod 122 in the first translational direction 102 while operating the motor 140 to rotate in a first rotational direction, thereby increasing the length of the linkage 126 between the attachment points 128 and 130 through coordinated operation of both the hydraulic system 134 and the motor 140. During other operating conditions, the electronic control system 170 may increase the hydraulic pressure in the second sub-hydraulic chamber 112B relative to the first sub-hydraulic chamber 112A to achieve a second pressure differential while operating the motor 140 to rotate in a second rotational direction opposite the first rotational direction, thereby reducing the length of the connecting rod 126 between the attachment points 128 and 130 through coordinated operation of both the hydraulic system 134 and the motor 140. Additional examples of coordinated operation between the hydraulic system 134 and the electric machine 140 will be described in further detail with reference to fig. 4 and 5.

The possibility of back-driving the motor 140 and drive train 160 may exist under conditions of hydraulic and/or control losses to the hydraulic system 134. Under these conditions, the motor 140 in combination with the threaded shaft 150 may be used as the primary control mode for the hydraulic piston assembly 118. However, if the force (e.g., aerodynamic load) applied to the controlled mechanical component 127 is greater than the static force resisting movement of the hydraulic piston assembly 118, then back-driving of the motor 140 may occur. In at least some examples, the motor 140, the drive train 160, and/or the threaded shaft 150 can be used with one or more electric brakes 149A, 149B, etc. that can be electrically actuated by an electronic control system 170. Electric brakes 149A and 149B are selectively engageable by electronic control system 170 to prevent or inhibit movement of hydraulic piston assembly 118 due to back-driving of the controlled mechanical components. The electric brake may be disposed in other suitable amounts and/or positions relative to the motor shaft 142, the output shaft 162, and/or the threaded shaft 150.

Fig. 2A and 2B illustrate an example electric brake 200 that may be used with the actuator system 100 of fig. 1, such as for the electric brakes 149A and 149B. The electric brake 200 includes a housing 210 mountable to the actuator body 110 of the actuator system 100; a coil 212 to which electric power is applied; a drive cup 214 mounted to a shaft to provide a brake to the shaft, such as the motor shaft 142; a support plate 216; an armature 218; an end plate 220; a set of friction disks 222 mounted between armature 218 and end plate 220; and a spring 224 mounted between the armature 218 and the support plate 216. In one example, electric brake 200 is an electric release brake that is engaged when coil 212 is not energized. When the coil 212 is not supplied with electrical energy, the spring 224 exerts a force on the set of friction disks 222 as shown in FIG. 2B, thereby applying a braking force to the rotation of the shaft and resisting torque in the shaft. In at least some examples, the brake does not disengage until power is supplied to the coil. In this case, the coil generates a magnetic field which acts to pull the armature plate towards or against the spring, overcoming the spring force and allowing the friction discs to separate from one another. Allowing the disk to rotate freely without transmitting or holding torque. Fig. 2A shows an example of supplying electrical energy to the coil 222, which pulls the armature 218 (e.g., containing a magnet or magnetically attractive material, such as metal) toward the support plate 216 and removes the braking force applied to the shaft. It should be understood that electric brake 200 is one example of an electric brake that may be used with actuator system 100, and that other electric brakes may be used, including an electric brake that applies a braking force to a shaft when electrical energy is applied to the brake.

Fig. 3A illustrates a detailed view of the actuator system 100 of fig. 1, including an example interface between the threaded shaft 150 and the threaded port 152. In one example, the threaded port 152 is formed by a ball screw nut 310 and the threaded shaft 150 forms a ball screw shaft 312. In this example, the ball screw nut 310 defines an externally threaded race 314, and the ball screw shaft 312 defines an internally threaded race 316. The threaded races 314 and 316 collectively contain a ball bearing 318 that reduces rotational friction and supports radial and axial loads between the ball screw nut 310 and the ball screw shaft 312.

Further, in the example shown in fig. 3A, the hydraulic piston assembly 118 defines a fluid passageway 320 between the internal chamber 154 and the first sub-hydraulic chamber 112A that is independent of the opening 322 of the threaded port 152 through which the threaded shaft 150 passes. The fluid passage 320 forms an exhaust port that allows hydraulic fluid that leaks past the ball bearing 318 to be exhausted into the internal chamber 154. If hydraulic fluid cannot be drained from the internal chamber 154, damage to the piston rod 122 and/or the hydraulic piston assembly 118 may occur. Accordingly, the fluid passage 320 may reduce or prevent damage caused by the accumulation of hydraulic fluid in the internal chamber 154.

In fig. 3A, a fluid passage 320 is formed in the ball screw nut 310; however, fluid passages may alternatively or additionally be formed in the body of hydraulic piston 120 and/or piston rod 122. The hydraulic piston assembly 118 also includes a one-way inline check valve 324 positioned along the fluid passageway 320 that provides greater resistance to hydraulic fluid flowing along the fluid passageway through the inline check valve toward the internal chamber 154 than hydraulic fluid flowing through the inline check valve from the internal chamber toward the first sub-hydraulic chamber 112A. Thus, when the threaded shaft 150 is rotated in a direction that increases its protrusion into the internal chamber 154, hydraulic fluid may be drained from the internal chamber 154 and flow back into the first sub-hydraulic chamber 112A via the fluid passage 320 and the check valve 324.

Fig. 3B shows a detailed view of the actuator system 100, including an example check valve 324 located between the internal chamber 154 and the first sub-hydraulic chamber 112A along the fluid passageway 320 of the hydraulic piston assembly 118. In this example, the check valve 324 includes a poppet 330 that is urged against a valve seat 332 by a spring element 334 disposed between the poppet and a mounting bracket 336 or other feature of the valve. Hydraulic fluid within the internal chamber 154 having sufficient pressure may overcome the spring force provided by the spring element 334, which causes the valve spool 330 to displace from the valve seat 332, thereby enabling hydraulic fluid to flow through the valve via the fluid passage 320 into the first sub-hydraulic chamber 112A. It should be understood that other suitable types or configurations of one-way in-line check valves may be used for check valve 324.

FIG. 4 is a flow chart illustrating an example method 400 for controlling a dual independent hybrid actuator system including the actuator system 100 of FIG. 1. As one example, the method 400 may be performed by the electronic control system 170 of fig. 1.

In at least some examples, method 400 can include, at 410, calibrating an actuator system. As one example of calibration, piston rod 122 may be extended and retracted over an operating range of motion thereof, and sensor measurements may be captured and recorded over the operating range of motion by the electronic control system. For example, in case the motor 140 forms a stepper motor, the rotational positioning data obtained over the operational range of motion of the piston rod may be mapped by the electronic control system, thereby enabling the electronic control system to later refer to the mapped data to identify the current position of the piston rod (i.e. the actuator position) at a given point in time. As another example, the position sensors 148A and 148B of fig. 1 enable the electronic control system to measure and determine an amount of rotation of the motor shaft 142 that can be mapped to an operating range of motion of the piston rod. Again, this initial calibration enables the electronic control system to later reference the mapping data to identify the current position of the piston rod (i.e., the actuator position) at a given point in time by observing the amount of rotation of the motor shaft 142 in either direction. At 410, calibration may be performed over the operating range of the piston rod relative to other sensors, including sensor 129 which measures the position and/or orientation of the controlled mechanical component. The positioning data captured by the electronic control system from sensor 129 may be mapped to data captured by other sensors, including position sensors 148A and 148B, as well as stepper motor positioning data.

At 412, the method includes receiving input data, which may include input from sensors (e.g., 129, 148A, 148B, rotational position from motor 140 in the case of a stepper motor, etc.), a position reference (position reference) representing control input for a mechanical component (e.g., flight control surface) to be controlled by the actuator system, and an indication of the selected operating mode (e.g., from an operator or computing system).

At 414, the method includes identifying a target change in the state of the actuator system based on the input data received at 412. As one example, the target change in state of the actuator system includes a target amplitude (e.g., distance) and a target translation direction (e.g., extension or retraction) that represents a difference between the current actuator position and a target actuator position identified based on the input data received at 412. Identifying a target change in the state of the actuator system may be further based on the calibration data obtained at 410.

At 416, the method includes identifying an operating mode of the dual independent hybrid actuator system based on the input data received at 412. As one example, the input data received at 412 may include a command identifying an operating mode selected by an operator or by a computing system (e.g., an onboard flight control computing system). As another example, the input data received at 412 may include data indicative of a fault condition, an error condition, or a normal operating condition (no fault operation).

In at least some examples, the dual independent hybrid actuator system may operate in a selected one of a plurality of operating modes, including an active/active (a/a) mode, an active/no-load (a/NL) mode, an active/passive (a/P) mode, or a passive/active (P/a) mode, each of which is represented by an activity of hydraulic system activity compared to an activity of the electric machine (i.e., hydraulic system activity/electric machine activity).

In the active/active mode, the hydraulic system and the electric motor are actively controlled to generate a combined force on the hydraulic piston assembly by hydraulic force applied by the hydraulic system and mechanical force applied by the electric motor. The active/active mode may be selected to balance the force contribution between the hydraulic system and the electric machine. For example, the hydraulic pressure difference that needs to be generated on the hydraulic piston to exert a given total force can be reduced due to the mechanical force contribution of the electric motor. The active/active mode may be used in situations where the hydraulic system is unable to generate sufficient hydraulic pressure or where operation at a lower hydraulic pressure differential is desired. The active/active mode may provide higher dynamics than the active/passive mode.

In the active/idle mode, the hydraulic system and the motor are actively controlled, but the hydraulic piston assembly is operated by hydraulic pressure applied by the hydraulic system, while the motor is operated to reduce, minimize or eliminate mechanical forces, including friction and drag, applied to the hydraulic piston assembly by the motor (and its drive train). The active/idle mode may be used with the electric machine serving as a backup to the hydraulic system, while also reducing or minimizing the hydraulic pressure differential required to overcome the resistance from the electric machine (and its intermediate drive train). The active/idle mode may provide higher dynamics than the active/passive mode. In at least some arrangements, the active/idle mode consumes less power, reduces ball screw wear, and improves the efficiency of an electro-hydraulic servo actuator (EHSA) as compared to the active/active mode.

In the active/passive mode, the hydraulic system is actively controlled to exert hydraulic force on the hydraulic piston assembly, and the electric motor and its drive train passively follow the movement of the hydraulic piston assembly. The active/passive mode may be used with the electric machine used as a backup for the hydraulic system while also avoiding control overhead with respect to the electric machine.

In the passive/active mode, the electric motor is actively controlled to apply mechanical force to the hydraulic piston assembly, and the hydraulic system is not operated or is operated to reduce, minimize or eliminate hydraulic force opposing the mechanical force of the electric motor. The passive/active mode may be used in situations where the hydraulic system is unable to generate sufficient hydraulic pressure, such as during a hydraulic system failure or partial failure.

At 418, the method includes operating the dual independent hybrid actuator system in the operating mode identified at 416 to achieve the target change in state of the actuator system identified at 418. As one example, an electronic control system controls the hydraulic system and/or the motor of the actuator system to move the hydraulic piston assembly to a target actuator position.

If the operating mode is identified as active/active at 416, the method includes controlling operation of one or more electro-hydraulic servo valves of the hydraulic system to produce a target hydraulic pressure differential between opposite sides of the hydraulic piston at 422 that urges the piston rod in a target translational direction, at 420. For example, with respect to the actuator system 100 of fig. 1, where the target translational direction is the extension direction 102, the hydraulic pressure difference includes a higher hydraulic pressure within the first sub-hydraulic chamber 112A than the second sub-hydraulic chamber 112B. In another example, where the target translational direction is the retraction direction 104, the hydraulic pressure difference includes a higher hydraulic pressure within the second sub-hydraulic chamber 112B than the first sub-hydraulic chamber 112A.

Concurrently and in cooperation with the hydraulic force applied by the hydraulic pressure differential at 422, the method includes controlling operation of the motor in a target rotational direction at 424 that urges the piston rod in a target translational direction. Controlling operation of the motor at 424 includes providing power to the motor in a sufficient amount and phase to rotate the motor shaft in a target rotational direction to rotate a threaded shaft engaged with the hydraulic piston assembly. The total force pushing the piston rod in the target translational direction comprises the sum of the hydraulic force applied by the hydraulic pressure difference and the mechanical force applied to the hydraulic piston assembly by the motor. The total force exerted by the hydraulic and mechanical forces may result in movement of the hydraulic piston assembly in a target translational direction, where the total force exceeds a force opposing such movement, such as a pneumatic load on a flight control surface.

If the operating mode is identified as an active/idle mode, then at 430 the method includes controlling operation of one or more electro-hydraulic servo valves of the hydraulic system to produce a target hydraulic pressure differential that urges the piston rod in the target translational direction at 432. Simultaneously and in coordination with the hydraulic pressure applied by the hydraulic pressure differential at 432, the method includes controlling operation of the motor to rotate the motor shaft in a target rotational direction corresponding to the target translational direction of the piston rod in a manner that reduces, minimizes, or eliminates resistance caused by movement of the piston rod by the motor (and its intermediate drive train) at 434. Because the electric motor is not used to apply mechanical force to the hydraulic piston assembly in the active/idle mode, the hydraulic force in the active/idle mode is greater than the hydraulic force in the active/active mode for a given total force applied to the hydraulic piston assembly.

If the operating mode is identified as an active/passive mode, then at 440, the method includes controlling operation of one or more electro-hydraulic servo valves of the hydraulic system to produce a target hydraulic pressure differential that urges the piston rod in the target translational direction at 442, and not operating the motor at 444 (i.e., not supplying electrical power to the motor to induce additional mechanical force on the hydraulic piston assembly). When the hydraulic piston assembly translates in the active/passive mode due to hydraulic pressure differences, the motor (and its intermediate drive train) is free to rotate and resistance to such rotation is applied to the hydraulic piston assembly.

If the operational mode is identified as a passive/active mode, at 450 the method includes controlling operation of the motor to rotate the motor shaft in a target rotational direction at 454, which pushes the piston rod in a target translational direction. At 452, the hydraulic system is not operated, or a dampening pressure differential urging the piston rod in a direction opposite the target translational direction is reduced, minimized, or eliminated by controlling operation of one or more electro-hydraulic servo valves and/or pressure relief valves of the hydraulic system. For example, with respect to the actuator system 100 of fig. 1, where the target translational direction is the extension direction 102, the hydraulic pressure within the second sub-hydraulic chamber 112B may be reduced, thereby reducing the hydraulic force on the hydraulic piston assembly that opposes the mechanical force applied by the motor. In another example, where the target translational direction is the retraction direction 104, the hydraulic pressure within the first sub-hydraulic chamber 112A may be reduced, thereby reducing the hydraulic pressure on the hydraulic piston assembly that opposes the mechanical force applied by the motor.

From any of the operational modes 420, 430, 440, and 450 performed as part of operation 418, the method returns to 412, where additional input data is received at a subsequent point in time. As one example, in response to the hydraulic system failing to produce a target hydraulic pressure difference between opposite sides of the hydraulic piston as identified based on the additional input data received at 412, the power provided to the motor may be increased to rotate the motor shaft in a target rotational direction, either alone or in combination with the hydraulic pressure difference provided by the hydraulic system, which urges the piston rod to move in the target translational direction to the target position. As a result of the transition between modes, the power supplied to the motor may be increased, for example from an active/idle mode or an active/passive mode to an active/active mode or a passive/active mode. Conversely, the power supplied to the motor may be reduced due to the transition from the active/active mode or the passive/active mode to the active/idle mode or the active/passive mode. Thus, during a first control operation (e.g., at a first point in time), one or more electro-hydraulic servo valves of the hydraulic system may be operated to generate a target hydraulic pressure differential that pushes a piston rod mounted for movement in a target translational direction; and during a second control operation (e.g., at a second point in time), the motor may be operated to rotate the motor shaft in the target rotational direction, which pushes the piston rod to move in the first translational direction with or without contribution from hydraulic pressure of the hydraulic system.

Fig. 5 schematically illustrates an example control architecture 500 for a dual independent hybrid actuator system that includes the actuator system 100 of fig. 1. The control architecture 500 may be implemented by an electronic control system, such as the electronic control system 170 of fig. 1, to perform the method 400 of fig. 4 or portions thereof. In this example, the control architecture 500 is described in the context of using the dual independent hybrid actuator system 100 of fig. 1 with respect to a flight control surface as an example of a mechanical component controlled by a piston rod of the actuator system. For example, actuator positions may be obtained from position sensors 148A and 148B, or from motors in the case of stepper motors, and control surface positions may be obtained from sensor 129 of fig. 1, during fault-free operation, position control of the control surfaces may be achieved by a proportional position control loop of an electro-hydraulic servo actuator (EHSA) controller, while load control may be achieved by an additional proportional position load control loop for a motor-driven ball screw (EMDLS) as an external cascade of position control loops. In fig. 5, a ball screw actuator is provided as one example of the motor 140 of fig. 1. In the event of an EHSA failure or loss of hydraulic power, control may therefore be switched to EMDLS position control. Fig. 5 also shows an example of a mode selector switch that enables selection among the active/passive (a/P), active/active (a/a) and active/idle (a/NL) modes of operation previously described with reference to fig. 4.

Fig. 6 illustrates an example planetary gear system 600 that may be included in the drive train 160 of the actuator system 100 of fig. 1. The planetary gear system 600 includes an outer ring gear 610 that meshes with a plurality of planet gears 612, 614, 616, 618, etc., which in turn mesh with a sun gear 620. It should be understood that a fewer or greater number of planetary gears may be used, depending on the embodiment. In fig. 6, the gear teeth are omitted, as any suitable gear tooth configuration may be used to achieve a particular gear ratio of the planetary gear system 600. In the case of the actuator system 100, the sun gear 620 is mounted on a sun gear shaft 622 having an axis of rotation that is coaxial with the translation axis 125 of fig. 1. The plurality of planet gears are mounted to a carrier 626 having a carrier shaft 624 extending from a side of the planetary gear system 600 opposite the sun gear shaft 622. The carrier shaft 624 may also be coaxial with the translation axis 125. As one example, one of the shafts 622 or 624 may be mechanically coupled to the motor shaft 142 of the motor 140, while the other of the shafts 622 or 624 may be mechanically coupled to the threaded shaft 150 to provide a desired gear ratio.

In at least some examples, the methods and processes described herein may be bound to a computing system of one or more computing devices. Fig. 7 illustrates an example computing system 700 that can implement the method 400 of fig. 4 and the control architecture 500 of fig. 5 for a dual independent hybrid actuator system, including the actuator system 100 of fig. 1. Computing system 700 is an example of an electronic control system for a dual independent hybrid actuator system, such as electronic control system 170 of fig. 1. In fig. 7, computing system 700 is shown in simplified form as including a logic machine 710, a storage machine 712, and an input/output subsystem 714.

Logic machine 710 includes one or more physical devices configured to execute instructions. For example, the logic machine may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more components, achieve a technical effect, or otherwise achieve a desired result.

Logic machine 710 may include one or more processors configured to execute software instructions. Additionally or alternatively, logic machine 710 may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. The processors of the logic machine may be single-core or multi-core, and the instructions executed thereon may be configured for sequential, parallel, and/or distributed processing. The various components of the logic machine may optionally be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. For example, the logic machine 710 may be implemented as a first logic machine component that controls operation of the hydraulic system 134, and a second logic machine component that controls operation of the electric machine 140.

The storage machine 712 includes one or more physical devices configured to hold instructions 724 and/or other data 722 that are executable by the logic machine 710 to implement the methods and operations described herein. When such methods and operations are implemented, the state of storage machine 712 may be transformed — e.g., to hold different data. Storage 712 may include one or more removable and/or built-in devices. The storage machine 712 may include optical memory (e.g., CD, DVD, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage machine 712 may include volatile, nonvolatile, dynamic, static, read/write, read-only, random-access, sequential-access, location-addressable, file-addressable, and/or content-addressable devices. The various components of the storage machine may optionally be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. For example, the storage machine 712 may be implemented as a first storage machine component that holds instructions and/or data for controlling the operation of the hydraulic system 134, and as a second storage machine component that holds instructions and/or data for controlling the operation of the electric machine 140.

Aspects of logic machine 710 and storage machine 712 may be integrated together into one or more hardware-logic components. For example, such hardware logic components may include Field Programmable Gate Arrays (FPGAs), program and application specific integrated circuits (PASIC/ASIC), program and application specific standard products (PSSP/ASSP), System On Chip (SOC), and Complex Programmable Logic Devices (CPLDs).

Input/output subsystem 714 may include or be connected with one or more input devices and/or output devices. Examples of input devices include the various sensors described herein (e.g., 129, 148A, 148B, motor 140 as a stepper motor that recognizes rotational position, etc.), user input devices (e.g., a cockpit controller in an aircraft, a computer mouse or controller, a touch screen, a natural language interface, etc.), communication interfaces (e.g., with another computing device), etc. Examples of output devices include motor 140, brake 149, hydraulic pump 136, servo valve 138, pressure reducing valves of the hydraulic system, user output interfaces (e.g., gauges, graphical display devices, audio speakers, indicator lights), and so forth.

Examples of the subject matter of the present disclosure are described in the paragraphs listed below.

A.1 a dual independent hybrid actuator system comprising:

an actuator body defining a hydraulic chamber within an interior of the actuator body, the actuator body further defining a first hydraulic fluid passage and a second hydraulic fluid passage in fluid communication with the hydraulic chamber; a hydraulic piston assembly comprising: a hydraulic piston disposed within the hydraulic chamber and dividing the hydraulic chamber into a first sub-hydraulic chamber in fluid communication with the first hydraulic fluid passage and a second sub-hydraulic chamber in fluid communication with the second hydraulic fluid passage; and a piston rod mounted to the hydraulic piston and passing through the second sub-hydraulic chamber, the piston rod having a distal end projecting outwardly from the actuator body; a motor mounted to the actuator body, the motor having a motor shaft; and a threaded shaft mechanically coupled to a motor shaft of the motor, the threaded shaft passing through the first sub-hydraulic chamber and engaging a threaded port formed in the hydraulic piston assembly.

A.2 the dual independent hybrid actuator system according to paragraph a.1, wherein rotation of the motor shaft of the motor in a first rotational direction forces the hydraulic piston to move within the hydraulic chamber in a first translational direction such that the distal end of the piston rod extends outwardly from the actuator body; and wherein rotation of a motor shaft of the motor in a second rotational direction opposite the first rotational direction urges the hydraulic piston to move within the hydraulic chamber in a second translational direction opposite the first translational direction to retract the piston rod inwardly toward the actuator body.

A.3 the dual independent hybrid actuator system according to paragraph a.2, wherein a first pressure differential between the first and second sub-hydraulic chambers urges the hydraulic piston to move in a first translational direction, wherein the first sub-hydraulic chamber has a higher hydraulic pressure than the second sub-hydraulic chamber; and wherein a second pressure difference between the first sub-hydraulic chamber and a second sub-hydraulic chamber urges the hydraulic piston to move in a second translational direction opposite to the first translational direction, wherein the second sub-hydraulic chamber has a higher hydraulic pressure than the first sub-hydraulic chamber.

A.4 the dual independent hybrid actuator system of paragraph a.3, further comprising: a hydraulic system in communication with the first and second hydraulic fluid passages of the actuator body; and a control system configured to coordinate operation of the electro-hydraulic servo valves of the electro-motor and hydraulic systems to: increasing the hydraulic pressure in the first sub-hydraulic chamber relative to the second sub-hydraulic chamber to achieve a first pressure difference while operating the motor to rotate in a first rotational direction; and increasing the hydraulic pressure in the second sub-hydraulic chamber relative to the first sub-hydraulic chamber to achieve a second pressure difference while operating the motor to rotate in a second rotational direction.

A.5 the dual independent hybrid actuator system according to any of paragraphs a.1 to a.4, wherein the threaded shaft is coaxial with the piston rod or with a translation axis of the piston rod.

A.6 the dual independent hybrid actuator system according to paragraph a.5, wherein the motor shaft is coaxial with the piston rod or with the translation axis of the piston rod.

A.7 the dual independent hybrid actuator system of any of paragraphs a.1 through a.6, wherein the hydraulic piston assembly further comprises a ball screw nut defining a threaded port; and wherein the threaded shaft forms a ball screw shaft.

A.8 the dual independent hybrid actuator system according to any of paragraphs a.1 to a.7, wherein the hydraulic piston assembly defines an internal chamber within the body of the hydraulic piston and/or piston rod, the internal chamber housing a portion of the threaded shaft protruding through the threaded port; wherein the body of the hydraulic piston and/or piston rod defines a fluid passage between the internal chamber and the first sub-hydraulic chamber, the fluid passage being independent of the threaded port; and wherein the hydraulic piston assembly further includes an inline check valve positioned along the fluid passageway that provides a greater resistance to hydraulic fluid flowing through the inline check valve toward the internal chamber than hydraulic fluid flowing through the inline check valve from the internal chamber.

A.9 the dual independent hybrid actuator system according to any of paragraphs a.1 to a.8, further comprising a drive train; wherein the threaded shaft is mechanically coupled to a motor shaft of the motor via a drive train; and wherein the drive train provides a non-coordinated effective gear ratio between the motor shaft and the threaded shaft.

A.10 the dual independent hybrid actuator system of paragraph a.9, wherein the non-coordinated effective gear ratio provides a reduced rate of rotation of the threaded shaft relative to the rate of rotation of the motor shaft.

A.11 the dual independent hybrid actuator system of paragraph a.9, wherein the drive train includes a planetary gear system.

A.12 the dual independent hybrid actuator system according to any of paragraphs a.1 to a.11, wherein the actuator body and the piston rod in combination form a linkage comprising: a first bearing attachment point at the distal end of the piston rod, and a second bearing attachment point at the distal end of the actuator body opposite the first bearing attachment point.

A method of controlling a dual independent hybrid actuator system, the method comprising: controlling operation of an electro-hydraulic servo valve of the hydraulic system to create a first hydraulic pressure difference between opposite sides of the hydraulic piston, which urges a piston rod mounted to the hydraulic piston to move in a first translational direction; controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft during movement of the piston rod in the first translational direction, wherein controlling operation of the motor includes providing power to the motor to rotate the motor shaft in a first rotational direction: this urges the piston rod to move in the first translational direction in coordination with the force exerted by the first hydraulic pressure difference, or reduces the resistance of the motor to the movement of the piston rod in the first translational direction.

B.2 the method of paragraph b.1, further comprising: in response to the hydraulic system being unable to generate a first hydraulic pressure differential between opposite sides of the hydraulic piston, power to the motor is increased to rotate the motor shaft in a first rotational direction, which urges the piston rod to move in a first translational direction to a target position.

B.3 the method of any of paragraphs b.1-b.2, further comprising: controlling operation of an electro-hydraulic servo valve of the hydraulic system to create a second hydraulic pressure differential between opposite sides of the hydraulic piston that urges the piston rod to move in a second translational direction opposite the first translational direction; controlling operation of the motor by providing power to the motor to rotate the motor shaft in a second rotational direction opposite the first rotational direction during movement of the piston rod in the second translational direction: this urges the piston rod to move in the second translational direction in coordination with the force exerted by the second hydraulic pressure difference, or reduces the resistance of the motor to the movement of the piston rod in the second translational direction.

B.4 the method of paragraph b.3, further comprising: in response to the hydraulic system being unable to generate a second hydraulic pressure differential between opposite sides of the hydraulic piston, power to the motor is increased to rotate the motor shaft in a second rotational direction, which urges the piston rod to move in a second translational direction to the target position.

B.5 the method of any of paragraphs b.1 through b.4, wherein controlling operation of the motor includes providing power to the motor to rotate the motor shaft in the first rotational direction, which eliminates resistance of the motor to movement of the piston rod in the first translational direction.

C.1 a method of controlling a dual independent hybrid actuator system, the method comprising: during a first control operation, controlling operation of an electro-hydraulic servo valve of the hydraulic system to generate a first hydraulic pressure difference between opposite sides of the hydraulic piston, which urges a piston rod mounted to the hydraulic piston to move in a first translational direction; and during a second control operation, controlling operation of a motor having a motor shaft mechanically coupled to the hydraulic piston via a threaded shaft to rotate the motor shaft in a first rotational direction, which urges the piston rod to move in a first translational direction.

C.2 the method of paragraph c.1, wherein the second control operation is performed in response to the hydraulic system failing to produce the first hydraulic pressure difference between the opposite sides of the hydraulic piston during the first control operation.

C.3 the method of any of paragraphs c.1-c.2, wherein the second control operation is performed simultaneously with the first control operation.

It will be appreciated that the configurations and/or techniques described herein are exemplary in nature, and that these specific examples are not to be considered in a limiting sense, because numerous variations are possible. The specific methods and operations described herein may represent one or more of any number of processing strategies. Accordingly, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Also, the order of the above-described operations may be changed according to the embodiments. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various configurations and techniques, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.