Abstract:
The subject matter of this specification can be embodied in, among other things, a positioning device that includes an actuator assembly configured to actuate an output shaft based on an input signal, and a position sensor assembly. The position sensor assembly includes a position sensor configured to detect a position of an input shaft not directly coupled to the output shaft, a first input receiver configured to receive the input signal, a first output transmitter configured to provide an output signal based on the position of the input shaft, and a second output transmitter configured to provide another output signal indicative of a failure of at least one of the input shaft and the output shaft. A moveable member is coupled to both the output shaft and the input shaft and is configured to alter the positional configuration of the input shaft and to be actuated by the output shaft.

Description:
TECHNICAL FIELD 
       [0001]    This instant specification relates to a valve device and more particularly to a rotary actuated valve having a mechanical valve position indicator. 
       BACKGROUND 
       [0002]    Rotary hydraulic actuators of various forms are currently used in industrial mechanical power conversion applications. This industrial usage is common for applications where continuous inertial loading is desired without the need for load holding for long durations, e.g. hours, without the use of an external fluid power supply. Aircraft flight control applications generally implement loaded positional holding, for example, in a failure mitigation mode, using substantially only the blocked fluid column to hold position. 
       SUMMARY 
       [0003]    In general, this document describes a rotary actuated valve having a mechanical valve position indicator. 
         [0004]    In a first aspect, a positioning device includes an actuator assembly coupled to an output shaft and configured to actuate the output shaft based on an input signal, and a position sensor assembly. The position sensor assembly includes a position sensor configured to detect a positional configuration of an input shaft not directly coupled to the output shaft, a first input receiver configured to receive the input signal, a first output transmitter configured to provide a first output signal based on the positional configuration of the input shaft, and a second output transmitter configured to provide a second output signal indicative of a failure of at least one of the input shaft and the output shaft based on a comparison of the input signal and the positional configuration. A moveable member is coupled to both the output shaft and the input shaft and spaced apart from both the actuator assembly and the position sensor, the moveable member being configured to alter the positional configuration of the input shaft and being configured to be actuated by the output shaft. 
         [0005]    Various embodiments can include some, all, or none of the following features. The input shaft and the output shaft be concentric. The device can include a housing arranged about the actuator assembly and the position sensor. The actuator assembly defines a cavity and the position sensor is arranged within the cavity. The device can include a valve assembly comprising a housing and a valve, wherein the moveable member is coupled to the valve. The actuator can be a rotary valve fluid actuator. The actuator can be a rotary vane fluid actuator. 
         [0006]    In a second aspect, a positioning device includes a moveable member, an actuator assembly spaced apart from the moveable member and configured to alter a positional configuration of the moveable member, a position sensor spaced apart from the moveable member and configured to detect both a position of the moveable member and a failure of the actuator assembly to alter the positional configuration of the moveable member. 
         [0007]    Various embodiments can include some, all, or none of the following features. The moveable member can be rotatably coupled to the actuator assembly by an input shaft, and the moveable member is rotatably coupled to the position sensor by an output shaft. The input shaft and the output shaft can be concentric. The device can include a housing arranged about the actuator assembly and the position sensor. The actuator assembly defines a cavity and the position sensor is arranged within the cavity. The device can include a valve assembly having a housing and a valve, wherein the moveable member is coupled to the valve. The actuator van be a rotary valve fluid actuator. The actuator can be a rotary vane fluid actuator. 
         [0008]    In a third aspect, a method of operating a positioning device includes providing an actuator assembly coupled to an output shaft and configured to actuate the output shaft, providing a position sensor configured to detect the positional configuration of an input shaft, coupling the output shaft indirectly to the input shaft through a moveable member spaced apart from both the actuator assembly and the position sensor, the moveable member being configured to alter the positional configuration of the input shaft and being configured to be actuated by the output shaft, actuating the output shaft in response to an input signal, actuating, by the output shaft, the moveable member, altering, by the moveable member; the positional configuration of the input shaft, detecting, by the position sensor, the positional configuration of the input shaft; and providing a first output signal based on the detected positional configuration. 
         [0009]    Various implementations can include some, all, or none of the following features. The method can include comparing the input signal to the first output signal, determining a positional error based on the input signal and the first output signal; and updating the input signal based on the positional error. The method can include determining that the positional error is greater than a threshold positional error limit, and providing a second output signal. The input shaft and the output shaft can be concentric. The actuator assembly defines a cavity and the position sensor is arranged within the cavity. The positioning device can include a valve assembly comprising a housing and a valve, wherein the moveable member is coupled to the valve. 
         [0010]    The systems and techniques described herein may provide one or more of the following advantages. First, a system can provide an indication of valve position to a position sensor through a shaft that is connected to a positionable member and is separate from a drive shaft. Second, the system can provide failure detection for the drive shaft and linkage without additional means of position error detection (e.g., additional sensors, mechanical or electrical over-travel detection). Third, the system can use a primary position sensor to detect both valve position and linkage failure. Fourth, the system can be embodied in configurations that use rotary and/or linear actuators, and can use a feedback shaft that is directly connected to the position sensor and concentric with the drive shaft. 
         [0011]    The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1A  is a diagram that shows a cross sectional view of an example of a positioning device. 
           [0013]      FIG. 1B  is a block diagram of an example of a position controller. 
           [0014]      FIGS. 2A and 2B  are diagrams that shows a top and cross sectional side view of another example of a positioning device. 
           [0015]      FIG. 3  is flow chart that shows an example of a process for operating a positioning device. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    This document describes systems and techniques for positioning a valve device and more particularly to a rotary actuated valve having a mechanical valve position indicator. In general, a controllable actuator is located apart from a valve, and the actuator is coupled to a valve member by an output shaft. A position sensor is also located apart from the valve, and is coupled to the valve member by an input shaft. The actuator can apply torque to the output shaft to position the valve member, and movement of the valve member can apply torque to the input shaft to position the position sensor. In general, a mechanical position feedback loop is formed, which can be used for applications in which an actuator is located apart from a valve to provide feedback for one or both of position sensing and mechanical failure (e.g., of the output shaft). 
         [0017]      FIG. 1A  is a diagram that shows a cross sectional view of an example positioning device  100 . The device  100  includes a fluid valve assembly  110 . The fluid valve assembly  110  includes a positionable member  112  (e.g., valve member, disc) that can be moved to controllably obstruct a fluid path  114  (e.g., contact a valve seat) passing through a central bore  116  of a flow body (e.g., valve body)  118 . 
         [0018]    The positionable member  112  is configured to be moved by a controllable actuator assembly  120  linked to the positionable member  112  by a linkage assembly  150 . In general, the actuator assembly  120  is located apart from the fluid valve assembly  110 . For example, the actuator assembly  120  may be located remote from the fluid valve assembly  110  to accommodate design issues such as extreme temperatures near the fluid valve assembly  110 , space constraints near the fluid valve assembly  110 , accessibility issues (e.g., ease of maintenance), or other design considerations. 
         [0019]    The actuator assembly  120  includes a housing  121 , an actuator  122 , and a position sensor  124 . In the illustrated example, the actuator  122  is depicted as a rotary fluid actuator, such as a rotary vane actuator or a rotary piston actuator. In some embodiments, the actuator  122  can be any appropriate type of actuator that can provide a rotary mechanical output (e.g., an electrical actuator, stepper, servo). 
         [0020]    In the illustrated example, the actuator  122  is removably coupled to an output shaft  152  of the linkage assembly  150 . The output shaft  152  is configured to receive torque provided by the actuator  122  and transfer the torque to the positionable member  112  and a moveable member  154 . The moveable member  154  is coupled to the positionable member  112 . In some embodiments, the moveable member  154  may be removable from the positionable member  112 . Rotary movement of the output shaft  152  urges rotary movement of the positionable member  112  and moveable member  154  within flow body  118 , which can control the flow of fluid through the flow path  114 . 
         [0021]    The moveable member  154  is also coupled to an input shaft  156 . The input shaft is configured to receive torque provided though the moveable member  154  and transfer the torque to a sensor shaft  160  of the position sensor  124 . The position sensor  124  provides a position configuration signal  182  (see  FIG. 1B ) that can be measured to determine the rotary position of the sensor shaft  160 . In the illustrated configuration, the position configuration signal  182  is representative of the position of the positionable member  112 , as positioned by the moveable member  154  and fed back mechanically through the input shaft  156  to the sensor shaft  160 . 
         [0022]    In the illustrated example, the output shaft  152  is formed as a cylinder with the input shaft  156  passing coaxially through the interior bore of the output shaft  152 . The output shaft  152  and the input shaft  156  are coupled substantially only at the moveable member  154 . For example, torque may be applied to the output shaft  152  at an end opposite from the moveable member  154 . The moveable member  154  couples the output shaft  152  to the input shaft  156 , causing the input shaft  156  to rotate along with the output shaft  152 . However, if either of the output shaft  152  or the input shaft  156  were to break or otherwise decouple, torque may no longer be transmitted from the distal end of the output shaft  152  to the moveable member  154  and back to the distal end of the input shaft  156 . In some implementations, the rotational movement of the input shaft  156  (e.g., or components coupled thereto) can be compared to the rotational movement of the output shaft  152  (e.g., or components coupled thereto) to detect a breakage in the linkage assembly  150 . 
         [0023]    In some embodiments, the output shaft  152  and the input shaft  156  may not be coaxial to each other. For example, the output shaft  152  may be coupled to the positionable member  112  at a first axial end of the positionable member  112 , and the input shaft  156  may be coupled to an opposite axial end of the positionable member  112  (e.g., with both the output shaft  152  and the input shaft  156  aligned along a common axis). In such a configuration, the position sensor  124  may be located apart from both the actuator assembly  120  and the fluid valve assembly  110 , coupled to the positionable member  112  at a distance by the input shaft  156 . In yet other embodiments, the output shaft  152  and the input shaft  156  may not be axially aligned. For example, the input shaft  156  may be rotated by torque provided by the output shaft  152  through a linkage or other coupling mechanism at or near the moveable member  154 . In some embodiments, the input shaft  156 , the output shaft  152 , the moveable member  154 , and/or other components of the device  100  can be made from corrosion-resistant steel, aluminum, composites, and combinations of these and any other materials that are appropriate for the environment and loading of the device  100 . 
         [0024]    Referring now to the example of a position controller shown in  FIG. 1B , the position configuration signal  182  is processed by a position controller  180  as part of a feedback control loop. The position controller  180  compares the position configuration signal  182  to a position input signal  184  (e.g., the desired position of the positionable member  112 ) to provide a position error signal  186 . In some implementations, the position error signal  186  can be used as part of a closed control feedback loop used to control the actuation of the actuator  122  and the positionable member  112 . 
         [0025]    The position controller  180  may also be configured to compare the difference between the position input signal  184  and the position configuration signal  182  as part of a fault detection process. For example, the position configuration signal  182  can be compared to the position input signal  184  to determine an error (e.g., difference, delta, provided as the position error signal  186 ) between the two signals. Under normal operating conditions, the sensor shaft  160  and the actuator  122  will rotate together since they are rotationally coupled together by the linkage assembly  150 . However, in the event of a mechanical malfunction, such as a break in the output shaft  152 , the sensor shaft  160  may become rotationally decoupled from the actuator  122 . As such, changes in the position input signal  184  may not cause a corresponding change in the position configuration signal  182 . The position input signal  184  and the position configuration signal  182  can be compared by the position controller  180 , and when the position controller  180  detects that the two signals differ by more than a predetermined amount (e.g., about ten or twenty degrees), a malfunction detection signal  188  may be provided to signal that a malfunction may have occurred in the linkage assembly  150 . 
         [0026]    In the illustrated example, the position sensor  124  occupies a cavity  170  defined within the actuator assembly  120 . The actuator  122  is able to rotate coaxially, but independent to, the rotation of the sensor input  160 . In some embodiments, the position sensor  124  and the actuator  122  may not be arranged concentrically. An example of such a non-concentric arrangement is discussed in the description of  FIGS. 2A and 2B . 
         [0027]      FIGS. 2A and 2B  are diagrams that shows a top and cross sectional side view of another example of a positioning device  200 . The positioning device  200  includes the fluid valve assembly  110  of  FIG. 1A , with the positionable member  112  that can be moved to controllably obstruct the fluid path  114  passing through the central bore  116  of the flow body  118 . 
         [0028]    The positionable member  112  is configured to be moved by a controllable actuator assembly  220  linked to the positionable member  112  by a linkage assembly  250 . In general, the actuator assembly  220  is located apart from the fluid valve assembly  110 . For example, the actuator assembly  220  may be located remote from the fluid valve assembly  110  to accommodate design issues such as extreme temperatures near the fluid valve assembly  110 , space constraints near the fluid valve assembly  110 , accessibility issues (e.g., ease of maintenance), or other design considerations. 
         [0029]    The actuator assembly  220  is a linear fluid actuator (e.g., hydraulic or pneumatic piston) that includes a piston  221  (shown in  FIG. 2A ) configured to urge linear movement of a piston rod  222 . In some embodiments, other forms of linear actuators can be used in place of the actuator assembly  220 , such as electric linear motors. The piston rod  222  is rotationally coupled to a crosshead bearing  223  and a connecting rod  224 . A crank bearing  225  rotationally couples the connecting rod  224  to a crank arm  226 . The crank arm is coupled to an output shaft  252  of a linkage assembly  250 . Reciprocal movement of the piston  221  is transformed by the actuator assembly  220  into rotary motion of the output shaft  252 . 
         [0030]    Referring primarily now to  FIG. 2B , the output shaft  252  transfers the rotary motion (e.g., torque) to the positionable member  112  and a moveable member  254 . The moveable member  254  is coupled to the positionable member  112 . In some embodiments, the moveable member  254  may be coupled to the positionable member  112  by brazing, welding, bolting, press fitting, or any other appropriate bond. In some embodiments, the moveable member  254  and the positionable member  112  may be formed from a unitary piece of material. Rotary movement of the moveable member  254  urges rotary movement of the positionable member  112  within flow body  118 , which can control the flow of fluid through the flow path  114 . 
         [0031]    The moveable member  254  is also coupled to an input shaft  256 . The input shaft is configured to receive torque provided though the moveable member  254  and transfer the torque to a sensor shaft  260  of a position sensor  270 . The position sensor  270  provides a position configuration signal (not shown) (e.g., the position configuration signal  182 ) that can be measured to determine the rotary position of the sensor shaft  260 . The position configuration signal is representative of the position of the positionable member  112 , as positioned by the moveable member  254  and fed back through the input shaft  256  to the sensor shaft  260 . 
         [0032]    In the illustrated example, the output shaft  252  is formed as a cylinder, with the input shaft  256  passing coaxially through the interior bore of the output shaft  252 . The output shaft  252  and the input shaft  256  are coupled substantially only at the moveable member  254 . For example, torque may be applied to the output shaft  252  at an end opposite from the moveable member  254 . The moveable member  254  couples the output shaft  252  to the input shaft  256 , causing the input shaft  256  to rotate along with the output shaft  252 . However, if the output shaft  252 , the input shaft  256 , or a component of the actuator assembly  220  were to break or otherwise decouple, torque may no longer be transmitted from the piston  221 , to the distal end of the output shaft  252 , to the moveable member  254 , and back to the distal end of the input shaft  256 . In some implementations, a position controller such as the position controller  180  of  FIG. 1B  can compare the rotational movement of the input shaft  256  (e.g., or components coupled thereto) to the rotational movement of the output shaft  252  (e.g., or the actuator assembly  220  or to components coupled thereto) to detect a breakage in the linkage assembly  250 . 
         [0033]    In some embodiments, the output shaft  252  and the input shaft  256  may not be coaxial to each other. For example, the input shaft  256  may be rotationally coupled to the output shaft  252  by a linkage or other coupling mechanism located in proximity to the moveable member  254 . 
         [0034]    In some embodiments, the position configuration signal can be processed by the position controller  180  of  FIG. 1B  as part of a feedback control loop. For example, the position configuration signal  182  can be compared to the position input signal  184  to form a portion of a closed control feedback loop used to control the actuation of the piston  221  and the positionable member  112 . 
         [0035]    In some embodiments, the position configuration signal  182  can be processed by the position controller  180  as part of a fault detection process. For example, the position configuration signal  182  can be compared to the position input signal  184  to determine an error (e.g., difference, delta) between the two signals. Under normal operating conditions, the sensor shaft  260  and the piston  221  will move proportionally together since they are coupled together by the actuator assembly  220  and the linkage assembly  250 . However, in the event of a mechanical malfunction, such as a break in the piston  221 , the piston rod  222 , the crosshead bearing  223 , the connecting rod  224 , the crank bearing  225 , the crank arm  226 , the moveable member  254 , or the output shaft  252 , the sensor shaft  260  may become rotationally decoupled from the actuator assembly  220 . As such, changes in the position input signal  184  may not cause a corresponding change in the position configuration signal  182 . The position input signal  184  and the position configuration signal  182  can be compared by the position controller  180 , and when the two signals differ by more than a predetermined amount a malfunction in the actuator assembly  220  and/or the linkage assembly  250  will be detected and indicated by the malfunction detection signal  188 . 
         [0036]      FIG. 3  is flow chart that shows an example of a process  300  for operating a positioning device. In some implementations, the process  300  can be performed using the positioning device  100  of  FIG. 1A , the positioning device  200  of  FIGS. 2A-2B , the position controller  180  of  FIG. 1B , and/or other devices configured to process information gathered from the positioning devices  100  or  200 . 
         [0037]    At  310 , an actuator assembly is provided. The actuator assembly is coupled to an output shaft and configured to actuate the output shaft. For example, the actuator  122  is coupled to the output shaft  152 . The actuator  122  is configured to urge rotation of the output shaft  152 . 
         [0038]    At  320 , a position sensor is provided. The position sensor is configured to detect the positional configuration of an input shaft. For example, the position sensor  124  is configured to detect the rotational position of the sensor input  160 . The position sensor  124  is coupled to the input shaft  156  at the sensor input  160 . Rotation of the input shaft  156  rotates the sensor input  160  such that the position sensor  124  can detect the rotational position of the input shaft  156 . 
         [0039]    In some embodiments, the input shaft and the output shaft can be concentric. For example, the input shaft  156  is configured as a rod that passes through a cylindrical bore that extends axially through the interior of the output shaft  152 . In some embodiments, the output shaft  152  may configured as a rod passing coaxially within a cylindrical bore formed within the input shaft  156 . 
         [0040]    At  330 , the output shaft is coupled indirectly to the input shaft through a moveable member spaced apart from both the actuator assembly and the position sensor, the moveable member being configured to alter the positional configuration of the input shaft and being configured to be actuated by the output shaft. For example, the output shaft  152  is coupled to the input shaft  156  through the moveable member  154 . The moveable member  154  is located proximal to one axial end of the linkage assembly  150 , spaced apart from the opposite axial end of the linkage assembly  150  where the actuator  122  is coupled to the output shaft  152  and the position sensor  124  is coupled to the input shaft  156 . 
         [0041]    At  340 , the output shaft is actuated in response to an input signal. In some embodiments, the input signal can be the position input  184 . In some embodiments, the output shaft  152  can be actuated in response to a fluidic pressure applied to the actuator  122  (e.g., a fluidic input signal). In some embodiments, the actuator  122  may be actuated by fluid pressure provided by a valve or pump in response to a control signal (e.g., an electrical input signal). 
         [0042]    At  350  the moveable member is actuated by the output shaft. For example, the output shaft  152  can transfer torque to the moveable member  154 . 
         [0043]    At  360 , the positional configuration of the input shaft is altered by the moveable member. For example, the output shaft  152  is coupled to the input shaft  156  through the moveable member  154 . Rotation of the moveable member  154  applies torque to the input shaft  156 . 
         [0044]    At  370 , the position sensor detects the positional configuration of the input shaft. For example, the position sensor  124  can detect the rotary position of the sensor input  160  which is rotationally coupled to the input shaft  156 . 
         [0045]    At  380 , a first output signal based on the detected positional configuration is provided. For example, the position sensor  124  can provide the position configuration signal  182  as an electrical or other signal that represents the rotary position of the input shaft  156 . 
         [0046]    In some implementations, the input signal and the first output signal can be compared, a positional error can be determined based on the input signal and the first output signal, and the input signal can be updated based on the positional error. For example, the linkage assembly  150  can provide a mechanical feedback loop that drives the position sensor  124  to determine the position error signal  186 . The position error signal  186  can be used as a feedback signal in a closed control feedback loop. For example, a closed loop position controller can use the position error signal  186  to determine an error between a desired position of the positionable member  112  and an actual position of the positional member  112  and alter an actuation signal to the actuator  122  (e.g., the position input signal  184 ) in an effort to compensate for the detected positional error. 
         [0047]    In some implementations, the positional error may be determined as being greater than a threshold positional error limit, and a second output signal may be provided. For example, relatively minor positional errors (e.g., less than about ten or twenty degrees) may be used by the a controller as part of a closed loop positional control scheme, while detection of relatively larger positional errors (e.g., greater than about ten or twenty degrees) by the position controller  180  may trigger the malfunction detection signal  188  to indicate the detection of a possible mechanical malfunction within the linkage assembly  150  or another component of the positioning device  100 . 
         [0048]    Although a few implementations have been described in detail above, other modifications are possible. For example, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.