Patent Application
20140100695
A C frame structure for carrying a working tool is provided in accordance with one embodiment of the present disclosure and, more particularly, a C frame structure configured to respond to loads generated by the working tool by compensating for deflection otherwise created by the loads.
A number of structures must be riveted and, indeed, some structures require hundreds or thousands of rivets to be installed. By way of example, a wing of an aircraft may require the installation of many rivets. In order to facilitate the installation of rivets, riveters have been developed that have first and second riveting assemblies that are positioned in alignment with one another proximate opposite surfaces of the structure, such as opposite surfaces of a wing. These riveters permit a rivet to be properly positioned and then installed and upset.
The installation and upsetting of a rivet may generate substantial force upon the riveter and may urge the first and second riveting assemblies positioned in alignment with one another proximate the opposite surfaces of the structure to be deflected away from the structure. Such deflection of the riveting assemblies may be deleterious in that their relative location with respect to the structure may be altered during the rivet installation process, thereby potentially causing the rivet to be mispositioned or misaligned. Additionally, the deflection of the riveter may cause the riveter to require maintenance sooner or more frequently than is desired and may sometimes shorten its useful life.
As such, riveters have been developed that are substantial in size and weight in order to withstand the deflection forces created during the riveting process. While these more substantial riveters may generally maintain their relative position with respect to the structure in which a rivet is being installed, the size and weight of these riveters may limit their mobility or portability. Thus, these more substantial riveters are oftentimes stationary such that the structure to be riveted, such as a wing, must be moved into alignment with the riveter and then repeatedly repositioned with respect to the riveter as each rivet is installed and upset. This process of positioning and then repositioning a structure, such as a wing, relative to the riveter may limit the flexibility of the manufacturing process by requiring the riveter to remain stationary and by correspondingly requiring the structure to be riveted to be carried by a material handling system that is sufficiently sophisticated to controllably position the structure, such as a relatively large structure such as a wing, in a number of relatively precise positions with respect to the riveter.
A C frame structure, a robotic system and an associated method are provided in accordance with an example embodiment of the present disclosure in order to respond to and accommodate the loads placed upon the C frame structure during actuation of a working tool, such as the deflection loads created during a riveting operation. The C frame structure of an example embodiment of the present disclosure may not only respond to and accommodate the loads created during operation, but may do so in a manner that reduces or eliminates the deflection of the C frame structure. Thus, the C frame structure to be lighter and therefore have increased mobility. For example, the C frame structure may be carried by a robot during performance of its operations, thereby increasing the efficiency of the manufacturing process by permitting the C frame structure and its associated working tool to be controllably positioned relative to a structure, such as a wing, thereby potentially reducing the handling and positioning required of the structure during the manufacturing process.
In one embodiment, a C frame structure for carrying a tool is provided that includes a plurality of links and a plurality of pins interconnecting the links to form a pinned truss configuration. At least one of the links is configured to carry the tool. In this embodiment, the pinned truss configuration of the links is responsive to a load imparted upon the C frame structure in response to actuation of the tool such that each link is placed in compression or tension. The links that are configured to be placed in tension may be formed of an anisotropic material, such as a composite material. The links configured to be placed in compression may be formed of a metal. The C frame structure of this embodiment also includes a plurality of hydraulic cylinders including first and second hydraulic cylinders connected to the plurality of links such that each hydraulic cylinder extends in parallel to a respective link. The first hydraulic cylinder of this embodiment is configured to operate in a compression mode in response to strain within the C frame structure attributable to actuation of the tool. The second hydraulic cylinder of this embodiment is configured to be in an extension mode in response to the first hydraulic cylinder operating in the compression mode.
The first and second hydraulic cylinders of one embodiment are in fluid communication such that the hydraulic fluid forced out of the first hydraulic cylinder in the compression mode is provided to the second hydraulic cylinder. Each of the first and second hydraulic cylinders of this embodiment includes a piston. As such, the first hydraulic cylinder may be configured to cause its respective piston to force hydraulic fluid out of the first hydraulic cylinder in the compression mode. In another embodiment, the C frame structure includes an external hydraulic control system configured to direct hydraulic fluid to the second hydraulic cylinder in response to operation of the first hydraulic cylinder in the compression mode.
In another embodiment, a robotic system is provided that includes a robot configured to provide for controlled movement and a C frame structure carried by the robot. The C frame structure may include a pinned truss configuration that includes a plurality of links interconnected by pins. The C frame structure of this embodiment also includes a plurality of hydraulic cylinders including first and second hydraulic cylinders connected to the plurality of links such that each hydraulic cylinder extends in parallel to a respective link. The robotic system of this embodiment may also include a tool, such as a riveter, carried by at least one of the links. The pinned truss configuration of one embodiment is responsive to a load imparted upon the C frame structure in response to actuation of the tool by the robot such that each link is placed in compression or tension. The links configured to be placed in tension may be formed of an anisotropic material, such as a composite material. The links configured to be placed in compression may be formed of a metal. The first hydraulic cylinder of this embodiment is configured to operate in a compression mode in response to strain within the C frame structure attributable to actuation of the tool. The second hydraulic cylinder of this embodiment is configured to be in an extension mode in response to the first hydraulic cylinder operating in the compression mode.
The first and second hydraulic cylinders of one embodiment may be in fluid communication such that the hydraulic fluid forced out of the first hydraulic cylinder in the compression mode is provided to the second hydraulic cylinder. In this embodiment, each of the first and second hydraulic cylinders may include a piston. As such, the first hydraulic cylinder may be configured to cause the respective piston to force hydraulic fluid out of the first hydraulic cylinder in the compression mode. The robotic system of another embodiment may also include an external hydraulic control system configured to direct hydraulic fluid to the second hydraulic cylinder in response to operation of the first hydraulic cylinder in the compression mode.
In a further embodiment, a method for accommodating deflection upon actuation of a tool is provided that includes providing a C frame structure. The C frame structure includes a pinned truss configuration that includes a plurality of links interconnected by pins and a plurality of hydraulic cylinders connected to the plurality of links such that each hydraulic cylinder extends in parallel to a respective link. The method of this embodiment also includes actuating the tool, such as a riveter, carried by the C frame structure. The pinned truss configuration of the links is responsive to a load imparted upon the C frame structure in response to the actuation of the tool such that each link is placed in compression or tension. The method of this embodiment also includes causing the first hydraulic cylinder to operate in a compression mode in response to strain within the C frame structure attributable to the actuation of the tool. The method of this embodiment also causes the second hydraulic cylinder to operate in an extension mode in response to the first hydraulic cylinder operating in the compression mode.
In regards to the operation of the first hydraulic cylinder in the compression mode, the method of one embodiment may force hydraulic fluid out of the first hydraulic cylinder in the compression mode. In this embodiment, the operation of the second hydraulic cylinder in the extension mode may include providing the hydraulic fluid forced out of the first hydraulic cylinder to the second hydraulic cylinder. Each of the first and second hydraulic cylinders of one embodiment may include a piston. In this embodiment, the method may force the hydraulic fluid out of the first hydraulic cylinder by causing the respective piston to force hydraulic fluid out of the first hydraulic cylinder in the compression mode. In regards to causing the first hydraulic cylinder to operate in the compression mode, the method of another embodiment may cause hydraulic fluid to be forced from the first hydraulic cylinder to an external hydraulic control system. In regards to causing the second hydraulic cylinder to operate in the extension mode, the method of this embodiment may cause the external hydraulic control system to direct hydraulic fluid to the second hydraulic cylinder in response to operation of the first hydraulic cylinder in the compression mode.
Having thus described certain embodiments of the present disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Embodiments of the present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments are shown. Indeed, these embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Referring now to
As described below, the robotic system may be configured in order to perform one or more operations, such as manufacturing operations, e.g., riveting, upon a workpiece. A workpiece in the form of a wing panel 12 is illustrated in
As shown in
As also shown in
The C frame structure 14 includes a plurality of links interconnected by pins so as to form a pinned truss configuration. The pinned truss configuration may remove many, if not all, of the bending loads from the C frame structure 14 that may otherwise be generated in response to actuation of the tool 16. Instead, the pinned truss configuration may cause all load paths to be supported by members that are placed in either tension or compression. As described below, the pinned truss configuration differs from a fixed end cantilevered beam load scenario by removing bending loads from the structure. Additionally, the pinned truss configuration may advantageously distribute the strain density throughout the structure.
While the pinned truss configuration may have various configurations, the pinned truss configuration of the illustrated embodiment of
The plurality of links of the illustrated embodiment also include two or more links 38 that extend along the first side portion of the C frame structure 14 from pin 32 to pin 40 and two or more links 42 that extend along the second side of the C frame structure from pin 36 to pin 44. From pin 40, the plurality of links of the illustrated embodiment also include two or more links 46 that extend at an angle to pin 22 at the proximal end of a respective jaw member 18 and two or more links 48 that extend at an angle to pin 50, positioned opposite to the opening defined by the jaw members. Similarly, from pin 44, the plurality of links of the illustrated embodiment include two or more links 52 that extend at an angle to pin 24 at the proximal end of a respective jaw member 18 and two or more links 54 that extend at an angle to pin 50. The plurality of links of the illustrated embodiment may also include two or more links 56 that extend at an angle from pin 32 to pin 58 positioned in alignment with, but rearward of the opening defined by the jaw members 18. Similarly, the plurality of links of the illustrated embodiment may also include two or more links 60 that extend at an angle from pin 36 to pin 58. Finally, the plurality of links may include two or more links 62 that extend between pins 50 and 58 so as to be in general alignment with the opening defined by the jaw members 18.
The jaw members 18 may be configured to carry the tool 16 such that the tool may be controllably positioned relative to a workpiece that may extend through the opening 20 defined by the jaw members. In response to actuation of the tool 16 by the robot 10, deflection forces may be imparted upon the distal ends of the jaw members 18 that tend to force the distal ends of the jaw members away from one another as shown by the upwardly and downwardly directed arrows of
In order to accommodate the deflection imparted to the C frame structure 14 in response to actuation of the tool 16, the C frame structure may also include a plurality of hydraulic cylinders. The hydraulic cylinders may be connected to the plurality of links such that each hydraulic cylinder extends in parallel to a respective link. In this regard, the plurality of hydraulic cylinders may be connected so as to extend between a pair of pins of the pinned truss configuration. The C frame structure 14 of the embodiment illustrated in
Each hydraulic cylinder may include hydraulic fluid disposed within a cylinder housing. Each hydraulic cylinder may also include a piston disposed within the cylinder housing and attached via a shaft to a respective pin. The piston is configured to move lengthwise within the cylinder housing in response to the links with which the hydraulic cylinders extend in parallel being placed in tension or compression.
In order to accommodate the deflection otherwise created within the C frame structure 14 in response to actuation of the tool 16, the pair of first hydraulic cylinders 64 may operate in a compression mode such that the pistons of the first hydraulic cylinders force fluid therefrom, while the pair of second hydraulic cylinders 66 operate in an extension mode by receiving additional hydraulic fluid that, in turn, causes the shaft to be further extended relative to the respective cylinder housing. See blocks 86 and 88 of
In another embodiment shown schematically in
By operating the first and second hydraulic cylinders 64, 66 in concert as described above, the deflection that is otherwise created at the distal ends of the jaw members 18 may be reduced. As such, the C frame structure 14 may be formed of links that provide the requisite strength to withstand the forces created during actuation of the tool 16 with the assistance of the hydraulic cylinders, but without having to be as heavy as required by some conventional tooling. Thus, the C frame structure 14 may be carried by a robot 10 so to be controllably positioned relative to a workpiece, such as a wing panel 12. Thus, the resulting manufacturing process, such as the riveting operations performed with respect to the workpiece, may be performed more quickly and efficiently in accordance with an example embodiment of the present disclosure.
Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which these embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments are not to be limited to the specific ones disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions other than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
