Abstract:
The invention relates to a modular positioning robotic system and method of use of the positioning system. In general, the modular positioning robotic system is comprised of a controller module, a positioning module and a base that can be either a stationary base or drive module. The positioning module also allows for additional flexibility by allowing for designs with multiple allowable adjustments that can be changed for a change in turn diameter, length, width and weight of a fixture and part combination.

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 60/822,467 filed Aug. 15, 2006, herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to the part fixture presentation as used in robotic systems and work cells and specifically to a modular design of the positioning robotic system that allows changes from one type of positioning module to another positioning module that can be selected from a variety of modules and can be used in conjunction with a stationary base or a drive unit that adapts without having to switch the control architecture. A positioning robotic system is originally assembled with a specific positioning device, drive and control module. When the use of the system needs to be changed to accommodate a change in weld locations of a new product because of a change in the diameter, length, width or weight of the fixture and part combination, the positioning device system can be changed to a different system configuration without having to necessarily change the entire system. Instead, only individual components need be changed. 
     II. Problems in the Art 
     Many manufacturing processes have become automated. Typically, robots consist of a single mechanical arm that has a limited number of axis about which the arm can move or rotate. The robot arm has a tool, such as a welder, attached to the end of the arm. To provide better robot access to a part fixture combination, modern assembly lines also provide work tables, or positioning modules that hold fixtures and parts, that can be moved to position a product being worked on by the robotic arm within the reach of the arm. 
     There are a great variety of positioning modules that can position material within the reach of a robot. One such module is a turntable. A turntable is essentially a flat round surface that rotates about an axis. The turntable typically enables the robotic arm to work on parts on one portion of the circular surface while the other portion of the table is loaded and unloaded. The table is rotated about an exchange axis to more safely separate the operator from the robotic arms&#39; movements. The turntable is ideal for situations in which the parts do not need to be repositioned while being processed. 
     Another positioning module design is the H-frame. The H-frame module rotates about an axis also, but instead of having a flat surface to mount fixtures and parts to, it has two sets of arms that products are mounted between. The addition of arms allows for the system to have two axis of rotation to better provide for the robot to work. 
     Another style of positioning module is termed a Ferris wheel frame. A Ferris wheel frame is essentially a rectangular shaped flat surface that pivots around an axis that extends along the length of the surface. Arms are mounted perpendicular to the planar surface of the Ferris wheel. Much like the H-frame, products or fixtures (devices used to hold smaller sized products) are suspended between the arms. 
     Modern assembly lines, work cells and factories typically consist of a mixture of work stations that require different types of positioning devices because of the unique processing needs of the part. Today&#39;s work station is set up and built around tool turning diameters and length, and are designed to function in a specific way. If the part being produced requires a change in the part fixture, then the entire work station and positioning module may need to be replaced or reconfigured. 
     When a manufacturing plant, assembly line or work cell is retooled to manufacture a new product there is a significant period of down time where the facility does not produce any product. Because of the complexity of the tools, changeover in a highly automated process can take even longer than more traditional assembly plants. Most often, robotic automation fixtures and part combinations come with fixed components that are only common to their tool fixture and part combination. 
     Several problems arise from this standardization by tool fixture and part combination. Because each tool fixture and part combination is unique and has unique components, a change in tool fixture and part combination can result in the need to buy new capital equipment because the existing station cannot be adjusted for positioning the new tool fixture or part combination because length or diameter changes. The change in systems often causes the utilities to need to be rerouted, which then cause additional down time. The more change overtime, the more money is lost. Additionally, having to replace an entire system is much more expensive than replacing a single component of a system. 
     It is therefore a primary objective of the present invention to provide a design for a modular system comprised of components that can easily be interchanged and adjusted. 
     A further feature of the present invention is to provide a modular positioning robotic system that has a control architecture which can be adjusted and used for any selected positioning module/system type utilized in a standard robotic system family. 
     A further feature of the present invention is to provide a modular system that is easily networked. 
     Yet another feature of the present invention is to provide a control module that interfaces with a robot controller wherein the robotic controller performs the logical functions. 
     A still further feature of the present invention is to provide a controller module that interfaces with and controls a drive module. 
     Another feature of the present invention is to provide a modular positioning robotic system that utilizes an adjustable H-frame positioning module that can add and/or delete an exchange axis drive module or turntable. 
     Yet another feature of the present invention is to provide a modular positioning robotic system that utilizes a turntable positioning module that can be interchanged with an adjustable H-frame. 
     Yet another feature of the present invention is to provide a modular positioning robotic system that utilizes an adjustable tool length and width Ferris wheel positioning module. 
     Yet another feature of the present invention is that the H-frame, turntable and Ferris wheel positioning modules are interchangeable. 
     A still further feature of the present invention is that the modular positioning system integrates with one or more robots. 
     A modular positioning robotic system and a method of accomplishing these and other features will become apparent from the following description of the invention. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention uses a controller module, and a positioning module in a positioning robotic system. Additionally, an exchange axis drive module can be utilized in the positioning robotic system. 
     Preferably, a typical workstation of the present invention uses a control module with a control architect that interfaces with a robot controller to effectively manipulate a drive module and a positioning module to effectively position products to be manufactured. The drive system is designed to provide at least 180° of exchange axis motion. The control module controls the major axis of rotation while the robot controller controls the minor axis of rotation. The major axis of rotation is driven by the drive module. The minor axis of rotation is defined by the attachments that facilitate manipulative fixture and part combination placement. A work piece is rotated about and positioned relative to either side of a robotic arm. 
     Positioning modules can be of varied by adjusting tool part diameter, tool length, tool width, and the number of operations that must be performed. Additionally, a positioning module can be adjustable to provide the most flexibility to the manufacturing site. 
     One method of practicing the present invention includes assembling the drive, positioning and control modules into a workstation. A generic controller module is assembled with a controller architecture that is adapted to communicate with multiple types of positioning modules and drive modules without having to be extensively modified. Both network connection and input/output ports are provided to facilitate connection to a myriad of devices. The controller module is attached to the drive unit and the positioning module is received by the drive unit. 
     When the positioning module needs to be changed to facilitate a different product, the old positioning module is disconnected from the control module. If an exchange axis is needed, the positioning model is attached to a drive module. If the only change necessary is adjustment of the tool length or tool diameter, the old drive unit is reused and only the spacer modules are changed to facilitate repositioning of the safety barrier system. The positioning module is attached to the drive module and connected to the control module without having to also change the control and drive modules when applicable. A new program is either selected on the control module or programmed into it to account for the change in the positioning module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an embodiment of the control module and control architecture. 
         FIG. 2  is a perspective view of an embodiment of the drive module. 
         FIG. 3  is a perspective view of a modular positioning robotic system utilizing an H-frame. 
         FIG. 4  is a perspective view of a modular positioning robotic system utilizing a turntable. 
         FIG. 5  is a perspective view of a modular positioning robotic system utilizing a Farris wheel in the horizontal position. 
         FIG. 6  is a perspective view of a modular positioning robotic system utilizing an H-frame without a drive unit. 
         FIG. 7  is a sectional view of the adjustability of the H-frame positioning module. 
         FIGS. 8 and 9  are sectional views of the H-frame clamping system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all modifications and alternatives, which may be included within the spirit and scope of the invention. 
     Referring to the drawings, numeral  10  generally refers to a control module. Numeral  12  refers to the positioning module generally and numeral  14  refers to the drive module. 
     The control module  10 , as seen in  FIG. 1 , has input/output port  16  that connect to the drive module  14  and positioning module  12 . The control module  10  also interfaces with the robotic controller  18 . The robotic controller  18  can be connected to the controller via a hardware connection or via other means. 
     The robotic controller  18  connects to a robot  20 . In the specific example disclosed by  FIG. 1 , a robot  20  is connected to a welder  22 . Other attachments for the robot  20  are contemplated. These attachments could include manipulators, sprayers, etc. 
     The control panel  10  connects to the power distribution panel  24 . Additionally, the control panel  10  connects to the operation station  26 . A connection to the operation station has both inputs and outputs that facilitate communication between the control panel  10  and the operation station  26 . The operation station  26  can include inputs for cycle start, positioning and adjustment of the positioning module, error fault reset, etc. The operation station could also include outputs such as a display or indicator lights that would indicate the device status. 
     In addition to communicating with the operation station  26 , the control module can also have direct input from remote sensors  28 . The sensors  28  could include light curtains, gates, reamers or wire snips. These sensors  28  would be external to the sensors integrated into the robot  20 , positioning module  12  or drive module  14 . 
     The control module  10  communicates with the external devices via the control architecture  30 . The control architecture  30  is comprised of a programmable logic controller (PLC)  32 , communication bus  34  and a separate input/output board  36 . The PLC  32  is essentially a small computer utilizing a microprocessor. The PLC manages and controls the stored information to effectively utilize input and output signals. Further, the PLC  32  coordinates the multiple modules by measuring the position of the drive module and positioning module. Further, the control module interacts with the robot controller that controls the minor axis of rotation. A personal computer would be sufficient to store and operate the modules. 
     The control architecture  30  also contains a communication bus  34 . The bus  34  facilitates communication between the external modules and the PLC  30 . There are many standards of communication that could be utilized, but the present embodiment prefers to use Ethernet communication or industrial protocol communication to form an open device level network. It is contemplated that the bus  34  could be a traditional ribbon cable as well as a wireless communication system. Additionally, traditional cabling could be utilized to effect communication between the varied modules and input devices. 
     The PLC  30  also connects to a block of input/output points  36 . The input and output block  34  connect external input devices to the PLC  34 . In addition, simple logic can also be integrated into the I/O block  36 . An example of a more intelligent I/O block would be a SLICE I/O point system where signals along the block can be converted to logic that could be manipulated and sent across Ethernet connections to the PLC  30 . 
       FIG. 2  discloses a drive unit  14 . The drive unit  14  is generally comprised of a frame  38 , a clevis plate  40  and brake assembly  42 . The drive module also includes an assembly  44  for rotating the clevis plate  40  through at least 180° of rotation. The clevis plate  40  is fashioned to have multiple attachment points  46  that facilitate mounting the positioning module  12  on the drive module  14 . 
       FIG. 3  discloses the drive module  16  attached to a control pallet  70 . The control pallet  70  is a mechanical structure used to mount the control module  10 , controller  18 , welder process equipment, valve packages and electrical enclosures. The control pallet is preferably designed to conform with the modular concept as shown such that a single control pallet  70  design is utilized across the multiple tool types. 
       FIG. 3  also discloses the positioning module  12  mounted to the drive module  14 .  FIG. 3  specifically discloses an H-frame  50  positioning module. The H-frame design  50  is shaped like an “H” with each open end  52  of the “H” used to mount head  54  and tailstock  56  positioning mechanisms. The head and tailstocks  54 ,  56  are used to rotate fixtures to position the products such that the robot  20  has access to the products. The dimensions of the H-frame  50  can be fixed such that an H-frame&#39;s length and width are permanently fixed after assembly. Additionally the H-frame  50  can be adjustable. The length, width, and rotation diameter of the H-frame  50  can each be independently adjusted after assembly. 
       FIG. 7  shows how the H-frame can be adjusted to change responsive to a change in the fixture and part combination. The main base  80  of the H-frame is designed to attach to either a drive module  14  or a stationary base  76 . The main parallel frame  82  is mounted to the main base  80  of the H-frame. 
     The first  86  and second  88  legs of the T-member  84  of the H-frame are inserted into the parallel frame  82 . The arms  52  are inserted into the T-member  84  to form the H-frame  50 . The head and tailstock positioning members  54  are attached to the ends of the arms  52 . 
     The H-frame is generally constructed of square metal tubular members. The frame of the H-frame could also be constructed of other geometrical tubular members, such as circular or octagonal. Additionally, the members could also be constructed of combinations of tubular and solid material. The frame does not necessarily need to be constructed of metal. Dependent upon the requirements of the fixture and part combination, i.e., weight, length, width and turning diameter, the H-frame could be constructed of plastics, ceramics, wood, etc. 
     The mechanism for clamping the different components together is simple and repeatable.  FIGS. 8 and 9  show the clamp comprising an I-bolt  90  and a standard bolt  92 . The standard bolt  92  passes through the I-bolt  90  that is passed through hole  94  along the walls of the tube. The two bolts are 90 degrees from each other, and as a result, the clamping system utilizes a coordinate system that allows for clamping in the x and y directions. The z position, or length of the combined member, can be adjusted by loosening and tightening the clamping bolts. The position can become fixed by drilling additional holes through the frame once the correct position has been determined for a fixture and part combination. 
       FIG. 3  further discloses a robot riser  58 . The robot riser  58  is attached to the frame  38  of the drive module  14 . The riser  58  does not rotate, and instead is fixed positionally. The riser  58  rises through the center of the H-frame  50 .  FIG. 3  depicts the riser  58  as having two mounting surfaces  60 . The riser  58  could have any number of surfaces  60  to facilitate mounting the correct number of robots  20 . 
       FIG. 3  also depicts a spacer module  62 . Spacer module  62  provides mechanical structure support to join, align, and support the drive module  14 , the control pallet  70  and screen  64 . The spacer modules help to adjust and control the footprint of the modular positioning robotic system  8 . Additionally, the spacer  62  enables screen  64  to be built to shield personnel from the movement of the system as well as blocking any light generated by the welder  22 . 
       FIG. 6  discloses a similar work cell as depicted in  FIG. 3 . In  FIG. 6 , the drive unit  14  is replaced with a stationary mounting base  76 . This system is utilized when the operator loads the two open ended arms  52  by traveling back and forth between the two sets. In a stationary model, there is no major exchange axis as the frame does not rotate. 
       FIG. 4  discloses the modular positioning robotic system  8  having a positioning module  14  utilizing a turntable  66 . The turntable  66  mounts to the clevis top plate  40 . The diameter of the turntable is typically fixed. When a different diameter table is needed, a different turntable  66  can be mounted to the drive module  14 . The change in diameter of the turntable  66  may require a change of the spacer module  62  to properly position the drive module  14  relative to the control pallet  70  and safety shield  64 . 
       FIG. 5  discloses another version of the modular positioning robotic system  8  having a position module  12  that utilizes a Ferris wheel frame  68 . Similar to the H-frame  50 , the Ferris wheel frame  68  can be a fixed dimension or adjustable. The Ferris wheel frame&#39;s  68  length, width and rotational diameter can be each independently adjusted if the Ferris wheel frame  68  is adjustable. 
     As seen in  FIG. 5 , the Ferris wheel frame mounts to an upright drive module  14 . The Ferris wheel frame rotates about an axis  72 . The Ferris wheel frame has arms  74 , that head and tailstock  54 ,  56  connectors that attach to fixtures (not shown) that hold parts to be manipulated by the robotic arm  20  (not shown in  FIG. 5 ). 
     The preferred embodiment is specifically designed with a control module  10  and drive module  14  that can have either an H-frame positioning module  54  or a turntable module  66  as the third module. The two styles of positioning modules are designed to be easily interchangeable. Additionally it is contemplated that the Ferris wheel style positioner  68  could easily be modified to swap into an existing system. 
     A general description of the present invention as well as the preferred embodiment and alternative embodiments of the present invention have been set forth above. Those skilled in the art to which the present invention pertains will recognize and be able to practice additional variations in the methods and systems described which fall within the teachings of this invention.