Abstract:
A robotic end effector system and method having a plurality of end effectors which are selectively suitable for particular applications on a workpiece. The end effectors include a resident controller adapted to execute tasks specific to the end effector and are rapidly attachable and removable from the robot for easy change over to different workpieces.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/145,695 filed Jan. 19, 2009 and U.S. Provisional Application Ser. No. 61/160,893 filed Mar. 17, 2009 both applications incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    The use of automated robots in manufacturing and assembly facilities has become commonplace for the efficient assembly of large and small, simple and complex devices and machines. One example of an application which has become more complex requiring the use and coordination of numerous robots is in the manufacture and assembly of automotive vehicles. 
         [0003]    An assembly line in a manufacturing facility may include a fluid applying system for applying fluid, such as a bead of sealant or adhesive, to a workpiece. Other applications include clamping two or more pieces together to be transferred, welded or secured together. In a technologically advanced facility, one or more of these operations, and typically most of them, require the use of robots. In the past, such robots were typically set-up, tooled and programmed to carry out a specific task, for example, welding or adhering certain pieces together, application of fasteners used later in an assembly process or coating with paint or other material protectant. Once set-up and programmed, it was laborious and time consuming to change the robot tooling or programming to re-task the robot to function in a different capacity or application. This made it difficult, time consuming and costly to, for example, change from the manufacture and assembly of one vehicle type to another. Thus, one a robot was set-up and programmed, that robot was dedicated to that application and was not useful to use in other applications or tasks without substantial changeover time. 
         [0004]    In one manufacturing and assembly application to provide fluid adhesive or sealant to a workpiece, for example a sheet metal vehicle body, typically such a fluid supply system includes a robot having a nozzle for applying fluid to the workpiece. The robot receives fluid from a fluid supply, such as one or more industrial sized drums of the fluid, disposed near the robot. A fluid supply line extends from at least one of the drums to the robot. The fluid supply line is often fixed to a ceiling or other support above the robot. An end of the fluid supply line coupled to the robot is typically a coiled line in order to prevent the fluid supply line from restricting movement of the robot, and the coiled line is in fluid communication with the robot. Such systems often required pumps and other capital equipment, sizable floor space and were very expensive. Further, changing from one fluid to another, for example to a different adhesive or sealant, required changing fluid lines and cleaning the existing line to comply with regulations and purity of the alternate fluid to be used. The robot can thus move the nozzle into an application position relative to the workpiece, and the nozzle can apply fluid to the workpiece. Additionally, other components, such as a pump and a control system, are typically necessary for operation of the system. 
         [0005]    Similarly, other robotic applications such as metal-to-metal spot welding, application of weld studs, and automated clamping and component transferring systems suffered from the same disadvantages. 
       SUMMARY 
       [0006]    A robotic end effector system and method is disclosed for use in the manufacturing and assembly of devices, for example, automotive sheet metal bodies and associated vehicle systems. The effector system allows a suitable robot to quickly change an end effector, for example an end effector used for applying an adhesive or sealant, to another end effector, for example a weld gun. The system and method substantially eliminates, or eliminates altogether, past restraints on dedicated robots for specific applications or tasks and provides for greatly increased flexibility of the robot to change tasks for more efficient use and efficient manufacturing and assembly as a whole. 
         [0007]    The end effector system and method uses a connector and data communication links or means so that the end effector itself can include an on-board or on-effector controller to receive and/or execute programs specific to the type of effector in use by the robot. On a need to change the application of the robot, the end effector may be disconnected from the robot connector and a new or alternate effector or appliance can be picked-up or otherwise secured to the robot, communication re-established between the effector and the robot, or other communication equipment, and the robot is retasked to another application or use. 
         [0008]    In an example of a fluid applying robot, for example the application of an adhesive or sealant, the end effector can include a receptacle for receiving and temporary holding of a canister of fluid. The robot, or preferably the end effector, can include a plunger or another structure for controlling the flow of fluid from the canister, and the robot can move the canister into a fluid applying position relative to the workpiece. With the canister in the fluid applying position, the plunger can be actuated to cause fluid to flow from the canister. When the canister is empty or a different fluid is required, the robot can maneuver to dispose of the canister and can obtain a new canister. In one example, the robot or end effector can include a blade or other cutting mechanism for removing a portion of an empty canister that contains any remaining fluid. 
         [0009]    The example of an end effector described herein for applying a fluid applying robot as described herein can have many advantages over known fluid applying systems. For example, the fluid applying robot can cost an order of magnitude less than known fluid applying systems, at least in part because the fluid applying robot as described herein can be used without the complex fluid storage and transport components of known fluid applying systems. Further, the fluid applying robot can be much more versatile than known fluid applying systems, as the fluid applying robot can be more easily moved in order to reconfigure an assembly line since the fluid applying robot can be used without separate components, some of which may be fixed in place. Additionally, the fluid applying robot as described herein can also be more versatile than known fluid applying systems since changing the fluid applied by the fluid applying robot can be accomplished by the robot obtaining a new fluid canister. Finally, disposal of empty canisters can be less expensive than cleaning the fluid sources used by known fluid applying systems since the plunger of the fluid applying robot can remove almost all of the fluid from the canister such that the only portion of the canister that should be cleaned is the portion removed by the blade. 
         [0010]    These advantages are also achievable with many other robotic end effectors including welding, for example changing the particular spot welding gun end effector to access and weld in a different area or applying a different weld stud or in a different location. An end effector which provides a holding or clamping fixture or function, may be quickly changed to clamp alternate components or in different areas. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0012]      FIG. 1  is a simplified schematic plan view of a manufacturing or assembly line; 
           [0013]      FIG. 2  is a perspective view of an example of the inventive end effector system in an exemplary application as a fluid applying robot at a workstation along the assembly line of  FIG. 1 ; 
           [0014]      FIG. 3  is a perspective view of an example of an adhesive applying end effector generally illustrated in  FIG. 2 ; 
           [0015]      FIG. 4  is a cross-section taken along line  4 - 4  in  FIG. 3 ; 
           [0016]      FIG. 5  is a schematic diagram of one example of a robotic and end effector control system for the exemplary application shown in  FIG. 2 ; 
           [0017]      FIG. 6  is a perspective view of the example system shown in  FIG. 2  with an example of a fluid tray rack disposed adjacent to the robot; 
           [0018]      FIG. 7  is a partial and alternate cross-section taken along line  4 - 4  in  FIG. 3  showing the plunger in a fully extended position and an exemplary cutter in a first position and the cutter in phantom in a second position; 
           [0019]      FIG. 8  is a schematic side view of an example of a robot having a stud welding end effector; 
           [0020]      FIG. 9  is a perspective view of an example of a spot welding end effector useful with the robot shown in  FIG. 2 ; 
           [0021]      FIG. 10  is a perspective view of an example of a tooling fixture end effector utilizing exemplary clamps for use with the robot shown in  FIG. 2 ; 
           [0022]      FIG. 11  is a perspective view of an example showing two alternate end effectors temporarily stored on an automatic guided vehicle along with the workpieces to be processed once positioned at a workstation; 
           [0023]      FIG. 12  is a side view of an example of an end effector connector in an exemplary use with a weld gun end effector; 
           [0024]      FIG. 13  is a perspective view of a portion of the end effector connector shown in  FIG. 12  without the weld gun effector; and 
           [0025]      FIG. 14  is a perspective view of the end effector connector shown in  FIG. 12  with enlarged view of a portion of the connector. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Examples of a robotic end effector system  10  and method are shown in  FIGS. 1-14 . Referring to  FIG. 1 , the inventive system and method is generally useful in a manufacturing and assembly facility or plant having mechanical robots  16  (four shown) each having an end effector  10  positioned along a manufacturing and/or assembly line  20 , and most useful positioned adjacent a workstation  24  where workpieces  30  are transferred to and positioned for further processing such as clamping, bonding, welding, sealing, painting or other processing known by those skilled in the art. 
         [0027]    In one example shown in  FIG. 2 , end effector  10  is in the form of an end effector for applying a fluid, for example an adhesive or sealant to a workpiece  30 , for example automobile sheet metal body components using a robot  16 . In the example, robot  16  includes a base  34 , a body  38 , an armature  42 , a wrist  44 , servo motors (not shown) and an exemplary end effector  10  in the form of an effector  60  for applying a fluid to workpiece  30  at a workstation  24 . The robot  16 , including base  34 , body  38 , armature  42  and wrist  44  is moveable in six degrees of freedom by servo motors and other devices and having other capabilities, movements and functions known by those skilled in the field. In the example shown, robot  16 , and more specifically wrist  44  is connected to a connector face plate  50  typically attached to a robot wrist  44 . Face plate  50  is used as a conduit and exit for service lines includine electrical, water air and other service fluids and power for robot  16  to end effector  10  described in further detail below. Face plate  50  is useful to attach a selected end effector  10  for various manufacturing and assembly uses described in further detail below. 
         [0028]    Referring again to  FIG. 2 , the robot  16  can additionally include a connector  50  for physical attachment to the end effector  10 . The connector face plate  50  can also include a data connection for communication between robot  16  and the end effector  10 , such as communication between the servos  46  and the controller  54 . The connector  50  can receive end effectors  10  other than the adhesive applying end effector  60 , such as a welding end effector  66  or clamping end effector  70 . Further, the robot  16  can be mounted on a movable platform  34  for mobility relative to the assembly line  20 . As a result, the robot  16  can be easily moved to different positions and can be configured to perform different operations, both of which can increase the versatility of the assembly line  20 . 
         [0029]    Referring to  FIG. 5 , an exemplary end effector control system  52  for exemplary end effector  60  is shown. A controller  54  is in electronic communication with several components on-board the effector  60  as well as in communication with a separate controller on the robot  16  (not shown). In a preferred example, end effector  10  includes a separate control system that is integral or on-board the effector  10 . See U.S. Provisional Application Ser. No. 61/160,893 filed Mar. 17, 2009, assigned to the same assignee herein, which is incorporated by reference in its entirety. In the example  52 , a controller  54  may include a microprocessor and memory storage (not shown). Controller  54  may be in electronic communication with on-board effector  60  (or  10 ) components including one or more servo motors  132 , a plunger  126  and first and second sensors  140  and  156  respectively described in more detail below. The use of a separate end effector control system  52  which is integral and dedicated to the particular end effector  10  allows the end effector  10  to communicate and carry-out end effector tasks or applications which are specifically designed or programmed for that particular end effector  10 . On changing of the end effector  10  by robot  16 , the effector control system  52  is placed in communication with robot  16  control system (not shown) and/or local or remote serves which provide programs, instructions and/or downloads of information and instructions for the alternate and installed end effector  10  allowing robot  16  to be quickly retasked, for example, a different vehicle body or other device to be manufactured and assembled. 
         [0030]    An example of an end effector  10  in the form of an end effector  60  useful for applying a fluid, for example an adhesive or sealant, is shown in  FIGS. 2 ,  3  and  4 . In the example, adhesive end effector  60  may include a receptacle  80  having a longitudinal axis  82  sized to receive a fluid canister  90 . The fluid canister  90  can enclose a chamber  94  which can contain an adhesive or another fluid (not shown) known by those skilled in the field. The canister  90  can include a nozzle  93  in fluid communication with the chamber  94 . The canister  90  can also include a slidable backing plate  100 . The backing plate  100  can have an outer diameter substantially the same as the inner diameter of the canister  90  such that the backing plate  100  seals the end of the chamber  94  opposite the nozzle  98 . The backing plate  100  can include a needle  104  extending toward the nozzle  98  along the longitudinal axis. The needle  104  preferably includes an outer diameter slightly larger than an inner diameter of the nozzle  98 , and the needle  104  can have a length slightly less than a length of the nozzle  98 . Movement of the backing plate  100  toward the nozzle  98  reduces the volume of the chamber  94 , thereby forcing fluid from the canister  90  via the nozzle  98  in the form of a fluid bead (not shown). The fluid bead may take the form of a thin, continuous cylinder or any other cross-sectional shape defined by the nozzle  98 . 
         [0031]    The fit between the backing plate  100  and interior diameter of the canister  90  can be sufficiently tight such that the backing plate  100  scrapes fluid from interior walls of canister  90 . As a result, only a small amount of fluid can remain in the canister  90  after the backing plate  100  is fully depressed, and the effort required to clean the canister  90  can be reduced. Further, the fit between the needle  104  and the nozzle  98  can be sufficiently tight such that the needle  104  scrapes fluid from interior walls of the nozzle  98 . As a result, the effort required to clean the portion of the nozzle  98  scraped by the needle  104  can be greatly reduced. 
         [0032]    Referring to  FIGS. 3 and 4 , the receptacle  80  can have two opposing end-walls  108  and  114  spaced apart by the length of the canister  90 . The length of recepticel  80  may be longer and in a preferred example, includes a semicircular or otherwise trough-shaped portion  118  between the end-walls  108  and  114 . The end-wall  108  can define an aperture  110 . The end-wall  114  can include a generally V-shaped cutout  116  through which the nozzle  98  of the canister  90  can project when the canister  90  is received in the receptacle  80 . The trough-shaped portion  118  can have an inner circumference with a same or slightly larger diameter than an outer circumference of the canister  90 . In an alternate example of a receptacle  80 , the end effector  60  can include a different receptacle  80 , such as a collar around the end-wall  114  and projecting toward end-wall  108  (not shown), or a pair of clamps (not shown) for engaging the canister  90 . Other shapes and orientations of receptacle  80  for use in holding and securing a fluid canister  90  known by those skilled in the field may be used. 
         [0033]    In the exemplary adhesive end effector  60 , the end effector  60  can also include a plunger  126  and a servo motor  132  (shown schematically in  FIG. 5 ), for actuating the plunger  126  for movement along the longitudinal axis  82 . The plunger  126  can have a diameter smaller than the inner diameter of the canister  90 , and the plunger  126  can extend through the aperture  110  in the end wall  108 . The servo  132  can actuate the plunger  126  to forcibly move the plunger  126  axially along longitudinal axis  82  relative to the canister  90  in response to an instruction from the controller  54  as shown in  FIG. 5 . Also, the functions described herein as performed by the controller  54  can alternatively be performed by more than one controller packaged with the robot  16  and/or the selected end effector  10  to suit the application. For example, when the canister  90  is initially positioned in the receptacle  80 , the servo  132  can move the plunger  126  to a starting position in which the plunger  126  exerts pressure on the backing plate  100  without moving the backing plate  100  by a large amount in order to aid retention of the canister  90  in the receptacle  80 . The servo  132  can additionally move the plunger  126  toward the end-wall  114 , thereby moving the backing plate  100  toward the end-wall  100 , reducing the size of the chamber  94 , and causing fluid to flow from the nozzle  98 . Also, instead of the servo  132 , another device can move the plunger  126 , such as another type of motor, pneumatic or hydraulic pistons or devices, motors and gears, or other devices (not shown) known by those skilled in the art. 
         [0034]    As shown in  FIGS. 2 ,  3  and  5 , end effector  60  (or  10 ) can include one or more vision or other sensors, for example end effector  60  sensor  140 . The sensor  140 , in an exemplary use to monitor the existence and/or quality of the fluid bead extruded from nozzle  98 , can be an ultrasonic sensor, a camera, or another type of sensor or vision system capable of detecting a bead of fluid exiting nozzle  98  onto work piece  30 . The sensor  140  can be oriented to view a bead of fluid applied to the workpiece  30  from the nozzle  98  of the canister  90 . For example, the sensor  140  can be coupled to the receptacle  80  and angled to face near the tip of the nozzle  98 . The sensor  140  can detect, for example, the width, height, and/or continuity of the bead of fluid. As shown in  FIG. 5 , the sensor  140  can be in communication with the controller  54  as well as other controllers and onsite or remote controllers and servers. As a result, the sensor  140  can provide feedback as to the quality of the bead of fluid applied to the workpiece  80 , and the controller  54  can instruct the servo  132  to control the plunger  126  and the servos  132  and  46  to control the robot  16  based on the bead quality. 
         [0035]    The exemplary end effector  60  (or  10 ) can additionally include a second sensor  146 , which can be a camera, an ultrasonic sensor, or another sensors known by those skilled in the field. As shown in  FIG. 2 , the sensor  146  can capture an image of an area  148  including the workpiece  30 . The signal captured by the sensor  146  can be relayed to the controller  54  as shown in  FIG. 5 , and the controller  54  can analyze the signal to determine the presence and position of the workpiece  30  and/or the type of workpiece  30 . The controller  54  can control the plunger servo  132  and the robot servos  46  based on the presence, position, and/or type of the workpiece  30 . Thus, multiple different types of workpieces  30  requiring different types of adhesives and/or different patterns of adhesive application can be accommodated. 
         [0036]    In a further example of adhesive end effector  60 ,  FIG. 6  shows an exemplary tray or carousel  156  can be disposed adjacent the robot  16 . The tray  150  can include canister receiving slots  154 , some or all of which can be loaded with additional or alternate canisters  90  containing fluid and some or all of which can be available to receive the canister  90  from the end effector  60 . The tray  150  can be mounted on an automation guided vehicle (AGV) (not shown), which can transport the tray  150  between robots  16  and other areas in a manufacturing plant. The controller  54  can determine if a new canister  90  should be loaded into the receptacle  80  in response to, as examples, a low amount of fluid in the canister  90  or the need for another canister  90  containing a different type of fluid. The controller  54  can determine the amount of fluid remaining in the canister  90  held by the receptacle  80  based on, for example, the position of the plunger  126 . The controller  54  can instruct the servos  46  and/or  132  to move the robot  16  such that the second sensor  146  is positioned to sense the tray  150 . The second sensor  146  can detect the position of canisters  90  on the tray  150  and/or the availability of canister receiving slots  154 . The robot  16  can then move the end effector  160  (or  10 ) to deposit the canister  90  in one of the canister receiving slots  154  and to obtain another canister  90 . Fluid canisters  90  can be disposable, one-time use devices, or may be refillable through a refilling station (not shown) for further use. The robot  16  may also be involved in such disposal, refilling and or cleaning of the canisters  90  and effector  10  as the application may require. 
         [0037]    As an example of interaction between the end effector  60  and tray  150 , each canister receiving slot  154  can include a hole sized to receive the nozzle  98  of one of the canisters  90 . The controller  54  can instruct the servos  46  to move the robot  16  such that the end effector  60  is in a position to move vertically to insert the nozzle  98  into the canister receiver slot  154 , and the end effector  60  can be controlled to at least partially insert the nozzle  98  into the slot  154 . Once the nozzle  98  is at least partially in the slot  154 , the controller  54  can instruct the servo  132  to disengage the plunger  126  from the canister  90 , and the robot  16  can move the end effector  60  laterally relative to the canister receiving slot  154 . Engagement between the nozzle  98  and canister receiving slot  154  can retain the canister  90  in position relative to the canister receiving slot  154  while the receptacle  80  is moved laterally away from the canister receiving slot  150 , thereby disengaging the receptacle  80  and canister  90 . The canister  90  can then be propelled by gravity into the canister receiving slot  154 . The robot  16  can move the empty receptacle  80  into position to engage another canister  90  by laterally moving the receptacle  80  to engage one of the canisters  90  by sliding between the canister  90  and tray  150 , then vertically lifting the canister  90  from the tray  150 . 
         [0038]    Alternatively, new canisters  90  can be loaded into the receptacle  80  in different ways known by those skilled in the field. For example, the end effector  60  can include a canister hopper (not shown) containing a stack of canisters  90 . A new canister  90  from the hopper can be released into the receptacle after disposing of the canister  90  previously in the receptacle  80 . As another example, canisters  90  can be loaded or unloaded by hand or by use of another robot. 
         [0039]    In another example, one of the robot  16  and end effector  60  can also include a cutter  156  as shown in  FIG. 7 . The cutter  156  can be positioned to remove a tip of the nozzle  98  of the canister  90  in the receptacle  80 . For example, the cutter  156  can depend from the end-wall  118  of the receptacle  80 . Alternately, cutter  156  could be a stand along device proximate robot  16 , tray  150 , delivered by an AGV or positioned elsewhere known by those skilled in the art. The cutter  156  can include, for example, a blade  158  movable radially relative to the nozzle  90 . Additionally, the cutter  156  can be movable between two positions, a first position in which the cutter  156  is positioned to remove a small portion of the nozzle  98  to create a path for fluid to flow from the nozzle  98  (shown in phantom in  FIG. 7 ) and a second position in which the cutter  156  is positioned to remove a portion  160  of the nozzle  98  not occupied by the needle  104  when the backing plate  100  is fully depressed as shown in  FIG. 7 . By removing the portion  160  of the nozzle  98  not occupied by the needle  104 , the cutter  156  can separate the canister  90  such that the removed portion  160  of the nozzle  98  can be cleaned if necessary to comply with, for example, environmental regulations. The remainder of the canister  98  (i.e., the canister  90  other than the portion  160 ) can be disposed of without additional cleaning if sufficiently cleaned by the backing plate  100  and its needle  104  as described above. Instead of the cutter  156  being movable, more than one cutter can be included (e.g., a first cutter at the first position and a second cutter at the second position). Other cutting devices other than  156  including an exposed blade, and in different locations and orientations known by those skilled in the art may be used. 
         [0040]    In an example of an alternate end effector  10 , an effector useful for positioning and securing a weld stud to a workpiece  30  is generally illustrated in  FIG. 8 . As shown, a robot  16  can include a stud welding end effector  74 . In one example shown, the end effector  74  can carry a part reservoir  164  and a welding head  106 . The part reservoir  104  can be coupled to the welding head  166  via a conduit  170 . The part reservoir  164  can be loaded with parts, and the part reservoir can transmit parts to the welding head  166 . The studs could be gravity fed or forced down conduit  170  by a vibratory device (not shown) or by other part transfer mechanisms known by those skilled in the art. By carrying the part reservoir  164  on the robot  16 , inexpensive and versatile stud welding can be provided. Alternatively, a robot can carry an integral part reservoir. 
         [0041]    In an alternate example of an end effector  10  useful with a robot  16  in the herein described end effector system described is illustrated in  FIG. 9 . An end effector  66  useful to spot weld two or more sheet metal components is shown. The effector  66  is connectable to a robot  16  or wrist  44  through a robot wrist connector face plate  50  and end effector or appliance connector  220  as further described below. 
         [0042]    In the example shown in  FIG. 9 , weld end effector  66  includes sideplates  180 , a first weld arm  184 , a second weld arm  186  opposing spot welding tips  190  and a power supply  194  to provide electricity to flow through the weld tips. Depending on the particular spot welding application, one or more displacement devices  186  used to move the arms  184  and  186  may be used. Additional components typically used in weld guns, for example a coolant system and other controls (not shown) may be included in the end effector. As described, end effector preferably includes its own on-board control system in communication with other controllers and servers as previously described. Other forms and configurations of weld gun effector  66  known by those skilled in the art may be used. 
         [0043]    In an alternate example of an end effector  10  useful with robot  16  in the herein described end effector system is illustrated in  FIG. 10 . An end effector  70  used as a positional and clamping fixture or tool is illustrated. In the example, end effector  70  includes a support or rail  200 , several pedestals connected to support  200 , and clamps or clamping fixtures  208  connected to the pedestals to position the clamps  208  in the desired position so as to properly position the workpieces  30  (not shown) in the desired location. Other devices commonly used with clamping tooling or fixtures such as pneumatic or hydraulic actuators (not shown) to open and close the clamps  208 , as well as other components known by those skilled in the art may be used. 
         [0044]    Although several alternate examples of end effectors  10  have been illustrated and described, other end effectors  10  known by those skilled in the art are useful in the inventive system and method. For example, instead of spot weld gun effector  66 , a laser or other seam or bead welding device may be used. As an alternate to an alternate adhesive or sealant effector  60 , a paint or other surface coating, or part cleaning fluid applying effectors may be used. Alternate fluids, for example compressed air or lubricating oils or fluids may be used. 
         [0045]    Referring to  FIG. 11 , an example of a use of the inventive end effector system is illustrated. Since the particular end effector  10  may be quickly changed and/or installed on any common robot with the appropriate connectors  50  and/or  300 , the particular end effectors  10  that are needed for particular parts or operations may travel or be transferred along with the components themselves as they travel down an assembly line  20  to a workstation  24  where the components are to be processed.  FIG. 11  illustrates two alternate effectors temporarily stored or attached to a transfer pallet  210  or other support for transferring workpiece  30  between workstations. The pallet  210  can be supported and transferred by an automated guided vehicle (AGV) or other transfer device such as a conveyor, overhead gantry conveyor and other such systems known by those skilled in the art. When the workpieces  30  arrive at the workstation  24  for processing, one or more robots  16  can pick up the applicable end effector  10 , establish electronic communication with its on-board controller  54  with the robot and/or other controllers, receive or execute instructions by its controller  54  and carryout the particular and required processing step or operation, for example, applying adhesive, welding or clamping one or more workpieces  30  together for additional processing. 
         [0046]    Referring to  FIGS. 12-14  an example of an end effector or appliance connector  220  is illustrated. The appliance connector  220  is shown in an exemplary use in connecting a weld gun effector  66  as described above and the connection detailed below. Other end effectors  10  may be operably connected to robot  16  through connector  220 . 
         [0047]    As best seen in  FIG. 13 , connector  220  may include a plate  224  that is rigidly connected to robot wrist face plate  50  though mechanical fasteners or other means known by those skilled in the field. In the example, plate  224  includes a first end  228  and a second end  230 . Each end includes several brackets  240  (four shown) rigidly connected to plate  226 . Each bracket defines a slot  246  all opening to the same direction (to the right as shown in  FIG. 13 ). 
         [0048]    In the example, connector  220  may further include an angle bracket  250  that connects to one end of plate  224  (to first end  228  in the example). Attached to bracket  250  is socket  256  which, as best seen in  FIG. 14 , receives service lines  270  from the robot  16  through wrist  44  and plate  50 . Service lines  270  may include hoses or rigid lines to transfer or communicate services, for example electric power, data communication, water or other conditioning fluid, compressed air and other services needed by the end effector  10  to function for the particular application. In a preferred example, a protective cover  260  is used to cover the socket  250  and service lines as they enter the socket  250 . 
         [0049]    In the example illustrated, connector system  220  further includes a plug  266  preferably affixed to the appliance or end effector  10 , a weld gun end effector  66  in the illustrations. Plug  266  provides the appropriate service lines (not shown) needed into the end effector  10  (shown as  66  for illustrative purposes only). As best seen in  FIG. 13  (although shown detached from end effector  66 ), plug  266  includes corresponding male prongs (not shown) or other communication plugs or ports that coincide with the plugs or ports in socket  256  for the effective transfer of the service lines  270  from the robot  16  to the end effector  10  to suit the particular application. 
         [0050]    An advantage of connector  220  over prior designs is its ability to substantially maintain or only minimally alter the center of gravity (CG) and tool center point (TCP) of an end effector  10  (illustrated as effector  66 ) while permitting all of the advantages described herein and as known by those skilled in the art. This is advantageous as relatively little or no reprogramming, readjustment or other modifications is required to change end effector  10  as described herein. 
         [0051]    It is understood that connector  220  may be attached to other parts of end effector  66  (or  10 ) other than in the position shown in  FIG. 12  (to the top of effector  66 ). Other connection points to the effector  10  to suit the particular application may be used. It is also understood that different components and configurations of the connection and interface points between the connector  224  and end effector  66  other than the specific plug and socket arrangements may be used without deviating from the present invention. 
         [0052]    Although connector  220  is shown with a weld gun end effector  66 , connector  220  is useable with other end effectors  10  described herein and known by those skilled in the field. Further, connection schemes other than studs  274  into bracket slots  246  may be used as known by those skilled in the field. For example, other quick connect fasteners or temporary locking systems may be used to securely attach end effector  10  to robot  16  while allowing relatively quick release to change the end effector. 
         [0053]    In operation to connect an appliance or end effector  10  to robot  16 , an appliance or end effector  10  is selected to suit the particular process or operation needed on work pieces  30  in a workstation  24 . The end effector, for example weld gun effector  66  includes studs  274  protruding outwardly and oriented so as to slide into slots  246  in brackets  240  as best seen in  FIGS. 12 and 14 . Socket  256  and coinciding plug  266  are oriented so as to engage on seating of the studs  274  into slots  246  for a positive locking engagement between the robot  16  and the end effector  10  thereby establishing communication of service lines between the robot  16  and end effector  10 . The end effector controller  54  is then placed in electronic and data communication with one or more controllers on the robot or other local or remote servers to receive additional programming or instructions, or is simply activated through on-board sensors and/or programs resident in its controller to begin the operation. As each end effector preferably includes its own controller, relatively little or no reprogramming, adjustment or other modifications are typically needed. When a change of end effector  10  is desired, the end effector  10  may be readily removed from connector  220  thereby sealingly severing the service lines  270  and terminating communication of controller  54  with the other controllers or servers. This allows robot  16  far greater versatility over prior end effector designs and connector systems which in effect, dedicated a robot to a specific task unless significant time and investment were expended to reconfigure, reprogram and re-equip the robot to serve an alternate task. 
         [0054]    The above-described examples have been described in order to allow easy understanding of the invention and do not limit the invention. On the contrary, the invention is intended to cover various modifications and equivalent arrangements, whose scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structure as is permitted under the law.