Abstract:
A robotic system for performing surface finishing processes on a large object, is provided, the system includes at least one platform having a connected robot, the robot performing a surface finishing process on the large object. Also included is an automatic guided vehicle (AGV) separable of the platform movable independent of the platform for moving under the platform, lifting up the platform and moving the platform multiple locations along or around the large object to extend a useful working envelope of the robot.

Description:
FIELD OF THE INVENTION 
       [0001]    There is an increasing need for robotic application of finishes to very large objects. On commercial aircraft for example, it is important to minimize the added weight of coatings, as well as control the consistency of the thickness of coatings for consistency of electrical resistance to electrostatic charge conduction. There is also an increased interest in more consistent, high quality finishes on executive aircraft that is only possible by robotic application. There is also economic pressure to reduce the large cost of manual labor involved in applying finishes to large objects. This invention provides the means to robotically perform surface finishing operations (inclusive of surface preparation including but not limited to sanding, washing, priming and chemical treating, surface filing, surface roughing) to large objects while overcoming the practical limitations that currently exist in the industry. 
       BACKGROUND OF THE INVENTION 
       [0002]    Robotic surface finishing operations such as sanding, washing and painting have been applied to large objects in the past by a number of means. One means has been to mount robots to large extended axis machines such as gantry cranes or floor supported rails in order to extend the limited reach of a typical 6-axis robot. Another means has been to mount a robot on a platform that moves along a fixed track that follows the contour of the part to be finished, thus allowing the robot to extend its useful envelope. Yet another means has been to mount a robot to a mobile platform such as a wheeled vehicle in order to extend the reach of the robot. While these solutions have been implemented, they have the following limitations: They are very costly and impractical for large complex shapes like a fully assembled commercial aircraft. They tend to be specific for a given large object to be processed and are not flexible enough by design to handle a broad range of sizes and shapes of large objects. A further limitation to the current state of the art is that of expandability. It is very difficult and costly if more robots need to be added to increase throughput or extend the system to process a larger object. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention herein described is a robotic system for performing surface finishing operations to large objects. The essential elements of the invention are; a plurality of movable platforms that include a robot and its associated support equipment for performing surface finishing operations such as washing, sanding or coating for example, a common means of moving these plurality of platforms (such as an automatic guided vehicle) about a work space such as a large aircraft hangar or marine ship yard, and a means of powering the robot platforms at their various locations in the workspace. Additionally, a means is disclosed of maintaining power to the robot platforms while they are being relocated to a new position. Those skilled in the art will understand that typically, surface finishing processes are performed in a potentially explosive or flammable atmosphere and therefore a safe means of powering the movable robot platforms in a flammable or explosive atmosphere is included in this invention. 
         [0004]    It will be understood that the disclosed system is highly flexible as the movable robot platforms can be moved to various locations about an object without the limitations of fixed rails or other mechanical constraints. Also, the platforms can be unique and customized for various operations or reach requirements. The platforms also can be sidelined for maintenance and a spare platform can be brought in as a replacement. The system is economically efficient because the placement and relocation of the robot platforms is performed by an independent entity (an AGV in the preferred embodiment) so that each robot platforms need not include the cost associated with independent mobility. One AGV can service a number of robot platforms. Additionally, because of the complete mobility and flexibility of the system, robot platforms and AGV&#39;s could be shared between two work environments. For example, two adjacent aircraft hangers could share movable robot platforms and AGVs. 
         [0005]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0007]    A clear understanding of the key features of the invention summarized above may be had by reference to the appended drawings, which illustrate the method and system of the invention, although it will be understood that such drawings depict preferred embodiments of the invention and, therefore, are not to be considered as limiting its scope with regard to other embodiments which the invention is capable of contemplating. Accordingly: 
           [0008]      FIG. 1  illustrates a movable platform  1  which includes a 6-axis robot arm  2 , which in turn is mounted to a group of auxiliary motion axis which in this embodiment includes a vertical axis  3 , a rotational axis  21 , and a horizontal axis  4 . The auxiliary axis being functional to enlarge the working envelope of the robot  2  for a given location of the movable platform  1 . Additionally the movable robot platform shown in  FIG. 1  includes support equipment including the following components: A robot control panel  8 , a process control panel  5 , a compressed air reservoir  7 , and an energy storage pack  6  to provide electrical power to the platform while not connected to outside power such as when it is being relocated. 
           [0009]      FIG. 2  illustrates a movable platform  1  which includes a 6-axis robot arm  2 , mounted on auxiliary motion axis  3 , 21 , 4  which provide the following extended motions: Vertical  13 , Horizontal  12 , and rotational  14 . An automatic guided vehicle (hereafter AGV)  9  is shown in two alternate positions approaching the movable platform  1  from either of two directions ( 45  and  46 ), in order to travel beneath the movable platform ( 1 ). The AGV in this embodiment includes powered casters  11 , and platform lifting points  10  functional to lift the movable platform in order to move it from one location to another. 
           [0010]      FIG. 3  illustrates two movable robot platforms  1  that include 6-axis process robot arms  6 , an AGV  9  for transporting the movable platforms  1 , around and along a large object  18  in this embodiment a large commercial aircraft. Further illustrated is a power and communication network  17  including plug-in points  16 , and a power distribution control center  19 . Further shown is a means to connect the movable platform  1  into the plug-in point  16  via a plug in connector  15  mounted to the movable platform  1 . The movable platforms  1  is supported by support columns  20 , which may be located over lock down anchors  22  ( FIG. 4 ) to eliminate tipping or instability of the movable platform  1  under dynamic conditions. 
           [0011]      FIG. 4  illustrates a movable robot platform  1  supporting a process robot  2  supported by axillary axis ( 2  and  3 ), a plug-in power and communication connection means  15  mounted to the movable robot platform  1 . A plurality of positionally fixed plug-in connection points  16  are shown such that the movable platform  1  could be moved to various locations around a large object  18  in order to extend the working envelope of the process robot  2 . A power, communication and utility network  17  provides power, communication and any required utilities such as compressed air or process liquids required to the movable robot platform  1  through the pug-in points  16  and the plug-in means  15 . Further shown are lock down anchor points  22  which allow the support columns  20  to be securely fixed to the ground in order to provide stability to the platform  1  under dynamic conditions. 
           [0012]      FIG. 5  illustrates a movable robot platform  1  supporting a process robot  2  supported by axillary axis ( 2  and  3 ), the movable robot platform  1  being shown supported by an AGV  9 . The AGV  9  being functional to move/relocate the robot platform  1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0014]    The preferred embodiment of this invention is a system of movable robot platforms  1  that allow for a flexible solution to performing surface process treatments such as (but not limited to) washing, scrubbing, sanding or painting to large objects such as commercial aircraft. The robot platforms will include a commercially available 6 axis robot arm  2  which may be mounted to extended auxiliary axis such as a vertical lift  3  which includes a rotational axis  21  and a linear translation axis  4 . The platform  1  will carry the equipment necessary to support the robot operations. This support equipment will typically be a robot controller panel  8 , a process control panel  5  for controlling the process equipment such as a paint applicator or robotic sanding head, a compressed air tank  7  for a temporary compressed air source for times when the platform is not connected to an outside source, and a battery pack  6  for temporary electrical power for when the platform is not connected to an outside electrical power source (when it is being transported between work positions for example). One that is skilled in the art would understand the temporary sources of air and electrical power could also be supplied by flexible hoses and cables that are connected to the movable platform form a fixed outside source. 
         [0015]    The preferred method of moving the robot platforms about a work area is by an Automatic Guided Vehicle (AGV)  9  which has connected lifting mechanisms  10  allowing it to move under the robot platform and lift it in order to relocate it to a new work location (illustrated in  FIGS. 2 and 4 ). The robot platform  1  can also be manually moved with a fork lift truck or other means. The robot platform can be moved along tracks in the floor or a tug along. In an alternative embodiment, item  10  can also be locator receptacles for extendable pins that are connected on the platform  1 . The AGV  9  is guided around the work area by traditional methods such as magnetic strips embedded in the floor of the work area or a dedicated local radio GPS operable to send position and direction data to the AGV. 
         [0016]    The system includes a power and utility distribution grid  17  that supplies the robot platforms with electrical power and compressed air for example, once the platform is positioned at a work area. The distribution grid includes a distribution control panel or center  19  that is located outside the hazardous or flammable work environment. The grid  17  includes connection points  16  at strategic locations along and around the large object to be processed such as an aircraft  18 . The movable robot platform  1  has a plug-in connection means  15  that enables the platform to receive power, utilities, and communication through the distribution grid  17  from the distribution control panel  19 . The connection point  16  and plug-in means  15  will require either a purge enclosure or explosion proof connectors due to the hazardous environment. One skilled in the art will understand the requirements for power connections in hazardous locations. In the preferred embodiment the power distribution control panel  19  will maintain the connection points  16  in a safe unpowered state until it senses through an intrinsically safe sensor that the platform connection means is engaged via explosion proof connections, at which point the distribution panel will allow power to connect to the platform  1 . 
         [0017]    The movable robot platforms  1  can be customized for specific duties. For example in  FIG. 3  two robot platforms are shown with different t vertical auxiliary axis heights in order to perform different operations. In the example shown in  FIG. 3 , one robot platform has a taller vertical reach in order to reach the top of the vertical stabilizer of a commercial aircraft.  FIG. 3  also illustrates two robot platforms  1  and one AGV  9  available to move either robot platform. 
         [0018]    The following sequence describes the operation of the preferred embodiment. For a large commercial aircraft painting operation the aircraft is typically positioned in a large paint hanger. The robotic painting system herein described would operate as follows: While the aircraft is transferred into the hanger the movable robotic platforms  1  and AGV  9  will be positioned in areas of the hanger so as to be out of the way and allow free uninhibited movement and positioning of the aircraft  18 . Once the aircraft is located either in a known predetermined location or its location identified by a position identification system such as a vision or laser measurement system (not part of this invention), The AGV  9  then moves to and positions itself under a robot platform  1 , moves the robot platform to a predetermined position near the aircraft and over a power connection plug-in point  16 , and lowers the robot platform unto lock-down anchor points  22 . The lock down anchor may be a mechanism that moves an anchor connected with the platform into a hook type device or striker attached with the floor, or in other applications may be an extendable latch that connects with a striker fixed to the platform. Even after the platform  1  has been locked down, there is clearance AGV  9  to remove itself from under the platform  1 . The AGV  9  then proceeds to another movable robot platform  1  and repeats the sequence. When the robot platforms are locked into position near the aircraft, the plug in means  15  are actuated to engage connections embedded in the network connection points  16  for utilities such as electrical power, communication, and any other utilities such as compressed air that are required. For safety reasons, the electrical connections remain un-energized until the connections are complete. When the power, communication and utility network  17  control panel  19  senses via an intrinsically safe sensor, that the robot platform is plugged in, power is turned on to that connection point to supply control power and communication to the robot platform  1 . 
         [0019]    In the preferred embodiment the robot platform will have a temporary power supply on board to maintain power to the robot controller  8  and the process control panel  5  as necessary during periods when the robot platform is not plugged into the power and communion distribution network  17 . Additionally, the robot platform will have a supply of stored compressed air on board to supply purge air to the robot while it is not plugged into the power, communication and utility network. Having temporary utilities on board allows the robot to begin operation quickly upon repositioning rather than go through time consuming power up sequences. When the movable robot platform is positioned, the robot can begin its painting (or sanding. Washing etc) process and work independently until it completely processes the area that it can reach from the current platform location. When complete, the robot controller sends a signal to the network control panel which in turn requests a position move to the AGV. 
         [0020]    As many movable robot platforms as required to complete the overall process in a required cycle time may be employed. Each movable robot platform may complete a number of sections of the aircraft or large object by being moved from one location to another along and around the aircraft or other large object to be processed. Robot platforms may differ from one another in that they may be uniquely fitted to perform specific functions. For example, the highest point of an object may be a small area that only requires one robot platform to have the vertical reach required to process that area. In this case there may be a number of robot platforms that process the bulk of the aircraft and only one or two platforms fitted to reach the top of the vertical stabilizer for example. 
         [0021]    In aircraft painting operations it is often the case that between coats of paint the aircraft is subjected to elevated temperatures to accelerate the cure of the coating. The elevated cure temperature required is sometimes higher than the process equipment mounted to the robot platform is designed to endure. It should be obvious that this invention has the distinct advantage of allowing the robot platforms to be removed from the painting area and into a separate room for example, while the temperature of the environment around the aircraft is elevated to cure the coating. 
         [0022]    It is also a distinct advantage of this invention that robot platforms may be added or subtracted from the system as needed, and even shared between adjacent paint systems as needed. It is also an advantage that a robot platform can be set aside for repair or maintenance without adversely affecting the overall system, by having spare robot platforms that can be rotated in or out of service. 
         [0023]    It is clear that many variations of the invention may be envisioned. Movable robot platforms could be manually moved into position for example instead of employing an AGV. Power and utilities could be supplied to the robot platform by overhead cables and hoses festooned from the ceiling or pulled across the ground for example instead of utilizing the power, communication and utility network herein described. Conversely, robot platforms could be powered by larger onboard energy storage packs (battery packs for example) that allow the platform to remain unconnected to the larger system while performing processing duties. These battery packs could either be recharged or traded for fully charged ones between process duties. 
         [0024]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.