Abstract:
In a computerized device for processing a robot control program, at least one local area of a robot path of a robot is displayed at a display screen, the robot path containing a support point that is to be modified. The display screen also shows the support point, as well as a path course therethrough and at least one direction also proceeding through the support point perpendicularly to the path course. An input device allows a user to modify the path course by modifying the position of the support at the display screen.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention concerns a device and a method for processing a robot control program. 
     2. Description of the Prior Art 
     The movement path of the center of a tool connected with the robot (thus the tool center point (TCP)) is designated as a robot path of a robot while, insofar as the position of the robot itself is discussed in the following, the position of the base or the pedestal of the robot or, respectively, of the zero point of the robot or global coordinate system is designated relative to the path. The points in the path course that have been taught or programmed offline and normally serve as support points for interpolation of the goods course between these points (for example in the scope of a spine interpolation) are designated as support points of a robot path or, respectively, a path course. 
     EP 0 852 346 discloses a device to display a robot program, with a memory device to store the robot program; a display device at which a position can be designated with a pointer device; and with a processing device to display a work interval and an air intersection interval as successive lines, with presentation of one of the lines if this is designated by the pointer device, wherein the presentation corresponds to a command for a work priority in the robot program in connection with one of the displayed lines. 
     Given use of industrial robots, it frequently occurs that data from support points of an existing robot control program (abbreviated as: robot program) must be changed. This can result from a modification requirement for an existing robot program, for example when the module to be processed has been slightly modified. However, point data must also frequently be adapted in order to achieve a required clock time. These point corrections are normally conducted “online”, i.e. while the robot program is executed. 
     In order to conduct such an “online correction” of a point in space, knowledge of a reference system is required of the robot controller. In this simplest case, this is the global coordinate system of the robot. However, an (external) tool coordinate system or an otherwise defined coordinate system is also frequently used. A point correction can then be conducted relative to this; but the user must thereby translate the actual correction direction and correction size of the point relative to the robot path into corresponding X, Y and Z values of the local reference system. 
     The correct values to be input can hardly be intuitively determined by the operator since the reference system at the point to be corrected is not visible. In practice, for the most part multiple iterations are required for adaptation of the X, Y and Z values in order to exactly achieve the desired point correction. It is clear that this method has a large potential for error due to its initial imprecision. 
     It is known to register graphically represented path points by means of an optical system such as a light intersection sensor, wherein an adaptation of path points of the robot program ensues via graphical editing and, for changes to graphical 2D representations, are converted back into a 3D position change and are transferred into the robot program. However, no support is thereby given to the user with regard to the classification and orientation of a path point to be edited in the course of the robot path. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a user with a simple online correction while avoiding the cited disadvantages, and to provide the user with tools for an intuitive manual correction so that he or she can modify the location of a selected support point matching the local conditions without repeatedly matching the local conditions. 
     According to the invention, the above object is achieved by a device of the aforementioned type with a device to display at least one local region of a robot path of a robot to support a modification of a location of a support point of the robot path, a device to display the support point to be changed, the path course through this support point and at least one direction through the support point, perpendicular to the path course; and a device to modify the path course. To achieve the above object, the invention furthermore provides a method of the aforementioned type in which at least one local region of a robot path of a robot (said robot path provided by the robot program) is adapted to support a change of a location of a support point; and the support point to be changed, the path course through this and at least one direction through the support point perpendicular to the path course are displayed; and wherein the robot program is automatically correspondingly adapted after changing the displayed elements of the robot path. 
     With the invention, path or support points are read out from the robot program and indicated to the user for online adaptation by means of graphical assistance elements, such that a modification via graphically oriented editing can occur. The conversion between different coordinate systems is taken away from the user, which leads to a distinct reduction of the robot operation complexity. 
     In a preferred embodiment, the path course is presented as tangent to the robot path at the support point, so a simple and clear representation is provided. 
     In an additional preferred embodiment, it is provided that a plane perpendicular to the path course is displayed, wherein in particular the plane is displayed at least as a circular disc. In a development of this, it can be provided that the plane is displayed as an outer ring with an offset inner circular disc. Through this presentation, the user is enabled to specify the direction change of the location of the support point to be corrected by an angle relative to the cited direction, perpendicular to the path course in the cited plane. 
     To select a support point to be corrected, in an embodiment of the invention the course of the robot path is initially presented in a primary plane of a Cartesian coordinate system and/or in a selected plane. In order to render a selection more precisely, and if necessary to be remain below undifferentiated or un-discriminated support points in the representation of the entire path course, in an embodiment the representation of the path course can be enlarged. 
     According to the invention, a shift of the presented circular disc in the direction of its surface normal causes a shift of the support point on the programmed path in the robot control program; that a rotation of the arrow in the plane of the circular disc around its surface normal determines the correction direction in a plane perpendicular to the programmed path; and/or that a shift of the displayed support point along the arrow produces a displacement of the support point in the robot control program, perpendicular to the direction of the programmed path. The device according to the invention is advantageously fashioned in a corresponding manner. 
     So that the user can also purely intuitively register the position of the robot relative to the path course, it is provided that this is likewise graphically depicted, wherein the position of the robot is presented relative to the path course. 
     The device according to the invention is fashioned to reproduce the preceding depiction and graphical representations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates an embodiment of a device according to the present invention. 
         FIG. 2  illustrates display of a local region of a robot path to support modification of the location of a support point, in accordance with the present invention. 
         FIG. 3  shows an initial representation at the display for selection of a support point to be corrected in terms of its location with the device of  FIG. 1 . 
         FIG. 4  shows the illustration of  FIG. 1 , with the path course enlarged. 
         FIGS. 5   a  and  5   b  respectively illustrate the use of the device according to the invention to display steps in the method according to the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The device A according to the invention essentially has a processing device (computer) B, a display device (C) and at least one input device (D) such as a keyboard ( FIG. 1 ). 
     To facilitate the correction—in particular the online correction of the support point as it is required for, for example, interpolation of the path course by means of a spline method and was normally taught or even programmed offline—the invention initially provides the depiction of a point to be changed and, as a further tool in addition to this, initially provides a representation for the path course through point  1 —in the shown exemplary embodiment, in the form of a tangent  2  relative to the path course through point  1  ( FIG. 2 ). The movement direction is indicated by an arrowhead  3  at the end of the tangent  2 . 
     An artificial line  4  (here a dashed line) through the support point to be corrected at a right angle to the path course or, respectively, the tangent  2  representing this and in the correction plane is shown as an additional orientation aid. This artificial line  4  also forms an “artificial horizon”. To illustrate the plane perpendicular to the path course or, respectively, the tangent  2 , an inner circular surface  5  is shown through the support point  1  in which the dashed artificial line  4  also lies, as well as circular ring  6  surrounding the surface  5 . The shown elements  1  through  6  can be formed with different colors. The circular disc  5  around the support point  2  can in particular indicate the correction limits within which a correction of the location of the support point whose location is to be corrected can be produced. In the shown exemplary embodiment, an arrow that represents the correction direction of the desired spatial correction (aligned at an angle of, for example, 15°) is furthermore designated with  7 . 
     The desired correction can be input via associated keys or as a numerical value in the lower half of the representation from  FIG. 1 , or even via typical input with the aid of a computer input means (such as a computer mouse) in that the origin point of the arrow  7  is moved along the tangent  2  and the end point of the arrow  7  is moved on the circle representation  5 ,  6 . Located in the lower display field are maximum correction values for the path correction along the path course or, respectively, the tangent  2  (with ±3 mm in the shown exemplary embodiment and with a maximum of 5 mm perpendicular to this), while the angle can be freely selected in the entire plane of the discs  5 ,  6 . 
     The selection of the support point to be corrected can be made corresponding to the representations of  FIGS. 3 and 4 . 
     The right upper window representation in  FIG. 2  shows the path course  8  in the selected correction plane, here in the X-Y plane of a Cartesian coordinate system (as is indicated in the left lower corner of this window representation). On the path course, the support point  1  ( FIG. 2 ) to be corrected (which is selected from a point list in the left window portion in  FIG. 2 ), which is designated with C — 005, for example, is selected and emphasized. Furthermore, the position of the robot  9  is represented by a schematic depiction of such a robot  9  relative to the path course  8 . 
     The representation of the path course can be enlarged, as this is presented in  FIG. 3 . Furthermore, given such an enlargement the movement direction can be reflected by an arrow  3  corresponding to  FIG. 2 . The location of the robot  9  relative to the path course  8  is represented by a marking  10  at the edge of the presentation region in the enlarged depiction of  FIG. 3 . Depending on the orientation of the location of the robot relative to the path course  8 , the marking can migrate around the presentation region for the path course  8 , thus also be located at a different location than shown in  FIG. 3 . 
     The invention supports the operating mode of a user for correction of a support point or multiple support points of the movement path of a robot in the following manner: 
     First, according to  FIG. 3  the user calls up the symbolic representation (left half) and graphical representation of the path course  8  with the individual support points. He then selects a support point  1 , be it in the symbolic reproduction to the left, be it on the graphical path course to the right. The user can then produce an enlargement of the path course via zooming. Furthermore, it is possible to show the path course not only in the reproduced X-Y plane of the Cartesian coordinate system but also in other primary plane of such a Cartesian coordinate system or in other desired planes, depending on which representation is most suitable for correction of the location of a support point. 
     If necessary, an enlargement of the depiction of the path course  8  can be effected in order to select for correction a different support point than that initially selected, if this appears to be necessary or more suitable in the enlarged depiction. A switch from the left symbolic representation to the graphical depiction in the left region of  FIG. 2  then ensues, and the user can then produce a correction of the location of the selected support point  1  in the manner described above. 
     Since the two-dimensional reproduction in the right area of  FIG. 2 through 4  contains a projection of the path course on the corresponding coordinate plane, it is not to be excluded that a point located in this reproduction actually represents two points in a path course, or, respectively, that these are no longer to be differentiated or, respectively, discriminated in the reproduction. If this is the case, in the representation from  FIG. 1  the arrowhead  3  is not displayed as well, which indicates to the user that the path support point  1  shown there is not unambiguous and provides him with an inducement to select a different plane as a presentation or, respectively, projection plane in which the two points in question are differentiable. 
     The disc  6  of  FIGS. 5   a  and  5   b  schematically represents the tolerance range for a correction. The arrow  7  on the disc  6  symbolizes only the correction device. The length of the arrow does not vary. 
     After a correction, the middle point  1  in the graphic wanders outward on the arrow  7  (disc). The middle of the disc  6  represents the nominal point. The correction values are stored in offset data with reference to the nominal point. The disc edge thus represents the tolerance limit of the correction. 
     A correction ensues via colored, associated or otherwise differentiated arrows. For this the device according to the invention respectively possesses one + and one − key per correction device. A numerical input is likewise additionally possible. 
     Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted heron all changes and modifications as reasonably and properly come within the scope of their contribution to the art.