Operating method for a working area comprising a robot enslaved to a bending press for working metal sheets

• US 5,988,855 A
• Filed: 05/15/1997
• Issued: 11/23/1999
• Est. Priority Date: 05/16/1996
• Status: Expired due to Term

• Current Assignee: Salvagnini Italia S.P.A. (Salvagnini Holding SpA)
• Original Assignee: Salvagnini Italia S.P.A. (Salvagnini Holding SpA)
• Inventors: Marobin, Mario
• Primary Examiner(s): Gordon, Paul P.
• Application Number:
  US08/856,683
• Time in Patent Office: 922 Days
• Field of Search: 364/472.01-476.01, 364/468.24, 72/7.1, 72/8.1, 72/422
• US Class Current: 700/145
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/40054 Supply sheet to bending machine
• CPC Class Codes: G05B 2219/40421 Motion planning for manipulator handling sheet metal profiles

Abstract

An operating method for a working area comprising an anthropomorphous robot enslaved to a bending press for working a metal sheet comprises a) detecting fixed input data formed by geometric positions in space of the robot, of the press and at least of one feeding unit, b) the definition of variable input data formed by thickness of the metal sheet, height, angle and direction of each bend, length and orientation of each bend, position of a bending tool, c) processing the above-mentioned data in a processing unit by an algorithm based on the solutions of the inverse kinematics in order to automatically generate cycles of feeding, bending and unloading of said metal sheet and d) the transfer of the cycles to a control unit of the robot so as to drive the bending press to start a complete productive working cycle of a finished metal sheet starting from the metal sheet to be bent.

Claims

1. An operating method for a working area comprising a robot enslaved to a bending press for working metal sheets, said metal sheets being fed by a feeding unit, said feeding unit, robot and bending press having prefixed geometric positions in space, said robot being provided with an arm and with a grasping member capable of moving a metal sheet and being operatively connected to a control unit, characterized in that (I) said robot is anthropomorphous and (ii), for a given metal sheet to be bent on at least one side,

a) fixed input data are detected that comprise said geometric positions in space, without resorting to CAD techniques;

b) variable input data are selected which are formed by

thickness of said metal sheet,

height, angle and direction of each bend,

length and orientation of each bend,

position of a bending tool,

without resorting to CAD techniques;

c) the above mentioned data are processed in a processing unit by an algorithm to automatically generate cycles of feeding, bending and unloading of said metal sheet; and

d) said cycles are transferred to said control unit of said robot so as to drive said robot and bending press to start an automatic complete productive working cycle of a finished bent metal sheet starting from said metal sheet to be bent.

2. An operating method according to claim 1, characterized in that said fixed input data comprise a prefixed position of said robot.

3. An operating method according to claim 1, characterized in that said fixed input data comprise shape of said robot and of a grasping member thereof.

4. An operating method according to claim 1, characterized in that said fixed input data comprise a prefixed position of said press.

5. An operating method according to claim 1, characterized in that said fixed input data comprise a prefixed position of said feeding unit of said metal sheet.

6. An operating method according to claim 1, characterized in that said fixed input data comprise a prefixed position of a tilter of said metal sheet.

7. An operating method according to claim 1, characterized in that said fixed input data comprise a prefixed position of an unloading unit of said finished metal sheet.

8. An operating method according to claim 1, characterized in that point c) comprises a step of interpretation of said variable and fixed input data for selecting said side to be bent, said interpretation consisting of a sequence of analyses of said data (block 3.1), of an examination of the direction of the bend with respect to a previous bend (block 3.2) and of an examination of the orientation of said bend with respect to said previous bend (block 3.3) so as to deduce two types of information:

geometry of said sheet to be bent and sequence of execution of said working cycle.

9. An operating method according to claim 8, characterized in that said step of interpretation of said variable and fixed input data is based on a decisional algorithm that interprets and divides said data so as to identify linked working steps of a working cycle and associate them with a component formed by one of said robot, press, tilter, feeding unit, unloading unit.

10. An operating method according to claim 9, characterized in that in relation to said working steps the trajectories that join the components involved at the beginning and at the end of a working step (blocks 4.1;

4.2;

4.3;

4.4;

4.5) are automatically planned.

11. An operating method according to claim 10, characterized in that said planned trajectories are constituted by

trajectory from said feeding unit to said press (block 4.1),

trajectory from said press to said tilter and vice versa (block 4.2),

trajectory from said press to said press for bending said metal sheet (block 4.3),

trajectory from said press to said press for rotating said metal sheet (block 4.4),

trajectory from said press to said unloading unit (block 4.5).

12. An operating method according to claim 11, characterized in that for each point of one of said planned trajectories, a calculation is made of (block 5):

solutions of inverse kinematics for said arm of said robot,

associations between said metal sheet and one or more of said robot, press, feeding unit, tilter, unloading unit, for each found solution.

13. An operation method according to claim 12, characterized in that it comprises a step of analysis of interferences (block 6) between said metal sheet and one or more of said robot, press, feeding unit, tilter and unloading unit so as to automatically select a suitable solution among the found solutions.

14. An operating method according to claim 12, characterized in that it comprises a step of graphic representation capable of visualising the sheet/machine interferences, out-of-strokes, and improper rotations of axes of said robot so as to select, for all the points of said trajectory, the most suitable solution among those calculated for each point.

15. An operating method according to claim 13, characterized in that it comprises a step of generation of variable output data (block 7) wherein the results of said decisional algorithm and a calculation algorithm are converted into variable output data in a specific programming language for said control unit of said robot, said converted output data being constituted by position vectors of axes of said robot and by a list with names and sequence of the parametric cycles to be executed in relation to the number of sides to be bent and to the number of bends for each side of said metal sheet to be bent.

16. An operating method according to claim 15, characterized in that it comprises a step of generation of final output data (block 8) wherein output data are generated in the form of fixed and parametric working cycles, said final output data being formed by a set of elementary parametric cycles related to feeding, rotation, bending, turning over, unloading, said elementary cycles being written according to said specific language for said control unit of said robot and being specifically designed to receive said variable output data so that the combination of said parametric cycles and variable output data allow said complete production cycle, specific for said metal sheet to be bent, to be obtained automatically.

17. An operating method according to claim 1, characterized in that said bending press is enslaved to said robot and is integrated with it through drive signals and state signals directly inserted into the parametric bending cycle, so as to obtain a synchronized movement of a bending tool and of relevant abutment projections of said bending press.

18. An operating method according to claim 1, characterized in that said positions of abutment projections are obtained directly from said variable input data and transferred automatically from said processing unit to a control unit of said bending press.

19. An operating method according to claim 1, characterized in that said positions of abutment projections are preset on a control unit of said bending press.

20. A robot enslaved to a bending press for working metal sheets, said metal sheets being fed by a feeding unit, said feeding unit, robot and bending press having prefixed geometric positions in space, said robot being provided with an arm and with a grasping member capable of moving a metal sheet and being operatively connected to a control unit, characterized in that (i) said robot is anthropomorphous and (ii) said control unit is capable of operating according to an operating method wherein, for a given metal sheet to be bent on at least one side,

a) fixed input data are detected that comprise said geometric positions in space, without resorting to CAD techniques;

b) variable input data arc selected which are formed by

thickness of said metal sheet,

height, angle and direction of each bend,

length and orientation of each bend,

position of a bending tool,

without resorting to CAD techniques;

c) the above mentioned data are processed in a processing unit by an algorithm in order to automatically generate cycles of feeding, bending and unloading of said metal sheet; and

d) said cycles are transferred to said control unit of said robot so as to drive said robot and bending press to start an automatic complete productive working cycle of a finished bent metal sheet starting from said metal sheet to be bent.

21. A robot according to claim 20, characterized in that in said method said fixed input data comprise a prefixed position of said robot.

22. A robot according to claim 20, characterized in that in said method said fixed input data comprise shape of said robot and of a grasping member thereof.

23. A robot according to claim 20, characterized in that in said method said fixed input data comprise a prefixed position of said press.

24. A robot according to claim 20, characterized in that in said method said fixed input data comprise a prefixed position of said feeding unit of said metal sheet.

25. A robot according to claim 20, characterized in that in said method said fixed input data comprise a prefixed position of a tilter of said metal sheet.

26. A robot according to claim 20, characterized in that in said method said fixed input data comprise a prefixed position of an unloading unit of said finished metal sheet.

27. A robot according to claim 20, characterized in that in said method point c) comprises a step of interpretation of said variable and fixed input data for selecting said side to be bent, said interpretation consisting of a sequence of analyses of said data (block 3.1), of an examination of the direction of the bend with respect to a previous bend (block 3.2) and of an examination of the orientation of said bend with respect to said previous bend (block 3.3) so as to deduce two types of information:

geometry of said sheet to be bent and sequence of execution of said working cycle.

28. A robot according to claim 27, characterized in that in said method said step of interpretation of said variable and fixed input data is based on a decisional algorithm that interprets and divides said data so as to identify linked working steps of a working cycle and associate them with a component formed by one of said robot, press, tilter, feeding unit, unloading unit.

29. A robot according to claim 28, characterized in that in said method, in relation to said working steps, the trajectories that join the components involved at the beginning and at the end of a working step (blocks 4.1;

4.2;

4.3;

4.4;

4.5) are automatically planned.

30. A robot according to claim 29, characterized in that in said method said planned trajectories are constituted by

trajectory from said feeding unit to said press (block 4.1),

trajectory from said press to said tilter and vice versa (block 4.2),

trajectory from said press to said press for bending said metal sheet block 4.3),

trajectory from said press to said press for rotating said metal sheet (block 4.4),

trajectory from said press to said unloading unit (block 4.5).

31. A robot according to claim 30, characterized in that in said method, for each point of one of said planned trajectories, a calculation is made of (block 5):

solutions of inverse kinematics for said arm of said robot,

associations between said metal sheet and one or more of said robot, press, feeding unit tilter, unloading unit, for each found solution.

32. A robot according to claim 31, characterized in that said method comprises a step of analysis of interferences (block 6) between said metal sheet and one or more of said robot, press, feeding unit, tilter and unloading unit so as to automatically select a suitable solution among the found solutions.

33. A robot according to claim 31, characterized in that said method comprises a step of graphic representation capable of visualising the sheet/machine interferences, out-of-strokes, and improper rotations of axes of said robot so as to select, for all the points of said trajectory, the most suitable solution among those calculated for each point.

34. A robot according to claim 32, characterized in that said method comprises a step of generation of variable output data (block 7) wherein the results of said decisional algorithm and a calculation algorithm are converted into variable output data in a specific programming language for said control unit of said robot, said converted output data being formed by position vectors of the axes of said robot and by a list with names and sequence of the parametric cycles to be executed in relation to the number of sides to be bent and to the number of bends for each side of said metal sheet to be bent.

35. A robot according to claim 34, characterized in that said method comprises a step of generation of final output data (block 8) wherein output data are generated in the form of fixed and parametric working cycles, said final output data being formed by a set of elementary parametric cycles related to feeding, rotation, bending, turning over, unloading, said elementary cycles being written according to said specific language for said control unit of said robot and being specifically designed to receive said variable output data so that the combination of said parametric cycles and variable output data allow said complete production cycle, specific for said metal sheet to be bent, to be obtained automatically.

36. A robot according to claim 20, characterized in that in said method said bending press is enslaved to said robot and is integrated with it through drive signals and state signals directly inserted into the parametric bending cycle, so as to obtain a synchronized movement of a bending tool and of relevant abutment projections of said bending press.

37. A robot according to claim 20, characterized in that in said method said positions of abutment projections are obtained directly from said variable input data and transferred automatically from said processing unit to a control unit of said bending press.

38. A robot according to claim 20, characterized in that in said method said positions of abutment projections are preset on a control unit of said bending press.

39. A computer software program product embodied in a memory and comprising instructions executed by a processor for controlling a working area comprising a robot enslaved to a bending press for working metal sheets, said metal sheets being fed by a feeding unit, said feeding unit, robot and bending press having prefixed geometric positions in space, said robot being provided with an arm and with a grasping member capable of moving a metal sheet and being operatively connected to a control unit, characterized in that (I) said robot is anthropomorphous and (ii), for a given metal sheet to be bent on at least one side, wherein upon execution the program performs the steps of:

a) detecting fixed input comprising geometric positions in space, without resorting to CAD techniques;

b) selecting variable input data which are formed by

thickness of said metal sheet,

height, angle and direction of each bend,

length and orientation of each bend,

position of a bending tool,

without resorting to CAD techniques;

c) processing the above-mentioned data to generate automatically cycles of feeding, bending, and unloading of sheet metal; and

d) transferring said cycle;

to said control unit of said robot so as to drive said robot and bending press to start an automatic complete productive working cycle of a finished bent metal sheet starting from said metal sheet to be bent.