System And A Method For Controlling Movements Of An Industrial Robot

• US 20080091301A1
• Filed: 11/07/2005
• Published: 04/17/2008
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Research Ltd. (ABB Ltd.)
• Inventors: Brantmark, Hakan, Falk, Mattias, Johansson, Gorgen
• Granted Patent: US 9,069,351 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: G05B 19/41825 machine tools and manipulators only, machining centre
• CPC Class Codes: G05B 2219/32159 Each hardware unit together with its software forms one object
• CPC Class Codes: G05B 2219/32247 Real time scheduler
• CPC Class Codes: G05B 2219/40097 Select stations with mouse to create process steps
• CPC Class Codes: G05B 2219/40113 Task planning
• CPC Class Codes: G05B 2219/40308 Machine, conveyor model in library contains coop robot path
• CPC Class Codes: G05B 2219/45137 Punch, stamp, also with use die, mould
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A system and a method for controlling movements of an industrial robot during a work cycle including visiting and performing work on a plurality of workstations in a work cell. The system includes a set of predefined workstations. Each workstation includes preprogrammed robot code adapted to the workstation, an entry point defining the entrance position to the workstation, and one or more predefined paths to be followed by the robot at the workstation. A user interface is adapted to provide information about the predefined workstations and allows an operator to select one or more of the predefined workstations and to specify a desired part flow between the workstations. A scheduling unit is adapted during execution of the work cycle to schedule the execution order for the workstations based on the workstations selected from the predefined workstations and the desired part flow, and to control the movements of the robot based on the scheduled execution order and the predefined paths.

Claims

1. A system for controlling the movements of an industrial robot during a work cycle including visiting and performing work on a plurality of workstations in a work cell, the system comprising:

a set of predefined workstations and a user interface (24), adapted to provide information about the predefined workstations and allowing an operator to select one or more of the predefined workstations and to specify a desired part flow between the workstations, wherein the system is adapted to receive information about external events and wherein said predefined workstations comprises;

preprogrammed robot code adapted to the workstation,

an entry point defining the entrance position to the workstation,

one or more predefined paths to be followed by the robot at the workstation, and

a scheduling unit (22), adapted to, during execution of the work cycle;

schedule the execution order for the workstations based on the workstations selected from said predefined workstations, the desired part flow and said information about external events, and

to control the movements of the robot based on the scheduled execution order and said predefined paths.

2. The system according to claim 1, wherein the system is adapted to receive information regarding the status of the workstations and wherein said scheduling unit is adapted to determine which of the workstations to be executed next based on the current status of the workstations.

3. The system according to claim 1, wherein the system is adapted to provide a possibility to point out an alternative workstation to be executed if the ordinary workstation is not ready to be executed, and that said scheduling unit is adapted to determine which of the workstations to be executed next based on pointed out alternative workstations.

4. The system according to claim 1, wherein the system is adapted to provide a possibility to assign different priorities to the chosen workstations, and that said scheduling unit is adapted to determine which of the workstations to be executed next based on the assigned priorities.

5. The system according to claim 1, wherein each of said predefined workstations comprises a model of a real workstation including a software object having an interface with one or more properties, methods and events, and the object is adapted to interact with the surrounding through its properties, methods and events.

6. The system according to claim 2, wherein said properties includes the status of the workstation.

7. The system according to claim 3, wherein said properties include the alternative workstation to the workstation.

8. The system according to claim 4, wherein said properties include the priority of the workstation.

9. The system according to claim 5, wherein said methods include one or more interrupt routines defining what to do when a specific interrupt signal arrives and said scheduling unit is adapted to execute the interrupt routine upon receiving the specific interrupt signal.

10. The system according to claim 5, wherein said events includes an event adapted to trigger on a change in a signal corresponding to the status of the workstation and based thereon to update the status of the workstation.

11. The system according to claim 1, wherein said predefined paths comprises a predefined station path defining the robot movement into and out of the workstation, wherein the station path comprises an entrance path defining the robot movement from the entry point to a process point defined inside the workstation and an exit path defining the robot movement from the process point out of the workstation.

12. The system according to claim 11, wherein said predefined paths comprise at least one predefined process path defining the robot movement inside the workstation, wherein the process path comprises a second entrance path defining the robot movement from said first process point to a second process point defined inside the workstation and a second exit path defining the robot movement from the second target point back to the first process point.

13. The system according to claim 1, wherein said predefined paths comprise an array of predefined path points and said scheduling unit is adapted to retrieve the path points from said array upon execution of the path.

14. The system according to claim 13, wherein said predefined path points comprise information about whether the point is a move-in or a move-out point, and the type of movement in the point.

15. The system according to claim 1, wherein said set of predefined workstations comprises at least one predefined work cell comprising:

an entry point of the work cell defining the entrance position to the work cell, and

predefined paths to be followed by the robot between the entry points of the workstations, and

predefined paths to be followed by the robot from each entry point of the workstations to the entry point of the work cell.

16. The system according to claim 5, wherein said predefined work cell comprises a model of the real work cell including a software object having an interface with one or more properties, methods and events, and the object is adapted to interact with the surroundings through its properties, methods and events and that the software object of the cell has the same interface as the software objects of the workstations.

17. The system according to claim 12, wherein the scheduling unit is adapted, upon receiving a fault interruption signal, to move the robot out of the workstation and to the entry point of the work cell by moving the robot along said predefined paths in dependence on the current position of the robot.

18. The system according to claim 17, wherein the scheduling unit is adapted to move the robot along said predefined paths in dependence on one or more predefined rules.

19. The system according to claim 18, wherein the rules comprise, in case the failure occurs when the robot position is on the entrance path, that the robot will reverse on the entrance path, and in case the failure occurs when the robot position is on the exit path, that the robot will continue to follow on the exit path.

41. Use of a system according to claim 1 in a die-cast application.

20. A method for controlling the movements of an industrial robot during a work cycle including visiting and performing work on a plurality of workstations in a work cell, the method comprising:

storing a set of predefined workstations, each comprising;

preprogrammed robot code adapted to a specific type of workstation,

an entry point defining the entrance position to the workstation, and

one or more predefined paths to be followed by the robot at the workstation,

receiving information about external events,

determining the execution order for the workstations based on a set of workstations chosen from said predefined workstations, a desired part flow, and external events, and

moving the robot based on the scheduled execution order and said predefined paths.

21. The method according to claim 20, further comprising:

receiving information regarding the status of the workstations and determining which of the workstations to be executed next based on the current status of the workstations.

22. The method according to claim 20, further comprising:

pointing out an alternative workstation to be executed if the ordinary workstation is not ready to be executed, and

determining which of the workstations to be executed next based on the pointed out alternative workstations.

23. The method according to claim 20, further comprising:

assigning different priorities to the chosen workstations, and

determining which of the workstations to be executed next based on the assigned priorities.

24. The method according to claim 20, wherein each of said predefined workstations comprises a model of a real workstation including a software object having an interface with one or more properties, methods and events, and the object interacts with the surroundings through its properties, methods, and events.

25. The method according to claim 21, wherein said properties include the status of the workstation.

26. The method according to claim 22, wherein said properties include the alternative workstation to the workstation.

27. The method according to claim 23, wherein said properties include the priority of the workstation.

28. The method according to claim 24, wherein said methods include one or more interrupt routines defining what to do when a specific interrupt signal arrives and the interrupt routines are executed upon receiving the specific interrupt signal.

29. The method according to claim 25, wherein said events include an event adapted to trigger on a change in a signal corresponding to the status of the workstation and based thereon to update the status of the workstation.

30. The method according to claim 20, wherein said predefined paths comprise a predefined station path defining the robot movement into and out of the workstation, wherein the station path comprises an entrance path defining the robot movement from the entry point to a process point defined inside the workstation and an exit path defining the robot movement from the process point and out of the workstation.

31. The method according to claim 30, wherein said predefined paths comprise at least one predefined process path defining the robot movement inside the workstation, wherein the process path comprises a second entrance path defining the robot movement from said first process point to a second process point defined inside the workstation and a second exit path defining the robot movement from the second target point back to the first process point.

32. The method according to claim 20, wherein said predefined paths comprise an array of predefined path points and retrieving the path points from said array upon execution of the path.

33. The method according to claim 32, wherein said predefined path points comprise information about whether the point is a move-in or a move-out point, and the type of movement in the point.

34. The method according to claim 20, further comprising:

defining at least one predefined work cell comprising;

an entry point of the work cell defining the entrance position to the work cell, and

predefined paths to be followed by the robot between the entry points of the workstations, and

predefined paths to be followed by the robot from each entry point of the workstations to the entry point of the work cell.

35. The method according to claim 24, wherein said predefined work cell comprises a model of the real work cell including a software object having an interface with one or more properties, methods and events, and the object is adapted to interact with the surroundings through its properties, methods and events and that the software object of the cell has the same interface as the software objects of the workstations.

36. The method according to claim 31, further comprising:

upon receiving a fault interruption signal, moving the robot out of the workstation and to the entry point of the work cell by moving the robot along said predefined paths in dependence on the current position of the robot.

37. The method according to claim 36, wherein, upon receiving said fault interruption signal, the robot is moved along said predefined paths in dependence on one or more predefined rules.

38. The method according to claim 37, wherein said rules comprise, in case the failure occurs when the robot position is on the entrance path, that the robot will reverse on the entrance path and, in case the failure occurs when the robot position is on the exit path, that the robot will continue to follow on the exit path.

39. A computer program product, comprising:

a computer readable medium; and

computer program instructions recorded on the computer readable medium and executable by a processor for carrying out a method for controlling the movements of an industrial robot during a work cycle including visiting and performing work on a plurality of workstations in a work cell, the method comprising;

storing a set of predefined workstations, each comprising;

preprogrammed robot code adapted to a specific type of workstation,

an entry point defining the entrance position to the workstation, and

one or more predefined paths to be followed by the robot at the workstation,

receiving information about external events,

determining the execution order for the workstations based on a set of workstations chosen from said predefined workstations, a desired part flow, and external events, and

moving the robot based on the scheduled execution order and said predefined paths.

40. (canceled)