SYSTEM AND METHOD FOR THE AUTOMATIC GENERATION OF ROBOT PROGRAMS

• US 20140371905A1
• Filed: 09/06/2012
• Published: 12/18/2014
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: Convergent Information Technologies GmbH
• Original Assignee: Convergent Information Technologies GmbH
• Inventors: Eberst, Christof, Ferri, Massimo, Stoeffler, Bernhard, Tornese, Riccardo, Umgeher, Gerald
• Granted Patent: US 9,701,019 B2
• Time in Patent Office: Days
• US Class Current: 700/253
• CPC Class Codes: B25J 9/1664 characterised by motion, path, trajectory planning
• CPC Class Codes: B25J 9/1671 characterised by simulation, either to verify existing program or to create and verify new program, CAD/CAM oriented, graphic oriented programming systems
• CPC Class Codes: G05B 19/4182 manipulators and conveyor only
• CPC Class Codes: G05B 2219/39102 Manipulator cooperating with conveyor
• CPC Class Codes: G05B 2219/45065 Sealing, painting robot
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

Workflow charts for processing (e.g., treating, machining) a workpiece with a tool of an industrial robot are automatically generated. An initial chart has a plurality of tool paths for a workpiece in a defined target position and for defined process parameters. The tool path determines the desired movement of the tool along the workpiece. A state space describing variable parameter values that impact the workpiece processing are defined. Each point in the space represents a concrete combination of possible parameter values. The space is discretized into individual states. The processing of the workpiece is simulated using the initial chart for one or several discrete states and the simulated process results are evaluated according to a pre-definable criterion. The initial chart is iteratively modified, subsequently workpiece processing is simulated using the modified chart for at least one discrete state, and the simulated processing results are evaluated with a pre-definable cost function.

Claims

1-12. -12. (canceled)

13. A method for the automatic, computer-assisted generation of workflow charts for processing a work piece with a tool using an industrial robot, the method comprising:

preparing an initial chart with a plurality of tool paths for a work piece in a specific target position and for specific process parameters that impact the processing of the work piece, a tool path defining a target movement of the tool along the work piece;

defining a state space describing variable parameter values that impact the processing of the work piece, wherein each point in the space represents a specific combination of potential parameter values;

discretizing the space into individual states;

simulating the processing of the work piece using the initial chart for one or more discrete states and analyzing a result of the simulated processing based on a pre-definable criterion;

iteratively modifying the initial chart and subsequently simulating the processing of the work piece using the modified chart for at least one discrete state, and evaluating the result of the simulated processing based on a pre-definable cost function; and

performing the iteratively modifying step until the cost function reaches a minimum or drops below a threshold value, indicating that an optimized chart for the respective state has been identified.

14. The method according to claim 13, which further comprises:

allocating the optimized chart and the state used in the iteration to a first group;

simulating the processing of the work piece using the optimized chart for a further discrete state and evaluating a result of the simulated processing of the work piece based on the pre-definable cost function; and

allocating the additional state used in the simulation to the first group when the cost function for the additional state drops below a further threshold value;

or

allocating the additional state used in the simulation to a further group when the cost function for the additional state does not drop below the further threshold value.

15. The method according to claim 14, which further comprises:

iteratively modifying the optimized chart, subsequently simulating the processing of the work piece using the modified chart for the additional state, and evaluating the result of the simulated processing of the work piece based on the cost function;

further iteratively modifying the chart until the cost function reaches a minimum or drops below a threshold value, indicating that a further optimized plan for the additional state has been identified; and

allocating the optimized chart and the state used in the iteration to a first group.

16. The method according to claim 13, which comprises, prior to an iterative modification of a chart for a specific state, testing through simulation to determine whether a previously optimized chart for the specific state will result in a processing result for which the cost function falls below a predefined threshold value.

17. The method according to claim 13, which comprises, prior to performing the step of iteratively modifying the initial chart, discarding all states for which the result of the processing simulated with the initial chart fails to satisfy a pre-definable criterion.

18. The method according to claim 13, wherein the step of modifying a chart comprises at least one of the following steps:

changing an execution sequence of the tool paths of a chart;

changing a speed of execution of a tool path or of a segment of a tool path;

shifting a position of a tool path or of individual segments of a tool path;

changing a position and an orientation of the tool relative to the work piece along individual tool paths or path segments;

changing a robot configuration for individual tool paths or path segments;

changing a force that is exerted by the tool on the work piece or another parameter that relates to an interaction between the work piece and the tool.

19. A method for the automatic, computer-assisted generation of workflow charts for processing a work piece with a tool of an industrial robot, the method comprising:

providing an initial chart containing a plurality of tool paths for a work piece in a specific target position and for specific process parameters that describe the processing, wherein a tool path defines a target movement of the tool along the work piece;

defining a state space, which describes possible sequences and starting times for the tool paths of the initial chart, wherein each point in the state space describes a specific sequence having a specific starting time;

discretizing the space into individual states;

simulating the processing of the work piece using the initial chart for different, discrete states, and analyzing a result of the simulated processing according to a pre-definable criterion;

iteratively modifying the initial chart, then simulating, factoring in a movement that superposes the work piece, the processing of the work piece using the modified chart for at least one discrete state and evaluating the result of the simulated processing according to a pre-definable cost function; and

performing the iteration until the cost function reaches a minimum or drops below a threshold value, indicating that an optimized chart for the respective state has been identified.

20. The method according to claim 19, which comprises, prior to performing the step of iteratively modifying the initial chart, discarding all states for which the result of the processing simulated with the initial chart fails to satisfy a pre-definable criterion.

21. The method according to claim 19, which further comprises specifying a motion pattern for a robot base of the industrial robot and factoring in the motion pattern in the simulation.

22. The method according to claim 19, wherein the simulating step comprises calculating a time slot and/or a window with respect to the displacement between robot base and work piece, for which a path point of a tool path can be achieved by the tool.

23. The method according to claim 22, wherein the cost function is greater, the closer the tool is to an edge of the time slot in the simulated execution of a tool path.

24. The method according to claim 19, which further comprises, for each optimized plan, assigning a target relative position between work piece and robot base to each path point on a tool path.

25. A method of controlling a robot for processing a moving work piece by way of a tool using an industrial robot according to a chart containing a plurality of robot motions defined by path points, wherein each path point is assigned a target position of the work piece, the method comprising the following steps, to be performed during an execution of a robot motion:

measuring an actual position of the work piece and determining a speed of the work piece;

calculating a current target position of the work piece for the current position of the robot using the target positions of the work piece that are assigned to the path points;

calculating a difference between the target position and the actual position of the work piece;

determining a next target position of the robot to be reached, and a time at which the next target position is to be reached, so as to decrease or minimize a difference between the target position and the actual position of the work piece.

26. The method according to claim 25, wherein the step of calculating the current target position is effected by interpolation.

27. The method according to claim 25, wherein the step of determining the next target position of the robot to be reached comprises selecting a path point according to the chart or interpolating between two path points according to the chart.