Intelligent system for generating and executing a sheet metal bending plan

• US 20020016647A1
• Filed: 08/16/2001
• Published: 02/07/2002
• Est. Priority Date: 11/09/1994
• Status: Active Grant

• Current Assignee: Amada America, Inc. (Amada Company Limited)
• Original Assignee: Amada America, Inc. (Amada Company Limited)
• Inventors: Hazama, Kensuke, Bourne, David Alan, Krishnan, Sivaraj Sivarama, Williams, Duane Thomas, Kim, Kyoung Hung
• Granted Patent: US 6,507,767 B2
• Time in Patent Office: Days
• US Class Current: 700/165
• CPC Class Codes: B21D 5/02 on press brakes without making use of clamping means
• CPC Class Codes: G05B 19/4069 Simulating machining process on screen G05B19/4068 takes precedence
• CPC Class Codes: G05B 19/4097 characterised by using design data to control NC machines, e.g. CAD/CAM G05B19/4093 takes precedence
• CPC Class Codes: G05B 19/41825 machine tools and manipulators only, machining centre
• CPC Class Codes: G05B 2219/31352 Expert system integrates knowledges to control workshop
• CPC Class Codes: G05B 2219/35189 Manufacturing function, derive gripper position on workpiece from cad data
• CPC Class Codes: G05B 2219/39105 Manipulator cooperates with moving machine, like press brake
• CPC Class Codes: G05B 2219/39467 Select hand as function of geometric form of hand
• CPC Class Codes: G05B 2219/45143 Press-brake, bending machine
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

An intelligent sheet metal bending system is disclosed, having a cooperative generative planning system. A planning module interacts with several expert modules to develop a bending plan. The planning module utilizes a state-space search algorithm. Computerized methods are provided for selecting a robot gripper and a repo gripper, and for determining the optimal placement of such grippers as they are holding a workpiece being formed by the bending apparatus. Computerized methods are provided for selecting tooling to be used by the bending apparatus, and for determining a tooling stage layout. An operations planning method is provided which allows the bending apparatus to be set up concurrently while time-consuming calculations, such as motion planning, are performed. An additional method or system is provided for positioning tooling stages by using a backstage guide member which guides placement of a tooling stage along the die rail of the bending apparatus. A method is provided for learning motion control offset values, and for eliminating the need for superfluous sensor-based control operations once the motion control offset values are known. The planning system may be used for facilitating functions such as design and assembly system, which may perform designing, costing, scheduling, and/or manufacture and assembly.

Claims

1. In a computer having at least one processor and a memory, a device that selects a gripper that holds a workpiece to be utilized by a bending apparatus that bends unfinished workpieces formed of sheets of malleable material, the device comprising:

a reader;

a former;

a chooser;

a predictor;

a determiner; and

an adjuster;

wherein said reader reads information describing the geometry of a library of grippers to be chosen from, said former forms a set of available grippers excluding grippers that have certain undesired geometric features, said chooser chooses a gripper from the set of available grippers as a function of the width of the gripper, the length of the gripper, and the knuckle height of the gripper, said predictor is adapted to predict, for each gripper within the set of available grippers, a repo number equal to an estimated number of times the bending apparatus will need to change the position at which the gripper holds the workpiece in order to perform a complete sequence of bending operations on the workpiece, said determiner is adapted to determine the smallest predicted repo number, and said adjuster is adapted to adjust the set of available grippers to include the available grippers having a repo number equal to the smallest predicted repo number, before choosing a gripper as a function of the width, length and knuckle height of the gripper.

2. The device according to claim 1, wherein the gripper comprises a gripper adapted to hold the workpiece while loading and unloading the workpiece into and from a die space of the bending apparatus in order to perform bending operations.

3. The device according to claim 1 the gripper comprising a repo gripper adapted to hold the workpiece while a robot changes a grip position of the robot on the workpiece.

4. The device according to claim 3, further comprising:

an intermediate shape determiner;

a constructor; and

a utilizer;

wherein said intermediate shape determiner is adapted to determine intermediate shapes of the workpiece, said constructor is adapted to construct data representations of the respective intermediate shapes of the workpiece when repo operations are to be performed by said bending apparatus, said utilizer is adapted to utilize said intermediate shapes to determine which grippers are excluded from the set of available grippers, and grippers that cannot securely grasp the workpiece considering all of the constructed intermediate shape representations are adapted to be excluded from the set of available grippers.

5. In a computer having at least one processor and a memory, an apparatus adapted to determine a gripper location, which is a location on a malleable sheet workpiece at which a gripper is adapted to hold the workpiece while a bending apparatus performs an operation on the workpiece, the bending apparatus adapted to perform a sequence of operations, including said operation on the workpiece in accordance with a bending plan, said sequence of operations comprising a sequence of bends from a first bend through an Nth bend, the shape of the workpiece adapted to change to at least one intermediate shape as said bending apparatus progresses through said sequence of bends, said apparatus comprising:

a former; and

a determiner;

wherein said former is adapted to form a set of topographic representations by repeatedly generating, along edges of the workpiece, a graphic representation of areas on the workpiece within which the gripper can be located without hindering performance of a plurality of operations in said sequence of operations, taking into consideration the intermediate shapes of the workpiece when each of said plurality of operations is performed, and said determiner is adapted to determine the intersection of all the graphic representations within said set to thereby determine the areas common to said plurality of operations in said sequence of operations.

6. The apparatus according to claim 5, wherein said apparatus comprises a changer adapted to change a robot'"'"'s grip on the workpiece between bends of said sequence of bends.

7. The apparatus according to claim 5, wherein said apparatus further comprises a performer adapted to perform a bend within said sequence of bends.

8. In a computer having at least one processor and a memory, an apparatus adapted to select tooling to be used in a bending apparatus for bending a workpiece comprising a sheet of malleable material, the tooling including at least a die and a punch, the bending apparatus adapted to perform, utilizing the selected tooling, a sequence of operations comprising a sequence of bends from a first bend through an Nth bend, said apparatus comprising:

a reader;

a former;

a chooser; and

a proposed subplan generator;

wherein said reader is adapted to read information describing the geometry of a library of dies and punches, said former is adapted to form sets of feasible dies and punches excluding dies and punches that have insufficient force capacity to bend the workpiece and that are incapable of forming bends in the workpiece resulting in desired bend angles and desired inside radii, said chooser is adapted to choose an appropriate die and appropriate punch that most closely satisfies force, bend angle, and inside radii requirements by excluding punches that will likely collide with the workpiece as determined by failure of a geometric collision test, and said proposed subplan generator is adapted to generate a proposed subplan to accompany each proposed bend in the sequence of bends, said proposed subplan comprising setup and control information for said bending apparatus.

9. The apparatus according to claim 8, further comprising a modeler adapted to perform the geometric collision test by modeling a finished 3-D workpiece;

and

an aligner adapted to align the modeled finished 3-D workpiece between a model of each feasible punch and a model of a chosen die, for each bend in the sequence of bends.

10. In a computer having at least one processor and a memory, an apparatus for determining a layout of tooling stages along a die rail of a bending apparatus, said bending apparatus adapted to bend workpieces comprising sheets of malleable material, by performing a sequence of operations comprising a sequence of bends from a first bend through an Nth, said apparatus comprising:

a decider;

a calculator;

a determiner; and

a spacer;

wherein said decider is adapted to decide on an arrangement of a plurality of tooling stages along said die rail, said calculator is adapted to calculate lateral limits based upon the amount by which the workpiece extends beyond a side edge of a tooling stage for the bends of said sequence of bends, said determiner is adapted to determine a largest lateral limit for each side of each tooling stage, and said spacer is adapted to space adjacently arranged tooling stages to have a gap between adjacent side edges that is greater than or equal to the larger of the determined largest lateral limits of adjacent side edges.