Workpiece transport system and workpiece transport method

{
  "publication_number": "US12248308B2",
  "country": "US",
  "kind": "B2",
  "title": "Workpiece transport system and workpiece transport method",
  "abstract": "A height error of a workpiece holding portion is detected based on a height from a mounting pedestal side floor surface, on which a mounting pedestal is mounted, to a connection point between the workpiece holding portion and an arm unit at a point in time at which contact with a detection target is detected by a surface detection sensor, a height from the mounting pedestal side floor surface to a surface of the detection target, and a theoretical value of a height of the workpiece holding portion, and an actual loading height of a workpiece mounted on the mounting pedestal is detected in consideration of the height error of the workpiece holding portion.",
  "claims": [
    "1. A workpiece transport system, comprising: a mounting pedestal on which a workpiece can be mounted; and a workpiece holding robot configured to be able to transport, from the mounting pedestal, the workpiece mounted on the mounting pedestal, the workpiece holding robot including a workpiece holding portion capable of holding the workpiece, an arm unit configured to bring the workpiece holding portion close to or away from a detection target, and a surface detection sensor capable of detecting that the workpiece holding portion is brought into contact with the detection target, the workpiece transport system being configured to detect a height error of the workpiece holding portion based on a height from a mounting pedestal side floor surface, on which the mounting pedestal is mounted, to a connection point between the workpiece holding portion and the arm unit at a point in time at which contact with the detection target is detected by the surface detection sensor, a height from the mounting pedestal side floor surface to a surface of the detection target, and a theoretical value of a height of the workpiece holding portion, and to detect an actual loading height of the workpiece mounted on the mounting pedestal in consideration of the height error of the workpiece holding portion.",
    "2. The workpiece transport system according to claim 1, wherein the height from the mounting pedestal side floor surface to the surface of the detection target includes: a height from the mounting pedestal side floor surface to a surface of the mounting pedestal; and a height of the detection target mounted on the mounting pedestal.",
    "3. The workpiece transport system according to claim 2, wherein the height from the mounting pedestal side floor surface to the surface of the mounting pedestal is detected based on: a mounting pedestal height from a robot side floor surface on which the workpiece holding robot is installed to the surface of the mounting pedestal; and a height gap between the mounting pedestal side floor surface and the robot side floor surface.",
    "4. The workpiece transport system according to claim 3, wherein the mounting pedestal height is detected based on: a height of a calibration jig mounted on the mounting pedestal; a height of a calibration gripper mounted to the arm unit in lieu of the workpiece holding portion; a height from the robot side floor surface to a predetermined reference part of the workpiece holding robot at a point in time at which the calibration gripper is brought into contact with the calibration jig; and a height from the reference part to a connection point between the calibration gripper and the arm unit at a same point in time.",
    "5. The workpiece transport system according to claim 1, further comprising a camera system configured to photograph the workpiece mounted on the mounting pedestal so as to detect a position and a loading height of the workpiece based on an image of the photographed workpiece, wherein the camera system includes: a camera capable of photographing the workpiece mounted on the mounting pedestal; and an image processor configured to detect the position and the loading height of the workpiece based on the photographed image of the workpiece photographed by the camera, and the image processor is configured to calculate the actual loading height in consideration of the height error of the workpiece holding portion.",
    "6. The workpiece transport system according to claim 5, wherein the image processor is configured to calculate the actual loading height based on: the height from the mounting pedestal side floor surface, on which the mounting pedestal is mounted, to the connection point between the workpiece holding portion and the arm unit; the height error of the workpiece holding portion; the height from the mounting pedestal side floor surface to the surface of the mounting pedestal; and the theoretical value of the height of the workpiece holding portion.",
    "7. The workpiece transport system according to claim 5, wherein the camera is configured to photograph the workpiece mounted on the mounting pedestal from obliquely above.",
    "8. A workpiece transport method for transporting, from a mounting pedestal, a workpiece mounted on the mounting pedestal with a workpiece holding robot, the workpiece holding robot including a workpiece holding portion capable of holding the workpiece, an arm unit configured to bring the workpiece holding portion close to or away from a detection target, and a surface detection sensor capable of detecting that the workpiece holding portion is brought into contact with the detection target, the workpiece transport method comprising: detecting a height error of the workpiece holding portion based on a height from a mounting pedestal side floor surface, on which the mounting pedestal is mounted, to a connection point between the workpiece holding portion and the arm unit at a point in time at which contact with the detection target is detected by the surface detection sensor, a height from the mounting pedestal side floor surface to a surface of the detection target, and a theoretical value of a height of the workpiece holding portion; and detecting an actual loading height of the workpiece mounted on the mounting pedestal in consideration of the height error of the workpiece holding portion."
  ],
  "description_excerpt": "The present invention relates to a workpiece transport system and a workpiece transport method for automatically transporting a workpiece arranged at a mounting place.\n\nConventionally, there is known a working system configured to hold a workpiece arranged at a mounting place such as a pallet with a workpiece holding robot so as to transport the workpiece to a working machine such as a bending machine (Patent Literature 1).\n\nThe working system described in Patent Literature 1 is configured to photograph the entire mounting place with one camera installed directly above the center of the mounting place and to detect the position and the loading height of the workpiece based on the photographed image of the workpiece so as to control a workpiece holding robot based on information on the detected position and loading height of the workpiece.\n\nFurther, in the working system described in Patent Literature 1, a sensor (an actual loading height detection unit) for detecting an actual loading height of the workpiece is attached to a portion holding the workpiece of the workpiece holding robot, and the working system is configured to update the latest actual loading height, which is obtained by subtracting the thickness of one sheet of workpiece from the actual loading height of the workpiece detected by the sensor, as a loading height of the workpiece after an uppermost workpiece is transported.",
  "cpc": [
    "G05B 19/4189",
    "B25J 9/10",
    "B25J 9/1687",
    "B25J 9/1692",
    "B25J 9/1697",
    "G05B 2219/37002",
    "G05B 2219/37555",
    "G05B 2219/40014",
    "G05B 2219/40252",
    "G05B 2219/40564",
    "G05B 2219/40607",
    "G05B 2219/45063",
    "G05B 2219/50378"
  ],
  "ipc": [
    "B25J 9/10",
    "B25J 9/16",
    "G05B 19/418"
  ],
  "assignees": [
    "Amada Co Ltd"
  ],
  "inventors": [
    "Satoshi TAKATSU",
    "Naofumi MIURA",
    "Shuhei TERASAKI",
    "Teruyuki Kubota"
  ],
  "filing_date": "2021-10-08",
  "publication_date": "2025-03-11",
  "grant_date": "2025-03-11",
  "priority_date": "2020-10-28",
  "application_number": "US-202118032359-A",
  "family_id": "81382494",
  "cited_by_count": 2,
  "citations": [
    "US20030088337A1",
    "JP2018120388A",
    "US20210094187A1"
  ]
}