Gripping device and method for taking out an article

{
  "publication_number": "US9757858B2",
  "country": "US",
  "kind": "B2",
  "title": "Gripping device and method for taking out an article",
  "abstract": "An article handling device includes: a gripper that grips an article; a driver that moves the gripper; an article recognition unit that recognizes a state of the article; a gripping recognition unit that recognizes a gripping state of the gripper; a determination unit that determines whether the gripping state is stable or unstable based on a recognition result of the gripping recognition unit; and a controller that controls a first gripping operation in which the gripper grips the article by a gripping position determined based on the recognition result of the article recognition unit, and, when the gripping state is determined as unstable, controls a second gripping operation in which the gripping position is changed and the gripper re-grips the article.",
  "claims": [
    "1. An article handling device comprising: a gripper which grips an article; a driver, connected to the gripper, which moves the gripper; an article recognition unit which recognizes a state of the article arranged in a storage area; a gripping recognition unit which recognizes a gripping state of the gripper; a determination unit which determines whether the gripping state is stable or unstable based on a recognition result obtained by the gripping recognition unit; and a controller which controls the gripper and the driver, wherein the controller controls a first gripping operation in which the gripper grips the article by a first gripping position to transfer the article, the first gripping position being determined based on a recognition result obtained by the article recognition unit, and, in a case that the gripping state in the first gripping operation is determined as unstable, controls a second gripping operation in which the gripper releases the article and re-grips the article by a second gripping position different from the first gripping position.",
    "2. The device according to claim 1, wherein the controller repeats controlling the second gripping operation until the gripping state is determined as stable.",
    "3. The device according to claim 1, wherein the gripper comprises a plurality of suction cups, the gripping recognition unit comprises a plurality of force sensors each of which detects a force acting on a corresponding suction cup, and the recognition result obtained by the gripping recognition unit includes an output value of the plurality of force sensors.",
    "4. The device according to claim 1, wherein the controller determines a new gripping position based on the recognition result obtained by the gripping recognition unit.",
    "5. The device according to claim 1, wherein the recognition result obtained by the article recognition unit includes a plurality of gripping position candidates including a first gripping position candidate and a second gripping position candidate, the gripper comprises a plurality of suction cups, and in a case that all of the plurality of suction cups fail in gripping when the gripper grips the article by the first gripping position candidate, the controller makes the gripper grip the article by the second gripping position candidate.",
    "6. The device according to claim 1, wherein the gripper comprises a plurality of suction cups, the gripping recognition unit detects pressure acting on the suction cups in a state that the article is gripped by the gripper, and the controller determines the second gripping position based on the detected pressure.",
    "7. An article handling device comprising: a gripper which grips an article; a driver, connected to the gripper, which moves the gripper; an article recognition unit which recognizes a state of the article, wherein the article recognition unit generates a first recognition result obtained by performing recognition before the article is gripped by the gripper, and a second recognition result obtained by performing recognition in a state that the article is gripped by the gripper; a determination unit which determines whether a gripping state of the gripper is stable or unstable based on the first recognition result and the second recognition result; and a controller configured to control the gripper and the driver, wherein the controller controls a first gripping operation in which the gripper grips the article by a first gripping position to transfer the article, the first gripping position being determined based on the first recognition result, and, in a case that the gripping state in the first tripping operation is determined as unstable, controls a second gripping operation in which the gripper releases the article and re-grips the article by a second gripping position different from the first gripping position.",
    "8. The device according to claim 7, wherein the controller repeats controlling the second gripping operation until the gripping state is determined as stable.",
    "9. The device according to claim 7, wherein the article recognition unit comprises an image sensor, the article recognition unit calculates a center position of the article as a first center position based on image information obtained by the image sensor before the article is gripped by the gripper, and calculates a center position of the article as a second center position based on image information obtained by the image sensor in a state that the article is gripped by the gripper, and the determination unit determines whether or not the gripping state is stable based on a distance between the first center position and the second center position.",
    "10. The device according to claim 7, wherein the controller determines a new gripping position based on the second recognition result.",
    "11. The device according to claim 7, wherein the first recognition result includes a plurality of gripping position candidates including a first gripping position candidate and a second gripping position candidate, the gripper comprises a plurality of suction cups, and in a case that all of the plurality of suction cups fail in gripping when the gripper grips the article by the first gripping position candidate, the controller makes the gripper grip the article by the second gripping position candidate.",
    "12. A method for controlling an article handling device comprising a gripper which grips an article and a driver which is connected to the gripper and moves the gripper, the method comprising: recognizing a state of the article arranged in a storage area to generate a first recognition result; recognizing a gripping state of the gripper to generate a second recognition result; determining whether the gripping state is stable or unstable based on the second recognition result; controlling a first gripping operation in which the gripper grips the article by a first gripping position to transfer the article, the first gripping position being determined based on the first recognition result; and in response to determining that the gripping state in the first gripping operation is unstable, controls a second gripping operation in which the gripper releases the article and re-grips the article by a second gripping position different from the first gripping position.",
    "13. A method for controlling an article handling device comprising a gripper which grips an article and a driver which moves the gripper, the method comprising; recognizing a state of the article to generate a first recognition result obtained by performing recognition before the article is gripped by the gripper, and a second recognition result obtained by performing recognition in a state where the article is gripped by the gripper; determining whether a gripping state of the gripper is stable or unstable based on the first recognition result and the second recognition result; controlling a first gripping operation in which the gripper grips the article by a first gripping position to transfer the article, the first gripping position being determined based on the first recognition result; and in response to determining that the gripping state in the first gripping operation is unstable, controlling a second gripping operation in which the gripper releases the article and re-grips the article by a second gripping position different from the first gripping position."
  ],
  "description_excerpt": "This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2015-007004, filed Jan. 16, 2015, the entire contents of which are incorporated herein by reference.\n\nEmbodiments described herein relate generally to an article handling device.\n\nSince handling of articles involves heavy labor, in recent years, it is becoming difficult to secure human resources. Therefore, there is a demand for automation of unloading operations, such as depalletizing. In a conventional article handling device for performing unloading operations, an optical sensor, such as an image sensor which is capable of acquiring a wide range of information at once, has been used to recognize articles to be unloaded. However, in cases such as articles having complicated patterns, articles arranged closely in contact with each other without a gap, or the edges of articles being hidden by obstacles such as ropes and labels, due to the nature of optical sensors, recognition would not be performed correctly. If the articles are gripped based on an incorrect recognition result, the gripping may fail.\n\nFIG. 1 is a side view showing a mechanical structure of an article handling device according to a first embodiment. FIG. 2 is a block diagram showing a control system of the article handling device according to the first embodiment. FIG. 3 is a diagram showing an example of a method for detecting articles forming a top surface of a stacked pile. FIG. 4 is a diagram showing an example of a surface selecting method to be utilized for the detection method shown in FIG. 3. FIG.",
  "cpc": [
    "B25J 9/1612",
    "B25J 15/0052",
    "B25J 15/0616",
    "B25J 9/1694",
    "B25J 9/1697",
    "G05B 2219/39484",
    "G05B 2219/39558"
  ],
  "ipc": [
    "B25J 15/00",
    "B25J 15/06",
    "B25J 9/16"
  ],
  "assignees": [
    "TOSHIBA KK"
  ],
  "inventors": [
    "ETO HARUNA",
    "NAKAMOTO HIDEICHI",
    "OGAWA AKIHITO",
    "SONOURA TAKAFUMI",
    "TANAKA JUNYA",
    "WATABE KAZUO"
  ],
  "filing_date": "2016-01-15",
  "publication_date": "2017-09-12",
  "grant_date": "2017-09-12",
  "priority_date": "2015-01-16",
  "application_number": "US-201614996330-A",
  "family_id": "56407132",
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}