Work pick-up apparatus

• US 5,350,269 A
• Filed: 01/15/1992
• Issued: 09/27/1994
• Est. Priority Date: 03/27/1989
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shibata, Masaru, Ishihara, Katsumi, Azuma, Yusaku
• Primary Examiner(s): Huppert, Michael S.
• Assistant Examiner(s): GORDON, STEPHEN T
• Application Number:
  US07/820,808
• Time in Patent Office: 986 Days
• Field of Search: 414/403, 414/416, 901/16, 901/47, 356/375, 364/478, 395/162
• US Class Current: 414/416.08
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 2219/37572 Camera, tv, vision
• CPC Class Codes: G05B 2219/45063 Pick and place manipulator
• CPC Class Codes: G05B 2219/49114 Go to coarse programmed reference, detector for fine alignment
• CPC Class Codes: G05B 2219/50151 Orient, translate, align workpiece to fit position assumed in program

Abstract

A work pick-up apparatus which picks up an object work out of a plurality of works held on a container case through visual recognition of the position of the object work by a visual sensor. The apparatus comprises: a memory circuit for storing shape characteristic information concerning the shape characteristic of the object work; an input circuit for externally inputting approximate position information representing an approximate position of the object work on the case, the approximate position information being expressed in terms of a coordinate system associated with the work pick-up apparatus; and a measuring circuit for measuring the pick-up position of the work in terms of the coordinate system associated with the pick-up apparatus, by processing the image information concerning the work obtained through the visual sensor in accordance with the approximate position information and the shape characteristic information.

Claims

1. A work pick-up apparatus which picks up an object work out of a plurality of works accommodated in units of a container case having a plurality of cells, each cell having a predetermined size and a predetermined location expressed in a coordinate system associated with said work pick-up apparatus, said work pick-up apparatus comprising:

visual sensor means for obtaining an image of said case;

memory means for storing shape characteristic information representative of the shape characteristics of said object work;

input means for inputting work position information representing a position of an object work to be picked up within said case, said work position information being expressed in terms of the coordinate system associated with said work pick-up apparatus; and

measuring means for determining a position of said work to be picked up in terms of said coordinate system associated with said pick-up apparatus,

said measuring means comprising;

first conversion means for converting the work position information expressed in the coordinate system associated with the apparatus into a work position expressed in terms of a coordinate system associated with said visual sensor means;

area setting means for setting an image area around the work position expressed in terms of the coordinate system associated with said visual sensor means, and for obtaining image information of the set image area, the image area being selected as incrementally larger than the size of the work accommodating unit of said container case;

processing means for subjecting an obtained work image to pattern recognition processing, and for searching an image having shape characteristics similar to those of an image of said object work from a processed image, the search being performed using shape characteristics of the work stored in the memory means;

computing means for computing a position of a searched image; and

second conversion means for converting said position of said searched image expressed in terms of the coordinate system associated with said visual sensor means into a coordinate position expressed in terms of the coordinate system associated with the apparatus.

2. A work pick-up apparatus according to claim 1, wherein

said computing means computes a position of a centroid of the searched image in terms of the coordinate system associated with the visual sensor means.

3. A work pick-up apparatus according to claim 1, wherein said visual sensor means is placed in a focal region of a camera fixed to said apparatus and has a field of vision which substantially covers the entire area of said container case, said area setting means further includes:

means for selecting, based on image information representative of the entire area of said container case, an area of a size being larger than the size of the work accommodating unit of said container case.

4. A work pick-up apparatus according to claim 1, wherein said plurality of works are arranged in said container case at arbitrary positions around said cell.

5. A work pick-up apparatus according to claim 1, wherein said visual sensor means has a visual sensor which is disposed in a focal region of a camera fixed to said apparatus and has a field of vision which covers area of a size incrementally larger than that of the work accommodating unit of said container case, and wherein said area setting means further includes:

means responsive to the first conversion means for moving said visual sensor to the converted work position.

6. A work pick-up apparatus according to claim 1, further comprising:

(a) a first control circuit for executing a work pick-up sequence;

(b) a second control circuit for performing an image processing control;

(c) a communication circuit for enabling data communication between said first and second control circuits, wherein said first control circuit includes;

(a1) an input circuit serving as said input means for inputting said work, position as a work pick-up instruction; and

(a2) a circuit for receiving, through said communication circuit, said coordinate position of said object work in terms of the coordinate system associated with said apparatus as determined by said measuring means; and

wherein said second control circuit includes;

(b1) a circuit for receiving, through said communication circuit, said work pick-up instruction from said input circuit and for converting said work pick-up instruction into a coordinate position on a sensor coordinate system associated with said visual sensor;

(b2) a reading circuit for reading an image of a portion of said container case around said coordinate position on said sensor coordinate system; and

(b3) a circuit for searching an image having shape characteristics similar to those of an object work within the read image, for computing the position of the centroid of the searched image, and for converting said position of said centroid into a coordinate position on said coordinate system associated with said apparatus.

7. A work pick-up apparatus according to claim 1, further comprising:

means for comparing said work position information input through said input means with a coordinate position of said object work determined by said measuring means; and

means for producing an error signal when said work position information and said coordinate position determined by said measuring means largely differ from each other.

8. A work pick-up apparatus according to claim 1, wherein said works are provided with characteristic recesses in their surfaces for identification of said works, said container case has cells for receiving respective works, said cells being sized to allow said works to move therein.