Automated assembly arrangement for vehicle body and method of assembly

• US 5,005,277 A
• Filed: 12/09/1988
• Issued: 04/09/1991
• Est. Priority Date: 12/10/1987
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Uemura, Satoshi, Kawada, Susumu, Miyauchi, Tatsuo, Sekine, Yoshitada
• Primary Examiner(s): Goldberg, Howard N.
• Assistant Examiner(s): Cuda, I.
• Application Number:
  US07/282,190
• Time in Patent Office: 851 Days
• Field of Search: 29/407, 29/430, 29/712, 29/714, 29/720, 901/7, 901/9
• US Class Current: 29/407.04
• CPC Class Codes: B62D 65/02 Joining sub-units or components to, or positioning sub-units or components with respect to, body shell or other sub-units or components
• CPC Class Codes: B62D 65/028 by determining relative positions by measurement
• CPC Class Codes: G05B 19/4182 manipulators and conveyor only
• CPC Class Codes: G05B 2219/45055 Assembly
• CPC Class Codes: G05B 2219/50071 Store actual surface in memory before machining, compare with reference surface
• 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: Y10T 29/49769 Using optical instrument [excludes mere human eyeballing]
• CPC Class Codes: Y10T 29/49771 Quantitative measuring or gauging
• CPC Class Codes: Y10T 29/49829 Advancing work to successive stations [i.e., assembly line]
• CPC Class Codes: Y10T 29/53052 including position sensor
• CPC Class Codes: Y10T 29/53061 Responsive to work or work-related machine element
• CPC Class Codes: Y10T 29/53087 with signal, scale, illuminator, or optical viewer

Abstract

A vehicle body is assembled in a number of stages each including robots which are automatically adjusted to move and secure work pieces such as panels to a basic body member or chasis. One of the stages includes a measuring arrangement which scans the assembled unit with laser beams to determine if the required tolerance have been set. In the event of deviations beyond permissible limits the appropriate correction is derived and fed back to the stage wherein the securing operation in question occured.

Claims

1. An arrangement wherein a work piece is to be connected with a given degree of precision to a structure, comprising:

a first assembly stage;

a second assembly stage which is separate and spaced from said first assembly stage;

means for determining a position in which said work piece should be disposed relative to said structure using pre-recorded data which relates to the design of said structure;

said first stage including;

(a) work support means, controlled by an inference type processing means, for supporting and moving said work piece into the determined position relative to said structure; and

(b) means for fixing said work piece to said structure;

means for determining a correct position for each of a plurality of reference points defined on said work piece, using pre-recorded structure design data;

shuttle conveyor means for moving the structure out of said first assembly stage into said second assembly stage;

said second stage including;

measuring means for determining a measured position of said plurality of reference points;

means for determining the deviation between each said measured position and a corresponding one of said correct reference point positions using said pre-recorded data;

a memory bank containing said pre-recorded data and said inference means, wherein said inference means is used in combination with said pre-recorded data to determine correction values for correcting the operation of said work support means in said first stage so as to reduce the magnitude of said deviations detected in said second stage.

2. In a method of assembling a structure wherein a plurality of work pieces are connected with a given degree of precision to a structure, the steps of:

determining a position in which said plurality of work pieces should be disposed relative to said structure using pre-recorded data which relates to the design of said structure;

using work support means to support and move said plurality of work pieces into the determined positions relative to said structure, said work support means being disposed in a first stage;

fixing said work pieces to said structure using fixing means disposed in the first stage;

determining a correct position for each of a plurality of reference points defined on each of said plurality of work pieces, using said pre-recorded data;

moving said structure out of the first stage to a second separate stage which is paced from the first stage using shuttle conveyor means;

determining a measured position for each among said plurality of reference points using a structure measuring means disposed in the second stage;

determining the deviation between each of said measured positions and its corresponding one from among said correct positions;

using said pre-recorded data in combination with inference data stored in a data storage means so as to determine correction values for correcting any deviations which are in excess of a predetermined tolerance in a manner which reduces or eliminates deviations; and

adjusting said work support means in said first stage using said correction values such that the deviation magnitudes detected in said second stage derived from subsequent structures assembled in said first stage which have identical form to said structure from which said correction values were derived, have a reduced magnitude.

3. An assembly system comprising:

a work piece support robot disposed in a first stage and having a jig with which a work piece can be supported, said jig including a device which can be shaped to assume the configuration of a portion of said work piece, said portion to be engaged by said device, said work piece support robot being arranged to move said work piece into a predetermined relationship with a body to which the work piece is to be connected;

a securing robot disposed in said first stage and which has a securing device via which the work piece can be secured to said body;

means for transporting said body out of the first stage and into a second stage;

measuring means for measuring a disposition of said work piece on said body and for producing data from which the disposition can be interpreted, said measuring means being disposed in the second stage;

control means responsive to said measuring means for controlling the operation of said work piece support and securing robots, said control means including;

a memory in which design, assembly and inference data is stored;

processing means for using said design, assembly and inference data for interpreting the data from said measuring means and for producing control signals via which said work piece support and securing robots and said measuring means are respectively controlled, said control means being arranged to;

move said robots from their home positions to ones wherein the work piece is supported in a position predetermined to place the work piece in the desired position on said body;

induce the securing robots to secure the work piece to said body;

induce said transport means to move said body to a second stage;

induce the measuring means disposed in said second stage to measure the position of a pre-determined reference point on said work piece;

compare said measured position of said reference point with the position derived from the design data and determine if there is a deviation between the two positions, and produce a correction value which is used to adjust said work piece support robot in a manner which tends to eliminate said deviation.

4. A method of assembly comprising:

supporting a work piece on a support robot having a jig, said jig including a device which can be shaped to assume the configuration of a portion of said work piece, said portion to be engaged to said device, said work support robot being disposed in a first stage;

moving said work piece into a position which has a predetermined relationship with a body to which the work piece is to be connected;

securing the work piece to said body using a securing robot while said workpiece is in the first stage;

transporting the body from the first stage into a second stage using a transportation means;

measuring the disposition of said work piece on said body in said second stage and producing data from which said disposition can be interpreted;

controlling the operation of said work piece support robot by way of a control means, said control means including;

a memory in which design, assembly and inference data is stored; and

processing means for using said design, assembly and inference data for interpreting the data from said measuring means and for producing control signals via which the work piece and securing robots and said measuring means are respectively controlled, said control means being arranged to;

move said robots to positions wherein the work piece is supported in a position predetermined to place the work piece in a desired position on said body;

induce the securing robot to secure the work piece to said body;

induce said transport means to move said body to the second stage;

induce the measuring means disposed in said second stage to measure the position of a predetermined reference point on the work piece;

compare the measured position of said reference point with that derived from the design data and to determine if there is a deviation between the two positions; and

produce a correction value which is used to adjust said work piece robot in a manner which tends to eliminate said deviation.