Calibration method and automation machining apparatus using the same

• US 10,209,698 B2
• Filed: 04/24/2015
• Issued: 02/19/2019
• Est. Priority Date: 12/26/2014
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Tai, Chung-Li, Tsai, Yao-Yang, Huang, Jay, Wang, Ko-Shyang, Chiu, Chih-Kai
• Primary Examiner(s): Fennema, Robert E
• Assistant Examiner(s): Poudel, Santosh R
• Application Number:
  US14/696,049
• Publication Number:
  US 20160187863A1
• Time in Patent Office: 1,397 Days
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37015 Adaptive online camera, vision calibration
• CPC Class Codes: G05B 2219/37563 Ccd, tv camera
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/85 Stereo camera calibration

Abstract

A calibration method applicable for an automation machining apparatus includes building a first stereoscopic characteristic model corresponding to an object, obtaining a stereoscopic image of the object, building a second stereoscopic characteristic model corresponding to the object based on the stereoscopic image, obtaining at least one error parameter corresponding to the second stereoscopic characteristic model by comparing the second stereoscopic characteristic model with the first stereoscopic characteristic model, and calibrating a machining parameter of the automation machining apparatus based on the at least one error parameter.

Claims

1. A calibration method applicable for an automation machining apparatus used in an automatic production line and performing processing actions to an object, the method comprising:

building a first stereoscopic characteristic model corresponding to the object based on a standard first two-dimension image and a standard second two-dimension image obtained in a tuning stage by a control device of the automation machining apparatus;

obtaining a stereoscopic image of the object based on a spatial relationship, a first two-dimension image and a second two-dimension image generated by photographing the object using two image capturing devices of the automation machining apparatus, wherein the spatial relationship is related to the two image capturing devices;

building a second stereoscopic characteristic model corresponding to the object based on the stereoscopic image by the control device;

obtaining at least one error parameter corresponding to the second stereoscopic characteristic model by comparing the second stereoscopic characteristic model with the first stereoscopic characteristic model by the control device;

calibrating a machining parameter of the automation machining apparatus by converting the machining parameter to a new machining parameter with a coordinate conversion matrix based on the at least one error parameter by the control device; and

controlling a work device to move to a position for machining on the object using the calibrated new machining parameter;

wherein the first stereoscopic characteristic model comprises a plurality of pieces of first information corresponding to a plurality of first characteristic nodes on the object, each piece of first information comprising a first spatial position of the corresponding first characteristic node, and the second stereoscopic characteristic model comprises a plurality of pieces of second information corresponding to a plurality of second characteristic nodes on the object, each piece of second information comprising a second spatial position of the corresponding second characteristic node, and the plurality of first characteristic nodes are respectively corresponding to the plurality of second characteristic nodes;

the error parameter specifies differences in spatial positions of characteristic nodes on the object between the first and second stereoscopic characteristic models; and

the coordinate conversion matrix is calculated based on the differences in spatial positions of characteristic nodes between the first and second stereoscopic characteristic models;

wherein calibrating the machining parameter with the coordinate conversion matrix comprises adjusting a position for obtaining the stereoscopic image of photographing the object.

2. The method of claim 1, wherein the coordinate conversion matrix is used for converting the plurality of first spatial positions into the plurality of second spatial positions.

3. The method of claim 2, wherein the machining parameter comprises a plurality of spatial working positions of the object, and calibrating the machining parameter with the coordinate conversion matrix comprises converting the plurality of spatial working positions by the coordinate conversion matrix to obtain a plurality of converted spatial working positions.

4. The method of claim 1, wherein the coordinate conversion matrix is used for converting the plurality of second spatial positions into the plurality of first spatial positions.

5. An automation machining apparatus, used in an automatic production line and performing processing actions to an object, comprising:

a plurality of image capturing devices for obtaining a stereoscopic image of an object based on a spatial relationship, a first two-dimension image and a second two-dimension image generated by photographing the object, with the spatial relationship related to the plurality of image capturing devices;

a storage device for storing a first stereoscopic characteristic model built based on a standard first two-dimension image and a standard second two-dimension image of the object in a tuning stage;

a controlling device electrically coupled to the image capturing device and the storage device, the controlling device for building a second stereoscopic characteristic model of the object based on the stereoscopic image, and

the controlling device for obtaining an error parameter by comparing the first stereoscopic characteristic model with the second stereoscopic characteristic model, and for calibrating a machining parameter of the automation machining apparatus by converting the machining parameter to a new machining parameter with a coordinate conversion matrix based on the error parameter; and

a working device electrically coupled to the controlling device and for being controlled to move to a position for machining on the object using the calibrated new machining parameter;

wherein the first stereoscopic characteristic model comprises a plurality of pieces of first information corresponding to a plurality of first characteristic nodes on the object, each piece of first information comprising a first spatial position of the corresponding first characteristic node, and the second stereoscopic characteristic model comprises a plurality of pieces of second information corresponding to a plurality of second characteristic nodes on the object, each piece of second information comprising a second spatial position of the corresponding second characteristic node, and the plurality of first characteristic nodes are respectively corresponding to the plurality of second characteristic nodes;

the error parameter specifies differences in spatial positions of characteristic nodes on the object between the first and second stereoscopic characteristic models;

the coordinate conversion matrix is calculated based on the differences in spatial positions of characteristic nodes between the first and second stereoscopic characteristic models; and

a position for obtaining the stereoscopic image of photographing the object is adjusted based on the coordinate conversion matrix to calibrate the machining parameter.

6. The apparatus of claim 5, wherein the coordinate conversion matrix is used for converting the plurality of first spatial positions into the plurality of second spatial positions, and the machining parameter comprises a plurality of spatial working positions, and the controlling device converts the plurality of spatial working positions with the coordinate conversion matrix to obtain a plurality of converted spatial working positions.

7. The apparatus of claim 5, wherein the coordinate conversion matrix is used for converting the plurality of second spatial positions into the plurality of first spatial positions, and the machining parameter comprises a position relationship between the working device and the object, and the controlling device adjusts a position of the working device based on the coordinate conversion matrix so as to calibrate the machining parameter.

8. The apparatus of claim 5, wherein the image capturing device is selected from the group consisting of a binocular 3D scanner and a texture projecting 3D scanner.