Method for repositioning a numerically controlled device

• US 8,477,987 B2
• Filed: 06/19/2006
• Issued: 07/02/2013
• Est. Priority Date: 06/22/2005
• Status: Active Grant

• Current Assignee: Sime Oy
• Original Assignee: Sime Oy
• Inventors: Erikkal, Jouni
• Primary Examiner(s): Akhavannik, Hadi
• Application Number:
  US11/921,636
• Publication Number:
  US 20090129633A1
• Time in Patent Office: 2,570 Days
• Field of Search: 382/154, 382/181, 348/148
• US Class Current: 382/100
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: B66C 13/48 Automatic control of crane drives for producing a single or repeated working cycle; Programme control
• CPC Class Codes: G05B 2219/39045 Camera on end effector detects reference pattern
• CPC Class Codes: G05B 2219/39046 Compare image of plate on robot with reference, move till coincidence, camera
• CPC Class Codes: G05B 2219/39397 Map image error directly to robot movement, position with relation to world, base not needed, image based visual servoing
• CPC Class Codes: G05B 2219/40003 Move end effector so that image center is shifted to desired position
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

The invention relates to a method for repositioning a numerically controlled device by using an image taken of an object as an aid. According to the method, the system is taught in such a way that a child image is defined for the camera'"'"'s image, either its own set of co-ordinates is formed for the element or a set of coordinates is retrieved from elsewhere, and the image thus obtained, together with its co-ordinates, is stored in the data system, and, in the repositioning situation, the real-time image is compared with the child image stored in the data system, in order to determine the real-time position of the imaging device relative to the stored image. The set of co-ordinates used is a set of co-ordinates retrieved using satellite positioning, or the device'"'"'s own internal set of co-ordinates. In the repositioning situation, the image stored in the teaching situation is sought as the co-ordinate point of the image stored in the memory is approached.

Claims

1. A method for repositioning a crane, moving material handling equipment, and other numerically controlled devices, in a system including a camera imaging device, a storage data system, and an operator display screen by using an image taken of an object in the field of vision of the operator of the numerically controlled device as an aid, the method including a step to teach the system first by defining a child image from the imaging device, by forming a set of coordinates pertaining to the properties or state data for the numerically controlled device, the set of coordinates including a fixing point of the child image, and recording the child image, together with the co-ordinates in the data system, and the system later repositioning by comparing a real-time image from the imaging device with the child image stored in the data system, in order to determine the real-time position of the imaging device relative to the stored child image, by displaying the taught child image and real-time image on the operator display screen, and by superimposing a substantially straight line on the operator display screen depicting a measured distance between the fixing point of the child image and a fixing point of the real-time image, whereby the line is adapted to show the direction in which the numerically controlled device is repositioned, characterized in that, in the repositioning step, the image stored in the teaching step is sought when the coordinates of the real-time imaging device first comes close to the co-ordinate point of the child image stored in the data system.

2. Method according to claim 1, characterized in that, in the repositioning step, the real-time image is compared with the child image stored in the data system, in order to determine the real-time position of the imaging device relative to the position of the stored child image on the display screen and in the set of coordinates.

3. Method according to claim 1 , characterized in that the set of co-ordinates includes co-ordinates retrieved using satellite global positioning system.

4. Method according to claim 1, characterized in that the set of co-ordinates includes the numerically controlled device'"'"'s own internal co-ordinates.

5. Method according to claim 1, characterized in that, in the teaching step, at least image information in a numerical form, the size of the image, X/Y/Z/R/S/Q states, and its location in the entire image are stored in the data system.

6. Method according to claim 1, characterized in that, in the repositioning step further comprising the step of defining a distance of the closest stored image point to be searched for, relative to present, real-time positioning data of the camera imaging device, using the equation

MIN(√

((X^image−

X^present)²+(Y^image−

Y^present)²+etc.)),

in which

MIN=select the smallest value

X^image=position data X at the moment of teaching the image

X^present=position data X at the camera now

Y^image=position data Y at the moment of teaching the image

Y^present=position data Y at the camera now.

7. Method according to claim 1, characterized in that the taught child image is selected from any image area imaged by the camera imaging device.

8. Method according to claim 1, characterized in that child images are selected from at least two camera imaging devices.

9. Method according to claim 1, characterized in that data is transferred by wireless means between the camera imaging device and the storage data system.

10. Method according to claim 8, characterized in that two or more cameras are used.

11. Method according to claim 10, characterized in that switching between the image source of the cameras is performed automatically, according to the co-ordinate point.