CN1419104A

CN1419104A - Object space position detector

Info

Publication number: CN1419104A
Application number: CN 02158692
Authority: CN
Inventors: 丁希仑; 解玉文; 战强
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2002-12-26
Filing date: 2002-12-26
Publication date: 2003-05-21

Abstract

The invention discloses an object space position and posture detection device, belonging to a precision automatic measurement device, which is composed of a camera, an ultrasonic sensor, and a computer installed at the end of a robot. The camera and the ultrasonic sensor are composed of a data line and an image acquisition card and an ultrasonic The information acquisition card is connected, and the robot is connected with the computer by a control bus. The detection device of the present invention replaces the traditional binocular vision detection, obtains the ideal coordinates of any point on the object in the image through a single image, and obtains the direction of the line connecting the point to the center of the camera, and then through the movement of the robot end, The guiding ultrasonic sensor coincides with the origin of the unmoved front camera coordinate system, and its axial direction is the same as the direction of the obtained connection line, and then the length of the connection line is measured by the ultrasonic sensor, so as to determine the position of the point in the camera coordinate system coordinates, and can be further transformed into the robot base coordinate system. By measuring the spatial coordinates of two points on the operating object, the spatial attitude of the object can be determined. The object pose detection method is simple and easy, with small calculation amount and high precision.

Description

The object space apparatus for detecting position and posture

Technical field

The present invention relates to a kind of accurate self-operated measuring unit, particularly relate to a kind of object space apparatus for detecting position and posture that carries out the object pose detection by robot, video camera, sonac, computing machine.

Background technology

Along with development of science and technology, robot has obtained application more and more widely, and for example assembling is automatically welded automatically, sprayed paint, the inspection of mechanical component etc.In these were used, the detection of testee pose was the prerequisite that realizes the testee operation.Conventional detection generally all is to utilize binocular vision to realize, but the data volume that this method need be handled is very big, the image matching algorithm in the binocular vision, and also perfect not to the utmost, error is bigger.

Summary of the invention

In order to overcome the deficiency of said method, the present invention proposes a kind of method of new inspected object pose, can only need to gather single sub-picture by video camera and the sonac that is contained in robots arm's end, processing through computing machine just can realize the detection to the testee pose.

A kind of object space apparatus for detecting position and posture of the present invention, form by the video camera that is contained in the robot end and sonac, computing machine, also relating to an object pose detection system is stored in the computing machine, video camera and sonac are installed in the end of robot arm, video camera and sonac are linked to each other with the ultrasound information capture card with image pick-up card in the computing machine by data line, and robot is linked to each other with computing machine by control bus.

Described pick-up unit, its video camera and the sonac fixing position that is arranged in parallel changes differently according to robot construction, be fixed on the end that robot picks up the object parts.

Described pick-up unit detects required information acquisition unit by single camera and single sonac constituent posture.

Described pick-up unit, the pose of object to be detected only need be gathered a sub-picture, by the direction of the point on the Image Acquisition object of camera acquisition and the video camera line of centres, is obtained the length of this line by sonac.

Described pick-up unit, a sub-picture of camera acquisition testee, and passed in the computing machine by video and data line by to treatment of picture, can obtain any 1 P on the object to the projection vector of video camera center O Direction, measure by sonac then Length, thereby can determine the coordinate of a P in camera coordinate system OXYZ, this coordinate can finally be transformed in the basis coordinates system of robot.Image coordinate by point is obtained its ideal coordinates, and corresponding point overlap with the line at video camera center on the point of this ideal coordinates correspondence and the line at video camera center and the object.

Described pick-up unit, sonac can adopt laser sensor.

Described pick-up unit is characterized in that: video camera and sonac also can parallel to the layout and installation at the end of bowl portion of robot.

The position of spatial point generally needs two width of cloth images, determines with the intersection point of two projection lines.The method that the present invention proposes then can add the position that ultrasonic (or laser) range finding can be determined spatial point with piece image.

Compare with binocular vision, the present invention has fundamentally avoided because caused uncertainty of images match and error.After the image coordinate of spatial point was determined, its coordinate in camera coordinate system can just can obtain by simple calculating.Binocular vision then will be carried out images match earlier, and then asks the intersection point of projection line.Obviously the present invention has significantly reduced calculated amount, has improved detection speed.

Description of drawings

Fig. 1 is a structural representation of the present invention.

Fig. 2 is that the direction synoptic diagram of determining projection vector produces.

Fig. 3 is a length synoptic diagram of determining projection vector.

Among the figure: 1. video camera 2. sonacs 3. testees 4. worktable 5. robots 6. computing machines, 7. data lines, 8. control buss, 9. planes of delineation

Embodiment

The present invention is further illustrated below in conjunction with drawings and Examples.

See also shown in Figure 1, object space apparatus for detecting position and posture of the present invention, form by the video camera that is contained in the robot end and sonac, computing machine and the object pose detection system that is stored in the computing machine, single camera and single sonac are installed in the end of robot arm, video camera and sonac are linked to each other with the ultrasound information capture card with image pick-up card in the computing machine by data line, and robot is linked to each other with computing machine by control bus.

In the present invention, testee 3 is placed on the worktable 4, gathers a sub-picture by video camera 1, this image is transferred in the computing machine 6 by video and ultrasound data line 7, and by the operation control software of storage in the computing machine 6 it is handled.For example, set 1 P on testee 3,1 P on the object will measure its coordinate in camera coordinate system OXYZ, needs to determine projection vector

Direction and length.Consider the distortion that camera lens causes, by the image coordinate P of a P _uCan obtain its ideal image coordinate (distortion that the distortion of compensation camera lens causes) P _i, because

Length known (being the camera lens focal distance f) so just can obtain Direction in camera coordinate system,

Direction be exactly with

Direction (as shown in Figure 2).By the motion of control robot 5, make the true origin of sonac 2 move to the O point, axis with Overlap, the measured value of sonac 2 is exactly so

Length.Like this, the coordinate of some P in video camera 1 coordinate system just can obtain, and can finally be converted into the coordinate in 5 basis coordinates system of robot.Can record the project objects center of gravity with this method is the coordinate in space in robot 5 basis coordinates, just the position coordinates of object.Be without loss of generality, can represent the attitude of object with the attitude of the major axis of project objects.The volume coordinate of this two end points can record with said process, just can further calculate the attitude of this axis in basis coordinates system of robot.The position of object and attitude are just decided fully like this.

For example, for the workpiece that is placed on the worktable, establishing its focus point is C, then can record With the angle of each between centers of camera coordinate system be: with the X-axis angle be 68.2694 °, with the Y-axis angle be 60.4186 °, with Z axle clamp angle be 38.1027 °, record Length be 42.2019mm, its coordinate in camera coordinate system is X=5.6250mm so, Y=20.8333mm, Z=33.2089mm, the coordinate of measured workpiece in basis coordinates system of robot is X=27.7815mm, Y=98.6157mm, Z=34.5791mm.The attitude angle of measured workpiece in robot basis coordinates system is: with the X-axis angle be 62.6605 °, with the Y-axis angle be 74.6356 °, with Z axle clamp angle be 32.0197 °.

The method that the present invention proposes can add the position that ultrasonic (or laser) range finding can be determined spatial point with piece image.

Claims

1. An object space pose detection device is composed of a robot, a video camera, an ultrasonic sensor, and a computer, and is characterized in that: an object pose detection system is also stored in the computer, and the camera (1) and the ultrasonic sensor (2) are parallel The arrangement is installed on the end of the robot arm, the camera (1) and the ultrasonic sensor (2) are connected with the image acquisition card and the ultrasonic information acquisition card in the computer by the data line, and the robot (5) is connected to the computer (6) by the control bus (8). connected.

2 . The detection device according to claim 1 , characterized in that: a single camera ( 1 ) and a single ultrasonic sensor ( 2 ) constitute an information acquisition unit required for object pose detection. 3 .

3. The detection device according to claim 1, characterized in that: the pose of the detected object (3) only needs to collect a pair of images, and the image captured by the camera (1) captures the points on the object and the camera (1) The direction of the central connection line, the length of the connection line is obtained by the ultrasonic sensor (2).

4. The detection device according to claim 1, 3, characterized in that: the camera (1) collects an image of the object (3) to be measured, and transmits it to the computer (6) by the video and data line (7) , by processing the image, the projection vector from any point P on the object to the center O of the camera (1) can be obtained direction, then measured by the ultrasonic sensor (2) The length of , so that the coordinates of point P in the camera coordinate system OXYZ can be determined, and the coordinates can be finally transformed into the base coordinate system of the robot.

5. The detection device according to claim 4, characterized in that: its ideal coordinates are obtained by the image coordinates of the point, and the connection line between the point corresponding to the ideal coordinates and the camera center coincides with the connection line between the corresponding point on the object and the camera center .

6. The detection device according to claim 1, characterized in that: the ultrasonic sensor (2) can be a laser sensor.

7. The detection device according to claim 1, characterized in that: the camera (1) and the ultrasonic sensor (2) are arranged in parallel and fixed positions vary according to the structural changes of the robot, and are fixed at the end where the robot picks up object parts.

8. The detection device according to claim 1, characterized in that: the camera (1) and the ultrasonic sensor (2) can also be arranged in parallel and installed at the end of the robot bowl.