Metallurgical technology probe insertion calibration method employing visual measurement and insertion system thereof

Abstract

A metallurgical technology probe insertion calibration method employing visual measurement and an insertion system thereof are provided. A vision sensor (5), a cylindrical rod (1), and a metallurgical technology probe (2) are used to construct an agreed region (6). In the agreed region (6), the vision sensor (5) acquires relative positions and orientations of the cylindrical rod (1) and the metallurgical technology probe (2), and an acquired position and orientation result is used to control a driving device (3) to insert the cylindrical rod (1) into the metallurgical technology probe (2). To improve the accuracy and reliability of the insertion, a standard probe (7) and a fixing device (4) are used together to perform effective calibration on an initial position, orientation, and axis in the insertion.

Claims

1. A metallurgical technology probe insertion system employing visual measurement comprises: a cylindrical rod and a metallurgical technology probe, wherein a front end of the metallurgical technology probe is an open end along which a deep hole is provided, and wherein the metallurgical technology probe is configured to be hollow for allowing a front end of the cylindrical rod to be inserted into the deep hole of the metallurgical technology probe along the open end, and wherein the metallurgical technology probe insertion system further comprises: a driving device, a fixing device, two vision sensors, a controller, and a standard probe, wherein the driving device is configured to be connected to and fix a rear end of the cylindrical rod, and to be capable of moving a position of the cylindrical rod and adjusting a-pose of the cylindrical rod; the fixing device is configured to fix the metallurgical technology probe, wherein the open end of the metallurgical technology probe is aligned with the front end of the cylindrical rod; an insertion length of the front end of the cylindrical rod and an insertion length of the open end of the metallurgical technology probe form an agreed area; the two vision sensors, one is located vertically above the agreed area by a fixed bracket and another one is located on a horizontal side of the agreed area by another fixed bracket, wherein the two vision sensors respectively detect and collect physical contours of the cylindrical rod and the metallurgical technology probe in the agreed area in real time; the controller acquires related data measured by the vision sensors, calculates a point angular deviation between an axis of the cylindrical rod and an axis of the metallurgical technology probe, and a distance between an end cross-section of the cylindrical rod and an open end cross-section of the metallurgical technology probe, obtains an adjustment amount of the cylindrical rod, and controls the driving device to adjust the pose of the cylindrical rod according to the adjustment amount; and the standard probe manufactured by imitating the metallurgical technology probe reproduces the deep hole of the metallurgical technology probe, and in order to facilitate the abutment of the cylindrical rod during calibration, a part of the deep hole is removed and exposed to form a deep-hole cross-section.

2. The metallurgical technology probe insertion system of claim 1, wherein the driving device is a multi-axis manipulator.

3. The metallurgical technology probe insertion system of claim 1, wherein the vision sensor is an industrial camera.

4. The metallurgical technology probe insertion system of claim 1, wherein the cylindrical standard probe is connected to a fixing block, and a support corresponding to the fixing block is provided with a groove, and wherein, when the standard probe is placed on the support, the deep-hole cross-section is vertically upward, and the fixing block is embedded in the groove and mated with the groove with a non-circular profile connection, and wherein the axis of the probe cannot move and rotate.

5. A metallurgical technology probe insertion calibration method using the metallurgical technology probe insertion system of claim 1, said method comprising the following steps: a) providing a standard probe manufactured by imitating the metallurgical technology probe, wherein the standard probe reproduces the deep hole of the metallurgical technology probe, and in order to facilitate the abutment of the cylindrical rod during calibration, a part of the deep hole is removed and exposed to form a deep-hole cross-section; b) determining a standard orientation, a standard axis and a standard position using the standard probe before insertion operation, wherein the driving device is used to move the cylindrical rod repeatedly to abut against the deep-hole cross-section of the standard probe to obtain the standard orientation, and no less than three points which are taken to obtain the standard axis; and wherein the standard position is in the standard axis and within the agreed area; and c) providing a calibration method comprising the following steps: i) driving the cylindrical rod to move to the standard insertion position and adjusting the cylindrical rod to a pre-calibrated and pre-collected standard orientation; ii) driving the cylindrical rod to initially move towards the metallurgical technology probe in a direction of a pre-calibrated standard axis with the standard orientation being maintained; iii) collecting physical contours of the cylindrical rod and the metallurgical technology probe in the agreed area in real time, measuring a spatial relative position between a front end face of the cylindrical rod and an open end face of the metallurgical technology probe, and a relative spatial angle between an axis of the cylindrical rod and an axis of the metallurgical technology probe, and calculating an adjustment amount by an algorithm; iv) according to the adjustment amount obtained in step iii), regulating the movement of the cylindrical rod to the metallurgical technology probe to ensure that the axis of the cylindrical rod is consistent with the axis of the metallurgical technology probe and the front end face of the cylindrical rod is inserted into the metallurgical technology probe; and v) continuing to measure a relative spatial angle between the axis of the cylindrical rod and the axis of the metallurgical technology probe, while obtaining an adjustment amount according to deformation of the cylindrical rod itself and by an algorithm, and continuing to move the cylindrical rod according to the adjustment amount to ensure that insertion length of the cylindrical rod meets a standard requirement.

6. The metallurgical technology probe insertion calibration method of claim 5, wherein the pre-calibrated and pre-collected standard orientation is adjusted by the following steps: a) using the standard axis as the rotation axis and rotating at a fixed angular interval by the cylindrical rod; and b) collecting a contour of the front end of the cylindrical rod every time the cylindrical rod is rotated by an angle, and comparing deviation values of the contour of the front end of the cylindrical rod at different rotation angles to obtain deformation parameters of the cylindrical rod.

7. The metallurgical technology probe insertion calibration method of claim 5, wherein the standard probe is made of an iron material, and is manufactured by imitating the metallurgical technology probe by machining.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural diagram of an insertion system of the present invention;

(2) FIG. 2 is a side view of the insertion system of the present invention of FIG. 1;

(3) FIG. 3A is a side view of a metallurgical technology probe in the insertion system of the present invention;

(4) FIG. 3B is an axonometric view of the metallurgical technology probe in the insertion system of the present invention;

(5) FIG. 4A is a side view of a standard probe in the insertion system of the present invention;

(6) FIG. 4B is an axonometric view of the standard probe in the insertion system of the present invention;

(7) FIG. 5A is a side view of a fixing device in the insertion system of the present invention;

(8) FIG. 5B is an axonometric view of the fixing device in the insertion system of the present invention;

(9) FIG. 6 is a schematic diagram of a standard orientation in an insertion calibration method of the present invention;

(10) FIG. 7 is a schematic diagram of a method for obtaining a standard axis in the insertion calibration method of the present invention;

(11) FIG. 8 is a schematic diagram of a method for obtaining a standard position in the insertion calibration method of the present invention;

(12) FIG. 9 is a side view of the calibration of a cylindrical rod in the insertion calibration method of the present invention;

(13) FIG. 10 is a schematic diagram of a method for calibrating a cylindrical rod in the insertion calibration method of the present invention; and

(14) FIG. 11 is a schematic diagram of the method for calibrating a cylindrical rod in FIG. 10 in the A-A direction.

DETAILED DESCRIPTION OF EMBODIMENTS

(15) The technical solutions of the invention are further described below with reference to the accompanying drawings and embodiments.

(16) As shown in FIGS. 1 to 3B, a metallurgical technology probe insertion system employing visual measurement provided in the present invention comprises: a cylindrical rod 1 and a metallurgical technology probe 2. A front end of the metallurgical technology probe 2 is an open end 21, and a deep hole 22 is provided along the open end 21 such that the metallurgical technology probe 2 is configured to be hollow for allowing a front end of the cylindrical rod 1 to be inserted into the deep hole 22 of the metallurgical technology probe 2 along the open end 21. The above is belongs to the prior art and will not be described in detail herein. Different from the prior art, the system further comprises: a driving device 3, a fixing device 4 and a vision sensor 5, wherein the driving device 3 and the vision sensor 5 are also connected to a computer (an implementation of a controller), and the computer acquires related data measured by the driving device 3 and the vision sensor 5, and thus controls the movement of the driving device 3 through a calculation method.

(17) Preferably, the driving device 3 is configured to be connected to and fix a rear end of the cylindrical rod 1, and to move the position of the cylindrical rod 1, and the driving device 3 takes the form of a multi-axis manipulator.

(18) Preferably, the fixing device 4 is configured to fix the metallurgical technology probe 2 such that the open end 21 of the metallurgical technology probe 2 can be aligned with the front end of the cylindrical rod 1.

(19) Preferably, the insertion length of the front end of the cylindrical rod 1 and the insertion length of the open end 21 of the metallurgical technology probe 2 form an agreed area 6, and the agreed area 6 includes the front end of the cylindrical rod 1 and the open end 21 of the metallurgical technology probe 2, and also includes a length, not shorter than the insertion length, of the cylindrical rod 1 and the metallurgical technology probe 2. The detection cost is reduced and the detection accuracy is improved. Regarding the agreed area 6, there is a small fit clearance and a high tightness of fit between the cylindrical rod 1 and the metallurgical technology probe 2 in practical applications, and thus the insertion length of the two requiring accurate detection is much smaller than the deep hole 22 of the metallurgical technology probe 2. For example, the metallurgical technology probe 2 has an inner diameter of 18 mm, and the cylindrical rod 1 has an outer diameter of 16 mm.

(20) Preferably, there are two vision sensors 5, both are industrial cameras, one of which is located vertically above the agreed area 6 by means of a fixed bracket and can clearly view, from the top, the relative position and angle between the cylindrical rod 1 and the metallurgical technology probe 2 in the agreed area 6, and the other is located on a horizontal side of the agreed area 6 by means of a fixed bracket and can clearly view, from the side, the relative position and angle between the cylindrical rod 1 and the metallurgical technology probe 2 in the agreed area 6. Through the image comparison and data analysis for the two cameras, the spatial positions and orientations of the cylindrical rod 1 and the metallurgical technology probe 2 are reproduced.

(21) It is conceivable that when there are multiple sets of metallurgical technology probes 2 and corresponding fixing devices 4, it is impossible to ensure that the vision sensor 5 is directly above each metallurgical technology probe 2, but there is a certain angle. However, the arrangement of the two vision sensors 5 can ensure that even if there is an angle, the two vision sensors 5 can obtain the spatial angle and position deviations between the cylindrical rod 1 and the metallurgical technology probe 2 through an image comparison algorithm.

(22) As shown in FIGS. 4A and 4B, a standard probe 7 is further comprised. The standard probe 7 is made of an iron material and is manufactured by imitating the metallurgical technology probe 2 by means of machining. The standard probe 7 reproduces the deep hole 71 of the metallurgical technology probe 2. Moreover, in order to facilitate the abutment of the cylindrical rod 1 during calibration, a part of the deep hole 71 is removed and therefore exposed to form a deep-hole cross-section 72. In addition, in order to ensure that the cylindrical standard probe 7 will not rotate and translate during calibration, the standard probe 7 is fixed by using a fixing block 8. When the standard probe 7 is placed on a supporting point 42, the deep-hole cross-section 72 is vertically upward, and an axis 9 of the probe cannot move or rotate.

(23) As shown in FIGS. 5A and 5B, the fixing device 4 comprises at least two supports 41, 42 for supporting the metallurgical technology probe 2. Supporting parts of the supports 41, 42 are both V-shaped, and can ensure that when the metallurgical technology probe 2 is placed, the axis 9 of the probe coincides with a horizontal axis 10. The support 42 is different from the support 41 in that the support 42 is further provided with a groove 11. The fixing block 8 is embedded into the groove 11, and the groove is therefore connected to the fixing block 8 and mated with the fixing block 8 with a profile connection, such that the axis 9 of the probe cannot move and rotate.

(24) The present invention further provides a metallurgical technology probe insertion calibration method employing visual measurement, comprising the following steps: a) a driving device 3 driving a cylindrical rod 1 to move to an insertion standard position 11, and adjusting the cylindrical rod 1 to a pre-calibrated and pre-collected standard orientation 12; b) the driving device 3 then driving the cylindrical rod 1 to initially move towards a metallurgical technology probe 2 in a direction of a pre-calibrated standard axis 13 with the standard orientation 12 being maintained; c) a vision sensor 5, which is located at the top of an agreed area 6, detecting and collecting physical contours of the cylindrical rod 1 and the metallurgical technology probe 2 in the agreed area 6 in real time, so as to obtain a point angular deviation of an axis 14 of the cylindrical rod and an axis of the probe 9, and also detecting a distance between an end cross-section 15 of the cylindrical rod and a cross-section of an open end 21 of the metallurgical technology probe 2; a vision sensor 5, which is located on aside of the agreed area 6, detecting the point angular deviation of the axis 14 of the cylindrical rod and the axis of the probe 9 in real time, and also detecting the distance between the end cross-section 15 of the cylindrical rod and the cross-section of the open end 21 of the metallurgical technology probe 2; and obtaining a pose offset, namely an adjustment amount (Δx, Δy, Δz, Δθx, Δ5θy, Δθz), of the cylindrical rod 1 according to the results of the two vision sensors 5 and by means of a certain calculation; d) regulating, according to the adjustment amount (Δx, Δy, Δz, Δθx, Δθy, Δθz) obtained in step c), the movement of the driving device 3 during the movement of the cylindrical rod 1 to the metallurgical technology probe 2, so as to ensure that the axis 14 of the cylindrical rod is consistent with the axis 9 of the probe, so that the front of the cylindrical rod 1 is inserted into the metallurgical technology probe 2; and e) the vision sensors 5 continuing to measure a relative spatial angle (Δθx, Δθy, Δθz) between the axis 15 of the cylindrical rod and the axis 9 of the probe, and at the same time, obtaining an adjustment amount (Δx, Δy, Δz, Δθx, Δθy, Δθz) according to the deformation (Δz, β, Δd) of the cylindrical rod 1 itself and by means of a certain calculation, and the driving device 3 continuing to move the cylindrical rod 1 according to the adjustment amount to ensure that the insertion length of the cylindrical rod 1 meets a standard requirement.

(25) Since the insertion process is actually to determine the actual relative pose deviation of the cylindrical rod 1 and the metallurgical technology probe 2, the high-precision visual detection is directly focused on the acquisition of the relative pose deviation through the insertion calibration method of the present invention, eliminating the need for intermediate conversion and the deviation caused by theoretical data.

(26) During the movement of the cylindrical rod 1 towards the metallurgical technology probe 2 in step a), the calculation of the adjustment amount by the vision sensor 5 in step c) is performed in real time.

(27) As shown in FIG. 6, the driving device 3 is used to move the cylindrical rod 1 to abut against a deep-hole cross-section 72 of a standard probe 7, and an orientation (θx, θy, θz) of the cylindrical rod 1 displayed in the driving device 3 is recorded, wherein the pose is the standard orientation 12.

(28) As shown in FIG. 7, the driving device 3 is used to move the cylindrical rod 1 to abut against the deep-hole cross-section 72 of the standard probe 7, the cylindrical rod is moved repeatedly, no less than three points are taken, ensuring that each point abuts against the deep-hole cross-section 72 of the standard probe 7, the acquired points are used to obtain the standard axis 13 and the standard axis is recorded in the driving device 3.

(29) As shown in FIG. 8, the driving device 3 is used to move the cylindrical rod 1 to abut against a deep-hole cross-section 72 of a standard probe 7, the cylindrical rod moves away from the deep-hole cross-section 72 area along the standard axis 13 by a certain distance, and a position (x, y, z), namely the standard position 11, of the cylindrical rod displayed in the driving device 3 is recorded.

(30) FIGS. 9 to 11 illustrate the process of calibrating the deformation of the cylindrical rod 1 itself by using the vision sensors 5. 1) The driving device 3 drives the cylindrical rod 1 to move to the insertion standard position 11, and adjusts the cylindrical rod 1 to a pre-calibrated and pre-collected standard orientation 12. 2) FIG. 9 shows the state of the cylindrical rod 1 in the standard position 11. The cylindrical rod 1 uses the standard axis 13 as the rotation axis, and rotates at a fixed angular interval a according to the rotation direction of the z-axis to obtain different states (as labeled B and C in FIG. 10) of the cylindrical rod 1. The total number of rotations is 360/α, and an angle sequence (0, α, . . . , 360-α) is obtained. For sake of convenience, α may be taken as a common divisor of 360. For example, if the total number of rotations is 4, rotating 90° each time, the angle sequence is (0°, 90°, 180°, 270°). 3) At each angle in the angle sequence, the vision sensors 5 collect the contour of the front end of the cylindrical rod 1 and the deviation values of the contour when the cross-section is at different angles are compared to obtain a deviation value group (S.sub.A, D.sub.0, D.sub.α, . . . , D.sub.180/α). For example, there is a cross-section A-A at a distance of S.sub.A from the end face 15 of the cylindrical rod, when the rotation angle is 0° and 180°, the contour difference D.sub.α=D1, and when the rotation angle is 90° and 270°, the contour difference D.sub.α=D2, thereby obtaining a deviation value group (S.sub.A, D1, D2). 4) According to the deviation value group (S.sub.A, D1, D2), under the premise that the cross-section of the cylindrical rod 1 is circular, the maximum deviation value ΔD of the contour of the cross-section of the cylindrical rod 1 and the rotation angle β at this time are calculated to obtain deformation parameters (S.sub.A, β, ΔD) at the cross-section A-A. 5) Since the cross-section A-A can be defined at different positions, in the present invention, it is set as S.sub.A=n*Δs (n=1, 2, . . . , n), and the obtained deformation parameters of the front end of the entire cylindrical rod 1 are (S.sub.A, β, ΔD).

(31) The measurement of the deformation of the cylindrical rod is versatile, and is not limited to ensuring that the difficulty and failure rate of the entire insertion process will not increase due to the excessive deviation of the cylindrical rod, and the deformation parameters are also used to adjust the pose of the cylindrical rod to reduce the difficulty of insertion in the insertion stage after the cylindrical rod has been inserted into the metallurgical technology probe. Before the start of the insertion, it is necessary to determine whether the deformation of the cylindrical rod itself is too large, and if it exceeds a rated value, the cylindrical rod needs to be replaced. Upon the start of the insertion, from the initial insertion of the cylindrical rod into the metallurgical technology probe until the insertion is completed, the deformation of the cylindrical rod itself can be used as a reference value for the pose of the cylindrical rod.

(32) It should be appreciated by those of ordinary skill in the art that the foregoing embodiments are only used to describe the invention rather to limit the invention. Changes or variations made to the embodiments within the essential spirit and scope of the invention fall within the scope of the claims of the invention.