CN115921605A - A method and device for real-time measurement of bending angle based on 3D vision technology - Google Patents

Abstract

The invention relates to a bending angle real-time measurement method based on a 3D vision technology, which comprises the following steps: s1, installing sensing heads of a 3D line laser measuring instrument, S2, adjusting the positions of two front sensing heads and two rear sensing heads, S3, measuring detection point data of the bottom end of the sheet metal part in real time, and S4, calculating the real-time bent angle of the sheet metal part. The beneficial effects are that: utilize 3D line laser survey appearance's sensing head to detect respectively the check point data of sheet metal component bottom around the bender under in real time, then calculate the angle that the sheet metal component was bent in real time, can be at the in-process that the sheet metal component was bent, not only can calculate respectively and obtain the sheet metal component and be located the angle of bending of bender front and back under, can also calculate and obtain the total angle of being bent of sheet metal component, the accuracy is high, it is convenient to detect.

Description

A method and device for real-time measurement of bending angle based on 3D vision technology

technical field

The invention relates to the technical field of angle measurement, in particular to a method and device for real-time measurement of bending angles based on 3D vision technology.

Background technique

When the bending machine bends the sheet metal part, the sheet metal part is placed on the top of the lower bending die, and then the bending machine is started to press down the upper bending die to bend the sheet metal part to be bent. When bending sheet metal parts, how to accurately control the bending angle of sheet metal parts is the bending performance that both bending machine manufacturers and application companies must pay attention to. However, the existing bending angle measurement methods are based on the accuracy of the upper and lower dies. Alignment and sheet metal bends are calculated under the assumption that both sides are symmetrical, and the accuracy of the calculation results is low.

Contents of the invention

The purpose of the present invention is to overcome the above problems in the prior art, and provide a real-time measurement method and device for bending angle based on 3D vision technology.

In order to achieve the above-mentioned technical purpose and achieve the above-mentioned technical effect, the present invention is realized through the following technical solutions:

A method for real-time measurement of bending angle based on 3D vision technology, comprising the following steps:

S1. Install the sensing head of the 3D line laser measuring instrument: install two left and right symmetrical front sensing heads of the 3D line laser measuring instrument in front of the lower bending die of the bending machine, and install them on the lower bending die of the bending machine Install the rear sensing heads of two left-right symmetrical 3D line laser measuring instruments at the rear, and make the plane where the linear laser beams emitted by the two front sensing heads be perpendicular to the long axis of the lower bending die, and the two rear sensing heads The plane where the linear laser beam emitted by the head is also perpendicular to the long axis of the lower bending die, the front sensing head and the rear sensing head are respectively connected to the controller of the 3D line laser measuring instrument with cables, and the controller is connected to the The computer is connected with a cable;

S2. Adjust the positions of the two front sensing heads and the two rear sensing heads: place a flat plate on the top of the lower bending die of the bending machine, and start the two front sensing heads and the two rear sensing heads at the same time , adjust the height and level of the two front sensing heads and the two rear sensing heads so that the two front sensing heads and the two rear sensing heads are at the same level;

S3. Real-time measurement: Start two front sensing heads and two rear sensing heads at the same time, place the sheet metal part to be bent on the top of the lower bending die of the bending machine, and place it on the upper bending die of the bending machine When pressing down, the detection point data of the bottom end of the sheet metal part before and after the lower bending die is detected in real time through two front sensing heads and two rear sensing heads;

S4. Calculate the real-time bending angle of the sheet metal part: calculate the inclination angle of the linear laser beam irradiation area emitted by each front sensing head and the slope angle of the linear laser beam irradiation area emitted by each rear sensing head on the sheet metal part respectively Inclination angle, add the average value of the inclination angles of the linear laser beam irradiation areas emitted by the two front sensing heads to the average value of the inclination angles of the linear laser beam irradiation areas emitted by the two rear sensing heads to form the sheet metal part The angle to be bent in real time.

A real-time measurement device for bending angle based on 3D vision technology, used for the above-mentioned real-time measurement method for bending angle, including a controller of a 3D line laser measuring instrument, a sensing head of the 3D line laser measuring instrument, and two sensing heads Mounting frame, a computer for calculating the bending angle, the two sensor head mounting frames are installed on the lower bending die of the bending machine with screwed bolts and nuts according to the front and back symmetrical layout, each Two left-right symmetrical sensing heads are installed on the sensing head mounting frame, and the laser emitting end of each sensing head is vertically upward, and the controller is respectively connected to the four sensing heads with cables , the controller is connected to the computer with a cable.

The beneficial effects of the present invention are: use the sensing head of the 3D line laser measuring instrument to detect the detection point data of the bottom of the sheet metal part before and after the lower bending die in real time, and then calculate the angle at which the sheet metal part is bent in real time, which can be used on the sheet metal part During the bending process of the metal parts, not only the bending angle of the sheet metal parts at the front and rear of the lower bending die can be calculated respectively, but also the total bending angle of the sheet metal parts can be calculated, which has high accuracy and is easy to detect.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is the three-dimensional structure schematic diagram of the first viewing angle of the partial bending angle real-time measuring device in the present invention;

Fig. 2 is a three-dimensional structure schematic diagram of a second viewing angle of a real-time measurement device for partial bending angles in the present invention;

Fig. 3 is a three-dimensional structural schematic diagram of the sensing head mounting frame in the present invention;

Fig. 4 is a schematic structural view of the sheet metal part in the present invention when it is bent to the first state;

Fig. 5 is a schematic structural view of the sheet metal part in the present invention when it is bent to the second state;

Explanation of symbols in the figure: lower bending die 100, sheet metal part 200, sensing head 1, front sensing head 11, rear sensing head 12, sensing head mounting frame 2, mounting plate 21, vertical mounting part 211, Strip hole 211a, circular through hole 211b, horizontal mounting part 212, rib 213, rib 214, spacer 22, round rod 221, bolt 3, nut 4.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

As shown in Figure 4 and Figure 5, a real-time measurement method of bending angle based on 3D vision technology includes the following steps:

S1. Install the sensing head of the 3D line laser measuring instrument: install two left and right symmetrical front sensing heads 11 of the 3D line laser measuring instrument in front of the lower bending die 100 of the bending machine. The rear sensing heads 12 of two symmetrical 3D line laser measuring instruments are installed at the rear of the bending die 100, and the plane where the linear laser beams emitted by the two front sensing heads 11 is perpendicular to the long axis of the lower bending die 100 The plane where the linear laser beams emitted by the two rear sensing heads 12 is also perpendicular to the long axis of the lower bending die 100, the front sensing head 11 and the rear sensing head 12 are respectively connected to the 3D line laser measuring instrument by cables. The controller is connected, and the controller is connected to the computer with a cable;

S2, adjust the positions of the two front sensing heads 11 and the two rear sensing heads 2: place a flat plate on the top of the lower bending die 100 of the bending machine, and start the two front sensing heads 11 and the two rear sensing heads simultaneously. Rear sensing head 12, adjust the height and levelness of two front sensing heads 11 and two rear sensing heads 12, so that the two front sensing heads 11 and the two rear sensing heads 12 are at the same level;

S3, real-time measurement: start two front sensing heads 11 and two rear sensing heads 12 at the same time, place the sheet metal part 200 to be bent on the top of the lower bending die 100 of the bending machine, When the upper bending die presses down, the detection point data of the bottom ends of the sheet metal parts 200 before and after the lower bending die 100 are detected in real time through the two front sensing heads 11 and the two rear sensing heads 12;

S4. Calculate the angle at which the sheet metal part is bent in real time: respectively calculate the inclination angle of the linear laser beam irradiation area emitted by each front sensor head 11 and the linear laser beam emitted by each rear sensor head 12 on the sheet metal part 200 The inclination angle of the irradiated area, the average value of the inclination angles of the linear laser beam irradiated areas sent by the two front sensor heads 11 and the average value of the inclination angles of the linear laser beam irradiated areas emitted by the two rear sensor heads 12 are added That is, the angle at which the sheet metal part 200 is bent in real time.

The real-time calculation of the bent angle of the sheet metal part 200 in step S4 specifically includes the following steps:

S41. Construct a Cartesian coordinate system for each sensing head: take the direction perpendicular to the long axis of the lower bending die 100 on the horizontal plane as the X axis, and take the direction perpendicular to the long axis of the lower bending die 100 on the vertical plane The direction is the Z axis, and a Cartesian coordinate system is constructed.

S42. Calculate the inclination angle α of the linear laser beam irradiation area emitted by each front sensing head 11 on the sheet metal part: at least n points are selected on the X-axis of the Cartesian coordinate system of each front sensing head 11, ( n is greater than or equal to 3), obtain the detection point coordinate data (X _n , Z _n ) of the surface of the sheet metal part 200 in the longitudinal direction where each point is located;

和公式2：

计算每个前感测头11检测处的倾斜角度α。According to formula 1:

and formula 2:

The inclination angle α at the detection point of each front sensor head 11 is calculated.

S43. Calculate the inclination angle β of the linear laser beam irradiation area emitted by each rear sensing head 12 on the sheet metal part 200: select at least n points on the X-axis of the Cartesian coordinate system of each rear sensing head 12, (n is greater than or equal to 3), obtain the detection point coordinate data (x _n , z _n ) of the sheet metal part 200 surface on the longitudinal direction where each point is located;

和公式4：

计算每个后感测头12检测处的倾斜角度β。According to formula 3:

and formula 4:

The inclination angle β at the detection point of each rear sensor head 12 is calculated.

计算钣金件200已折弯的角度γ。S44. Calculation of the real-time bent angle of the sheet metal part 200: according to formula 5:

The angle γ by which the sheet metal part 200 has been bent is calculated.

It also includes calculating the forming angle θ of the bent part after 200 bends of the sheet metal part, specifically:

The angle θ after bending of the sheet metal part 200 is calculated according to formula 6: θ=180°−γ.

As shown in Figures 1 to 3, a real-time measurement device for bending angles based on 3D vision technology is used for the above-mentioned real-time measurement method for bending angles, including the controller of the 3D line laser measuring instrument and the controller of the 3D line laser measuring instrument. Sensor head 1, two sensor head mounts 2, a computer for calculating the bending angle.

The two sensing head mounting frames 2 are installed on the lower bending die 100 of the bending machine with screwed bolts 3 and nuts 4 according to the front-rear symmetrical layout. Specifically, the sensing head mounting frame 2 includes an L-shaped mounting frame. Plate 21, cross-section is "convex" font block 22, between the vertical mounting part 211 of mounting plate 21 and the horizontal mounting part 212 of mounting plate 21, a plurality of right-angled triangular ribs 213 are fixedly connected, and the ribs improve Strength and stability between the vertical mounting portion 211 of the mounting plate 21 and the horizontal mounting portion 212 of the mounting plate 21; the two ends of the vertical mounting portion 211 of the mounting plate 21 are respectively provided with a bar-shaped hole 211a, and the tail portions of the bolts 3 are in turn After passing through two adjacent and coaxial strip-shaped holes 211a, it is screwed with the nut 4, and the vertical installation parts 211 of the two installation plates 21 are relatively fixed on the lower bending die 100; the vertical installation of the installation plate 21 A plurality of uniformly distributed circular through-holes 211b are provided in the middle of the part 211, and a round rod 221 is fixedly connected to one side of the spacer 22, and the round rod 221 is plugged and fitted with the circular through-hole 211b, and the spacer 22 is clamped on the mounting plate. Between the vertical mounting part 211 of the lower bending die 100, it is convenient to change the thickness of the spacer 22 according to the width of the lower bending die 100, so as to ensure that the linear laser beam emitted by the sensing head is not blocked by the lower bending die 100 and adjust the level of sensor head 1.

The vertical mounting portion 211 of the mounting plate 21 is provided with two vertically parallel ribs 214 on the side close to the lower bending die 100, and the side of the spacer 22 fixed to the round rod 221 is stuck between the two ribs 214, The ribs 214 not only increase the bending resistance of the vertical mounting portion 211 of the mounting plate 21 , but also limit the spacer 22 .

Two left-right symmetrical sensing heads 1 are installed on each sensing head mounting frame 2, specifically, the sensing heads 1 are installed on the top of the horizontal mounting portion 212 of the mounting plate 21 with screws, and each sensing head 1 The laser emitting end of the laser is vertically upward, and the controller is respectively connected with the four sensing heads by cables, and the controller is connected with the computer by cables.

Among them, the 3D line laser measuring instrument adopts the principle of laser triangulation, uses the transmitter to project the laser onto the surface of the object to be measured, and obtains the complete contour measurement result through the movement of the sensor/object to be measured. The sensor head of the 3D line laser measuring instrument is integrated with a laser, an outgoing laser lens, a light receiving lens, a CCD element, and an image processor. Finally, a part of the laser light is shot onto the CCD element through the light-receiving lens, and the image processor processes the light received on the CCD element and sends it to the controller of the 3D line laser measuring instrument.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements all fall within the scope of the claimed invention.

Claims (10)

1. A bending angle real-time measurement method based on a 3D vision technology is characterized by comprising the following steps:

s1, mounting a sensing head of a 3D line laser measuring instrument: installing two front sensing heads of the 3D line laser measuring instruments which are bilaterally symmetrical in front of a lower bending die of a bending machine, installing two rear sensing heads of the 3D line laser measuring instruments which are bilaterally symmetrical in rear of the lower bending die of the bending machine, enabling the planes of linear laser beams emitted by the two front sensing heads to be vertical to the long axis of the lower bending die, enabling the planes of the linear laser beams emitted by the two rear sensing heads to be vertical to the long axis of the lower bending die, respectively connecting the front sensing heads and the rear sensing heads with a controller of the 3D line laser measuring instruments through cables, and connecting the controller with a computer through cables;

s2, adjusting the positions of the two front sensing heads and the two rear sensing heads: placing a flat plate at the top end of a lower bending die of a bending machine, simultaneously starting two front sensing heads and two rear sensing heads, and adjusting the heights and levelness of the two front sensing heads and the two rear sensing heads to enable the two front sensing heads and the two rear sensing heads to be at the same horizontal height;

s3, real-time measurement: starting the two front sensing heads and the two rear sensing heads simultaneously, placing a sheet metal part to be bent at the top end of a lower bending die of a bending machine, and detecting detection point data of the bottom ends of the sheet metal part in front of and behind the lower bending die in real time through the two front sensing heads and the two rear sensing heads when an upper bending die of the bending machine is pressed downwards;

s4, calculating the real-time bent angle of the sheet metal part: and respectively calculating the inclination angle of the linear laser beam irradiation region emitted by each front sensing head and the inclination angle of the linear laser beam irradiation region emitted by each rear sensing head on the sheet metal part, and adding the average value of the inclination angles of the linear laser beam irradiation regions emitted by the two front sensing heads and the average value of the inclination angles of the linear laser beam irradiation regions emitted by the two rear sensing heads to obtain the angle of the sheet metal part which is bent in real time.

2. The method for measuring the bending angle in real time according to claim 1, wherein the step S4 of calculating the bending angle of the sheet metal part in real time specifically comprises the following steps:

s41, constructing a rectangular coordinate system for each sensing head;

s42, calculating the inclination angle alpha of a linear laser beam irradiation area emitted by each front sensing head on the sheet metal part;

s43, calculating the inclination angle beta of a linear laser beam irradiation area emitted by each rear sensing head on the sheet metal part;

and S44, calculating the bending angle of the sheet metal part in real time.

3. The method for measuring bending angle in real time according to claim 2, wherein in step S41, a rectangular coordinate system is constructed for each sensing head, specifically:

and constructing a rectangular coordinate system by taking the direction vertical to the long axis of the lower bender on the horizontal plane as an X axis and the direction vertical to the long axis of the lower bender on the vertical plane as a Z axis.

4. The method for measuring the bending angle in real time according to claim 2, wherein in the step S42, the inclination angle α of the linear laser beam irradiation region emitted by each front sensor head on the sheet metal part is calculated, specifically:

at least n point positions (n is more than or equal to 3) are selected on the X axis of the rectangular coordinate system of each front sensing head, and detection point coordinate data (X) of the surface of the sheet metal part in the longitudinal direction of each point position is obtained _n ，Z _n )；

According to equation 1:

and equation 2: />

The inclination angle alpha at the detection of each front sensor head is calculated.

5. The method for measuring the bending angle in real time according to claim 2, wherein the step S43 is performed by calculating an inclination angle β of an irradiation region of a linear laser beam emitted by each rear sensing head on the sheet metal part, specifically:

at least n point positions are selected on the X axis of the rectangular coordinate system of each rear sensing head, (n is more than or equal to 3), and the coordinate data (X) of the detection point on the surface of the sheet metal part in the longitudinal direction of each point position is obtained _n ，z _n )；

According to equation 3:

and equation 4: />

The tilt angle β at each rear sensing head detection is calculated.

6. The bending angle real-time measurement method according to claim 2, wherein the calculation of the angle γ at which the sheet metal part is bent in real time in step S44 specifically includes:

according to equation 5:

and calculating the bent angle gamma of the sheet metal part.

7. The bending angle real-time measurement method according to claim 6, further comprising calculating a forming angle θ of a bent part of the sheet metal part after bending, specifically:

according to equation 6: and calculating the angle theta of the bent sheet metal part according to the theta = 180-gamma.

8. A bending angle real-time measuring device based on 3D vision technology is used for the bending angle real-time measuring method of any one of claims 1 to 7, and is characterized in that: including 3D line laser surveying appearance's controller, 3D line laser surveying appearance sense head, two sense first mounting brackets, a computer that is used for calculating the angle of bend, two the sense first mounting bracket is installed on the lower bender of bender with the bolt and the nut that spiral shell mutually closed according to symmetrical overall arrangement from beginning to end, every install two bilateral symmetry's sense head on the sense first mounting bracket, and every the laser emission end of sense head is vertical upwards, the controller is connected with four sense heads with the cable respectively, the controller is connected with the cable for the computer.

9. The real-time bending angle measuring device according to claim 8, wherein: the sensing head mounting frame comprises an L-shaped mounting plate and a cushion block with a convex cross section, the sensing head is mounted at the top end of a horizontal mounting part of the mounting plate by using screws, two ends of a vertical mounting part of the mounting plate are respectively provided with a strip-shaped hole, the tail part of each bolt sequentially penetrates through two adjacent and coaxial strip-shaped holes and then is screwed with a nut, and the vertical mounting parts of the two mounting plates are relatively fixed on a lower bending die; the middle of the vertical installation portion of mounting panel is equipped with a plurality of evenly distributed's circular through-hole, one side rigid coupling of cushion has the round bar, the cooperation is inserted with circular through-hole to the round bar pulling out, the cushion presss from both sides between the vertical installation portion of mounting panel and the lower bender.

10. The real-time bending angle measuring device according to claim 9, wherein: a plurality of right-angled triangular rib plates are fixedly connected between the vertical mounting part of the mounting plate and the horizontal mounting part of the mounting plate; one side that the vertical installation department of mounting panel is close to down the bender is equipped with the rib that the twice is parallel from top to bottom, one side card that the cushion rigid coupling has the round bar is between the rib.

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