CN102645182B - Surface profile scanning type workpiece precut part weighing device - Google Patents

Abstract

The invention relates to a surface profile scanning type workpiece precut part weighing device. The practicability of the existing device is not high and the accuracy is comparatively low. The surface profile scanning type workpiece precut part weighing device comprises a digital controller, laser displacement sensors, a scanning stepping motor, a feeding stepping motor, supports and a feeding table. The laser displacement sensors are installed on the supports on the two sides of a workpiece and are driven by the scanning stepping motor. The moving direction of the scanning stepping motor is in parallel with the longitudinal section of the workpiece. The feeding table is driven by the feeding stepping motor and is used for feeding the workpiece. The laser displacement sensors, the scanning stepping motor and the feeding stepping motor are connected with the digital controller through signals. The surface profile scanning type workpiece precut part weighing device has the advantages that the workpiece is not damaged and the long-term measurement is facilitated; by adopting a laser ranging technique, the speed is fast, the efficiency is high, the requirement on the environment is not strict and the measurement under all kinds of working conditions is facilitated; and the structure of the device is simple and the accuracy is higher than the accuracy of manual measurement.

Description

Surface contour scanning workpiece pre-cut part weighing device

technical field

The invention relates to a weighing device for a pre-cut part of a workpiece, in particular to a weighing device for a pre-cut part of a workpiece which adopts surface contour scanning and reconstruction.

Background technique

In some fields of industrial processing, the weight of the workpiece to be processed must meet certain requirements, such as within 3%, which requires adding a device to judge the weight of the workpiece before processing the workpiece. Regular workpieces are generally cylindrical, and the weight requirements at this time can be guaranteed according to the length of the workpiece. For workpieces with irregular volumes, how to ensure that the weight of the cut workpieces meets the requirements depends on how to measure the volume of irregular objects.

Due to the irregularity of the cutting material, how to obtain the volume of the cutting material is also a difficult problem. There are mainly two methods of volume measurement: contact measurement and non-contact measurement. Contact measurement includes manual measurement and measurement based on Archimedes' principle. Manual measurement has a large workload, requires a lot of manpower and material resources, has poor practicability, and relatively low accuracy. The volume measuring instrument of the patent of the publication number CN1423111 is based on the Archimedes principle, and the weight reduced by the object in the water is equal to the weight of the same volume of water displaced by the object. Non-contact measurement includes image measurement method and laser imaging method. The patent of publication number CN101266131 is an image-based volume measurement device and its measurement method. It is based on the image measurement method, and uses three cameras installed on the stage to measure the three-dimensional data of the measured object, and then obtains the actual volume of the measured object. volume. The volume measurement error of the image measurement method is relatively large, which is not suitable for applications with high precision requirements, and the cost is relatively high, so it is not suitable for wide application on band sawing machines. The laser displacement sensor is used to calculate the volume by measuring the cross-sectional area of the irregular object, which is simple to implement and can meet the accuracy requirements well.

Contents of the invention

The purpose of the present invention is to provide an accurate weighing device for the pre-cut part of the workpiece; it is a two-dimensional cross-sectional area obtained by accumulating the line area of the workpiece surface profile cross-section direction from top to bottom, and then calculating the workpiece feeding direction. A measuring device that accumulates the two-dimensional cross-sectional area to obtain the three-dimensional workpiece quality; it is a non-contact measuring device that integrates two one-dimensional laser ranging on the surface of the workpiece contour, up and down stepping drive and feeding stepping drive.

The technical scheme that the present invention solves technical problem adopts is:

The weighing device of the surface contour scanning workpiece pre-cut part includes a digital controller, a laser displacement sensor, a scanning stepping motor, a feeding stepping motor, a bracket and a feeding table. Laser displacement sensors are installed on the brackets on both sides of the workpiece. The laser displacement sensor is driven by a scanning stepping motor, and the moving direction of the scanning stepping motor is parallel to the longitudinal section of the workpiece; the feeding table is driven by the feeding stepping motor for feeding the workpiece. ; The laser displacement sensor, the scanning stepping motor and the feeding stepping motor are all connected with the digital controller signal.

Beneficial effects of the present invention: as a non-contact detection technology, the laser ranging technology will not cause damage to the workpiece, which is beneficial to long-term measurement; the laser ranging technology is fast and efficient, and has no strict environmental requirements, which is beneficial Measurement under various working conditions; the structure of the device is simple, and it has higher accuracy than manual measurement. According to the observation and analysis of the actual sawing process, the existing two-dimensional workpiece scanning system in the market is very expensive on the one hand, and the size range of the workpiece to be detected is relatively limited (diameter is less than 100mm). Therefore, one-dimensional laser measurement Based on the distance principle, combined with the dynamic scanning mode driven by the xy axis, the three-dimensional size model of the pre-intercepted part is established to obtain weight prediction.

Description of drawings

Fig. 1 is a three-dimensional diagram of a weighing device;

Fig. 2 is a composition diagram of the weighing device system;

Fig. 3 is a schematic diagram of weighing device control calculation;

In the figure: 1. Scanning stepper motor; 2. Slide rail; 3. Slide rail base; 4. Slider; 5. Laser receiving window; 6. Laser emitting window; 7. Workpiece; 8. Laser displacement sensor; 9. Feeding stepper motor; 10. Gear box; 11. Drive roller; 12. Screw rod.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the present invention adopts the method of surface contour scanning, and specifically realizes that two laser displacement sensors 8 are used to scan the left and right contour surfaces of the workpiece 7 respectively. The slide rail base 3 is respectively installed on both sides of the feeding table. The laser displacement sensor 8 is fixed on the slider 4 by bolts, the slider 4 is installed on the slide rail 2, and forms two moving pairs with the slide rail 2, the slide rail 2 is fixed on the slide rail base 3, and the middle of the two slide rails 2 Leading screw 12 is housed, and the rotating shaft of scanning stepping motor 1 is directly connected with leading screw 12. The screw rod 12 is connected with the slide block 4 through a ball screw pair. The moving direction of the scanning stepper motor 1 is parallel to the longitudinal section of the workpiece 7 . The laser displacement sensor 8 is driven by the scanning stepper motor 1, and the moving speed is uniform, which is convenient for the laser displacement sensor 8 to sample at equal intervals. The laser distance measurement adopts the triangulation method. The laser emitting window 6 emits laser light onto the workpiece 7, and the laser receiving window 5 detects the workpiece 7 and calculate the distance from the laser bright spot to the laser displacement sensor 8, the laser emission window 6, the laser bright spot and the laser receiving window 5 form a triangular area. The advancement of the workpiece 7 is driven by the driving drum 11, which is connected to the reduction box 10, and the reduction box 10 is connected to the feeding stepping motor 9, and the reduction box 10 provides the function of reducing the speed and increasing the torque. When the laser displacement sensor 8 scans, the feeding stepping motor 9 must stop, and the feeding stepping motor 9 will advance a certain distance after the laser displacement sensor 8 completes a scan.

As shown in Figure 2, the digital controller is the core of the system and is responsible for all calculations. The laser displacement sensor, the scanning stepping motor and the feeding stepping motor are all connected with the digital controller signal. On the one hand, the digital controller controls the pulse to send a stepping drive signal to the feeding stepping motor 9, so that the feeding stepping motor 9 moves in the feeding direction, and stops after feeding 1mm each time. The specific feeding distance can be adjusted according to the actual accuracy, and the feeding stepping After the motor 9 stops, the digital controller controls the pulse to send a stepping drive signal to the scanning stepping motor 1, driving the scanning stepping motor 1 to move up and down at a uniform speed, driving the laser displacement sensor 8 to sample the outer contour of the workpiece 7 at equal intervals, and feeding after the sampling is completed Stepping motor 9 advances 1mm again. After each stepping drive, the scanning stepping motor and the feeding stepping motor will feed back the pulse count of the digital controller through the encoder. On the other hand, the digital controller is connected with the laser displacement sensor 8 and receives the data collected by the laser displacement sensor 8 in real time. The specific calculation principle of the device is as follows: the distance between the left and right laser range finders is L , the distance measured by the left range finder (the distance between the range finder and point A on the workpiece) l _y1 , and the distance measured by the right range finder ( The distance between the range finder and point B on the workpiece) l _y2 , then the distance l _y on both sides of the same height of the workpiece section at a certain moment can be obtained by the following formula:

In this way, the cross-sectional area S ( i ) of the workpiece at a certain moment can be obtained by superimposing the area of small rectangles in the y-axis direction, which can be specifically expressed as:

In the formula, m is the number of measurements in the y direction; dy is the feeding distance of the scanning stepping motor each time. It is the distance value of the i -th measurement in the x- direction and the j -th measurement in the y-direction. Therefore, the workpiece weight G of the pre-cut part is

In the formula, n is the number of measurements in the x direction; dx is the feeding distance of the stepping motor; ρ is the workpiece density.

 As shown in Figure 3, the schematic diagram of the weighing device control, how to complete the synchronization of feeding and obtaining the outer contour of the workpiece 7 under the coordination of the digital controller. At the beginning, you can set the information about the weighing device by the digital controller, including the density of the workpiece 7, the specified weight, the scanning interval time, the feeding step distance, etc. After completing the information setting, initialize and reset the weight, and then digitally control The controller controls the feeding stepping motor 9 to make the workpiece 7 advance, and the workpiece 7 stops after advancing 1 mm. The digital controller controls the scanning stepping motor 1 to move up and down, so that the laser displacement sensor 8 samples the contour of the workpiece 7 at equal intervals, and calculates the workpiece after the sampling is completed. 7 The cross-sectional area is accumulated and accumulated. When the accumulated weight reaches the specified requirements, the digital controller sends a signal to cut the part of the workpiece. After the cutting is completed, the data is cleared and the next weight calculation is performed.

Claims (2)

1. Surface contour scanning workpiece pre-cut part weighing device, including digital controller, laser displacement sensor, scanning stepper motor, feeding stepper motor, bracket and feeding table, laser displacement sensor is installed on the brackets on both sides of the workpiece , the laser displacement sensor is driven by a scanning stepping motor, and the moving direction of the scanning stepping motor is parallel to the longitudinal section of the workpiece; the feeding platform is driven by a feeding stepping motor for feeding the workpiece; the laser displacement sensor, scanning stepping motor and feeding The motors are all connected to the digital controller signal; it is characterized in that: On the one hand, the digital controller controls the pulse to send a stepping drive signal to the feeding stepping motor, so that the feeding stepping motor moves in the feeding direction, and stops after feeding 1mm each time. After the feeding stepping motor stops, the digital controller controls the pulse sending step The drive signal is given to the scanning stepping motor, which drives the scanning stepping motor to move up and down at a uniform speed, and drives the laser displacement sensor to sample the outer contour of the workpiece at equal intervals. After the sampling is completed, the feeding stepping motor advances 1mm; Both the feeding motor and the feeding stepping motor will feed back the pulse count to the digital controller through the encoder; on the other hand, the digital controller receives the data collected by the laser displacement sensor in real time; Suppose the distance between the two laser displacement sensors is L, the distance measured by the laser displacement sensor on one side is _ly1 , and the distance measured by the laser displacement sensor on the other side _{is ly2} , then the distance between the two sides of the same height of the workpiece section at a certain moment is given by _ly The following formula is obtained: l _y =Ll _y1 -l _y2 In this way, the cross-sectional area S(i) of the workpiece at a certain moment is obtained by superimposing the integral of the small rectangular area in the y-axis direction, which can be specifically expressed as: $\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dy</span>}$ In the formula, m is the number of measurements in the y direction; dy is the feeding distance of the scanning stepping motor each time; l _y (i, j) is the distance value of the i-th measurement in the x-direction and the j-th measurement in the y-direction; Therefore, the workpiece weight G of the pre-cut part is: $\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dydx</span>}$ In the formula, n is the number of measurements in the x direction; dx is the feeding distance of the stepping motor; ρ is the workpiece density. 2. The surface contour scanning type workpiece pre-intercepting part weighing device according to claim 1, wherein the support includes a slide rail base, a slide rail, a slide block and a screw mandrel, and the slide rail is installed on the slide rail base The slider is installed on the slide rail, and the screw rod is installed in the middle of the two slide rails and connected with the slider; the laser displacement sensor is installed on the slider.