A non-contact dual material detection system and method

Abstract

The application discloses a kind of non-contact double material detection system and method in press field, including anti-magnetic ranging unit, anti-magnetic ranging unit is connected with data transmission unit, data transmission unit is connected with control processing unit, control processing unit is connected with display unit.Data measurement is carried out using anti-magnetic ranging unit, data is sent to control processing unit through data transmission unit, and is presented on display unit after being processed by control processing unit, which can be suitable for magnetic conveying line and does not limit the material and conveying speed of the measured metal, has wide applicability and lower cost.

Description

Technical Field

[0001] This invention relates to a non-contact dual-material detection system and method in the field of presses. Background Technology

[0002] In the robotic loading section of an automated stamping line, steel plates often stick together due to the oil film on their surface. To prevent these oil-stained plates from damaging the molds and presses after stamping, a dual-material detection system must be installed. This system is redundant, meaning both the destacking and loading stations are equipped with dual-material detection systems. Typically, the destacking station uses contact sensors, while the loading station uses non-contact sensors installed on the front conveyor belt. Both detection systems are generally based on electromagnetic induction. This detection method has poor adaptability to different materials and mainly relies on imports, making it expensive and difficult for customers to accept and promote, thus limiting the development of the stamping automation industry. Summary of the Invention

[0003] The purpose of this invention is to provide a non-contact dual-material detection system and method that can be applied to magnetic conveyor lines and does not limit the material and conveying speed of the metal being tested. It has wide applicability and lower cost.

[0004] To achieve the above objectives, the present invention provides a non-contact dual-material detection system, including an anti-magnetic ranging unit, which is connected to a data transmission unit, which is connected to a control processing unit, and the control processing unit is connected to a display unit.

[0005] Compared with the prior art, the beneficial effects of the present invention are that it uses an antimagnetic ranging unit to measure data, sends the data to the control processing unit through the data transmission unit, and displays the data on the display unit after processing by the control processing unit. It can be applied to magnetic conveying lines and does not limit the material and conveying speed of the measured metal, thus having wide applicability and lower cost.

[0006] As a further improvement of the present invention, the antimagnetic ranging unit includes four laser distance sensors. The laser distance sensors are two-wire current-type sensors, with one group above and one below, for a total of two groups. Each group of laser distance sensors is installed on brackets extending from both sides of the conveyor line, located directly above and below the middle span of the conveyor line, respectively. The vertical installation spacing of each group of laser distance sensors is based on the range of the laser distance sensors, ensuring that the readings of both laser distance sensors are within the range when the material is on the conveyor line. The vertical installation position of each group of laser distance sensors is based on the upper plane of the conveyor line, with the beam points of the two laser distance sensors perpendicular to this plane and on the same straight line. The lateral distribution spacing of the two groups of laser distance sensors is based on the size of the product being measured, ensuring that the lateral spacing between the two groups of laser distance sensors is less than the width of the product.

[0007] This allows for more accurate data measurement without interference between components, makes installation easier, and provides double error protection and strong redundancy by using two sets of sensors. It is also suitable for production lines with one mold and two parts.

[0008] As a further improvement of the present invention, the data transmission unit includes a remote I / O module, which is installed below the conveyor line and is equipped with an analog input module, which is a current-type two-wire four-channel module, used to receive the analog signal of the laser distance sensor, convert the current signal of the laser distance sensor into a digital signal, and send it to the control processing unit through the PN bus.

[0009] This converts the analog signals from the sensor into digital signals, which are then transmitted to the control processing unit for data processing, resulting in more stable signal transmission and stronger anti-interference capabilities.

[0010] As a further improvement of the present invention, the control processing unit includes a programmable controller, which is installed in the main control cabinet of the automated line. The programmable controller communicates with the remote IO module through the PN bus, reads the readings of each laser distance sensor, calibrates and stores data for different products using the laser triangulation method, calls the TRIMMEAN algorithm during detection, calculates the measurement results, and sends instructions to the robot and camera to perform corresponding actions.

[0011] This method results in smaller data processing errors, higher accuracy, faster speed, and higher reliability.

[0012] As a further improvement of the present invention, the display unit includes a touch screen, which is connected to a programmable controller and is used to display sensor data.

[0013] This allows for real-time data display and convenient touch operation, parameter setting, and other functions.

[0014] To achieve the above objectives, the present invention also provides a non-contact dual-material detection method, comprising the following steps:

[0015] Step 1, Calibration Settings;

[0016] Step 2, data reading and collection;

[0017] Step 3, Data Processing: The programmable controller uses the TRIMMEAN algorithm to calculate the average sheet thickness L measured by each sensor group using the recorded array data. n ;

[0018] Step 4: Determine the result. The programmable controller will calculate the average thickness L of each group of sensors. n Compare with the upper and lower limits of the standard material thickness set by the touch screen.

[0019] As a further improvement to the present invention, the specific content of step 1 is as follows.

[0020] Step 1.1: The detection system is activated, and the programmable controller performs initialization, resetting the output detection completion signal, no material signal, single material signal, and double material signal.

[0021] Step 1.2: The programmable controller determines whether calibration needs to be performed. If there is no calibration data in the current recipe data, calibration must be performed first. If calibration is performed, proceed to step 1.3. If calibration is completed, proceed to step 1.10.

[0022] Step 1.3: Click the calibration mode button on the touch screen to start calibration. The programmable controller will clear the calibration data and calibration memory of the current product formula.

[0023] Step 1.4, Teach a single sheet: Place the single sheet into the sensing beams of the two sets of laser distance sensors, and click the single sheet teaching button on the touch screen to calculate the single sheet standard value A for each set of laser distance sensors. X1 :

[0024] A X1 =A1+d+A2

[0025] Where A1 is the upper sensor reading of each group of laser distance sensors, A2 is the lower sensor reading, and d is the thickness of the material sheet.

[0026] Step 1.5, Teach the double sheet: Place the double sheet of error-proof material into the sensing beams of the two sets of laser distance sensors. Click the double sheet teaching button on the touch screen to calculate the double standard value A for each set of laser distance sensors. X2 :

[0027] A X2 =A1+d+d+A2

[0028] Step 1.6, calculate the coefficient. Under ideal conditions, the standard value A for a single material is... X1 With double standard value A X2 The measured data should be equal. However, in practical applications, the beams of each set of laser distance sensors cannot be guaranteed to be perfectly parallel, and the linearity of the laser also has an error of 0.3% for different materials, which needs to be corrected. The programmable controller calculates the ratio k between the thickness measured by each set of sensors and the teaching difference. n :

[0029] k n =d / (A X1 -A X2 +d)

[0030] Where n is the serial number of each group of laser distance sensors.

[0031] Step 1.7, Dynamic Teaching: Considering that in actual production, the sheet will not be stationary during measurement, and the light beam will refract when the sheet passes through the sensor, dynamic compensation is required. Place a single sheet on the conveyor line, click the Dynamic Teaching button on the touch screen, and the sheet will pass through two sets of laser distance sensors at the set speed of the conveyor line. Record the instantaneous readings A1 and A2 of each set of laser distance sensors only when all four sensors have valid readings.

[0032] Step 1.8, Dynamic Compensation: The programmable controller calculates the deviation value measured by each group of laser distance sensors and the conveyor linear speed V based on the readings obtained from the dynamic teaching. f proportional relationship b n :

[0033] b n =(A X1 -A1-A2-d) / V f

[0034] Step 1.9: Calibration complete. The programmable controller compiles the calibration data of the current product and calculates the thickness D measured by each sensor group. n The expression:

[0035] D n =k n *(A X1 -A1-A2)+b n *V f

[0036] The programmable controller sets the calibration memory for the current recipe and saves the data. Calibration is complete, and the process returns to step 2.

[0037] Step 1.10, Measurement begins. The programmable controller receives the detection start command from the peripheral device and clears the previously recorded sensor array data.

[0038] As a further improvement to the present invention, the specific content of step 2 is as follows.

[0039] Step 2.1, Waiting for the sensors: The programmable controller records the current reading value of each laser distance sensor with a 10Hz pulse. It is determined that the conveyor line has delivered the material to the detection range of the two sets of sensors only when the reading values ​​of the four sensors in the current cycle have changed from the previous recorded value. The waiting for the sensors process ends.

[0040] Step 2.2, Data Collection: The programmable controller (PLC) is set to have a fixed minimum cycle time that must be greater than the response time of the laser distance sensor. The PLC reads the laser distance sensor's readings in each scanning cycle and calculates the sheet thickness D based on the calibrated data and formulas. nThe data is then stored in a record array, the size of which is determined by the material passing time and the PLC scanning cycle.

[0041] As a further improvement to the present invention, the method for a programmable controller to run the TRIMMEAN algorithm is as follows:

[0042] Step 3.1: Traverse all array data to find the maximum value and its array index;

[0043] Step 3.2: Traverse all array data to find the minimum value and its array index;

[0044] Step 3.3: Based on the array indices obtained from the traversal, assign the corresponding maximum and minimum values ​​in the data array to 0.0;

[0045] Step 3.4: If the array indices obtained by traversal are the same, the effective data is the array size minus 1; if the indices are different, the effective data is the array size minus 2.

[0046] Step 3.5: Sum all the array data and divide by the number of valid data points to obtain the measured average sheet thickness L for each group. n .

[0047] As a further improvement to the present invention, the specific content of step 4 is as follows.

[0048] Step 4.1 When the average thickness L measured by the two sets of sensors n If either of these values ​​is less than the lower limit of material thickness, output measurement completion and no material signal;

[0049] Step 4.2 When the average thickness L measured by the two sets of sensors n If both values ​​are greater than the lower limit of material thickness and less than the upper limit of material thickness, output measurement completion and single material signal;

[0050] Step 4.3 When the average thickness L measured by the two sets of sensors n If either of these values ​​exceeds the material thickness limit, output a measurement completion and dual-material signal.

[0051] Compared with existing technologies, the advantages of this invention are as follows: it uses a laser distance sensor as a non-contact sensor in the dual-material inspection system, calculates thickness based on triangulation, and is not limited by the material of the metal being inspected; it has low manufacturing costs, as the programmable controller and touch screen used are based on existing equipment on the automated line, requiring no additional purchase; it has high inspection efficiency, as the inspection process is not limited by the conveyor speed, and magnetic belts can be used to transport the sheets at high speed, saving time from destacking to loading and improving production line efficiency; it has high reliability, using data from two sets of laser distance sensors for calculation, providing double error prevention and strong redundancy, and is also applicable to single-mold dual-piece production lines. This invention has high product competitiveness in the field of dual-material inspection in stamping automated lines and helps promote the development of the stamping automation industry. Attached Figure Description

[0052] Figure 1 This is a system block diagram of the present invention.

[0053] Figure 2 This is the control flowchart of the present invention. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings:

[0055] like Figure 1 The non-contact dual-material detection system shown includes an antimagnetic ranging unit, which is connected to a data transmission unit, which is connected to a control processing unit, and the control processing unit is connected to a display unit.

[0056] The anti-magnetic ranging unit includes four laser distance sensors. These are two-wire current-type laser distance sensors, arranged in two groups, one vertically and one horizontally. Each group of laser distance sensors is mounted on brackets extending from both sides of the conveyor line, directly above and below the middle span of the conveyor line, respectively. The vertical mounting distance between each group of laser distance sensors is based on their measuring range, ensuring that the readings of both sensors are within their range when the material is on the conveyor line. The vertical mounting position of each group of laser distance sensors is based on the upper plane of the conveyor line, with the beam points of the two sensors perpendicular to this plane and aligned on the same straight line. The lateral spacing between the two groups of laser distance sensors is based on the size of the product being measured, ensuring that the lateral distance between the two groups is less than the width of the product.

[0057] The data transmission unit includes a remote I / O module, which is installed below the conveyor line and has an analog input module. It is a current-type two-wire four-channel module used to receive the analog signal from the laser distance sensor, convert the current signal of the laser distance sensor into a digital signal, and send it to the control processing unit through the PN bus.

[0058] The control and processing unit includes a programmable logic controller (PLC), which is installed in the main control cabinet of the automated line. The PLC communicates with remote I / O modules via a PN bus, reads the readings of each laser distance sensor, calibrates different products using laser triangulation, and stores the data. During detection, it calls the TRIMMEAN algorithm to calculate the measurement results and sends instructions to the robot and camera to perform corresponding actions. The display unit includes a touchscreen, which is connected to the PLC and used to display the sensor data.

[0059] like Figure 2 The non-contact dual-material detection method shown includes the following:

[0060] Step 1, Calibration Settings;

[0061] Step 1.1: The detection system is activated, and the programmable controller performs initialization, resetting the output detection completion signal, no material signal, single material signal, and double material signal.

[0062] Step 1.2: The programmable controller determines whether calibration needs to be performed. If there is no calibration data in the current recipe data, calibration must be performed first. If calibration is performed, proceed to step 1.3. If calibration is completed, proceed to step 1.10.

[0063] Step 1.3: Click the calibration mode button on the touch screen to start calibration. The programmable controller will clear the calibration data and calibration memory of the current product formula.

[0064] Step 1.4, Teach a single sheet: Place the single sheet into the sensing beams of the two sets of laser distance sensors, and click the single sheet teaching button on the touch screen to calculate the single sheet standard value A for each set of laser distance sensors. X1 :

[0065] A X1 =A1+d+A2

[0066] Where A1 is the upper sensor reading of each group of laser distance sensors, A2 is the lower sensor reading, and d is the thickness of the material sheet.

[0067] Step 1.5, Teach the double sheet: Place the double sheet of error-proof material into the sensing beams of the two sets of laser distance sensors. Click the double sheet teaching button on the touch screen to calculate the double standard value A for each set of laser distance sensors. X2 :

[0068] A X2 =A1+d+d+A2

[0069] Step 1.6, calculate the coefficient. Under ideal conditions, the standard value A for a single material is... X1 With double standard value A X2 The measured data should be equal. However, in practical applications, the beams of each set of laser distance sensors cannot be guaranteed to be perfectly parallel, and the linearity of the laser also has an error of 0.3% for different materials, which needs to be corrected. The programmable controller calculates the ratio k between the thickness measured by each set of sensors and the teaching difference. n :

[0070] k n =d / (A X1 -A X2 +d)

[0071] Where n is the serial number of each group of laser distance sensors.

[0072] Step 1.7, Dynamic Teaching: Considering that in actual production, the sheet will not be stationary during measurement, and the light beam will refract when the sheet passes through the sensor, dynamic compensation is required. Place a single sheet on the conveyor line, click the Dynamic Teaching button on the touch screen, and the sheet will pass through two sets of laser distance sensors at the set speed of the conveyor line. Record the instantaneous readings A1 and A2 of each set of laser distance sensors only when all four sensors have valid readings.

[0073] Step 1.8, Dynamic Compensation: The programmable controller calculates the deviation value measured by each group of laser distance sensors and the conveyor linear speed V based on the readings obtained from the dynamic teaching. f proportional relationship b n :

[0074] b n =(A X1 -A1-A2-d) / V f

[0075] Step 1.9: Calibration complete. The programmable controller compiles the calibration data of the current product and calculates the thickness D measured by each sensor group. n The expression:

[0076] D n =k n *(A X1 -A1-A2)+b n *V f

[0077] The programmable controller sets the calibration memory for the current recipe and saves the data. Calibration is complete, and the process returns to step 2.

[0078] Step 1.10, Measurement begins. The programmable controller receives the detection start command from the peripheral device and clears the previously recorded sensor array data.

[0079] Step 2, data reading and collection;

[0080] Step 2.1, Waiting for the sensors: The programmable controller records the current reading value of each laser distance sensor with a 10Hz pulse. It is determined that the conveyor line has delivered the material to the detection range of the two sets of sensors only when the reading values ​​of the four sensors in the current cycle have changed from the previous recorded value. The waiting for the sensors process ends.

[0081] Step 2.2, Data Collection: The programmable controller (PLC) is set to have a fixed minimum cycle time that must be greater than the response time of the laser distance sensor. The PLC reads the laser distance sensor's readings in each scanning cycle and calculates the sheet thickness D based on the calibrated data and formulas. n The data is then stored in a record array, the size of which is determined by the material passing time and the PLC scanning cycle.

[0082] Step 3, Data Processing: The programmable controller uses the TRIMMEAN algorithm to calculate the average sheet thickness L measured by each sensor group using the recorded array data. n ;

[0083] The method for a programmable logic controller (PLC) to run the TRIMMEAN algorithm is as follows:

[0084] Step 3.1: Traverse all array data to find the maximum value and its array index;

[0085] Step 3.2: Traverse all array data to find the minimum value and its array index;

[0086] Step 3.3: Based on the array indices obtained from the traversal, assign the corresponding maximum and minimum values ​​in the data array to 0.0;

[0087] Step 3.4: If the array indices obtained by traversal are the same, the effective data is the array size minus 1; if the indices are different, the effective data is the array size minus 2.

[0088] Step 3.5: Sum all the array data and divide by the number of valid data points to obtain the measured average sheet thickness L for each group. n .

[0089] Step 4: Determine the result. The programmable controller will calculate the average thickness L of each group of sensors. n Compare with the upper and lower limits of the standard material thickness set by the touch screen.

[0090] Step 4.1 When the average thickness L measured by the two sets of sensors n If either of these values ​​is less than the lower limit of material thickness, output measurement completion and no material signal;

[0091] Step 4.2 When the average thickness L measured by the two sets of sensors n If both values ​​are greater than the lower limit of material thickness and less than the upper limit of material thickness, output measurement completion and single material signal;

[0092] Step 4.3 When the average thickness L measured by the two sets of sensors n If either of these values ​​exceeds the material thickness limit, output a measurement completion and dual-material signal.

[0093] In this invention, such as Figure 1 As shown, there are four laser distance sensors, arranged in pairs, one above the other, for a total of two groups. Laser distance sensor one and laser distance sensor two are considered as one pair, and laser distance sensor three and laser distance sensor four are considered as one pair, and laser distance sensor four are considered as one pair, and laser distance sensor four is considered as one pair, and laser distance sensor three is considered as one pair, and laser distance sensor four ...

[0094] Laser distance sensor one and laser distance sensor two are installed on brackets extending from both sides of the conveyor line, located directly above and directly below the middle span of the conveyor line, respectively. The second group is installed in the same way.

[0095] The remote I / O module is installed below the conveyor line and is equipped with an analog input module. It has two wires and four channels and is current type. It is used to connect the analog signal of the laser distance sensor, convert the current signal of the laser distance sensor into a digital signal, and send it to the programmable controller through the PN bus.

[0096] The programmable logic controller (PLC) is installed in the main control cabinet of the automated production line. The PLC communicates with remote I / O modules via a PN bus, reads the readings of each sensor, calibrates different products using laser triangulation, and stores the data. During testing, it calls the TRIMMEAN algorithm to calculate the measurement results and sends commands to the robot and camera to perform corresponding actions. A touchscreen is installed on the automated production line's control panel and communicates with the PLC via a PN bus for human-machine interaction.

[0097] In this embodiment, the main technical parameters of the laser distance sensor are as follows: range 60mm-180mm, accuracy 0.01mm, response time 2ms, the first and second groups of sensors are installed horizontally at an interval of 800mm, laser distance sensor one and laser distance sensor two are each about 100mm from the upper surface of the conveyor line, and the same applies to laser distance sensor three and laser distance sensor four. The beam point of each group of sensors is consistent. The programmable controller is set to a minimum cycle time of 10ms, which is greater than the sensor response time of 2ms. The material sheet is an aluminum plate with a width of 900mm-1700mm and a standard thickness of 2mm. The conveyor line speed is 2m / s. The touch screen is set to a detection lower limit of 70% (1.4mm) and an upper limit of 120% (2.4mm).

[0098] In actual operation:

[0099] Step 1: The detection system is activated, and the programmable controller performs initialization, resetting the output detection completion signal, no material signal, single material signal, and double material signal.

[0100] Step 2: The programmable controller determines whether calibration needs to be performed. If there is no calibration data in the current recipe data, calibration must be performed first. If calibration is performed, proceed to step 3. If calibration is completed, proceed to step 10.

[0101] Step 3: Click the calibration mode button on the touch screen to start calibration. The programmable controller will clear the calibration data and calibration memory of the current product formula.

[0102] Step 4, teach a single sheet: Place the single sheet into the sensing beam of the two sets of laser distance sensors, and click the single sheet teaching button on the touch screen to calculate the single sheet standard value A for each set of laser distance sensors.X1 :

[0103] A X1 =A1+d+A2

[0104] Where A1 is the upper sensor reading of each group of laser distance sensors, A2 is the lower sensor reading, and d is the sheet thickness. In this embodiment, the measured data for the first group are A1 = 98.20 mm and A2 = 100.10 mm, i.e., A... X1 The first set of data equals 200.30mm; the second set of data, A1, is 97.88mm, and A2 is 99.80mm, i.e., A... X1 It equals 199.68mm.

[0105] Step 5, Teach the double sheet: Place the double sheet of error-proof material into the sensing beams of the two sets of laser distance sensors. Click the double sheet teaching button on the touch screen to calculate the double standard value A for each set of laser distance sensors. X2 :

[0106] A X2 =A1+d+d+A2

[0107] In this embodiment, the first set of data A1 was measured to be 96.25 mm and A2 to be 100.00 mm, i.e., A X2 The first set of data equals 200.25mm; the second set of data, A1, is 95.79mm and A2, is 99.81mm, i.e., A... X2 It equals 199.60mm.

[0108] Step 6: Calculate the coefficient. Under ideal conditions, the standard value A for a single material is... X1 With double standard value A X2 The measured data should be equal. However, in practical applications, the beams of each laser distance sensor cannot be guaranteed to be perfectly parallel. Furthermore, the linearity of the laser can have an error of 0.3% for different materials, requiring correction. The programmable controller calculates the ratio k between the thickness measured by each sensor and the teaching difference. n :

[0109] k n =d / (A X1 -A X2 +d)

[0110] Where n is the serial number of each group of laser distance sensors. In this embodiment, substituting the data, we get k1 as 0.9756 and k2 as 0.9615.

[0111] Step 7, Dynamic Teaching: Considering that in actual production, the sheet will not be stationary during measurement; the light beam will refract as the sheet passes through the sensor, requiring dynamic compensation. Place a single sheet on the conveyor line, click the dynamic teaching button on the touchscreen, and the sheet will pass through two sets of laser distance sensors at the set speed of the conveyor line. Record the instantaneous readings A1 and A2 of each set of laser distance sensors only when all four sensors have valid readings. 2， .

[0112] Step 8, Dynamic Compensation: The programmable controller calculates the deviation value measured by each group of laser distance sensors and the conveyor linear speed V based on the readings obtained from the dynamic teaching. f proportional relationship b n :

[0113] b n =(A X1 -A1-A2-d) / V f

[0114] In this embodiment, the first set of data was measured as A1 = 98.35 mm and A2 = 100.25 mm, meaning b1 equals -0.15. The second set of data was measured as A1 = 97.92 mm and A2 = 99.86 mm, meaning b2 equals -0.05.

[0115] Step 9: Calibration complete. The programmable controller compiles the calibration data of the current product and calculates the thickness D measured by each sensor group. n The expression:

[0116] D n =k n *(A X1 -A1-A2)+b n *V f

[0117] In this embodiment, the expression for the thickness measured by the first pair of sensors is D1 = 0.9756 * (200.3 - A1 - A2) - 0.3, and the expression for the thickness measured by the second pair of sensors is D2 = 0.9615 * (199.6 - A1 - A2) - 0.1. The programmable controller sets the calibration memory of the current formula and saves the data. The calibration ends and returns to step 2.

[0118] Step 10, Measurement begins. The programmable controller receives the detection start command from the peripheral device and clears the previously recorded sensor array data.

[0119] Step 11: Wait for the sensors. The programmable controller records the current reading value of each laser distance sensor with a 10Hz pulse. Only when the reading values ​​of all four sensors in the current cycle have changed from the last recorded value, it is determined that the conveyor line has delivered the material to the detection range of the two sets of sensors, and the waiting for the sensors process ends.

[0120] Step 12, data collection. In this embodiment, the programmable controller reads five sets of sensor readings at intervals greater than 10ms and substitutes them into the formula. The material thicknesses measured by the first pair of sensors are: 1.82, 1.86, 1.95, 1.98, and 2.01; the material thicknesses measured by the second pair of sensors are: 1.98, 1.96, 2.05, 2.18, and 2.03.

[0121] Step 13, Data Processing: The programmable controller uses the TRIMMEAN algorithm to calculate the average sheet thickness L measured by each sensor group based on the recorded array data. n The method for the programmable controller 6 to run the TRIMMEAN algorithm is as follows:

[0122] Step 13.1 Traverse all array data to find the maximum value and its array index;

[0123] Step 13.2: Traverse all array data to find the minimum value and its array index;

[0124] Step 13.3: Based on the array indices obtained from the traversal, assign the corresponding maximum and minimum values ​​in the data array to 0.0;

[0125] Step 13.4 If the array indices obtained by traversal are the same, there are 4 groups of valid data; if the indices are different, there are 3 groups of valid data.

[0126] Step 13.5 Sum all array data and divide by the number of valid data points to obtain the measured average sheet thickness L for each group. n :

[0127] In this embodiment, according to the TRIMMEAN algorithm, L1 = 1.93 and L2 = 2.02.

[0128] Step 14, determine the result. The programmable controller will calculate the average thickness L of each group of sensors. n Comparison with the upper and lower limits of the standard material thickness set by the touchscreen:

[0129] Step 14.1 When the average thickness L measured by the two sets of sensors n If either of these values ​​is less than the lower limit of material thickness, output measurement completion and no material signal.

[0130] Step 14.2 When the average thickness L measured by the two sets of sensors n If both values ​​are greater than the lower limit of material thickness and less than the upper limit of material thickness, output measurement completion and single material signal.

[0131] Step 14.3 When the average thickness L measured by the two sets of sensors n If either of these values ​​exceeds the material thickness limit, output a measurement completion and dual-material signal.

[0132] In this embodiment, the average thickness L1: 1.4 < 1.93 < 2.4, and the average thickness L2: 1.4 < 2.02 < 2.4, satisfying step 14.2. The programmable controller confirms that it is a single material and outputs a measurement completion and single material signal to the camera to take a picture. Then, the material is transported by the loading robot to the press mold to complete the cycle.

[0133] This invention boasts wide applicability, employing laser distance sensors as non-contact sensors in dual-material inspection systems. Thickness is calculated based on triangulation, without limiting the material of the metal being inspected. Manufacturing costs are low, as the programmable controller and touchscreen used are based on existing equipment on the automated production line, requiring no additional purchase. Inspection efficiency is high, with no restrictions on conveyor speed; magnetic belts can be used for high-speed material transport, saving time between destacking and loading, thus improving production line efficiency. Reliability is high, utilizing data from two sets of laser distance sensors for calculation, providing double error prevention and strong redundancy, and is also applicable to single-mold dual-piece production lines. Therefore, this invention possesses high product competitiveness in the field of dual-material inspection in stamping automated lines, contributing to the development of the stamping automation industry.

[0134] This invention is not limited to the above embodiments. Based on the technical solutions disclosed herein, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A non-contact dual-material detection method, characterized in that: It includes an antimagnetic ranging unit, which consists of four laser distance sensors. The laser distance sensors are two-wire current-type sensors, with one set at the top and one at the bottom, for a total of two sets. Includes the following: Step 1, Calibration Settings; Step 2, data reading and collection; Step 3, Data Processing: The programmable controller uses the TRIMMEAN algorithm to calculate the average sheet thickness L measured by each sensor group using the recorded array data. n ; Step 4: Determine the result. The programmable controller will calculate the average thickness L of each group of sensors. n Compare with the upper and lower limits of the standard material thickness set by the touchscreen; The specific details of step 1 are as follows: Step 1.1: The detection system is activated, and the programmable controller performs initialization, resetting the output detection completion signal, no material signal, single material signal, and double material signal. Step 1.2: The programmable controller determines whether calibration needs to be performed. If there is no calibration data in the current recipe data, calibration must be performed first. If calibration is performed, proceed to step 1.

3. If calibration is completed, proceed to step 1.

10. Step 1.3: Click the calibration mode button on the touch screen to start calibration. The programmable controller will clear the calibration data and calibration memory of the current product formula. Step 1.4, Teach a single sheet: Place the single sheet into the sensing beams of the two sets of laser distance sensors, and click the single sheet teaching button on the touch screen to calculate the single sheet standard value A for each set of laser distance sensors. X1 : A X1 =A1+d+A2 Where A1 is the upper sensor reading of each group of laser distance sensors, A2 is the lower sensor reading, and d is the thickness of the material sheet; Step 1.5, Teach the double sheet: Place the double sheet of error-proof material into the sensing beams of the two sets of laser distance sensors. Click the double sheet teaching button on the touch screen to calculate the double standard value A for each set of laser distance sensors. X2 : A X2 =A1+d+d+A2 Step 1.6, calculate the coefficient. Under ideal conditions, the standard value A for a single material is... X1 With double standard value A X2 The measured data should be equal. However, in practical applications, the beams of each set of laser distance sensors cannot be guaranteed to be perfectly parallel, and the linearity of the laser also has an error of 0.3% for different materials, which needs to be corrected. The programmable controller calculates the ratio k between the thickness measured by each set of sensors and the teaching difference. n : k n =d / (A X1- A X2 +d) Where n is the serial number of each group of laser distance sensors; Step 1.7, Dynamic Teaching: Considering that in actual production, the sheet will not be stationary during measurement, and the light beam will refract when the sheet passes through the sensor, dynamic compensation is required. Place a single sheet on the conveyor line, click the dynamic teaching button on the touch screen, and the sheet will pass through two sets of laser distance sensors at the set speed of the conveyor line. Record the instantaneous readings A1 and A2 of each set of laser distance sensors only when all four sensors have valid readings. 2； Step 1.8, Dynamic Compensation: The programmable controller calculates the deviation value measured by each group of laser distance sensors and the conveyor linear speed V based on the readings obtained from the dynamic teaching. f proportional relationship b n : b n = (A X1 -A1-A2-d) / V f Step 1.9: Calibration complete. The programmable controller compiles the calibration data of the current product and calculates the thickness D measured by each sensor group. n The expression: D n =k n *(A X1 -A1-A2)+b n *V f The programmable controller sets the calibration memory of the current recipe and saves the data. The calibration is completed, and the process returns to step 2. Step 1.10, Measurement begins. The programmable controller receives the detection start command from the peripheral device and clears the previously recorded sensor array data.

2. A non-contact dual-material detection method according to claim 1, characterized in that: The specific details of step 2 are as follows: Step 2.1, Waiting for the sensors: The programmable controller records the current reading value of each laser distance sensor with a 10Hz pulse. It is determined that the conveyor line has delivered the material to the detection range of the two sets of sensors only when the reading values ​​of the four sensors in the current cycle have changed from the previous recorded value. The waiting for the sensors process ends. Step 2.2, Data Collection: The programmable controller (PLC) is set to have a fixed minimum cycle time that must be greater than the response time of the laser distance sensor. The PLC reads the laser distance sensor's readings in each scanning cycle and calculates the sheet thickness D based on the calibrated data and formulas. n The data is then stored in a record array, the size of which is determined by the material passing time and the PLC scanning cycle.

3. A non-contact dual-material detection method according to claim 2, characterized in that: The method for a programmable logic controller (PLC) to run the TRIMMEAN algorithm is as follows: Step 3.1: Traverse all array data to find the maximum value and its array index; Step 3.2: Traverse all array data to find the minimum value and its array index; Step 3.3: Based on the array indices obtained from the traversal, assign the corresponding maximum and minimum values ​​in the data array to 0.0; Step 3.4: If the array indices obtained by traversal are the same, the effective data is the array size minus 1; if the indices are different, the effective data is the array size minus 2. Step 3.5: Sum all the array data and divide by the number of valid data points to obtain the measured average sheet thickness L for each group. n .

4. A non-contact dual-material detection method according to claim 3, characterized in that: The specific details of step 4 are as follows: Step 4.1 When the average thickness L measured by the two sets of sensors n If either of these values ​​is less than the lower limit of material thickness, output measurement completion and no material signal; Step 4.2 When the average thickness L measured by the two sets of sensors n If both values ​​are greater than the lower limit of material thickness and less than the upper limit of material thickness, output measurement completion and single material signal; Step 4.3 When the average thickness L measured by the two sets of sensors n If either of these values ​​exceeds the material thickness limit, output a measurement completion and dual-material signal.

Images