Non-contact double sheet detection system and method

Abstract

Disclosed in the present invention are a non-contact double sheet detection system and method. The non-contact double sheet detection system comprises an antimagnetic ranging unit, the antimagnetic ranging unit is connected to a data transmission unit, the data transmission unit is connected to a control processing unit, and the control processing unit is connected to a display unit. Data measurement is performed by using the antimagnetic ranging unit, and data is transmitted to the control processing unit via the data transmission unit, processed by the control processing unit, and then displayed on the display unit. The present invention is applicable to magnetic conveyor lines without restricting the material and conveying speed of metal under test, thereby achieving high applicability and lower costs.

Description

Non-contact double material detection system and method TECHNICAL FIELD

[0001] The present application relates to a non-contact double material detection system and method in the field of presses. BACKGROUND

[0002] In the robot feeding part of the stamping automatic line, the steel plates are often stuck together due to the effect of the oil film on the surface of the steel plate and other reasons. In order to prevent the material pieces stuck together due to oil stains from damaging the die and press after stamping, a double material detection system must be installed, and the system is redundantly designed, that is, the double material detection system is provided at the unstacking station and the feeding station. The unstacking station is usually a contact sensor, and the feeding station is provided with a non-contact sensor on the front end of the conveying belt. Both detection systems are generally based on the principle of electromagnetic induction. This detection method has poor adaptability to different materials and mainly relies on imports, which is expensive and difficult for customers to accept and promote, thereby limiting the development of the stamping automation industry. SUMMARY

[0003] The purpose of the present application is to provide a non-contact double material detection system and method which can be applied to a magnetic conveying line and does not limit the material and conveying speed of the measured metal, has wide applicability and lower cost.

[0004] To achieve the above-mentioned purpose, the present application provides a non-contact double material detection system, which comprises a magnetic shielding distance measuring unit, the magnetic shielding distance measuring unit is connected with a data transmission unit, the data transmission unit is connected with a control processing unit, and the control processing unit is connected with a display unit.

[0005] Compared with the prior art, the present application has the beneficial effects that the magnetic shielding distance measuring unit is used for data measurement, the data is sent to the control processing unit through the data transmission unit, and the data is displayed on the display unit after being processed by the control processing unit. The non-contact double material detection system and method can be applied to a magnetic conveying line and does not limit the material and conveying speed of the measured metal, has wide applicability and lower cost.

[0006] As a further improvement of the present application, the magnetic shielding distance measuring unit comprises four laser distance sensors, the laser distance sensors are two-wire current type, and each laser distance sensor is installed on a bracket extending from both sides of the conveying line and located directly above and below the middle pitch of the conveying line. The installation spacing of the upper and lower laser distance sensors of each group is based on the range of the laser distance sensor, so as to ensure that the readings of the upper and lower laser distance sensors are within the range when the material piece is located on the conveying line. The installation position of the upper and lower laser distance sensors of each group is based on the plane on the conveying line, and the beam points of the two laser distance sensors are perpendicular to the plane and on the same straight line. The transverse distribution interval of the two groups of laser distance sensors is based on the size of the measured product, so as to ensure that the transverse interval of the two groups of laser distance sensors is less than the width of the product.

[0007] This can more accurately measure data, no interference between each other, more convenient installation, and the use of two sets of sensors, double error prevention, strong redundancy, but also applicable to a mold double piece production line.

[0008] As a further improvement of the present application, the data transmission unit comprises a remote IO module, which is installed below the conveying line and is provided with an analog input module, which is a current type two-wire four-channel for connecting the analog signal of the laser distance sensor and converting the current signal of the laser distance sensor into a digital signal and sending it to the control processing unit through the PN bus.

[0009] In this way, the analog signal of the sensor can be converted into a digital signal and transmitted to the control processing unit for data processing, and the transmission signal is more stable and has strong anti-interference performance.

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

[0011] In this way, the data processing error is small, the precision is higher, the speed is faster, and the reliability is high.

[0012] As a further improvement of the present application, the display unit comprises a touch screen connected with the programmable controller for displaying the data of the sensor.

[0013] In this way, the data is displayed in real time, and the touch operation, parameter setting, etc. are facilitated.

[0014] In order to achieve the above-mentioned purpose, the present application also provides a non-contact double material detection method, comprising the following steps,

[0015] Step 1, calibration setting;

[0016] Step 2, data reading and collection;

[0017] Step 3, data processing; the programmable controller uses the TRIMMEAN algorithm to calculate the average measured material thickness L n of each group of sensors using the recorded array data.

[0018] Step 4, judgment result, the programmable controller compares the measured average thickness L n of each group of sensors 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 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 A X1 =A1+d+A2

[0024] 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.

[0025] 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

[0026] 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)

[0027] Where n is the serial number of each group of laser distance sensors.

[0028] Step 1.7, dynamic demonstration, considering that the material sheet will not be measured statically in actual production, the light beam will be refracted when the material sheet passes through the sensor, and dynamic compensation is required. Place a single material sheet on the conveying line, click the dynamic demonstration button on the touch screen, and the material sheet will pass through the two sets of laser distance sensors at the set speed of the conveying line. Only when there are valid readings of the four sensors, the instantaneous readings A1 and A2 of each set of laser distance sensors are recorded.

[0029] Step 1.8, dynamic compensation, the programmable controller calculates the deviation value measured by each set of laser distance sensors and the conveying line speed V f of the proportional relationship b n : b n =(A X1 -A1-A2-d) / V f

[0030] Step 1.9, calibration end, the programmable controller calculates the thickness D n measured by each set of sensors according to the calibration data of the current product n : D n =k X1 *(A n -A1-A2)+b f *V f

[0031] The programmable controller sets the calibration memory of the current formula and saves the data, and the calibration ends and returns to step 2

[0032] Step 1.10, measurement start, the programmable controller receives the detection start command of the peripheral device and clears the last recorded sensor array data.

[0033] As a further improvement of the present application, the specific content of step 2 is as follows,

[0034] Step 2.1, waiting for the sensor, the programmable controller records the current reading value of each laser distance sensor at 10Hz pulse. Only when the reading values of the four sensors in the current period have all changed from the last recorded values, it is determined that the conveying line has sent the material sheet to the detection range of the two sets of sensors, and the waiting for the sensor process ends.

[0035] Step 2.2, data collection, the programmable controller sets a fixed minimum cycle time greater than the response time of the laser distance sensor. The programmable controller reads the reading of the laser distance sensor in each scanning period, calculates the thickness D n of the material sheet according to the data obtained by calibration and the formula, and stores it in the record array. The size of the array is determined according to the material passing time and the PLC scanning period.

[0036] As a further improvement of the present application, the programmable controller runs the TRIMMEAN algorithm as follows:

[0037] Step 3.1, traverse all array data to find the maximum value and the maximum value array index;

[0038] Step 3.2, traverse all array data to find the minimum value and the minimum value array index;

[0039] Step 3.3, according to the array index obtained by traversing, the corresponding maximum value and minimum value in the data array are assigned as 0.0;

[0040] Step 3.4, if the array index obtained by traversing is the same, the valid data is the array size minus 1, if the index is different, the valid data is the array size minus 2;

[0041] Step 3.5, sum all array data and divide by the number of valid data to get the measured average sheet thickness L n .

[0042] As a further improvement of the present application, the specific content of step 4 is as follows,

[0043] Step 4.1 when two groups of sensors measure the average thickness L n Any one is less than the lower limit of the thickness, output the measurement completion and no material signal;

[0044] Step 4.2 when two groups of sensors measure the average thickness L n Both are greater than the lower limit of the thickness and less than the upper limit of the thickness, output the measurement completion and single material signal;

[0045] Step 4.3 when two groups of sensors measure the average thickness L n Any one is greater than the upper limit of the thickness, output the measurement completion and double material signal.

[0046] Compared with the prior art, the present application has the beneficial effects that the laser distance sensor is used as a non-contact sensor in the double material detection system, the thickness is calculated based on the triangulation, and the measured metal material is not limited; the manufacturing cost is low, the programmable controller and touch screen used are based on the original equipment of the automatic line, and no additional purchase is needed; the detection efficiency is high, the detection process has no limit to the conveying line speed, the sheet can be transported at high speed using the magnetic belt line, the time from unstacking to feeding is saved, and the production line efficiency is improved; the reliability is high, the detection data of the two groups of laser distance sensors are used for calculation, double error prevention is achieved, the redundancy is strong, and it can also be applied to a one-mold double-piece production line. The present application has high product competitiveness in the field of double material detection of stamping automatic line, and helps to promote the development of stamping automation industry. BRIEF DESCRIPTION OF DRAWINGS

[0047] Fig. 1 is a system block diagram of the present application.

[0048] Figure 2 is a control flow chart of the present application. DETAILED DESCRIPTION

[0049] The present application is further described below in conjunction with the accompanying drawings:

[0050] A non-contact double material detection system as shown in Figure 1, including a magnetic shielding distance measuring unit, the magnetic shielding distance measuring unit is connected with a data transmission unit, the data transmission unit is connected with a control processing unit, the control processing unit is connected with a display unit.

[0051] The magnetic shielding distance measuring unit includes four laser distance sensors, the laser distance sensor is a two-wire current type, and the upper and lower are a group, a total of two groups; each group of laser distance sensors is installed on the bracket extending from both sides of the conveying line, and is located directly above and below the middle span of the conveying line; the upper and lower installation spacing of each group of laser distance sensors is based on the range of the laser distance sensor, to ensure that the readings of the upper and lower two laser distance sensors are within the range when the material sheet is located on the conveying line; the upper and lower installation positions of each group of laser distance sensors are based on the plane of the conveying line, and the beam points of the two laser distance sensors are perpendicular to the plane and on the same straight line; the lateral distribution interval of the two groups of laser distance sensors is based on the size of the measured product, to ensure that the lateral interval of the two groups of laser distance sensors is less than the width of the product.

[0052] The data transmission unit includes a remote IO module, the remote IO module is installed below the conveying line, and is provided with an analog input module, which is a current type two-wire four-channel, used for connecting the analog signal of the laser distance sensor, converting the current signal of the laser distance sensor into a digital signal, and sending the digital signal to the control processing unit through the PN bus.

[0053] The control processing unit includes a programmable controller, the programmable controller is installed in the automatic line main control cabinet, the programmable controller communicates with the remote IO module through the PN bus, reads the readings of each laser distance sensor, calibrates different products through the laser triangulation method and stores the data, calls the TRIMMEAN algorithm during detection, calculates the measurement result, and sends instructions to the robot and the camera to make corresponding actions. The display unit includes a touch screen connected with the programmable controller, used for displaying the data of the sensor.

[0054] A non-contact double material detection method as shown in Figure 2, including the following contents,

[0055] Step 1, calibration setting;

[0056] Step 1.1, the detection system is activated, the programmable controller performs initialization, and resets the output detection completion signal, no material signal, single material signal and double material signal;

[0057] 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.

[0058] 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.

[0059] Step 1.4, 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 A X1 =A1+d+A2

[0060] 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.

[0061] 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

[0062] 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)

[0063] Where n is the serial number of each group of laser distance sensors.

[0064] 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.

[0065] 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

[0066] 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

[0067] The programmable controller sets the calibration memory of the current recipe and saves the data. The calibration is complete, and the process returns to step 2.

[0068] 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.

[0069] Step 2, data reading and collection;

[0070] 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.

[0071] 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.

[0072] 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 ;

[0073] The method for a programmable logic controller (PLC) to run the TRIMMEAN algorithm is as follows:

[0074] Step 3.1: Traverse all array data to find the maximum value and its array index;

[0075] Step 3.2, traverse all array data to find the minimum value and minimum array index;

[0076] Step 3.3, according to the array index obtained by traversing, the corresponding maximum value and minimum value in the data array are assigned as 0.0;

[0077] Step 3.4, if the array index obtained by traversing is the same, the valid data is the array size minus 1, if the index is different, the valid data is the array size minus 2;

[0078] Step 3.5, sum all array data and divide by the number of valid data to get the measured average thickness L of each group of material pieces n .

[0079] Step 4, judge the result, the programmable controller compares the measured average thickness L of each group of sensors n With the upper and lower limits of the standard material thickness set by the touch screen.

[0080] Step 4.1 when the average thickness L measured by the two groups of sensors n Any one is less than the lower limit of the material thickness, output the measurement complete and no material signal;

[0081] Step 4.2 when the average thickness L measured by the two groups of sensors n Both are greater than the lower limit of the material thickness and less than the upper limit of the material thickness, output the measurement complete and single material signal;

[0082] Step 4.3 when the average thickness L measured by the two groups of sensors n Any one is greater than the upper limit of the material thickness, output the measurement complete and double material signal.

[0083] In the present application, as shown in Figure 1, the number of laser distance sensors is four, one pair up and down, a total of two groups, laser distance sensor one and laser distance sensor two are a pair, regarded as the first group, laser distance sensor three and laser distance sensor four are a pair, regarded as the second group.

[0084] Laser distance sensor one and laser distance sensor two are installed on the brackets extending from both sides of the conveying line, respectively located directly above and below the middle span of the conveying line, and the second group is the same.

[0085] The remote IO module is installed below the conveying line, provided with an analog input module, two-wire four-channel, current type, used for connecting the analog signal of the laser distance sensor, converting the current signal of the laser distance sensor into a digital signal, and sending it to the programmable controller through the PN bus.

[0086] The programmable controller is installed in the main control cabinet of the automatic line. The programmable controller communicates with the remote IO module through the PN bus, reads the readings of each sensor, calibrates different products through the laser triangulation method and stores the data, calls the TRIMMEAN algorithm during detection, calculates the measurement result, and sends instructions to the robot and the camera to make corresponding actions. The touch screen is installed on the operation table of the automatic line, communicates with the programmable controller through the PN bus, and is used for human-computer interaction.

[0087] In the embodiment, the main technical parameters of the laser distance sensor are: range 60mm-180mm, accuracy 0.01mm, response time 2ms, first group and second group sensor transverse installation interval 800mm, laser distance sensor one and laser distance sensor two are about 100mm away from the upper surface of the conveying line, laser distance sensor three and laser distance sensor four are the same, and each group of sensor beam points are consistent. The programmable controller sets the minimum cycle time to 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 conveying line speed is 2m / s. The touch screen sets the lower limit of detection to 70%, i.e. 1.4mm, and the upper limit to 120%, i.e. 2.4mm.

[0088] In actual operation:

[0089] Step 1, the detection system is activated, and the programmable controller executes initialization, resets the output detection completion signal, no material signal, single material signal, and double material signal.

[0090] Step 2, the programmable controller judges whether calibration needs to be performed. If there is no calibration data in the current formula data, calibration must be performed first. Calibration jumps to step 3. If calibration is completed, it jumps to step 10.

[0091] Step 3, click the calibration mode button on the touch screen, and calibration starts. The programmable controller clears the calibration data and calibration memory of the current product formula.

[0092] Step 4, single sheet teaching, place a single sheet into the sensing beam of the two groups of laser distance sensors, and click the single sheet teaching button on the touch screen. Calculate the single material standard value A of each group of laser distance sensors. X1 : A X1 = A1+d+A2

[0093] Wherein, A1 is the reading of the upper sensor of each group of laser distance sensors, A2 is the reading of the lower sensor, and d is the thickness of the sheet. In the embodiment, the measured first group data A1 is 98.20mm, A2 is 100.10mm, i.e. A X1 is equal to 200.30mm; the second group data A1 is 97.88mm, A2 is 99.80mm, i.e. AX1 Equal to 199.68 mm.

[0094] Step 5, double teaching, put double error-proof material sheet into the sensing beam of two sets of laser distance sensors, click double teaching button on the touch screen, calculate the double material standard value A of each set of laser distance sensors X2 : A X2 = A1+d+d+A2

[0095] In this embodiment, the measured first group data A1 is 96.25 mm, A2 is 100.00 mm, that is, A X2 equals 200.25 mm; the second group data A1 is 95.79 mm, A2 is 99.81 mm, that is, A X2 equals 199.60 mm.

[0096] Step 6, calculate the coefficient, in the ideal condition, the single material standard value A X1 and the double material standard value A X2 measured data should be equal, but in actual application, due to the installation of the beam of each set of laser distance sensors cannot be guaranteed to be completely parallel, and the linearity of laser also has an error of 0.3% for different materials, which needs to be corrected, and the proportional relationship k of the measured thickness and the teaching difference value of each set of sensors is calculated by the programmable controller n : k n = d / (A X1 -A X2 +d)

[0097] Wherein n is the serial number of each set of laser distance sensors, in this embodiment, substituting the data obtains k1 is 0.9756, k2 is 0.9615.

[0098] Step 7, dynamic teaching, considering that the material sheet will not be measured statically in actual production, when the material sheet passes through the sensor, the beam will be refracted, and dynamic compensation is needed. Place a single material sheet on the conveying line, click the dynamic teaching button on the touch screen, and the material sheet passes through the two sets of laser distance sensors at the set speed of the conveying line, and only when there are valid readings of the four sensors, record the instantaneous readings A1, A2 of each set of laser distance sensors.

[0099] Step 8, dynamic compensation, the programmable controller calculates the proportional relationship b of the deviation value measured by each set of laser distance sensors and the conveying line speed V f : b n = (A n -A1-A2-d) / V X1 f

[0100] ​In this embodiment, the first group of data A1 is 98.35 mm, A2 is 100.25 mm, i.e. b1 is equal to -0.15, and the second group of data A1 is 97.92 mm, A2 is 99.86 mm, i.e. b2 is equal to -0.05

[0101] Step 9, calibration ends, the programmable controller calculates the calibration data of the current product, and calculates the thickness D measured by each group of sensors n The expression of the thickness measured by the first pair of sensors is D1 = 0.9756 * (200.3 - A1 - A2) - 0.3, and the expression of the thickness measured by the second pair of sensors is D2 = 0.9615 * (199.6 - A1 - A2) - 0.1 n = k n *(A X1 -A1-A2)+b n *V f

[0102] In this embodiment, the expression of the thickness measured by the first pair of sensors is D1 = 0.9756 * (200.3 - A1 - A2) - 0.3, and the expression of 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, and the calibration ends, returning to step 2.

[0103] Step 10, measurement starts, the programmable controller receives the detection start command of the peripheral device, and clears the last recorded sensor array data.

[0104] Step 11, waiting for the sensor, the programmable controller records the current reading value of each laser distance sensor at a pulse of 10 Hz, and only when the reading values of the four sensors in the current period have all jumped from the last recorded values, it is determined that the conveying line has sent the sheet to the detection range of the two groups of sensors, and the waiting for the sensor process ends.

[0105] Step 12, data collection, in this embodiment, the programmable controller reads the sensor readings of 5 groups at an interval of more than 10 ms and substitutes them into the formula, and the sheet thickness measured by the first pair of sensors is respectively 1.82, 1.86, 1.95, 1.98, and 2.01; the sheet thickness measured by the second pair of sensors is respectively 1.98, 1.96, 2.05, 2.18, and 2.03.

[0106] Step 13, data processing, the programmable controller calculates the average sheet thickness L n measured by each group of sensors using the TRIMMEAN algorithm on the recorded array data. The method for the programmable controller 6 to run the TRIMMEAN algorithm is as follows:

[0107] Step 13.1, traverse all array data to find the maximum value and the array index of the maximum value;

[0108] Step 13.2, traverse all array data to find the minimum value and the array index of the minimum value;

[0109] Step 13.3 According to the array index obtained by traversal, the corresponding maximum and minimum values in the data array are assigned as 0.0;

[0110] Step 13.4 If the array index obtained by traversal is the same, that is, the effective data is 4 groups, if the index is different, the effective data is 3 groups;

[0111] Step 13.5 Sum all array data and divide by the number of effective data to get the measured average sheet thickness L of each group n :

[0112] In this embodiment, according to the TRIMMEAN algorithm, L1=1.93, L2=2.02.

[0113] Step 14, the result, the programmable controller will measure the average thickness L of each group of sensors n Compared with the upper and lower limits of the standard sheet thickness set by the touch screen:

[0114] Step 14.1 When the average thickness L measured by the two groups of sensors n Any one is less than the lower limit of the sheet thickness, output the measurement completion and no material signal.

[0115] Step 14.2 When the average thickness L measured by the two groups of sensors n Both are greater than the lower limit of the sheet thickness and less than the upper limit of the sheet thickness, output the measurement completion and single material signal.

[0116] Step 14.3 When the average thickness L measured by the two groups of sensors n Any one is greater than the upper limit of the sheet thickness, output the measurement completion and double material signal.

[0117] In this embodiment, the average thickness L1: 1.4<1.93<2.4, the average thickness L2: 1.4<2.02<2.4, meet step 14.2, the programmable controller confirms single material, outputs the measurement completion and single material signal to the camera to take a picture, and then is carried by the feeding robot into the press mold to complete the cycle.

[0118] The application has wide applicability, uses a laser distance sensor as a non-contact sensor in a double material detection system, calculates thickness based on triangulation, and does not limit the metal material to be detected; the manufacturing cost is low, the programmable controller and the touch screen used are based on the original equipment of the automatic line, and additional purchase is not required; the detection efficiency is high, the detection process is not limited to the conveying line speed, a magnetic belt line can be used to transport the material at high speed, the time from disassembling to feeding is saved, and the production line efficiency is improved; the reliability is high, two groups of laser distance sensors are used to detect data and then calculate, double error prevention is used, and the redundancy is strong, and the application can also be applied to a one-mold double-piece production line. Therefore, the application has high product competitiveness in the field of double material detection of a stamping automatic line, and helps to promote the development of the stamping automation industry.

[0119] The application is not limited to the above-mentioned embodiments, and based on the technical solutions of the present disclosure, those skilled in the art can make some substitutions and modifications to some technical features according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the application.

Claims

1. A non-contact dual material detection system, characterized by, The application relates to a kind of automatic line detection system, 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.

2. A non-contact dual material detection system according to claim 1, characterized in that: Anti-magnetic ranging unit includes four laser distance sensors, laser distance sensor is two-wire system current type, up and down is a group, a total of two groups; Each group of laser distance sensors is installed on the bracket extended from both sides of the conveying line, and is located directly above and below the middle interval of the conveying line; The installation interval of each group of laser distance sensors is based on the range of laser distance sensor, to ensure that the readings of the two laser distance sensors are within the range when the sheet is on the conveying line; The installation position of each group of laser distance sensors is based on the plane of the conveying line, and the beam points of the two laser distance sensors are perpendicular to the plane and on the same straight line. The lateral distribution interval of the two groups of laser distance sensors is based on the size of the measured product, to ensure that the lateral interval of the two groups of laser distance sensors is less than the width of the product.

3. A non-contact dual material detection system according to claim 2, wherein: The data transmission unit includes a remote IO module, which is installed below the conveying line and has an analog input module, which is a current two-wire four-channel for connecting the analog signal of the laser distance sensor, converting the current signal of the laser distance sensor to a digital signal, and sending it to the control processing unit through the PN bus.

4. A non-contact dual material detection system according to claim 3, wherein: The control processing unit includes a programmable controller, which is installed in the automatic line main control cabinet, and communicates with the remote IO module through the PN bus to read the readings of each laser distance sensor, calibrate different products through laser triangulation method and store data, call TRIMMEAN algorithm during detection, calculate the measurement result, and send instructions to the robot and camera to make corresponding actions.

5. A non-contact dual material detection system according to claim 4, wherein: The display unit includes a touch screen connected to the programmable controller for displaying sensor data.

6. A non-contact dual material detection method, characterized by: The application includes the following, Step 1, calibration setting; Step 2, data reading and collection; Step 3, data processing; the programmable controller calculates the average measured sheet thickness L for each group of sensors using the TRIMMEAN algorithm on the recorded array data n ; Step 4, the result of the judgment, the programmable controller will measure each set of sensor average thickness L n Compared with the upper and lower limits of the standard thickness set by the touch screen.

7. A non-contact dual material detection method according to claim 6, characterized in that: The specific content of step 1 is as follows, Step 1.1, the detection system is activated, and the programmable controller performs initialization to reset the output detection completion signal, no material signal, single material signal and double material signal; Step 1.2, the programmable controller judges whether calibration is needed, if there is no calibration data in the current formula data, calibration must be performed, and calibration jumps to step 1.3, if calibration is completed, it jumps to step 1.10; Step 1.3, click the calibration mode button on the touch screen, calibration starts, and the programmable controller clears the calibration data and calibration memory of the current product formula; Step 1.4, single sheet teaching, put single sheet into the sensing beam of two groups of laser distance sensors, click single sheet teaching button on the touch screen, calculate the single sheet standard value A of each group of laser distance sensors X1 : A X1 = A1 + d + A2 Wherein, 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 sheet. Step 1.5, double sheet teaching, put double sheet into the sensing beam of two sets of laser distance sensors, click double sheet teaching button on the touch screen, calculate the double sheet standard value A of each set of laser distance sensors X2 : A X2 = A1 + d + d + A2 Step 1.6, calculate coefficient, in ideal condition, single material standard value A X1 and double material standard value A X2 Measured data should be equal, but in actual application, due to the installation of each group of laser distance sensor beams cannot be guaranteed completely parallel, and for different materials, the linearity of the laser also has 0.3% error, need to be corrected, by programmable controller to calculate the measured thickness of each group of sensors and the proportion of teaching difference k n : k n = d / (A X1- A X2 +d) Wherein n is the serial number of each group of laser distance sensors. Step 1.7, dynamic teaching, considering that the sheet will not be measured statically in actual production, the light beam will be refracted when the sheet passes through the sensor, and dynamic compensation is needed. Place a single sheet on the conveying line, click the dynamic teaching button on the touch screen, and the sheet passes through the two groups of laser distance sensors at the set speed of the conveying line. Only when there are valid readings of the four sensors, record the instantaneous readings A1 and A2 of each group of laser distance sensors. Step 1.8, dynamic compensation, the programmable controller calculates the deviation value measured by each group of laser distance sensors and the conveying line speed V according to the readings measured by dynamic teaching f the proportional relationship b n : b n = (A X1 -A1-A2-d) / V f Step 1.9, calibration end, the programmable controller calculates the calibration data of the current product, and calculates the thickness D measured by each group of sensors n Expression: D n = k n *(A X1 -A1-A2)+b n *V f The programmable controller sets the calibration memory of the current formula and saves the data, and returns to step 2 after the calibration is completed Step 1.10, measurement starts, the programmable controller receives the detection start command of the peripheral device, and clears the last recorded sensor array data.

8. A non-contact dual material detection method according to claim 7, characterized in that: The specific content of step 2 is as follows, Step 2.1, wait for the sensor, the programmable controller records the current reading value of each laser distance sensor at 10Hz pulse, and only when the reading values of the four sensors in the current period have all jumped from the last recorded values, it is determined that the conveying line has sent the material sheet to the detection range of the two groups of sensors, and the waiting sensor process is ended; Step 2.2, data collection, the fixed minimum cycle time of the programmable controller must be greater than the response time of the laser distance sensor, the programmable controller reads the reading of the laser distance sensor every scanning period, and according to the data obtained by calibration and the formula, the thickness D of the material sheet is calculated n and is stored in the record array, the size of the array is determined according to the material sheet passing time and the PLC scanning period.

9. A non-contact dual material detection method according to claim 8, characterized in that: The method of the programmable controller running the TRIMMEAN algorithm is as follows: Step 3.1, traverse all array data to find the maximum value and the maximum value array index; Step 3.2, traverse all array data to find the minimum value and the minimum value array index; Step 3.3, according to the array index obtained by traversing, assign the corresponding maximum value and minimum value in the data array to 0.0; Step 3.4, if the array index obtained by traversing is the same, the valid data is array size minus 1, if the index is different, the valid data is 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 wafer thickness L for each set n .

10. A non-contact dual material detection method according to claim 9, characterized in that: The specific content of step 4 is as follows, Step 4.1 When the average thickness L n Any one of the thicknesses is less than the lower thickness limit, output the measurement complete and no material signals. Step 4.2 When both groups of sensors measure average thickness L n greater than the lower limit of thickness and less than the upper limit of thickness, output a measurement complete and single material signal; Step 4.3 When the average thickness L n Any one of the above is greater than the upper limit of the thickness, output the measurement is complete and double material signal.

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