Tea in-process product quality detection method based on mechanical properties

Abstract

The invention relates to the field of tea quality detection, in particular to a mechanical property-based tea product quality detection method, which comprises the following steps of: 1, providing mechanical property-based tea product quality detection equipment; 2, tea leaf treatment; 3, detecting the compressive elastic modulus; 4, tensile elastic modulus detection; 5, detecting the breaking strength; 6, calculating elasticity modulus parameters of the tea leaves, and checking whether the tea leaves are qualified or not; the physical quantities (mechanical characteristics) of the tea leaves, which are mainly detected, comprise the elasticity modulus and the breaking strength, and whether the processed tea leaves are qualified or not is judged by measuring the compression elasticity modulus, the tensile elasticity modulus and the breaking strength of the tea leaves and comparing the measured compression elasticity modulus, the measured tensile elasticity modulus and the measured breaking strength with corresponding mechanical characteristic parameters of the tea leaves which are determined to be qualified. And the professional machine detection standard is more visual and does not depend on the experience of workers, and corresponding parameters can be adjusted according to different links and different tea varieties, so that the manpower and material resource cost is greatly reduced, and the accuracy of tea quality judgment is improved.

Description

Technical Field

[0001] The invention relates to the field of tea quality detection, and in particular to a method for detecting the quality of tea products based on mechanical properties. Background Art

[0002] At present, the tea processing production line requires the realization of unmanned intelligent automatic production, the construction of a production and manufacturing intelligent control center platform, and the centralized connection, collection, and control of all process equipment. At present, the main processing steps such as spreading, twisting, deblocking, fermentation, and initial baking have corresponding professional mechanical equipment involved in automated processing. However, the quality inspection of tea processing conditions is still required between the two corresponding processing links to remove unqualified tea leaves and avoid further processing, resulting in waste of production capacity. At present, most of the processing lines on the market rely on experienced processing workers to manually rub tea leaves and other methods to judge whether the tea processing in each link is qualified by comparing the feel and experience. Among them, the quantitative standard of "experience judgment" varies from person to person, and qualified products of different types and links need to be tested separately to collect relevant qualified parameters, so the workload of data statistics is large; in the prior art, most of them are to judge whether the quality of tea leaves is qualified by inspecting the internal components of tea leaves. In this way, higher precision equipment is required, which has higher use cost and labor cost. Therefore, it is very necessary to propose a tea product quality detection method based on mechanical properties. Summary of the invention

[0003] The purpose of the present invention is to provide a method for detecting the quality of tea products based on mechanical properties, so that the quality of tea can be detected by detecting the physical quantity of tea, and the labor cost and manufacturing cost can be reduced to improve the accuracy of tea processing quality, so as to solve the existing technical defects and unattainable technical requirements.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for detecting the quality of tea products based on mechanical properties, comprising the following steps: 1. Provide a device for testing the quality of tea products based on mechanical properties, including: Frame; A clamping frame, the clamping frame is arranged on the frame body, and the clamping frame includes a fixed clamping frame and a movable clamping frame, the fixed clamping frame and the movable clamping frame are arranged opposite to each other, and the fixed clamping frame and the movable clamping frame are both provided with a clamping piece, and the clamping piece clamps the tea leaves by applying an adjustable pressure to the tea leaves; A pressure component, which is arranged on the frame, and is arranged above the clamping frame, and at least includes a pressure block; A breaking assembly, which is arranged on the frame, is arranged below the supporting frame, and at least comprises a breaking piece; The moving assembly includes a first moving assembly, a second moving assembly and a third moving assembly. The first moving assembly is arranged between the moving clamping frame and the frame body, and is used to move the position of the moving clamping frame. The second moving assembly is arranged between the pressure assembly and the frame body, and is used to move the position of the pressure assembly. The third moving assembly is arranged between the breaking assembly and the frame body, and is used to move the position of the breaking assembly. A detection component, the detection component includes a tension sensor, an industrial camera and a pressure sensor. One end of the tension sensor is connected to the mobile clamping frame, and the other end is connected to the first mobile component. The pressure sensor is respectively arranged on the pressure block and the breaking piece, and is used to detect the pressure values ​​of the pressure block and the breaking piece on the tea leaves respectively. The industrial camera is arranged on the frame, and is used to obtain images of the deformation process of the tea leaves, the movement process of the pressure block, and the movement process of the breaking piece, and is used to measure the deformation amount of the tea leaves, the displacement amount of the pressure block, and the lifting amount of the breaking piece; A driving assembly, wherein the driving assembly comprises a first driving motor, a second driving motor and a third driving motor, wherein the first driving motor, the second driving motor and the third driving motor are sequentially connected to the first moving assembly, the second moving assembly and the third moving assembly to drive the first moving assembly, the second moving assembly and the third moving assembly; In the present application, the driving motor is controlled by an electromagnetically controlled loading system. The control system is a commonly used technical content in this field and will not be described in detail here. After the industrial camera is started, it shoots at a set frequency of 30 frames per second.

[0005] 2. Tea Processing 2.1. Tea selection; 2.2. Stack the selected tea leaves horizontally on the clamping rack.

[0006] 3. Compression elastic modulus test 3.1. Apply downward pressure to the tea leaves and record the pressure changes and images of the tea leaves’ deformation process; 3.2. Calculate the compressive elastic modulus parameters of tea leaves based on the acquired image information and pressure data; 4. Tensile elastic modulus test 4.1. Remove the downward pressure on the tea leaves, apply a lateral pulling force to the tea leaves, and re-record the images and pulling force data of the tea leaves’ deformation process; 4.2. Calculate the tensile elastic modulus parameters of the tea leaves based on the acquired image information and tension data; 5. Breaking strength test 5.1. Remove the lateral pulling force on the tea leaves and apply a pressure upward to the tea leaves to make them just break. Record the image of the tea leaves deformation process, pressure data and the distance between the fixed clamping frame and the mobile clamping frame; 5.2. Calculate the breaking strength R of the tea leaves based on the data obtained in step 5.1; It should be emphasized that in the present application, the data measured by the sensor can be manually read by the methods in the prior art or displayed centrally by other devices.

[0007] 6. Calculate the mechanical properties of tea and check whether the quality of tea is qualified 6.1. Select qualified tea leaves and perform corresponding mechanical property tests on the qualified tea leaves in accordance with steps 1 to 5 in sequence to obtain standard compressive elastic modulus parameters, standard tensile elastic modulus parameters and standard breaking strength; 6.2. Substitute the mechanical property test parameters of the tea to be judged and the mechanical property test parameters of qualified tea into the comprehensive evaluation model, determine the qualified range, and compare the comprehensive evaluation coefficient V to determine whether the quality of the tea is qualified.

[0008] Preferably, in step 2.1, the criteria for selecting tea leaves are: After the tea leaves are processed, randomly select some tea leaves, at least ten leaves of similar shape and size, with complete and clear stem and leaf veins, and test them in groups of two, for at least five groups; Alternatively, after the tea processing process is completed, some tea leaves are randomly selected, and the number of branch veins on the leaves is used as the judging standard. If the number of branch veins on the selected tea leaves is small, the leaves must be selected to ensure that the number of branch veins is equal and the leaf area is basically the same for testing. If the number of branch veins on the tested tea leaves is greater than 5, it is allowed to select tea leaves with a difference of less than 1 in the number of branch veins for group testing, with two leaves as a group, and at least five groups shall be tested.

[0009] Preferably, in step 2.2, the standard for placing tea leaves on the clamping rack is: One end of the horizontally stacked tea leaves is fixed by a clamp on a fixed clamping frame, and the other end is fixed by a clamp on a movable clamping frame. After fixation, pressure is applied to the tea leaves through each clamp to ensure that there is no gap between the tea leaves and keep the leaf surface flat.

[0010] Preferably, in step 3.1, a certain value of pressure is applied to the tea leaves by moving the pressure block downward, and the pressure change during the process is recorded by a pressure sensor, wherein the pressure applied to the tea leaves is in the range of 5N-20N; In step 4.1, the tension sensor is pulled to move the mobile clamping frame, giving the tea leaves a certain value of lateral stretching force, and the tension change during the process is recorded by the tension sensor, wherein the tension range given to the tea leaves is 5N-20N.

[0011] Preferably, the image information is obtained by an industrial camera, and upward pressure is applied to the tea leaves by moving the breaking piece; In step 3.1, the information to be included in the image to be recorded by the industrial camera includes: the motion image changes of the pressure block in the initial state and after compression, and the motion image changes of the tea leaves in the initial state and after compression; In step 4.1, the information to be included in the image to be recorded by the industrial camera includes: the motion image change diagram of the tea leaves from the initial state to the compressed state, and the tensile elastic modulus parameters of the tea leaves calculated in step 4.2 when necessary. Multiple sets of data can be taken for calculation; In step 5.1, the information to be recorded by the industrial camera in the image includes: the displacement of the broken part from the time it contacts the tea leaves until the tea leaves break, and the motion image change diagram of the tea leaves from the initial state to the broken state. The specific calculation method is: 3.2.1. By comparing the dynamic image changes of the pressure block in the initial state and after compression, the number of pixels of the tea leaves before and after changes can be obtained using the image analysis software. , calculate the front and rear compression distance according to the following formula :

[0012] in, is the actual length corresponding to the unit pixel in the image, and the length used in subsequent image calculations is calculated using this formula; 3.2.2. From step 3.2.1, we can get the specific compression deformation of tea leaves. , the pressure block exerts a gravity of The cross-sectional area of ​​the pressure block is S , the thickness of tea group is d , we can get the compressive elastic modulus parameters of tea leaves ; .

[0013] Preferably, in step 4.2, the tensile elastic modulus parameter of the tea leaves is calculated. The specific method is: 4.2.1. Extracting the tea leaf positions corresponding to the readings of multiple tension sensors from the image information to calculate the deformation of the tea leaves; 4.2.2. Based on the data in step 4.2.1, obtain the specific tensile deformation of the tea leaves And the corresponding tension sensor reading : 4.2.3. Pass And the corresponding tension sensor reading , use the following formula to calculate the tensile elastic modulus parameters of tea leaves :

[0014] in, is the average length of the tea group, b is the average width of the tea group, d is the thickness of the tea set.

[0015] Preferably, in step 5.2, the breaking strength of the tea leaves is calculated R The specific method is: 5.2.1. Obtaining the lifting amount of the fractured part from the image , and the angle between the tea set and the fixture at the moment the tea set breaks , where the lifting amount is the displacement of the breaking piece from the time it contacts the tea leaves until the tea leaves break.

[0016] It should be noted in this application that It can be understood as the angle between the position of the tea set at the moment of breaking and the initial flat clamping position of the tea set. This angle is an acute angle located on the tea set near the clamped end. It can also be understood as the angle between the position of the tea set at the moment of breaking and the clamp. This is an obtuse angle, which is complementary to the acute angle mentioned above. However, because of the following content, The calculation uses the sine function sin, so no matter which understanding is used, the final calculated value is the same.

[0017] 5.2.2. According to the lifting amount of the broken part The shortest distance between the two clamping frames , the deformation of tea leaves is calculated by the following formula : ）； in, The unit is millimeter; 5.2.3. Select elastic modulus: ; 5.2.4. Since the processed tea leaves tend to be brittle materials, they basically do not undergo plastic deformation. It can be considered that the force at the moment before the break is the resultant elastic force generated by the elastic deformation of the tea leaves, which are basically the same in value. Therefore, the maximum load when the tea leaves just break can be calculated according to the following formula: ,in The angle between the tea leaves and the fixture at the moment of the tea set breaking

[0018]

[0019] in is the angle between the tea set and the fixture at the moment of fracture; 5.2.5. Calculate the breaking strength R of tea leaves according to the following formula:

[0020] Right now

[0021] in, b is the average width of the tea group in millimeters, d is the thickness of the tea leaves in millimeters. Compared with the original calculation formula for breaking strength R, the instantaneous maximum force is converted into the measurement of the mold lifting amount. Compared with the instantaneous maximum force which is difficult to measure, the lifting amount is easier to detect and has higher accuracy. At the same time, the influence of the average width b of the tea group is ignored, thereby improving the accuracy.

[0022] Preferably, in step 6.2, the comprehensive evaluation model is:

[0023] in, is the corresponding correction factor, V is the comprehensive evaluation coefficient; The judgment standard of the quality of the tea leaves to be tested in step 6.2 is: take the qualified tea leaves in the processing line and perform the same test, calculate the comprehensive evaluation coefficient, determine a range threshold, and the tea leaves with the comprehensive evaluation coefficient within the threshold range are qualified tea leaves.

[0024] Preferably, in step one, the clamping frame is made of a flexible material and is provided with wavy patterns, the wavy patterns are arranged below the clamping piece, and the tea leaves are clamped between the clamping piece and the wavy patterns, that is, it can be understood that the tea leaves are clamped between the clamping frame and the clamping piece in the vertical direction, and in the horizontal direction, one end of the tea leaves is clamped between the fixed clamping frame and the clamping piece, and the other end of the tea leaves is clamped between the movable clamping frame and the clamping piece, and the "clamp" in this application refers to a component for clamping tea leaves, including a clamping frame (a movable clamping frame and a fixed clamping frame) and a clamping piece.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. The physical quantities (mechanical properties) of tea mainly tested in this application include elastic modulus and breaking strength. The quality of the processed tea is judged by measuring the compressive elastic modulus, tensile elastic modulus and breaking strength of the tea and comparing them with the corresponding mechanical property parameters of the qualified tea. Compared with manual inspection, professional machine inspection standards are more intuitive and do not rely on the experience of workers. The corresponding parameters can be adjusted according to different links and different tea varieties, thereby greatly reducing manpower and material costs and improving the accuracy of tea quality judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a device for detecting the quality of tea products based on mechanical properties in the present invention; Figure 2 For the present invention Figure 1 A partial enlarged schematic diagram shown in the middle; Figure 3 It is a schematic diagram of the overall process of the present invention; In the figure: frame 1, fixed clamping frame 2, movable clamping frame 3, clamping piece 4, pressure block 5, breaking piece 6, first movable assembly 7, second movable assembly 8, third movable assembly 9, tension sensor 10, industrial camera 11, pressure sensor 12, first drive motor 13, second drive motor 14, third drive motor 15. DETAILED DESCRIPTION

[0027] The following will be combined with the attached embodiment of the present invention Figure 1-Figure 3 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Figure 1-Figure 3 , Embodiments of the present invention: Embodiment 1:

[0029] like Figure 1-Figure 2 As shown: Test objects: qualified and unqualified tea produced in the withering stage of a tea processing factory in Zhejiang.

[0030] A method for detecting the quality of tea products based on mechanical properties, comprising the following steps: 1. Provide a device for testing the quality of tea products based on mechanical properties, including: Frame 1; Specifically, frame 1 is a hollow giant rectangular parallelepiped frame, that is, The clamping frame is arranged on the frame body 1, and the clamping frame includes a fixed clamping frame 2 and a movable clamping frame 3, the fixed clamping frame 2 and the movable clamping frame 3 are arranged relatively to each other, and the fixed clamping frame and the movable clamping frame 3 are both provided with a clamping piece 4, and the clamping piece 4 clamps the tea leaves by applying an adjustable pressure to the tea leaves; specifically, the clamping piece 4 is located at the top of the movable clamping frame and the fixed clamping frame 2.

[0031] A pressure component, which is arranged on the frame 1 and above the clamping frame, and at least includes a pressure block 5; A breaking component, which is arranged on the frame 1 and below the support frame, and at least comprises a breaking piece 6; The moving assembly includes a first moving assembly 7, a second moving assembly 8 and a third moving assembly 9. The first moving assembly 7 is arranged between the moving clamping frame 3 and the frame body 1, and is used to move the position of the moving clamping frame 3. The second moving assembly 8 is arranged between the pressure assembly and the frame body 1, and is used to move the position of the pressure assembly. The third moving assembly 9 is arranged between the breaking assembly and the frame body 1, and is used to move the position of the breaking assembly. Specifically, the second moving assembly 8 is configured as a slide rail, and is composed of two independent and vertical slide rails, which have completed the multi-dimensional movement of the pressure block 5 in the horizontal and vertical directions to improve adaptability.

[0032] A detection component, the detection component includes a tension sensor 10, an industrial camera 11 and a pressure sensor 12. One end of the tension sensor 10 is connected to the mobile clamping frame, and the other end is connected to the first mobile component 7. The pressure sensor 12 is respectively arranged on the pressure block 5 and the breaking piece 6, and is respectively used to detect the pressure value of the pressure block 5 and the breaking piece 6 on the tea leaves. The industrial camera 11 is arranged on the frame 1. In this embodiment, three industrial cameras 11 are specifically arranged, which are respectively arranged near the pressure block, the clamping frame and the breaking piece. The industrial camera 11 is used to obtain tea images. The industrial camera 11 is used to obtain images of the deformation process of the tea leaves, the movement process of the pressure block 5 and the movement process of the breaking piece 6, and is used to measure the deformation amount of the tea leaves, the displacement amount of the pressure block 5 and the lifting amount of the breaking piece 6; A driving assembly, the driving assembly comprising a first driving motor 13, a second driving motor 14 and a third driving motor 15, wherein the first driving motor 13, the second driving motor 14 and the third driving motor 15 are connected to the first moving assembly 7, the second moving assembly 8 and the third moving assembly 9 in sequence, and are used to drive the first moving assembly 7, the second moving assembly 8 and the third moving assembly 9; In this embodiment, specifically, the clamping frame is made of a flexible material, and a wavy pattern is provided on the clamping frame. The wavy pattern is provided below the clamping piece 4, and the tea leaves are clamped between the clamping piece 4 and the wavy pattern. The purpose is to increase the friction force of the contact surface between the device and the tea leaves. The role of the flexible material is to adjust adaptively according to the shape of the tea leaves to ensure the natural state of the tea leaves.

[0033] The mobile clamping frame and the tension and pressure sensor form a whole that guarantees a controllable stroke of at least 50 mm, and the first drive motor 13 is specifically configured as a servo motor with a resolution of 0.00125 (8 subdivisions). The first moving component 7 is connected to the mobile clamping frame 3, and the tension acting on the clamp can be detected in real time, thereby reflecting the tension acting on the tea leaves.

[0034] The specific setting of the breaking piece 6 is: the top of the breaking piece 6 is in an arc shape, and when the compressive elastic modulus and the breaking strength are measured, since there is enough operating space between the fixed clamping frame 2 and the movable clamping frame 3, when the pressure block 5 applies pressure to the tea leaves, there is enough deformation space under the tea leaves, and when the breaking strength is measured, the breaking piece 6 also has enough space to apply pressure to the tea leaves, that is, the breaking piece 6 passes through between the two clamping frames to apply pressure to the tea leaves.

[0035] like Figure 3 As shown: 2. Tea processing 2.1. Tea selection; Specifically, in step 2.1, the criteria for selecting tea leaves are: After the tea processing process is completed, some tea leaves are randomly selected. The number of branch veins on the leaves is used as the judging standard. If the number of branch veins on the selected tea leaves is small, the leaves must be selected to ensure that the number of branch veins is equal and the leaf area is basically the same for testing. If the number of branch veins on the tested tea leaves is greater than 5, tea groups with a difference of less than 1 in the number of branch veins are allowed to be selected for group testing, with two leaves as a group and ten groups tested.

[0036] 2.2. Stack the selected tea leaves horizontally on the clamping rack.

[0037] Specifically, in step 2.2, the standard for placing tea leaves on the clamping rack is: One end of the transversely stacked tea leaves is fixed by a clip 4 on a fixed clamping frame 2, and the other end is fixed by a clip 4 on a movable clamping frame. After fixation, a pressure of 3N is applied to the tea leaves through each clip 4 to ensure that there is no gap between the tea leaves and keep the leaf surface flat.

[0038] 3. Compression elastic modulus test 3.1. Recording images of the tea deformation process by an industrial camera 11; 3.2. Apply a certain amount of pressure to the tea leaves by moving the pressure block 5 downward; the pressure applied by the pressure block 5 to the tea leaves is 5N; 3.3. Calculate the compressive elastic modulus parameters of tea leaves based on the image information obtained by the industrial camera 11 and the data collected by the pressure sensor 12 ; Specifically, in this embodiment, the driving assembly is controlled by the electromagnetically controlled loading system, thereby controlling the movement of the pressurizing block, the breaking piece 6 and the movable clamping frame 3 .

[0039] Specifically, in step 3.3, the information to be included in the image to be recorded by the industrial camera 11 includes: the motion image changes of the pressure block 5 in the initial state and after compression, and the motion image changes of the tea leaves from the initial state to after compression; It should be noted in the present application that obtaining relevant parameters through changes in various motion images is a common technical content in the prior art and will not be repeated in the present application.

[0040] In step 3.3, the compressive elastic modulus parameter of tea leaves The specific calculation method is: 3.3.1. By comparing the dynamic image changes of the pressure block 5 in the initial state and after compression, the number of pixels of the tea leaves before and after the change is obtained according to the image analysis software. , calculate the front and rear compression distance according to the following formula :

[0041] in, is the actual length corresponding to the unit pixel in the image, and the length used in subsequent image calculations is calculated using this formula; 3.3.2. From step 3.3.1, we can get the specific compression deformation of tea leaves. , the corresponding weight exerted by the weight is , cross-sectional area of ​​pressure block S , tea set thickness d , we can get the compressive elastic modulus parameters of tea leaves ; .

[0042] Due to mechanical errors, this parameter cannot accurately represent the elastic modulus parameter of tea leaves. Therefore, it can be compared with the calibration value to determine a range of compressive elastic modulus of processed qualified tea leaves. The calibration value needs to be tested with standard parts with known compressive elastic modulus (or qualified tea leaves with known compressive elastic modulus. The definition of qualified tea leaves should be classified and defined according to different varieties and different process stages. It mainly relies on manual identification and inspection of a batch of tea leaves. After it is considered qualified, the same experiment is carried out to measure this type of parameter. Fluctuations within a certain range are allowed. After measuring this type of parameter, it can be used as a range interval for subsequent judgment of whether the tea leaves are qualified) to test the corresponding deformation amount under this compressive elastic modulus.

[0043] 4. Tensile elastic modulus test 4.1. Remove the pressing block and re-record the image of the tea deformation process through the industrial camera 11; Specifically, after the compression modulus test is completed, the system controls the pressure block 5 to be lifted and returned to its original position, and then controls the servo motor on the side to work, and pulls the mobile clamping frame 3 through the tension sensor 10 to give the tea a stretching force.

[0044] 4.2. Pull the tension sensor 10 to move the mobile clamping frame to apply a certain value of tensile force to the tea leaves; the tension range of the mobile clamping frame 3 applied to the tea leaves is 5N.

[0045] 4.3. Calculate the tensile elastic modulus parameters of tea leaves based on the image information obtained by the industrial camera 11 and the data of the tension sensor 10 ; Specifically, in step 4.3, the information to be included in the image to be recorded by the industrial camera 11 includes: a motion image change diagram of tea leaves from an initial state to a compressed state; In step 4.3, the tensile elastic modulus parameter of tea leaves is calculated. The specific method is: 4.3.1. Extracting the positions of tea leaves corresponding to the readings of the multiple tension sensors 10 from the image information to calculate the deformation amount of the tea leaves; 4.3.2. Based on the data in step 4.3.1, obtain the specific tensile deformation of the tea leaves And the corresponding tension sensor 10 reading ; 4.3.3, through And the corresponding tension sensor 10 reading , use the following formula to calculate the tensile elastic modulus parameters of tea leaves :

[0046] in, is the average length of the tea group,b is the average width of the tea group, d is the thickness of the tea set; Specifically, before testing the quality of tea or after checking the quality of tea, the parameter values ​​corresponding to qualified tea are measured according to the steps of this application, which serve as standard reference data for judging the quality of tea to be tested.

[0047] 5. Breaking strength test 5.1. Remove the lateral pulling force on the tea leaves, and re-record the images of the tea leaves deformation process through the industrial camera 11; 5.2. Apply a certain amount of pressure to the tea leaves by moving the breaking member 6 so that the tea leaves just break; Specifically, after measuring the tensile elastic modulus, the surface of the tea leaves is stretched, so the surface is relatively flat, and then the breaking member 6 is controlled to rise until the tea leaves are just broken.

[0048] 5.3. Based on the image information obtained by the industrial camera 11, the data of the tension sensor 10, and the distance between the fixed clamping frame 2 and the mobile clamping frame 3 Calculate the breaking strength of tea leaves R ; Specifically, in step 5.3, the information to be included in the image to be recorded by the industrial camera 11 includes: the displacement of the breaking member 6 from the time it contacts the tea leaves until the tea leaves break, and the motion image change diagram of the tea leaves from the initial state to the broken state.

[0049] In step 5.3, the specific method for calculating the breaking strength R of tea leaves is: 5.3.1. Obtaining the lifting amount of the broken part 6 from the image , and the angle between the tea set and the fixture at the moment the tea set breaks , where the lifting amount is the displacement of the breaking piece from the time it contacts the tea leaves until the tea leaves break; 5.3.2. According to the lifting amount of the broken part 6 The shortest distance between the two clamping frames , the deformation of tea leaves is calculated by the following formula : ）； in, The unit is millimeters, The actual length of the tea group when the top cracks ; 5.3.3. Select elastic modulus: ; 5.3.4. Since the processed tea leaves tend to be brittle materials, they basically do not undergo plastic deformation. It can be considered that the force at the moment before the break is the resultant elastic force generated by the elastic deformation of the tea leaves, which are basically the same in value. Therefore, the maximum load when the tea leaves just break can be calculated according to the following formula: ,in The angle between the tea set and the fixture at the moment of fracture:

[0050] in is the angle between the tea set and the fixture at the moment of fracture; 5.3.5. Calculate the breaking strength R of tea leaves according to the following formula:

[0051] Right now

[0052] in, b is the average width of the tea group in millimeters, d is the thickness of the tea leaves in millimeters. Compared with the original calculation formula for breaking strength R, the instantaneous maximum force is converted into the measurement of the mold lifting amount. Compared with the instantaneous maximum force which is difficult to measure, the lifting amount is easier to detect and has higher accuracy. At the same time, the influence of the average width b of the tea group is ignored, thereby improving the accuracy.

[0053] 6. Calculate the mechanical properties of tea and check whether the quality of tea is qualified. 6.1. Select qualified tea leaves and perform corresponding mechanical property tests on the qualified tea leaves in accordance with steps 1 to 5 to obtain standard compressive elastic modulus parameters. , Standard tensile elastic modulus parameters and standard breaking strength ; 6.2. Substitute the mechanical property test parameters of the tea to be judged and the mechanical property test parameters of qualified tea into the comprehensive evaluation model, determine the qualified range, and compare the comprehensive evaluation coefficients V , to determine whether the quality of tea is qualified.

[0054] In step 6.2, the comprehensive evaluation model is:

[0055] in, is the corresponding correction factor, V is the comprehensive evaluation coefficient; The judgment standard of the quality of the tea leaves to be tested in step 6.2 is: take the qualified tea leaves in the processing line and perform the same test, calculate the comprehensive evaluation coefficient, determine a range threshold, and the tea leaves with the comprehensive evaluation coefficient within the threshold range are qualified tea leaves.

[0056] Specifically: 10 groups of qualified tea leaves were selected for the above test. The corresponding test data are as follows: Take 15mm, :

[0057] Combining the above three data, we select group a2 close to the middle value as the detection standard to determine The value of , and the comprehensive evaluation coefficient is calculated for the remaining groups, where , In order to balance the order of magnitude, we take 0.01, and the corresponding data are as follows:

[0058] Group a2 is the standard group, so the corresponding total evaluation coefficient is 0. In this embodiment, the threshold V is set to be less than 0.2 as qualified tea, then groups a7 and a8 are unqualified tea, and the rest are qualified tea. Therefore, from the above test, it can be seen that the determination rate of qualified tea in this application is 80%. Comparative Example 1:

[0059] In order to test the difference between the patented method and the manual method, five senior tea processing quality inspectors from a tea factory in Zhejiang were invited to conduct qualified processing judgment on the same 10 groups of qualified tea leaves. The specific results are as follows:

[0060] It can be seen from the above table that the accuracy of manual judgment of qualified tea is 74%.

[0061] Embodiment 2: This embodiment differs from Embodiment 1 in that: Take 10 groups of unqualified tea leaves and perform the same experimental calculation as in Example 1. The corresponding data are as follows:

[0062] By comparing the comprehensive evaluation coefficient V, it can be seen that the tea in the unqualified group is all judged as unqualified tea, that is, the accuracy rate is 100%.

[0063] Comparative Example 2: The difference between this comparative example and comparative example 1 is: Comparative Example 2 The same 10 groups of unqualified and qualified tea leaves as in Example 2 were processed and determined to be qualified. The specific results are as follows:

[0064] From the above table, it can be seen that the accuracy rate of manual judgment on unqualified tea leaves in Comparative Example 2 is 78%.

[0065] In summary, in Comparative Example 1, 5 employees identified the qualified rate of tea processing by manual rubbing and other methods, and their correct rate of judging qualified tea was 74%, the correct rate of judging unqualified tea was 78%, and the correct rate of comprehensive judgment was 76%, while the correct rate of judging qualified tea in Example 1 was 80%, and the correct rate of judging unqualified tea in Example 2 was 100%. The correct rate of comprehensive judgment was 80%, so it can be seen that the correct rate of judging tea by the method of the present application is higher than the correct rate of judging qualified tea processing manually.

[0066] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that those skilled in the art can understand.

Claims

1. A method for detecting the quality of tea products based on mechanical properties, characterized in that: The following steps are involved:

1. Provided is a device for testing the quality of tea products based on mechanical properties, comprising at least: a clamping frame, wherein the clamping frame comprises a fixed clamping frame (2) and a movable clamping frame (3), the two being arranged opposite to each other; 2. Tea Processing 2.

1. Tea selection; 2.

2. Stack the selected tea leaves horizontally on the clamping rack; 3. Compression elastic modulus test 3.

1. Apply downward pressure to the tea leaves and record the pressure changes and images of the tea leaves’ deformation process; 3.

2. Calculate the compressive elastic modulus parameters of tea leaves based on the acquired image information and pressure data ; 4. Tensile elastic modulus test 4.

1. Remove the downward pressure on the tea leaves, apply a lateral pulling force to the tea leaves, and re-record the images and pulling force data of the tea leaves’ deformation process; 4.

2. Calculate the tensile elastic modulus parameters of tea leaves based on the acquired image information and tensile force data ; 5. Breaking strength test 5.

1. Remove the lateral pulling force on the tea leaves and apply a pressure upward to the tea leaves so that the tea leaves just break. Record the image of the tea leaves deformation process, the pressure data and the distance between the fixed clamping frame (2) and the movable clamping frame (3). ; 5.

2. Calculate the breaking strength R of the tea leaves based on the data obtained in step 5.1; 6. Calculate the mechanical properties of tea and check whether the quality of tea is qualified 6.

1. Select qualified tea leaves and perform corresponding mechanical property tests on the qualified tea leaves according to steps 1 to 5 to obtain the standard compressive elastic modulus parameters. , Standard tensile elastic modulus parameters and standard breaking strength ; 6.

2. Substitute the mechanical property test parameters of the tea to be judged and the mechanical property test parameters of qualified tea into the comprehensive evaluation model, determine the qualified range, and compare the comprehensive evaluation coefficient V to determine whether the quality of the tea is qualified.

2. A method for detecting the quality of tea products based on mechanical properties according to claim 1, characterized in that: In step 2.1, the criteria for selecting tea leaves are: After the tea leaves are processed, randomly select some tea leaves, at least ten leaves of similar shape and size, with complete and clear stem and leaf veins, and test them in groups of two, for at least five groups; Alternatively, after the tea processing process is completed, some tea leaves are randomly selected, and the number of branch veins on the leaves is used as the judging standard. If the number of branch veins on the selected tea leaves is small, the leaves must be selected to ensure that the number of branch veins is equal and the leaf area is basically the same for testing. If the number of branch veins on the tested tea leaves is greater than 5, it is allowed to select tea leaves with a difference of less than 1 in the number of branch veins for group testing, with two leaves as a group, and at least five groups shall be tested.

3. A method for detecting the quality of tea products based on mechanical properties according to claim 2, characterized in that: In step 2.2, the standard for placing tea leaves on the clamping rack is: One end of the transversely stacked tea leaves is fixed by a fixed clamping frame (2), and the other end is fixed by a movable clamping frame (3), so as to ensure that there is no gap between the tea leaves and keep the leaf surface flat.

4. A method for detecting the quality of tea products based on mechanical properties according to claim 3, characterized in that: In the step 1, a device for detecting the quality of tea products based on mechanical properties further includes: A frame body (1), the clamping frame being arranged on the frame body (1), a pressure block (5) being arranged above the clamping frame, a breaking piece (6) being arranged below the clamping frame, and a tension sensor (10) being connected to one end of the movable clamping frame (3) away from the fixed clamping frame (2); An industrial camera (11), the industrial camera (11) being arranged on the frame (1), and being respectively located near the pressure block (5), the clamping frame and the breaking piece (6), and being used to obtain images of the deformation process of the tea leaves, the movement process of the pressure block (5) and the movement process of the breaking piece (6), so as to measure the deformation amount of the tea leaves, the displacement amount of the pressure block (5) and the lifting amount of the breaking piece (6); A pressure sensor (12), wherein the pressure sensor (12) is respectively arranged on the pressure block (5) and the breaking piece (6), and is used to respectively detect the pressure values ​​of the pressure block (5) and the breaking piece (6) on the tea leaves.

5. The method for detecting the quality of tea products based on mechanical properties according to claim 4, characterized in that: In step 3.1, a certain pressure is applied downward to the tea leaves by moving the pressure block (5), and the pressure change during the process is recorded by the pressure sensor (12), wherein the pressure applied to the tea leaves is in the range of 5N-20N; In step 4.1, the movable clamping frame (3) is moved by pulling the tension sensor (10), thereby applying a certain value of lateral tensile force to the tea leaves, and the tension change during the process is recorded by the tension sensor (10), wherein the tension applied to the tea leaves ranges from 5N to 20N.

6. A method for detecting the quality of tea products based on mechanical properties according to claim 5, characterized in that: The image information is obtained by an industrial camera (11), and upward pressure is applied to the tea leaves by moving the breaking piece (6); In step 3.1, the information to be included in the image to be recorded by the industrial camera (11) includes: the motion image changes of the pressure block (5) in the initial state and after compression, and the motion image changes of the tea leaves in the initial state and after compression; In step 4.1, the information to be included in the image to be recorded by the industrial camera (11) includes: a motion image change diagram of tea leaves from an initial state to a compressed state; In step 5.1, the information to be included in the image to be recorded by the industrial camera (11) includes: the displacement of the breaking piece (6) from the time it contacts the tea leaves until the tea leaves break, and the motion image change diagram of the tea leaves from the initial state to the broken state.

7. A method for detecting the quality of tea products based on mechanical properties according to claim 6, characterized in that: In step 3.2, the compressive elastic modulus parameter of tea leaves The specific calculation method is: 3.2.

1. By comparing the dynamic image changes of the pressure block (5) in the initial state and after the tea leaves are compressed, the number of pixels of the tea leaves before and after the changes are obtained using the image analysis software. , calculate the front and rear compression distance according to the following formula : in, is the actual length corresponding to the unit pixel in the image, and the length used in subsequent image calculations is calculated using this formula; 3.2.

2. From step 3.2.1, we can get the specific compression deformation of tea leaves. , the pressure value applied by the pressure block (5) , the cross-sectional area of ​​the pressure block S, the thickness of the tea group d, the compressive elastic modulus parameters of the tea can be obtained ; 。 8. A method for detecting the quality of tea products based on mechanical properties according to claim 7, characterized in that: In step 4.2, the tensile elastic modulus parameter of tea leaves is calculated. The specific method is: 4.2.

1. Extracting the tea leaf positions corresponding to the tension readings shown by the sensor from the image information to calculate the deformation of the tea leaves; 4.2.

2. Based on the data in step 4.2.1, obtain the specific tensile deformation of multiple groups of tea leaves And the corresponding tension sensor (10) reading : 4.2.

3. Pass And the corresponding tension sensor (10) indicates the tension , use the following formula to calculate the tensile elastic modulus parameters of tea leaves : in a is the average length of the tea leaves, b is the average width of the tea leaves, and d is the thickness of the tea leaves.

9. A method for detecting the quality of tea products based on mechanical properties according to claim 8, characterized in that: In step 5.2, the specific method for calculating the breaking strength R of tea leaves is: 5.2.

1. Obtaining the lift of the broken tea piece (6) from the image , and the angle between the tea set and the fixture at the moment the tea set breaks , wherein the lifting amount is the displacement of the breaking member (6) from the time it contacts the tea leaves until the tea leaves break; 5.2.

2. The lifting amount of tea leaves according to the broken piece (6) The shortest distance between the two clamping frames , because the tea leaves clamped by the clamp do not deform, It is also the initial length of the tea group that actually undergoes deformation. The deformation of the tea leaves is calculated by the following formula: : ）； in, The unit is millimeters, The actual length of the tea group when the top cracks ; 5.2.

3. Select elastic modulus: ; 5.2.

4. Calculate the maximum load at which the tea leaves break using the following formula : in is the angle between the tea leaves and the fixture at the moment of the tea set breaking; 5.2.

5. Calculate the breaking strength R of tea leaves according to the following formula: Right now Wherein, b is the average width of the tea group, in millimeters, and d is the thickness of the tea group, in millimeters.

10. A method for detecting the quality of tea products based on mechanical properties according to claim 9, characterized in that: In step 6.2, the comprehensive evaluation model is: in, is the corresponding correction coefficient, V is the comprehensive evaluation coefficient; The judgment standard of the quality of the tea leaves to be tested in step 6.2 is: take the qualified tea leaves in the processing line and perform the same test, calculate the comprehensive evaluation coefficient, determine a range threshold, and the tea leaves with the comprehensive evaluation coefficient within the threshold range are qualified tea leaves.

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