A method for visual imaging and detection of products on hydraulic presses

Abstract

The present invention relates to the technical field of product molding, and in particular to a method for visual imaging and detection molding of products on a hydraulic press, wherein the hydraulic press comprises a lower beam, a movable beam, a main cylinder, a mobile operating table, a hydraulic station, a liquid filling box, a visual sensor, a safety light curtain, and a background service display platform, wherein the visual sensors are respectively located on both sides of the movable beam for collecting the initial state and molding process of the product, and are connected with the background service display platform for information exchange; the safety light curtain is located on one side of the lower beam, and the following methods are included in the visual imaging and detection: S1, inputting relevant parameters for setting the product in the system of the background service display platform; S2, the visual sensors are fixed on both sides of the movable beam; S3, visually positioning the product; S4, visual imaging by the visual sensor; S5, the visual sensor generates a data feedback signal and sends it to the background service display platform; S6, the background service display platform performs data comparison to determine whether the product is qualified during the molding process.

Description

Technical Field

[0001] The invention relates to the technical field of product molding, and in particular to a method for visual imaging and detecting molding of products on a hydraulic press. Background Art

[0002] At present, the known hydraulic press is usually used in pressing and forming processes, such as forging, stamping, cold extrusion, straightening, bending, flanging, sheet metal drawing, powder metallurgy, embossing, etc. Whether the size of various formed products meets the requirements needs to be manually detected, and the labor cost and time cost are relatively large. In order to solve the above technical problems, the present invention provides a method for visual imaging and detection of forming of products based on hydraulic presses. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art and to propose a method for visual imaging and detection of forming of products on a hydraulic press.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for visual imaging and detection of forming of products on a hydraulic press, comprising a lower beam, a movable beam, a main cylinder, a mobile operating table, a hydraulic station, a liquid filling tank, a visual sensor, a safety light curtain, and a background service display platform in the hydraulic press. The visual sensors are respectively located on both sides of the movable beam to collect the initial state and forming process of the product, and are connected to the background service display platform for information exchange; the safety light curtain is located on one side of the lower beam, and the following methods are included in the visual imaging and detection:

[0006] S1. Input and set the characteristics of the product and the relevant parameters required for molding in the system of the backend service display platform;

[0007] S2, fix the visual sensor on both sides of the movable beam;

[0008] S3. Visual positioning of products during the pressing process;

[0009] S4, visual sensor visual imaging;

[0010] S5, the visual sensor generates a data feedback signal of the image and sends it to the backend service display platform;

[0011] S6. The backend service display platform compares the data to determine whether the product is qualified during the molding process.

[0012] Furthermore, S3 includes that before the hydraulic press presses the product, the visual sensor will position the product to ensure that the product on the lower beam is imaged at the correct position, and the positioning method steps include two-dimensional coordinate positioning of the product on the hydraulic press or the center point positioning of the product, and the two-dimensional coordinate positioning of the product includes: setting the center point coordinates of the product to be pressed on the hydraulic press to (x, y), and obtaining the feature point coordinates or outer contour coordinate information of the product as (x', y') through graphic processing and analysis of the product by the visual sensor. Then, the offset of the product on the hydraulic press Δx=x-x', Δy=y-y' can be calculated, and the position deviation of the target product to be pressed relative to the center of the image is obtained according to the offset, and the position of the product is adjusted accordingly according to the deviation position.

[0013] Furthermore, S3 includes collecting n image data of the appearance of the product on the hydraulic press by a visual sensor; and extracting feature information of the product from the n image data, where n≥1.

[0014] Furthermore, the extracted characteristic information of the product includes the length, width and thickness of the initial state of the product before molding; it also includes collecting the length, width, thickness and deformation of the product during each molding process, storing these characteristic information and comparing them with the product parameters stored in the system, the visual sensor continuously images the product, and compares the obtained size with the standard model; and adjusts the output pressure to make the product continuously approach the standard model.

[0015] Furthermore, during the forming process, the visual sensor collects the length, width and thickness of the product each time it is formed, calculates the current deformation of the product in real time, and compares it with the deformation stored in the system. The deformation includes the linear deformation of the product, the shear deformation of the product, the bending deformation of the product and the torsional deformation of the product;

[0016] The linear deformation of the product is calculated as: ε=ΔL / L0, where ε represents the linear deformation of the product, ΔL represents the length change, and L0 represents the initial length of the product;

[0017] The calculation of the shear deformation of the product is: γ=Δx / h, where γ represents the shear deformation of the product, Δx represents the shear amount, and h represents the thickness of the current product;

[0018] The calculation of the bending deformation of the product is: δ = (M × L 2 ) / (2×E×I), where δ represents the bending deformation of the product, M represents the bending moment of the material, L represents the length of the current product, E represents the elastic modulus, and I represents the section inertia moment;

[0019] The torsional deformation of the product is calculated as: φ=(T×L) / (G×J), wherein φ represents the torsional deformation of the product, T represents the torque, L represents the length of the current product, G represents the shear modulus, and J represents the polarization moment of inertia.

[0020] Furthermore, in said S6, during the data determination process, when the difference between the molding parameters of the product and the storage parameters of the standard model in the system is 2% or less, it is judged as a qualified product and the system stops pressing; when the difference is above 2%, it is judged as an unqualified product, indicating that the product still does not meet the molding requirements, and the background service display platform feeds back the information to the visual sensor, and repeats steps S3-S6.

[0021] Furthermore, during the molding and pressing process, the system detects the product every 0.1 seconds, and compares the product imaging model with the standard model in the system, adjusts the output pressure according to the difference in model size between the two, and uses the output pressure as the system's output signal for pressing. The system can optimize the output signal every time it detects.

[0022] Furthermore, the forming and pressing process can be regarded as a second-order system, and its transfer function can be expressed as: Where G(s) is the transfer function, s is the complex frequency variable, Y(s) is the output signal of the system, U(s) is the input signal of the system, ζ is the inherent property value of the system damping ratio, ω n is the undamped natural frequency of the system. This transfer function is used to analyze the stability and frequency response of the system and to design the controller.

[0023] Furthermore, U(s) is the input signal of the system, which can be regarded as The step signal is calculated based on the step signal: Then the time domain expression changes to: Further calculation: Among them, σ represents the damping ratio or attenuation rate of the system, y(t) is the output of the function, which represents the function of time t, and represents the difference between the product's external dimensions during the pressing process and the standard model. 1 represents the constant term, which is the initial value of the function. e represents the base of the natural logarithm. -σt represents the exponential part of the function. Among them, σ represents the damping ratio or attenuation rate of the system, cosω d t represents the cosine function, where ω d is the angular frequency of the damped oscillation; sinω d t represents the sine function; represents a damped oscillation where the combination of the cosine and sine functions describes the phase and amplitude of the oscillation.

[0024] Furthermore, during the molding and pressing process, the calculation formula of the output signal is: At this time, ζ=1, where represents the standard form of the transfer function, ω n is the undamped natural frequency of the system, s is the complex frequency variable, is the zero term of the transfer function, representing an integrator, is the pole term of the transfer function, indicating a second-order pole; is another pole term of the transfer function, indicating a first-order pole; its time domain output function changes to: Among them, 1 is a constant term, which represents the initial value of the function in the system. is an exponential decay term, representing the decay part of the system response, (1+ω n t) is a polynomial term, which represents the growth part of the system response, and c(t) is the output value of the transfer function in the system, which represents the difference between the pressed product dimensions and the standard model. The standard model uses the constant term 1 as a reference.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The present invention proposes a method for visual imaging and detection of forming products on a hydraulic press. During the entire pressing process, no personnel participation in detection is required, and round-the-clock production is achieved, reducing labor and time costs. The visual sensor can also be used on other types of hydraulic presses, with a wide range of applicability and is not affected by various working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process framework diagram of visual imaging and detection molding in the present invention;

[0028] Figure 2 A perspective view of a hydraulic press of the present invention;

[0029] Figure 3 For the present invention Figure 2 The main view;

[0030] Figure 4 For the present invention Figure 2 Side view of

[0031] In the figure, 1-lower beam; 2-main cylinder; 3-movable beam; 4-mobile operating table; 5-hydraulic station; 6-liquid filling tank; 7-visual sensor; 8-safety light curtain. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0033] Example 1, a method for visual imaging and detecting molding of products on a hydraulic press, please refer to the attached drawings in the specification, Figure 2-Figure 4 , the hydraulic press includes a lower beam 1, a movable beam 3, a main cylinder 2, a mobile operating table 4, a hydraulic station 5, a liquid filling box 6, a visual sensor 7, a safety light curtain 8, and a background service display platform. In this embodiment, there are two visual sensors 7, which are respectively located on both sides of the movable beam 3 for collecting the initial state of the product and the product state during the molding process, and are connected with the background service display platform for information exchange. The visual sensor 7 feeds back the image data of the initial state of the product and the product molding process to the background server display platform 9 in real time; wherein, the background server display platform 9 in this embodiment has the function of summarizing, analyzing and judging data, and the safety light curtain 8 is located on one side of the lower beam 1. The function of the safety light curtain 8 in this embodiment is to send an emergency stop command to the mobile operating table 4 when other objects other than the product are identified, and automatically stop all operations, so as to stop the operation of the equipment in time and avoid injuries to workers due to contact with dangerous areas. It has the characteristics of high sensitivity, fast response speed, strong reliability, etc., so it can effectively prevent accidents and improve the safety guarantee of workers when operating the hydraulic press.

[0034] Example 2: In this example, please refer to the accompanying drawings in the specification. Figure 1 , visual imaging and detection include the following methods:

[0035] S1. Input and set the characteristics of the product and the relevant parameters to be met by the molding in the system of the backend service display platform. The parameters include the material, performance, length, width, thickness of the product in its initial state, and the size and deformation requirements to be met by the product after molding;

[0036] S2, fix the visual sensor 7 on both sides of the movable beam 3 so as to be able to capture the actual product on the hydraulic press;

[0037] S3. Visual positioning of the product in the pressing process: During the process of pressing the product into shape, the visual sensor 7 first visually positions the product. In this embodiment, the visual sensor 7 is the direct source of information for the entire machine vision system. It is mainly composed of one or two graphic sensors, and sometimes equipped with a light projector and other auxiliary equipment. The main function of the visual sensor 7 is to obtain enough of the most original image to be processed by the machine vision system. The working principle is: visual sensing is an electronic image technology applied to production equipment. The image is captured by the visual sensor 7, and then the image is transmitted to the processing unit. Through digital processing, the size, shape and color are judged according to the pixel distribution, brightness, color and other information, and the operation of the production equipment is controlled according to the judgment results. The working process of the visual sensor 7 can be divided into four steps: image detection, image analysis, image drawing and image recognition. The visual sensor 7 has the ability to capture thousands of pixels from an image; visual information is generally converted into electrical signals through photoelectric detection, and the characteristic information such as the shape and position of the object can be judged by the change of image information;

[0038] S4, visual imaging of the visual sensor 7. In this embodiment, the working principle of the visual imaging of the visual sensor 7 is to measure and identify various parameters such as size, defect, type, matching, text, etc. according to the image obtained by the object in a certain environment, so as to help customers improve production efficiency and reduce the influence of uncertain factors in manual work on product quality;

[0039] S5, the visual sensor 7 sends the imaged image generation data feedback signal to the backend service display platform;

[0040] S6. The backend service display platform compares data to determine whether the product is qualified during the molding process. If the product is judged to be qualified after molding, the backend service display platform commands the system to stop working. If the product is judged to be unqualified after molding, the backend service display platform feeds back information to the visual sensor 7 to re-visually position the product in the pressing process until the visual sensor 7 generates a data feedback signal from the image and sends it to the backend service display platform to determine whether the product molding meets the qualified requirements. In addition, when the product is judged to be unqualified, the working parameters of the hydraulic press system, such as pressure value, speed value, etc., can be adjusted.

[0041] Embodiment 3, on the basis of the above embodiment, said S3 includes that before the hydraulic press presses the product, the visual system will position the product to ensure that the product located on the lower beam 1 is imaged at the correct position, and the positioning method steps include two-dimensional coordinate positioning of the product on the hydraulic press or the center point positioning of the product, and the two-dimensional coordinate positioning of the product includes: setting the center point coordinates of the product to be pressed on the hydraulic press to (x, y), and obtaining the feature point coordinates or outer contour coordinate information of the product by processing and analyzing the product through the visual sensor 7 (x', y'), and the offset of the product on the hydraulic press Δx=x-x', Δy=y-y' can be calculated through the coordinates of the feature points of the product or the outer contour coordinate information, and the position deviation of the target product to be pressed relative to the center of the image is obtained according to the calculated offset, and the position of the product is adjusted accordingly according to the deviation position.

[0042] Embodiment 4, the step S3 includes collecting n image data of the product shape on the hydraulic press through the visual sensor 7; extracting the characteristic information of the product from the n image data, n≥1; the extracted characteristic information of the product includes the length, width and thickness of the initial state of the product before molding; and also includes collecting the length, width, thickness and deformation of the product during each molding process, storing these characteristic information and comparing them with the product parameters stored in the system, the visual sensor 7 continuously performs imaging processing on the product, and compares the obtained size with the standard model; and adjusts the output pressure to make the product continuously approach the standard model.

[0043] Embodiment 5, during the forming process, the visual sensor 7 collects the length, width and thickness of the product each time it is formed, calculates the current deformation of the product in real time, and compares it with the deformation stored in the system, wherein the deformation includes the linear deformation of the product, the shear deformation of the product, the bending deformation of the product and the torsional deformation of the product;

[0044] The linear deformation of the product is calculated as: ε=ΔL / L0, where ε represents the linear deformation of the product, ΔL represents the length change, and L0 represents the initial length of the product;

[0045] The calculation of the shear deformation of the product is: γ=Δx / h, where γ represents the shear deformation of the product, Δx represents the shear amount, and h represents the thickness of the current product;

[0046] The calculation of the bending deformation of the product is: δ = (M × L 2 ) / (2×E×I), where δ represents the bending deformation of the product, M represents the bending moment of the material, L represents the length of the current product, E represents the elastic modulus, and I represents the section inertia moment;

[0047] The torsional deformation of the product is calculated as: φ=(T×L) / (G×J), wherein φ represents the torsional deformation of the product, T represents the torque, L represents the length of the current product, G represents the shear modulus, and J represents the polarization moment of inertia.

[0048] Example 6, based on the above Example 5, the linear deformation is calculated as follows:

[0049] ε=ΔL / L0, set

[0050] ΔL = 0.05 m (length change),

[0051] K0 = 1 meter (initial length of the product),

[0052]

[0053] In this embodiment, during the linear deformation process, the product is subjected to tensile or compressive forces, causing the product to elongate or shorten along the direction of the force. This deformation will affect the dimensional stability and shape of the product, and may cause changes in the strength and stiffness of the product. For example, in metal processing, shear force shears metal sheets into the desired shape, and shear force can also cause the product to bend, twist, and other deformations to meet specific engineering requirements.

[0054] Example 7, based on the above Example 5, the shear deformation is calculated as follows:

[0055] γ=Δx / h, set

[0056] Δx=0.02m (cutting distance)

[0057] h = 0.2 m (thickness of the product);

[0058]

[0059] In this embodiment, shear deformation is usually caused by shear force parallel to the surface, which causes relative slippage of the layers inside the product, thereby changing the shape of the product. Shear deformation not only changes the shape of the product, but also affects the mechanical properties of the product, such as increasing the fracture toughness inside the product, and improving the ductility and impact resistance of the product. In addition, shear force can also cause changes in the hardness and strength of the product, as well as changes in the grain structure and distribution of precipitated phases inside the product.

[0060] Example 8, based on the above Example 5, the bending deformation is calculated as follows:

[0061] δ=(M×L2) / (2×E×I), set

[0062] M = 1000 Newton meter

[0063] L = 2.0 m (length of material)

[0064] E = 200 × 10 9 Pascal (elastic modulus)

[0065] I=0.01 4 m (section moment of inertia);

[0066]

[0067] In this embodiment, when the product is subjected to a bending force, bending deformation will occur, and this deformation is usually related to the elastic modulus and cross-sectional characteristics of the product. Bending deformation will affect the bearing capacity and shape of the product, and may cause local stress concentration of the product, thereby affecting the fatigue life of the product. For example, the magnitude of the bending deformation is proportional to the yield strength of the product, that is, the greater the yield strength of the product, the greater the springback; the smaller the strain hardening index of the product, the greater the springback.

[0068] Example 9, based on Example 5, calculation of torsional deformation:

[0069] φ=(T×L) / (G×J), set

[0070] T = 500 Nm (torque)

[0071] L = 2.0 m (length of the product)

[0072] G = 80 × 10 9 Pascal (shear modulus)

[0073] J=0.005 4 m (polarization moment of inertia);

[0074]

[0075] In this embodiment, when the product is subjected to torsional force, torsional deformation will occur, and this deformation is related to the shear modulus and polarization moment of inertia of the product. Torsional deformation will affect the torsional stiffness and bearing capacity of the product, and may cause torsional fatigue and fracture of the product. The degree of influence of shear deformation on displacement depends not only on the height-span ratio, but also on the cross-sectional form. In particular, in thin-walled cross-sectional beams, the influence of shear deformation on displacement is greater, especially for short and high thin-walled beams, and the displacement caused by shear deformation cannot be ignored.

[0076] In the above-mentioned Examples 6 to 9, these data are selected based on the standard deformation amounts stored in the system, and are used to demonstrate how to apply these formulas to calculate data close to the standard deformation amounts. By comparing the standard deformation amount data stored in the system with the deformation amount calculated in actual applications during the forming process, these data will be appropriately adjusted according to the specific circumstances.

[0077] Example 10. On the basis of the above Example 2, in S6, during the data determination process, when the difference between the molding parameters of the product and the storage parameters of the standard model in the system is 2% or less, it is judged as a qualified product and the system stops pressing. When the difference is above 2%, it is judged as an unqualified product, indicating that the product still does not meet the molding requirements. The background service display platform feeds back the information to the visual sensor 7 and repeats steps S3-S6.

[0078] Example 11, in the process of the above embodiment, during the molding and pressing process, the system detects the product once every 0.1 seconds, and compares the product imaging model with the standard model in the system, adjusts the output pressure according to the difference in the model size between the two, and uses the output pressure as the output signal of the system for pressing. The system can optimize the output signal every time it detects; during the molding and pressing process, it can be regarded as a second-order system, and the calculation of its transfer function and system damping ratio can help detect and analyze various problems in the product molding process. The natural frequency ω in the transfer function n and the damping ratio ζ, the time characteristics of the system response can be predicted, so that the time required for the product to reach a stable state can be evaluated. Its transfer function can be expressed as:

[0079] Where G(s) is the transfer function, s is the complex frequency variable, Y(s) is the output signal of the system, U(s) is the input signal of the system, ζ is the inherent property value of the system damping ratio, ω n is the natural frequency of the system without damping. This transfer function is used to analyze the stability and frequency response of the system and to design the controller. In the calculation formula of this embodiment, ω n is the undamped natural frequency of the system. If a mechanical system oscillates 5 times per second without damping, then ω n will be 2π×5=10π radians / second; the inherent property value ζ of the system damping ratio, in this embodiment, if the system is critically damped, then ζ will be 1, if the system is underdamped, then ζ will be less than 1, such as 0.5, if the system is overdamped, then ζ will be greater than 1, such as 1.5; in this embodiment, the damping of the system (underdamped, critically damped, overdamped) affects its oscillation behavior. An underdamped system will oscillate several times and then tend to equilibrium, while a critically damped system can return to equilibrium as quickly as possible without oscillating. An overdamped system takes longer to recover equilibrium. These characteristics are crucial for controlling the pressing process of a hydraulic press to ensure the consistency and quality of product molding. U(s) is the input signal of the system, which can be a step function, a ramp function, or other form of signal. For example, if the input is a step function, then U(s) will be In this embodiment, Y(s) is the output signal of the system, which is the result of the input signal being processed by the system transfer function. If the input is a step function, the output will be Y(s)=G(s)·U(s); the transfer function G(s) is a description of the system's behavior in the frequency domain. For example, if ω n =10π, and ζ = 0.5, then the transfer function is:

[0080]

[0081] Embodiment 12, based on the above embodiment, the input signal of the U(s) system can be regarded as The step signal is calculated based on the step signal:

[0082] The above calculation formula:

[0083] Substitution

[0084] Calculate

[0085] In this embodiment, the complex variable s=5π is set as an embodiment, and s=5π is substituted into the above formula to obtain

[0086] Calculate the denominator:

[0087] Add these values ​​together: 25π 2 +50π 2 +100π 2 =175π 2 ,

[0088] 175π 2 Substituting back into the formula,

[0089] get

[0090] Simplify the fraction:

[0091] The expression becomes:

[0092] Therefore, in this embodiment, when s=5π,

[0093] Then the time domain expression changes to: Further calculation: Among them, σ represents the damping ratio or attenuation rate of the system, y(t) is the output of the function, which is a function of time t, indicating the difference between the product's external dimensions during the pressing process and the standard model, 1 represents the constant term, which is the initial value of the function, e represents the base of the natural logarithm, which is approximately equal to 2.71828, and -σt represents the exponential part of the function, where cosω d t represents the cosine function, where ω d is the angular frequency of the damped oscillation, t is the time variable; sinω d t represents the sine function; Represents a damped oscillation, where the combination of the cosine function and the sine function describes the phase and amplitude of the oscillation; in this embodiment, to create a specific embodiment, it is necessary to set σ, ω n and t, set σ = 0.5, ω n =2π, t = 1 second, first calculate Assuming ζ = 0.1 (a common damping ratio),

[0094]

[0095] In this embodiment, σ=0.5, ω d ≈6.249, and t=1 are substituted into the expression for y(t),

[0096] Calculate the exponential term: e -0.5 ≈0.60653,

[0097] Then calculate the cosine and sine terms: cos(6.249)≈0.9994, sin(6.249)≈-0.0342,

[0098]

[0099] Bringing these values ​​back into the expression,

[0100] y(1)=1-0.60653×0.9994+(-0.00274),

[0101] First calculate: 0.60653×0.9994≈0.60617,

[0102] Substituting this result into the original formula:

[0103] Therefore, when σ=0.5, ω n The specific embodiment data when =2π, ζ=0.1 and t=1 is: y(1)≈0.39109.

[0104] Embodiment 13, based on the above embodiment, during the molding and pressing process, a signal can also be output to: At this time, ξ=1, where represents the standard form of the transfer function, ω n is the undamped natural frequency of the system, s is the complex frequency variable, is the zero term of the transfer function, representing an integrator, is the pole term of the transfer function, indicating a second-order pole; is a zero pole term of the transfer function, indicating a first-order pole; in this embodiment, by analyzing the pole position of the transfer function, the stability of the system can be judged. If the system pole is located in the left half of the complex plane, the system is stable. This is crucial to ensure the stability and safety of the hydraulic press during the pressing process; in this embodiment, its time domain output function is changed to: Among them, 1 is a constant term, which represents the steady-state output of the system, is an exponential decay term, representing the decay part of the system response, (1+ω n t) is a polynomial term, which represents the growth part of the system response, c(t) is the output value of the system transfer function over time, which represents the difference between the product pressed size and the standard model. The standard model uses the constant term 1 as a reference. In this embodiment, a specific embodiment can be created to select a specific value for ω n and t, assuming ω n =2, t = 1 second, now ω n =2, t=1 are substituted into the expression of c(t):

[0105]

[0106] Calculate the exponential term: e -2 ≈0.1353,

[0107] E -2 ≈0.1353 Substituting back into the expression:

[0108]

[0109] Therefore, when ω n The specific embodiment data when t=2 and t=1 is c(1)≈0.5941. The above embodiment data can be adjusted according to the actual situation during the molding process.

[0110] In the above-mentioned embodiments of the technical solution of this article, the quality of the finished products pressed by the hydraulic press can be controlled through visual imaging and detection molding. Combined with the relevant calculations of the transfer function and damping ratio of the second-order system, the detection standards can be set more accurately, and the qualification of the products can be automatically determined. The calculation of the transfer function and the damping ratio of the second-order system is of great significance for the quality control, process optimization and stability analysis in the process of hydraulic press product molding. Through these analyses, the quality and consistency of product molding can be ensured, thereby achieving the beneficial effect of improving production efficiency.

[0111] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for visual imaging and detecting molding of products on a hydraulic press, comprising a lower beam (1), a movable beam (3), a main cylinder (2), a mobile operating table (4), a hydraulic station (5), a liquid filling tank (6), a visual sensor (7), a safety light curtain (8), and a background service display platform in the hydraulic press, wherein the visual sensor (7) is respectively located on both sides of the movable beam (3) for collecting the initial state and molding process of the product, and is connected to the background service display platform for information exchange; the safety light curtain (8) is located on one side of the lower beam (1), and is characterized in that: The following methods are included in visual imaging and detection: S1. Input and set the characteristics of the product and the relevant parameters required for molding in the system of the backend service display platform; S2, fixing the visual sensor (7) on both sides of the movable beam (3); S3. Visual positioning of products during the pressing process; S4, visual sensor (7) visual imaging; S5, the visual sensor (7) generates a data feedback signal of the image and sends it to the background service display platform; S6. The backend service display platform compares data to determine whether the product is qualified during the molding process; S3 includes that before the hydraulic press presses the product, the visual sensor (7) will position the product to ensure that the product on the lower beam (1) is imaged at the correct position, and the positioning method steps include two-dimensional coordinate positioning of the product on the hydraulic press or the center point positioning of the product. The two-dimensional coordinate positioning of the product includes: setting the center point coordinates of the product to be pressed on the hydraulic press as (x, y), and obtaining the feature point coordinates or peripheral contour coordinate information of the product as (x,,y,) by the visual sensor (7) for the image processing and analysis of the product, and then calculating the offset Δx=xx, of the product on the hydraulic press, Δy=yy, and according to the offset, the position deviation of the target product to be pressed relative to the center of the image is obtained, and the position of the product is adjusted accordingly according to the deviation position; the S3 includes collecting n image data of the product shape on the hydraulic press through the visual sensor (7); extracting the characteristic information of the product from the n image data, n≥1; the extracted characteristic information of the product includes the length, width and thickness of the initial state of the product before molding; and also includes collecting the length, width, thickness and deformation of the product during each molding process, storing these characteristic information and comparing them with the product parameters stored in the system, the visual sensor (7) continuously performs imaging processing on the product, and compares the obtained size with the standard model; and adjusts the output pressure so that the product continuously approaches the standard model; during the molding process, the visual sensor (7) collects the length, width and thickness of the product each time it is molded, calculates the current deformation of the product in real time, and compares it with the deformation stored in the system. The deformation includes the linear deformation, shear deformation, bending deformation and torsional deformation of the product. In S6, when the difference between the molding parameters of the product and the storage parameters of the standard model in the system is 2% or less, the product is judged as a qualified product and the system stops pressing. When the difference is above 2%, the product is judged as an unqualified product, indicating that the product still does not meet the molding requirements. The background service display platform feeds back the information to the visual sensor (7) and repeats steps S3-S6. During the molding and pressing process, the system detects the product every 0.1 second and compares the product imaging model with the standard model in the system. The output pressure is adjusted according to the difference in the model sizes of the two. The output pressure is used as the output signal of the system for pressing. The system can optimize the output signal every time it detects. During the molding and pressing process, it can be regarded as a second-order system, and its transfer function can be expressed as: Where G(s) is the transfer function, s is the complex frequency variable, Y(s) is the output signal of the system, U(s) is the input signal of the system, ζ is the inherent property value of the system damping ratio, ω n is the undamped natural frequency of the system. This transfer function is used to analyze the stability and frequency response of the system and to design the controller. U(s) is the input signal of the system, which can be regarded as The step signal is calculated based on the step signal: Then the time domain expression changes to: Further calculation: Among them, σ represents the damping ratio or attenuation rate of the system, y(t) is the output of the function, which represents the function of time t, and represents the difference between the product's external dimensions during the pressing process and the standard model. 1 represents the constant term, which is the initial value of the function. e represents the base of the natural logarithm. -σt represents the exponential part of the function. Among them, σ represents the damping ratio or attenuation rate of the system, cosω d t represents the cosine function, where ω d is the angular frequency of the damped oscillation; sinω d t represents the sine function; represents a damped oscillation where the combination of the cosine and sine functions describes the phase and amplitude of the oscillation.

2. A method for visual imaging and detecting molding of products on a hydraulic press according to claim 1, characterized in that: The calculation of the linear deformation of the product is: ε =ΔL / L0, where ε represents the linear deformation of the product, ΔL represents the length change, and L0 represents the initial length of the product; The calculation of the shear deformation of the product is: γ=Δx / h, where γ represents the shear deformation of the product, Δx represents the shear amount, and h represents the thickness of the current product; The calculation of the bending deformation of the product is: δ = (M × L 2 ) / (2×E×I), where δ represents the bending deformation of the product, M represents the bending moment of the material, L represents the length of the current product, E represents the elastic modulus, and I represents the section inertia moment; The torsional deformation of the product is calculated as: φ =(T×L) / (G×J), where φ It represents the torsional deformation of the product, T represents the torque, L represents the length of the current product, G represents the shear modulus, and J represents the polarization moment of inertia.

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