Intelligent flexible composite material molding hydraulic press and control method thereof

Abstract

The present invention relates to an intelligent flexible composite material molding hydraulic press and a control method thereof. The hardware system mainly includes: a mainframe, which is a closed frame that bears the internal force of forming and serves as a mounting carrier for hydraulic actuators, lower molds and other devices; a hydraulic actuator, which is used to drive a movable workbench; a displacement sensor, which is used to measure the displacement of the hydraulic actuator; a laser displacement sensor, which is used to measure the displacement of the center of the movable workbench; an inclination sensor, which is used to measure the two-dimensional inclination angle of the movable workbench; a force sensor, which is used to measure the output force of the hydraulic actuator; a movable workbench, which is used to install the upper mold; an electro-hydraulic control system, which is used to collect the physical state of the system, record process parameters, and execute intelligent algorithms to realize the movement and output force control of the hydraulic actuator. The advantages are excellent process adaptability, which helps to shorten the process development cycle of composite parts, improve the production efficiency of parts and the quality of finished products.

Description

Technical Field

[0001] The invention relates to a composite material hydraulic press, to a composite material molding hydraulic press and a control method thereof, in particular to an intelligent flexible composite material molding hydraulic press and a control method thereof. Background Art

[0002] With the surge in demand for lightweight, green material reduction, strength and output improvement in the automotive, rail transit and other manufacturing industries, composite material technology has advanced by leaps and bounds and the forming process is changing with each passing day. The compression molding process of composite materials is more complex than that of traditional metal materials, and the process parameter control requirements are higher, showing the characteristics of multiple processes and flexibility. How to make a composite hydraulic press as compatible as possible with a variety of different forming processes, intelligently help product developers to efficiently complete process finalization, and help product manufacturers obtain more quality control data and upgrade processes is a hot direction for the development of technology in the entire composite parts research and development and production system. Summary of the invention

[0003] The purpose of the present invention is to provide an intelligent flexible composite material molding hydraulic press and a control method thereof, which can realize intelligent online optimization compensation for equipment structure deformation, part size, and part density, thereby improving the development speed, production efficiency, and finished product quality of composite material products.

[0004] The technical solution of the present invention is as follows:

[0005] The hardware system at least includes:

[0006] The mainframe is a closed frame that bears the internal force of forming. It can be a frame structure such as an integral gantry, a prestressed combination, a column combination, etc. It generally includes structural units such as an upper crossbeam, a column (or a tie rod plus a column), and a lower workbench. It also serves as an installation carrier for devices such as hydraulic actuators and lower molds.

[0007] Hydraulic actuator, used to drive the movable workbench;

[0008] Displacement sensors for measuring the displacement of hydraulic actuators s ci , i =1, 2, …, n, where n is the number of hydraulic actuators;

[0009] Laser displacement sensor for measuring the displacement of the center of the movable table s o ;

[0010] Inclination sensor, used to measure the two-dimensional tilt angle of the movable worktable i x and iy ;

[0011] Force sensors for measuring the output force of hydraulic actuators F ci , i =1, 2, …, n, where n is the number of hydraulic actuators;

[0012] A movable workbench for installing the upper die;

[0013] The electro-hydraulic control system is used to collect the physical state of the system, record process parameters, and execute intelligent algorithms to achieve motion and output force control of the hydraulic actuator. It has basic control functions for the hydraulic actuator, such as synchronous leveling control and motion-force composite control.

[0014] Among them: the stationary part of the hydraulic actuator is installed on the upper crossbeam of the main machine body, the active part is connected to one end of the force sensor, the other end of the force sensor is connected to the movable workbench, and the active part of the hydraulic actuator, the force sensor and the movable workbench belong to the same assembly; the active detection end of the displacement sensor and the active part of the hydraulic actuator belong to the same assembly, and the stationary end is installed on the corresponding stationary structure; the active detection end of the laser displacement sensor is installed at the center of the upper surface of the movable workbench, and the stationary end is correspondingly installed on the lower plane of the upper crossbeam of the main machine body; the inclination sensor is located at the center of the upper surface of the movable workbench; the electro-hydraulic control system is connected to the hydraulic actuator through a hydraulic circuit, and is electrically connected to the displacement sensor, laser displacement sensor, inclination sensor and force sensor.

[0015] A control method for an intelligent flexible composite material molding hydraulic press, characterized in that:

[0016] At least the following steps are included:

[0017] Step 1: Establish the coordinate system. With the center of the upper surface of the movable worktable as the origin O, the left and right as the X-axis direction, and the front and back as the Y-axis direction, establish the XOY orthogonal rectangular plane coordinate system on the upper surface of the movable worktable, with the right as the positive direction of the X-axis, the front as the positive direction of the Y-axis, and the clockwise rotation direction along the axial direction as the positive direction of the inclination. Assume that the upper surface of the movable worktable is connected to a hydraulic actuator in the first quadrant of the coordinate system, and the projection coordinates of the connection point C1 on the plane are ( x c1 , y c1 ).

[0018] Step 2: Compensation for elastic deformation of the mainframe. Place parallel pressure test pads between the movable workbench and the lower workbench of the mainframe. The electro-hydraulic control system automatically controls the output force of each hydraulic actuator. F ciApply any load to the parallel pressure test pad, and the electro-hydraulic control system records the difference between the displacement sensor and the laser displacement sensor under no load and under various loads, that is, the deformation of the host body and the corresponding output force. F ci The electro-hydraulic control system generates a deformation-load association mapping table based on the data. In the actual part pressing process, the electro-hydraulic control system estimates the deformation of the host body using the table lookup interpolation method to correct the measurement values ​​of the displacement sensor and the laser displacement sensor.

[0019] Step 3: Compensation for elastic deformation of the movable workbench. When conducting process tests on composite parts, the electro-hydraulic control system automatically records the displacement of the center of the upper surface of the movable workbench during the operation of the hydraulic press. s o , displacement of each hydraulic actuator s ci and output force F ci , Inclination of movable worktable i x and i y , i x is the rotation angle of the movable table around the X axis, i y is the rotation angle of the movable workbench around the Y axis. If the movable workbench is assumed to be a rigid body without force deformation, the displacement of the hydraulic actuator at point C1 is

[0020]

[0021] If the movable workbench does not deform at point C1, then The actual difference between the two It reflects the deformation of the movable workbench at point C1. At the same time, the electro-hydraulic control system calculates the deformation d c1 The corresponding torque around the C1O orthogonal axis T c1 , and establish the relationship between deformation and torque d c1 — T c1 Associative mapping table, assuming that the displacement of the active workbench is expected to be s oc In the subsequent pressing process, the electro-hydraulic control system uses the table lookup interpolation method to estimate d c1 , and ( s oc −d c1 ) is used as the displacement expectation of the hydraulic actuator at point C1 for compensation control.

[0022] Step 4: Part thickness compensation. After manufacturing a certain number of composite parts, the deviation Δ between the actual thickness of the part and the standard thickness can be obtained. t c1 Distribute the data, and change the deviation Δ t c1 The distribution data is uploaded to the electro-hydraulic control system, which further automatically generates Δ t c1 — d c1 — T c1 The associated mapping table, in the subsequent pressing process, the electro-hydraulic control system also uses the table lookup interpolation method to estimate Δ t c1 , and ( s oc −d c1 − Δ t c1 ) is used as the displacement expectation of the hydraulic actuator at point C1 for compensation control.

[0023] Step 5: Compensation for the density of the workpiece. If the density distribution sample data of the workpiece is obtained, combined with the corresponding output force recorded by the electro-hydraulic control system F ci The forming force distribution that meets the density requirements can be obtained by using the data. The optimal forming force distribution data can be retrieved through the electro-hydraulic control system, and the electro-hydraulic control system will automatically distribute the output force of each hydraulic actuator. F ci In order to meet the expectation, the motion-force composite control function is used to achieve the optimal forming force distribution.

[0024] The control method of the intelligent flexible composite material molding hydraulic press is applicable to the case where the number of hydraulic actuators is greater than or equal to 2. The corresponding calculation and control methods of hydraulic actuators in other positions can be obtained by analogy with the above steps. Multiple hydraulic actuators maintain coordinated operation under the synchronous control of the electro-hydraulic control system. d c1 — T c1 Association mapping table, Δ t c1 — d c1 — T c1 The association mapping table, forming force distribution, etc. can be continuously optimized online during the test or production process.

[0025] Compared with traditional products, the beneficial effects of the present invention are as follows:

[0026] 1. The composite material molding hydraulic press and the control method thereof proposed in the present invention have an automatic compensation function for the structural deformation of the hydraulic press, and can reduce the influence of the structural rigidity of the hydraulic press on the dimensional accuracy of the composite material product.

[0027] 2. The composite material molding hydraulic press and control method thereof proposed in the present invention can utilize test or production data to automatically compensate and control process parameters, thereby further improving the forming accuracy and finished product quality of composite material parts.

[0028] 3. The compensation control database for structural deformation, part size, and part density involved in the control method proposed in the present invention can be continuously updated and optimized during the test and production process. If the technical solution of the present invention is adopted, both process developers, product manufacturers, and quality managers can obtain effective help in terms of efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the hydraulic press of the present invention.

[0030] Figure 2 It is a schematic diagram of a plane coordinate system on the movable workbench of the present invention.

[0031] Figure 3 It is a schematic diagram of the elastic deformation of the movable workbench described in the present invention.

[0032] Figure 4 This is a schematic diagram of the thickness deviation of the workpiece described in the present invention.

[0033] Figure 1 Middle: 1-main machine body, 101-upper beam, 102-column, 103-lower workbench, 104-parallel pressure test pad, 2-hydraulic actuator, 3-displacement sensor, 4-laser displacement sensor, 5-tilt sensor, 6-force sensor, 7-movable workbench, 8-electro-hydraulic control system.

[0034] Figure 4 Middle: 701-workpiece, 702-upper die, 703-lower die. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 , the hardware system of the present invention at least includes:

[0037] The mainframe 1 is a closed frame that bears the forming internal force, and can be a frame structure such as an integral gantry, a prestressed combination, a column combination, etc., generally including structural units such as an upper crossbeam 101, a column 102 (or a tie rod plus a column), and a lower workbench 103, and also serves as a mounting carrier for devices such as a hydraulic actuator 2 and a lower die 703;

[0038] A hydraulic actuator 2, used for driving a movable workbench 7;

[0039] Displacement sensor 3, used to measure the displacement of the hydraulic actuator 2 s ci , i =1, 2, …, n, n is the number of hydraulic actuators 2;

[0040] Laser displacement sensor 4, used to measure the displacement of the center of the movable workbench 7 s o ;

[0041] Inclination sensor 5, used to measure the two-dimensional inclination angle of the movable workbench 7 i x and i y ;

[0042] Force sensor 6, used to measure the output force of the hydraulic actuator 2 F ci , i =1, 2, …, n, n is the number of hydraulic actuators 2;

[0043] A movable workbench 7, used for installing an upper mold 702;

[0044] The electro-hydraulic control system 8 is used to collect the physical state of the system, record process parameters, and execute intelligent algorithms to achieve motion and output force control of the hydraulic actuator 2. It has basic control functions for the hydraulic actuator 2, such as synchronous leveling control and motion-force composite control.

[0045] Among them: the stationary part of the hydraulic actuator 2 is installed on the upper cross beam 101 of the main machine body 1, the active part is connected to one end of the force sensor 6, the other end of the force sensor 6 is connected to the movable workbench 7, and the active part of the hydraulic actuator 2, the force sensor 6, and the movable workbench 7 belong to the same assembly; the displacement sensor 3 is built into the structure of the hydraulic actuator 2, the active detection end of the displacement sensor 3 and the active part of the hydraulic actuator 2 belong to the same assembly, and the stationary end is installed on the stationary part of the hydraulic actuator 2; the active detection end of the laser displacement sensor 4 is installed at the center of the upper surface of the movable workbench 7, and the stationary end is correspondingly installed on the lower plane of the upper cross beam 101 of the main machine body 1; the inclination sensor 5 is located at the center of the upper surface of the movable workbench 7; the electro-hydraulic control system 8 is connected to the hydraulic actuator 2 through a hydraulic circuit, and is electrically connected to the displacement sensor 3, the laser displacement sensor 4, the inclination sensor 5, and the force sensor 6.

[0046] See also Figure 2 , Figure 3 , Figure 4 Taking a hydraulic press equipped with four hydraulic actuators 2 as an example, the control method of the present invention comprises at least the following steps:

[0047] Step 1: Coordinate system establishment. Figure 2 , with the center of the upper surface of the movable workbench 7 as the origin O, the left and right as the X-axis direction, the front and back as the Y-axis direction, and the XOY orthogonal rectangular plane coordinate system established on the upper surface of the movable workbench 7, with the right as the positive direction of the X-axis, the front as the positive direction of the Y-axis, and the clockwise rotation direction along the axial direction as the positive direction of the inclination. Assume that the upper surface of the movable workbench 7 is connected to a hydraulic actuator 2 in the first quadrant of the coordinate system, and the projection coordinates of the connection point C1 on the plane are ( x c1 , y c1 ).

[0048] Step 2: Compensation for elastic deformation of the mainframe 1. A parallel pressure test pad 104 is placed between the movable workbench 7 and the lower workbench 103 of the mainframe 1. The electro-hydraulic control system 8 automatically controls the output force of each hydraulic actuator 2. F ci Apply any load to the parallel pressure test pad 104, and the electro-hydraulic control system 8 records the difference between the displacement sensor 3 and the laser displacement sensor 4 under no load and under various loads, that is, the deformation of the host body 1 and the corresponding output force. F ci The electro-hydraulic control system 8 generates a deformation-load association mapping table. During the actual pressing process of the workpiece 701, the electro-hydraulic control system 8 estimates the deformation of the host body 1 by using a table lookup interpolation method to correct the measurement values ​​of the displacement sensor 3 and the laser displacement sensor 4.

[0049] Step 3: Compensation for elastic deformation of movable workbench 7. Figure 2 , Figure 3 When the process test of the composite material product 701 is carried out, the electro-hydraulic control system 8 automatically records the displacement of the center of the upper surface of the movable worktable 7 during the operation of the hydraulic press. s o , displacement of each hydraulic actuator 2 s ci and output force F ci , Inclination angle of movable workbench 7 i x and i y , i x is the rotation angle of the movable workbench 7 around the X axis, i y is the rotation angle of the movable workbench 7 around the Y axis. If the movable workbench 7 is assumed to be a rigid body and does not produce force deformation, the displacement of the hydraulic actuator 2 at point C1 is

[0050]

[0051] If the movable workbench 7 is not deformed at point C1, then The actual difference between the two This reflects the deformation of the movable workbench 7 at point C1. At the same time, the electro-hydraulic control system 8 calculates the deformation d c1 The corresponding torque around the C1O orthogonal axis T c1 , T c1 The calculation formula is

[0052]

[0053] Electro-hydraulic control system 8 establishes the relationship between deformation and torque d c1 — T c1 Associative mapping table, assuming that the displacement of the movable workbench 7 is expected to be s oc In the subsequent pressing process, the electro-hydraulic control system 8 uses the table lookup interpolation method to estimate d c1 , and ( s oc − d c1 ) is used as the displacement of the hydraulic actuator 2 at point C1 and compensation control is desired.

[0054] Step 4: Compensation for component thickness. After manufacturing a certain number of composite components 701, the deviation Δ between the actual component thickness and the standard thickness can be obtained. t c1 Distribute the data, and change the deviation Δ t c1 The distribution data is uploaded to the electro-hydraulic control system 8, which further automatically generates Δ t c1 — d c1 — T c1 The associated mapping table, in the subsequent pressing process, the electro-hydraulic control system 8 also uses the table lookup interpolation method to estimate Δ t c1 , and ( s oc −d c1 − Δ t c1 ) is used as the displacement of the hydraulic actuator 2 at point C1 and compensation control is desired.

[0055] Step 5: Compensation for the density of the workpiece. If the density distribution sample data of the workpiece 701 is obtained, combined with the corresponding output force recorded by the electro-hydraulic control system 8 F ci The forming force distribution that meets the density requirements can be obtained by using the data. The optimal forming force distribution data can be retrieved through the electro-hydraulic control system 8, and the electro-hydraulic control system 8 will automatically distribute the output force of each hydraulic actuator 2. F ci In order to meet the expectation, the motion-force composite control function is used to achieve the optimal forming force distribution.

[0056] All hydraulic actuators 2 maintain coordinated operation under the synchronous control of the electro-hydraulic control system 8. The corresponding calculation and control methods of the hydraulic actuators 2 at points C2, C3, and C4 can be obtained by analogy with the above steps. The above method can be further extended to any situation where the number of hydraulic actuators 2 is greater than or equal to 2. d c1 — T c1 Association mapping table, Δ t c1 — d c1 — T c1 The association mapping table, forming force distribution, etc. can be continuously optimized online during the test or production process.

Claims

1. An intelligent flexible composite material molding hydraulic press, characterized by: The hardware system at least includes: The main machine body (1) is a closed frame that bears the internal force of forming, or a frame structure composed of an integral gantry, a prestressed structure and a column. The frame structure includes an upper crossbeam, a column and a lower workbench, and also serves as a mounting carrier for the hydraulic actuator (2) and the lower die. A hydraulic actuator (2) for driving a movable workbench (7); A displacement sensor (3) for measuring the displacement of the hydraulic actuator (2) s ci , i =1, 2, …, n, where n is the number of hydraulic actuators (2); A laser displacement sensor (4) for measuring the displacement of the center of the movable worktable (7) s o ; The inclination sensor (5) is used to measure the two-dimensional inclination angle of the movable workbench (7) θ x and θ y ; A force sensor (6) for measuring the output force of the hydraulic actuator (2) F ci , i =1, 2, …, n, where n is the number of hydraulic actuators (2); A movable workbench (7) for mounting an upper die; The electro-hydraulic control system (8) is used to collect the physical state of the system, record process parameters and execute intelligent algorithms to achieve motion and output force control of the hydraulic actuator (2), and has basic control functions of synchronous leveling control and motion-force composite control for the hydraulic actuator (2); Wherein: the stationary part of the hydraulic actuator (2) is mounted on the upper crossbeam of the main machine body (1), the movable part is connected to one end of the force sensor (6), the other end of the force sensor (6) is connected to the movable workbench (7), and the movable part of the hydraulic actuator (2) and the force sensor (6) and the movable workbench (7) belong to the same assembly; the movable detection end of the displacement sensor (3) and the movable part of the hydraulic actuator (2) belong to the same assembly, and the stationary end is mounted on the corresponding stationary structure; the movable detection end of the laser displacement sensor (4) is mounted at the center of the upper surface of the movable workbench (7), and the stationary end is correspondingly mounted on the lower plane of the upper crossbeam of the main machine body (1); the inclination sensor (5) is located at the center of the upper surface of the movable workbench (7); the electro-hydraulic control system (8) is connected to the hydraulic actuator (2) through a hydraulic circuit, and is electrically connected to the displacement sensor (3), the laser displacement sensor (4), the inclination sensor (5) and the force sensor (6); When the intelligent flexible composite material molding hydraulic press is used, At least the following steps are included: Step 1: Establish a coordinate system; take the center of the upper surface of the movable workbench (7) as the origin O, take the left and right as the X-axis direction, and the front and back as the Y-axis direction, and establish an XOY orthogonal rectangular plane coordinate system on the upper surface of the movable workbench (7), with the right as the positive direction of the X-axis, the front as the positive direction of the Y-axis, and the clockwise rotation direction along the axial direction as the positive direction of the inclination angle; assume that the upper surface of the movable workbench (7) is connected to a hydraulic actuator (2) in the first quadrant of the coordinate system, and the projection coordinates of the connection point C1 on the plane are ( x c1 , y c1 ); Step 2: Compensation for elastic deformation of the main machine body (1); placing a parallel pressure test pad between the movable workbench (7) and the lower workbench of the main machine body (1), and the electro-hydraulic control system (8) automatically controls the output force of each hydraulic actuator (2) F ci When any load is applied to the parallel pressure test pad, the electro-hydraulic control system (8) records the difference between the displacement sensor (3) and the laser displacement sensor (4) under no load and under various loads, i.e., the deformation of the mainframe (1) and the corresponding output force. F ci The electro-hydraulic control system (8) generates a deformation amount-load association mapping table, and in the actual part pressing process, the electro-hydraulic control system (8) estimates the deformation amount of the host body (1) by using a table lookup interpolation method to correct the measurement values ​​of the displacement sensor (3) and the laser displacement sensor (4); Step 3: Compensation for elastic deformation of the movable workbench (7); when conducting a process test of a composite material part, the electro-hydraulic control system (8) automatically records the displacement of the center of the upper surface of the movable workbench (7) during the operation of the hydraulic press. s o , displacement of each hydraulic actuator (2) s ci and output force F ci , Inclination angle of the movable workbench (7) θ x and θ y , θ x is the rotation angle of the movable table (7) around the X axis, θ y is the rotation angle of the movable workbench (7) around the Y axis; if it is assumed that the movable workbench (7) is a rigid body and does not produce force deformation, then the displacement of the hydraulic actuator (2) at point C1 is ; If the movable table (7) is not deformed at point C1, then ; The actual difference between the two It reflects the deformation of the movable workbench (7) at point C1; at the same time, the electro-hydraulic control system (8) calculates the deformation δ c1 The corresponding torque around the C1O orthogonal axis T c1 , and establish the relationship between deformation and torque δ c1 — T c1 Assume that the displacement of the active workbench (7) is expected to be s oc In the subsequent pressing process, the electro-hydraulic control system (8) uses the table lookup interpolation method to estimate δ c1 , and ( s oc − δ c1 ) is used as the displacement expectation of the hydraulic actuator (2) at point C1 for compensation control; Step 4: Part thickness compensation; after manufacturing a certain number of composite parts, the deviation Δ between the actual thickness of the part and the standard thickness can be obtained t c1 Distribute the data, and change the deviation Δ t c1 The distribution data is uploaded to the electro-hydraulic control system (8), which further automatically generates Δ t c1 — δ c1 — T c1 The associated mapping table, in the subsequent pressing process, the electro-hydraulic control system (8) also uses the table lookup interpolation method to estimate Δ t c1 , and ( s oc −δ c1 − Δ t c1 ) is used as the displacement expectation of the hydraulic actuator (2) at point C1 for compensation control; Step 5: Compensation for the density of the workpiece: If the density distribution sample data of the workpiece is obtained, the corresponding output force recorded by the electro-hydraulic control system (8) is combined F ci The forming force distribution that meets the density requirements is obtained, and the optimal forming force distribution data is retrieved through the electro-hydraulic control system (8). The electro-hydraulic control system (8) automatically distributes the output force of each hydraulic actuator (2). F ci The optimal forming force distribution is achieved by using the motion-force composite control function. The intelligent flexible composite material molding hydraulic press is suitable for the case where the number of hydraulic actuators (2) is greater than or equal to 2. The corresponding calculation and control methods of hydraulic actuators (2) at other positions can be obtained by analogy with the above steps. The multiple hydraulic actuators (2) maintain coordinated operation under the synchronous control of the electro-hydraulic control system (8). The δc1-Tc1 association mapping table and the Δtc1-δc1-Tc1 association mapping table and the forming force distribution are continuously optimized online during the test or production process.

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