Electro-hydraulic servo anti-deformation control system of numerical control bending machine

Abstract

The invention discloses an electro-hydraulic servo anti-deformation control system of a numerical control bending machine. The electro-hydraulic servo anti-deformation control system comprises a main controller, a servo driving module, an electro-hydraulic servo valve, a hydraulic executing mechanism, an anti-deformation detection module and a closed-loop control module. According to the electro-hydraulic servo anti-deformation control system of the numerical control bending machine, the anti-deformation detection module is integrated, so that the system can continuously monitor the actual deformation state of the sliding block in the bending process, and the information is fed back to the closed-loop control module in real time. The module can immediately calculate the required compensation amount and dynamically adjust a control instruction output to the servo driving module. According to the closed-loop control mechanism, the previous static and passive compensation mode is converted into dynamic and active intervention, real-time deformation caused by factors such as load, mechanical clearance and hydraulic fluctuation can be effectively counteracted, and therefore it is ensured that the sliding block is always kept in the ideal working posture in the whole bending stroke.

Description

Technical Field

[0001] This invention relates to the field of bending machine technology, and in particular to an electro-hydraulic servo anti-deformation control system for a CNC bending machine. Background Technology

[0002] As a core piece of equipment in modern sheet metal processing, CNC bending machines directly determine the forming quality of thin-plate components, box structures, and other products through their processing accuracy and efficiency. Traditional bending machines generally use electro-hydraulic servo systems for control. The main controller issues commands to drive the electro-hydraulic servo valve, which in turn controls the hydraulic actuator to move the slide block up and down, thus achieving the bending operation of the sheet metal. Although such systems offer significant improvements in control accuracy compared to purely mechanical or ordinary hydraulic systems, a long-standing technical bottleneck remains difficult to overcome in actual production, especially when bending large-span, long-dimension workpieces or high-strength materials—namely, the elastic deformation of the slide block under enormous loads.

[0003] The deformation problem is mainly caused by the following factors: First, as a large metal component, the bending machine slider inevitably undergoes slight elastic bending, i.e., deflection deformation, when subjected to concentrated loads from the two side cylinders and the reaction force from the middle of the sheet metal. Second, due to inherent errors in machining and assembly, the gap between the slider and the machine body guide rail, as well as the differences in the friction coefficients of various moving pairs, may cause slight tilting or torsional deformation of the slider during movement. In addition, factors such as inconsistent dynamic response characteristics of the two side cylinders of the hydraulic system, viscosity changes caused by oil temperature rise, and pressure fluctuations within the system all exacerbate the instability of the slider's motion posture.

[0004] Without effective compensation for the aforementioned deformation, the working plane of the slider will not be able to maintain an ideal parallel state with the worktable. The direct consequence is that the uniformity of the bending angle of the workpiece bent along the length of the bending machine will be severely degraded. Specifically, the bending angles at both ends of the workpiece will meet the requirements, while the middle will show a significant under- or over-bending angle, commonly known as a "bulging belly" or "collapsed waist" phenomenon. This not only leads to workpieces exceeding precision tolerances and becoming scrap, but for some critical structural components requiring subsequent welding or assembly, even minor angular deviations may be amplified in subsequent processes, seriously affecting the final product's assembly quality and structural strength.

[0005] To address this challenge, various methods have been attempted in existing technologies. One is the passive compensation method, which involves pre-machining the slider with an "arch" (convex shape) opposite to the expected deformation direction during the machine tool manufacturing stage, aiming to restore its straightness after deformation under stress. However, this method has a fixed compensation amount, making it unsuitable for different molds, sheet materials, and variations in bending force, resulting in extremely poor versatility. Another method is to use a manually adjustable wedge mechanism, but this method is cumbersome to adjust, has a slow response, cannot achieve real-time compensation during dynamic processes, and relies on the operator's experience, making it difficult to guarantee accuracy. With the increasing demand for high-precision machining, the aforementioned traditional methods are no longer sufficient to meet the high standards of bending accuracy, efficiency, and intelligence required by modern manufacturing.

[0006] Therefore, it is necessary to provide a new electro-hydraulic servo anti-deformation control system for CNC bending machines to solve the above-mentioned technical problems. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention provides an electro-hydraulic servo anti-deformation control system for a CNC bending machine.

[0008] This invention provides an electro-hydraulic servo anti-deformation control system for a CNC bending machine, comprising:

[0009] The main controller is used to receive bending processing parameters and generate control commands;

[0010] The servo drive module is electrically connected to the main controller and is used to receive the control commands and output servo drive signals.

[0011] An electro-hydraulic servo valve, electrically connected to the servo drive module, is used to adjust the flow rate and direction of hydraulic oil according to the servo drive signal;

[0012] At least one hydraulic actuator is connected to the electro-hydraulic servo valve via a hydraulic line for driving the slide movement of the bending machine;

[0013] A deformation detection module, installed on the slider or the worktable of the bending machine, is used to detect the deformation parameters of the slider in real time during the bending process; and

[0014] The closed-loop control module, integrated into the main controller, is configured as follows:

[0015] a. Receive deformation parameters from the deformation detection module;

[0016] b. Compare the deformation parameters with a preset deformation threshold to generate a deformation compensation signal;

[0017] c. The deformation compensation signal is superimposed on the control command to adjust the output of the servo drive module, and then the action of the hydraulic actuator is controlled by the electro-hydraulic servo valve to achieve real-time dynamic compensation for the deformation of the slider.

[0018] Preferably, the anti-deformation detection module includes:

[0019] At least one displacement sensor is used to detect the real-time displacement values ​​of both ends of the slider relative to the machine body;

[0020] The deformation parameter is the deflection or tilt angle of the slider calculated based on the real-time displacement value.

[0021] Preferably, the displacement sensor is an optical grating ruler, a magnetic grating ruler, or a laser displacement sensor.

[0022] Preferably, the anti-deformation detection module includes:

[0023] At least one strain gauge sensor is attached to the deformable area of ​​the slider to detect the strain data of the slider in real time.

[0024] The deformation parameters are the strain data.

[0025] Preferably, there are two hydraulic actuators, which are respectively located on the left and right sides of the bending machine body, and are used to independently drive the corresponding side of the slider.

[0026] Preferably, the electro-hydraulic servo valve is a proportional servo valve or a three-stage electro-hydraulic servo valve.

[0027] Preferably, the closed-loop control module uses a PID control algorithm, a fuzzy PID control algorithm, or an adaptive control algorithm to generate the deformation compensation signal.

[0028] Preferably, it also includes a human-machine interface connected to the main controller, used to input the bending processing parameters and the preset deformation threshold, and to display the deformation parameters and system operating status in real time.

[0029] Preferably, the main controller is a programmable logic controller, an industrial computer, or a digital signal processor.

[0030] Compared with related technologies, the electro-hydraulic servo anti-deformation control system for CNC bending machines provided by this invention has the following beneficial effects:

[0031] This invention provides an electro-hydraulic servo anti-deformation control system for a CNC bending machine. By integrating an anti-deformation detection module, the system can continuously monitor the actual deformation state of the slider during the bending process and feed this information back to the closed-loop control module in real time. This module can immediately calculate the required compensation amount and dynamically adjust the control commands output to the servo drive module. This closed-loop control mechanism transforms the previous static and passive compensation method into a dynamic and active intervention, effectively offsetting real-time deformation caused by factors such as load, mechanical clearance, and hydraulic fluctuations, thereby ensuring that the slider maintains an ideal working posture throughout the entire bending stroke. Attached Figure Description

[0032] Figure 1 A schematic diagram of the electro-hydraulic servo anti-deformation control system for a CNC bending machine provided by the present invention.

[0033] The following are the labels in the diagram: 1. Main controller; 2. Servo drive module; 3. Electro-hydraulic servo valve; 4. Hydraulic actuator; 5. Slider; 6. Anti-deformation detection module; 61. Displacement sensor; 62. Strain gauge sensor; 7. Human-machine interface. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Please see Figure 1 This invention provides an electro-hydraulic servo anti-deformation control system for a CNC bending machine, which dynamically compensates for the deformation of the slider during the bending process through real-time detection and closed-loop control, thereby ensuring bending accuracy.

[0036] Example 1

[0037] In this embodiment, the electro-hydraulic servo anti-deformation control system of the CNC bending machine includes a main controller 1, a servo drive module 2, an electro-hydraulic servo valve 3, a hydraulic actuator 4, a slider 5, an anti-deformation detection module 6, and a human-machine interface 7.

[0038] The main controller 1 is a programmable logic controller (PLC), which serves as the control center of the system. It receives bending processing parameters set by the operator through the human-machine interface 7 and generates basic motion control commands based on these parameters.

[0039] The servo drive module 2 is electrically connected to the main controller 1 via an industrial bus, receives control commands from the main controller 1, and converts them into servo drive signals that can drive the electro-hydraulic servo valve 3.

[0040] In this embodiment, the electro-hydraulic servo valve 3 is preferably a high-precision proportional servo valve, which is electrically connected to the servo drive module 2. According to the received servo drive signal, it precisely adjusts the opening degree and direction of its valve core, thereby controlling the flow rate and direction of the hydraulic oil entering the hydraulic actuator 4.

[0041] There are two hydraulic actuators 4, namely a left hydraulic cylinder and a right hydraulic cylinder, which are connected to the electro-hydraulic servo valve 3 through hydraulic pipelines. The two hydraulic cylinders are respectively installed on the left and right sides of the bending machine body, and are used to independently drive the corresponding sides of the slider 5 to perform up-and-down reciprocating motion.

[0042] The anti-deformation detection module 6 is mounted on the slider 5 and specifically includes two high-precision grating rulers 61. The two grating rulers 61 are respectively installed at the left and right ends of the slider and are used to detect the real-time displacement values ​​of the slider ends relative to the bending machine body.

[0043] The main controller 1 integrates a closed-loop control module, configured to perform the following steps:

[0044] a. Receive real-time displacement values ​​from the two grating rulers 61;

[0045] b. Based on the difference between these two displacement values, the current deflection or tilt angle of slider 5 is calculated in real time, and this calculated value is used as the deformation parameter;

[0046] c. Compare the deformation parameter with the preset deformation threshold (which can be set through the human-computer interaction interface 7);

[0047] d. Based on the comparison results, a deformation compensation signal is generated using the built-in PID control algorithm;

[0048] e. This deformation compensation signal is superimposed on the initially generated control command in real time to form a revised, new control command.

[0049] The modified control commands are transmitted through the servo drive module 2 and the electro-hydraulic servo valve 3, and ultimately act on the two hydraulic actuators 4. For example, when the system detects that the middle of the slider has sunk due to deflection deformation, the compensation signal generated by the closed-loop control module will instruct the hydraulic cylinders on both sides to make a small, asymmetrical movement, so that the middle of the slider is relatively lifted, thereby offsetting the deformation and realizing real-time dynamic compensation for the deformation of the slider 5.

[0050] The human-machine interface 7 is connected to the main controller 1. It provides the operator with an interface to input bending processing parameters and deformation thresholds, and can display the actual deformation parameters of the slider, system operating status and alarm information in real time, making the whole control process transparent and intuitive.

[0051] Example 2

[0052] The main difference between this embodiment and Embodiment 1 lies in the structure and detection principle of the anti-deformation detection module 6.

[0053] In this embodiment, the anti-deformation detection module 6 includes at least one strain gauge sensor 62. The strain gauge sensor 62 is directly attached to the easily deformable area of ​​the slider 5, as determined by finite element analysis, using a high-strength adhesive. When the slider 5 undergoes elastic deformation under bending load, the micro-strain on its surface is synchronously transmitted to the strain gauge sensor 62, causing a change in its resistance value.

[0054] The system uses measurement circuits such as a Wheatstone bridge to detect and calculate the strain data in real time. Here, the strain data itself is directly transmitted as a deformation parameter to the closed-loop control module within the main controller 1. The closed-loop control module compares the real-time strain data with a preset strain threshold and uses a fuzzy PID control algorithm to generate a deformation compensation signal. The fuzzy PID algorithm combines the intelligence of fuzzy logic with the accuracy of PID, and can better handle nonlinear and time-varying factors in hydraulic systems, making the compensation process smoother and more adaptive. The subsequent compensation signal superposition and execution process is the same as in Example 1.

[0055] Example 3

[0056] In this embodiment, the main controller 1 may also be an industrial computer (IPC) or a digital signal processor (DSP) to provide stronger data processing capabilities and faster response speed, making it suitable for high-frequency, high-precision compensation scenarios.

[0057] The electro-hydraulic servo valve 3 can be selected as a higher-performance three-stage electro-hydraulic servo valve according to the system's requirements for dynamic response and load capacity.

[0058] The displacement sensor 61 is not limited to an optical grating ruler, but can also be replaced by a magnetic grating ruler or a laser displacement sensor, as long as it can meet the requirements of detection accuracy and on-site environment.

[0059] The control algorithm used by the closed-loop control module can select advanced control strategies such as adaptive control algorithms according to actual needs, so that the system can automatically adjust its control parameters to adapt to different processing conditions and machine tool states.

[0060] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An electro-hydraulic servo anti-deformation control system for a CNC bending machine, characterized in that, include: The main controller (1) is used to receive bending processing parameters and generate control commands; The servo drive module (2) is electrically connected to the main controller (1) and is used to receive the control command and output the servo drive signal; An electro-hydraulic servo valve (3) is electrically connected to the servo drive module (2) and is used to adjust the flow rate and direction of hydraulic oil according to the servo drive signal. At least one hydraulic actuator (4) is connected to the electro-hydraulic servo valve (3) via a hydraulic line for driving the movement of the slider (5) of the bending machine; A deformation detection module (6) is installed on the slider (5) or the worktable of the bending machine to detect the deformation parameters of the slider (5) in real time during the bending process; and The closed-loop control module, integrated in the main controller (1), is configured as follows: a. Receive deformation parameters from the anti-deformation detection module (6); b. Compare the deformation parameters with a preset deformation threshold to generate a deformation compensation signal; c. The deformation compensation signal is superimposed on the control command to adjust the output of the servo drive module (2), and then the action of the hydraulic actuator (4) is controlled by the electro-hydraulic servo valve (3) to realize real-time dynamic compensation for the deformation of the slider (5).

2. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The anti-deformation detection module (6) includes: At least one displacement sensor (61) is used to detect the real-time displacement values ​​of both ends of the slider (5) relative to the body; The deformation parameter is the deflection or tilt angle of the slider (5) calculated based on the real-time displacement value.

3. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The displacement sensor (61) is a grating ruler, magnetic grating ruler, or laser displacement sensor.

4. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The anti-deformation detection module (6) includes: At least one strain gauge sensor (62) is attached to the deformable area of ​​the slider (5) for real-time detection of strain data of the slider (5); The deformation parameters are the strain data.

5. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: There are two hydraulic actuators (4), which are respectively located on the left and right sides of the bending machine body and are used to independently drive the corresponding side of the slider (5).

6. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The electro-hydraulic servo valve (3) is a proportional servo valve or a three-stage electro-hydraulic servo valve.

7. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The closed-loop control module uses a PID control algorithm, a fuzzy PID control algorithm, or an adaptive control algorithm to generate the deformation compensation signal.

8. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: It also includes a human-machine interface (7), which is connected to the main controller (1) for inputting the bending processing parameters and the preset deformation threshold, and for displaying the deformation parameters and system operating status in real time.

9. The electro-hydraulic servo anti-deformation control system for a CNC bending machine according to claim 1, characterized in that: The main controller (1) is a programmable logic controller, an industrial computer, or a digital signal processor.

Images