Copper bar folding control system and device

Abstract

The present application relates to copper bar processing equipment technical field, disclose a copper bar bending control system and device, including the following control steps: S1, the initial temperature of the copper bar to be processed, the real-time temperature of the bending template and the actual pressure in the hydraulic cylinder working chamber are collected;S2, the actual pressure collected by the multi-source state perception module is recorded to obtain pressure attenuation data, and the final accurate stress relaxation time constant of the current workpiece is calculated based on the pressure attenuation data;S3, according to the final accurate stress relaxation time constant, the target pressure set value is generated;S4, the deviation value between the generated target pressure set value and the actual pressure collected in S1 is calculated in real time and obtained control signal according to the deviation value;S5, receiving control signal, adjusting the pressure in the hydraulic cylinder working chamber.The present application can effectively inhibit the rebound difference caused by temperature fluctuation by online identification and dynamic adjustment of pressure maintaining strategy, improve the consistency and precision of product bending.

Description

Technical Field

[0001] This invention relates to the field of copper busbar processing equipment technology, specifically to a copper busbar bending control system and device. Background Technology

[0002] In wind power generation technology, the wind turbine, as the core equipment, typically has a very large motor size and power output. To meet the requirements of high current transmission, copper busbars with excellent conductivity are usually used internally to replace traditional cable conductors and are widely used in key components such as terminals, making them one of the important components of the wind turbine. The dimensional accuracy of these copper busbars, especially the angle and shape after bending, directly affects the reliability of the generator's electrical connections, assembly quality, and even long-term operational stability. Bending is a key process in the forming of copper busbars, and the springback after bending is the main factor affecting its final angular accuracy. To reduce and stabilize springback, a pressure holding process is usually applied after bending to release the internal stress of the material.

[0003] In existing copper busbar bending processes, the control methods for the pressure holding process are usually relatively fixed. However, this control method faces challenges in actual production. The initial temperature of the copper busbar to be processed varies due to storage environment and season. Simultaneously, during continuous production, the die experiences temperature rise due to continuous contact and friction with the workpiece. These temperature fluctuations alter the mechanical properties of the copper busbar material, especially its stress relaxation characteristics. Existing technologies typically lack the ability to sense and process these temperature variables in real time. The fixed control logic cannot compensate for the differences in stress relaxation caused by temperature changes, resulting in inconsistent springback amounts for different workpieces, affecting the stability of bending angles and dimensional accuracy in mass production.

[0004] Furthermore, the process parameters used in existing control systems, such as holding pressure and holding time, are mostly set based on offline experiments or experience. These fixed parameters cannot automatically adapt to changes in the physical properties of the workpiece caused by different batches of raw materials, variations in ambient temperature and humidity, or heat accumulation due to continuous equipment operation. Once the operating conditions change, the original parameters are no longer the optimal solution, and the processing quality deteriorates accordingly. Manual intervention is required for readjustment and verification, reducing the degree of automation and stability of production, and increasing reliance on the experience of operators.

[0005] Meanwhile, to ensure acceptable springback suppression under various operating conditions, existing technologies often adopt a conservative strategy when setting the critical parameter of holding time: selecting a relatively long fixed holding time sufficient to cover the worst-case scenario. While this approach guarantees the lower limit of processing capability, it is redundant for most workpieces operating under normal or good conditions. This mode, which fails to determine the minimum required holding time based on the actual condition of each workpiece, results in unnecessary waste of process time, prolongs overall production time, and reduces production efficiency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a copper busbar bending control system and device, which solves the problem that existing technologies use a fixed pressure holding control strategy and lack the ability to perceive and adaptively adjust dynamic process variables such as temperature and material batches in real time, thus making it difficult to simultaneously ensure the consistency of bending angles and processing efficiency in mass production.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] The first aspect of this invention provides a copper busbar bending control system, comprising the following control steps:

[0009] Step S1: Collect the initial temperature of the copper busbar to be processed, the real-time temperature of the bending template, and the actual pressure in the working chamber of the hydraulic cylinder through the multi-source state sensing module.

[0010] Step S2: In the initial bending and pressure holding stage, the central processing module records the actual pressure collected by the multi-source state sensing module to obtain pressure attenuation data, and based on the pressure attenuation data, uses the pressure attenuation fitting model formula to solve for the final accurate stress relaxation time constant of the current workpiece.

[0011] Step S3: In the adaptive pressure holding stage, the central processing module generates the target pressure setpoint based on the final accurate stress relaxation time constant obtained in step S2 and the target pressure trajectory generation formula.

[0012] Step S4: The central processing module calculates the deviation between the target pressure setpoint generated in step S3 and the actual pressure collected in step S1 in real time, and calculates the control signal based on the deviation.

[0013] Step S5: The precision hydraulic actuator receives and adjusts the pressure in the working chamber of the hydraulic cylinder according to the control signal calculated in step S4. By dynamically compensating for pressure loss, the actual pressure is made to approach the target pressure setting value, thereby performing bending and pressure holding control on the copper busbar.

[0014] Preferably, the central processing module includes a feedforward compensation parameter calculation unit, which is used to: receive and calculate an initial estimated value of the stress relaxation time constant based on the initial temperature and the real-time temperature, using a stress relaxation time constant estimation formula. This initial estimated value is used as the iterative starting value for solving the final accurate stress relaxation time constant in the pressure attenuation fitting model formula, thereby providing an initial condition closer to the true solution for subsequent fitting calculations, in order to improve the solution speed and convergence.

[0015] In one specific embodiment, the central processing module includes an online identification algorithm unit. This unit continuously records the sequence of actual pressures collected by the multi-source state sensing module at a high sampling frequency to obtain the pressure decay data. Subsequently, the unit invokes a nonlinear numerical fitting algorithm, employing the pressure decay fitting model formula, and uses the initial estimated value of the stress relaxation time constant as the starting point for iteration to fit and calculate the pressure decay data until the final accurate stress relaxation time constant is obtained.

[0016] Furthermore, the central processing module includes a target trajectory generation unit, which is used to: acquire and dynamically generate the target pressure setpoint for the adaptive pressure holding stage by executing the target pressure trajectory generation formula, based on the final accurate stress relaxation time constant solved by the online identification algorithm unit, the actual pressure at the end of the initial bending pressure holding stage, and the preset target endpoint pressure at the end of the pressure holding stage. The target endpoint pressure is a value preset by the process procedure.

[0017] In one embodiment, the central processing module includes a trajectory tracking control unit, which is used to: calculate the pressure deviation between the target pressure setpoint and the actual pressure using a pressure error calculation formula during each control cycle of the adaptive pressure holding phase. Subsequently, the unit uses the pressure deviation as input, executes a PID control output formula to calculate the control signal, and outputs the control signal to the precision hydraulic actuation module.

[0018] Preferably, the multi-source state sensing module includes: a high-precision pressure sensor unit for measuring the actual pressure; a workpiece initial temperature sensor unit for measuring the initial temperature; and a mold temperature sensor unit for measuring the real-time temperature.

[0019] In one specific embodiment, the high-precision pressure sensor unit is a pressure sensor installed on the pipeline near the oil inlet of the hydraulic cylinder; the workpiece initial temperature sensor unit is a non-contact infrared thermometer installed on the feeding path of the bending area; and the mold temperature sensor unit is a thermocouple embedded inside the mold template near the workpiece contact area.

[0020] Preferably, the precision hydraulic actuation module includes: a pressure holding and isolation unit, which is used to cut off the fluid connection between the hydraulic pump station and the hydraulic cylinder at the beginning of the initial bending and pressure holding stage, forming a partially closed pressure-bearing circuit; and a micro-energy compensation unit, which is used to receive and inject a micro amount of high-pressure oil into the partially closed pressure-bearing circuit according to the control signal.

[0021] In one specific embodiment, the pressure-holding isolation unit is a high-pressure two-position two-way solenoid valve installed in the oil circuit between the hydraulic pump station and the hydraulic cylinder. The micro-energy compensation unit is an integrated unit consisting of a small bladder accumulator and a micro-flow electro-hydraulic proportional valve connected in series, and this integrated unit is connected in parallel in the circuit between the pressure-holding isolation unit and the hydraulic cylinder.

[0022] A second aspect of the present invention provides a copper busbar bending device, which is applied to the copper busbar bending control system described in any of the foregoing embodiments. The device includes a workbench and a hydraulic pump station. A hydraulic cylinder, a template, and a limiting plate are mounted on the top of the workbench. An extrusion plate is fixedly connected to the output end of the hydraulic cylinder, and the extrusion plate is slidably connected between the workbench and the limiting plate. The position where the extrusion plate and the template face each other constitutes the bending area. The hydraulic pump station is connected to the hydraulic cylinder via hydraulic pipelines to provide high-pressure hydraulic oil as a power source to the hydraulic cylinder.

[0023] This invention provides a copper busbar bending control system and device. It has the following beneficial effects:

[0024] 1. This invention uses a multi-source state sensing module to collect the initial temperature of the copper busbar and the real-time temperature of the mold in real time. The central processing module identifies the stress relaxation time constant under the current working condition online during the initial bending and holding pressure stage. Then, it dynamically generates a specific target pressure trajectory for each workpiece. The precision hydraulic actuation module controls the actual pressure to tend towards the target pressure trajectory, so that the copper busbar under different temperature conditions can undergo a controlled stress relaxation process, suppressing the difference in springback caused by temperature fluctuations and improving the consistency of bending angle and dimensional accuracy in mass production.

[0025] 2. The control of this invention is not based on fixed offline parameters, but rather on setting an online identification link for each processing cycle, using real-time sensed temperature data for feedforward compensation, and solving for the key stress relaxation time constant based on the actual pressure decay data of the initial bending and holding pressure stage. This allows the control system to automatically adapt to changes in the physical properties of the workpiece caused by raw material batches, ambient temperature, or continuous production heat accumulation, and maintain the stability of processing quality without the need for manual recalibration.

[0026] 3. This invention improves the physical execution accuracy of pressure control by employing a precision hydraulic execution module composed of a pressure holding isolation unit and a micro-energy compensation unit. During the pressure holding stage, the controlled hydraulic cylinder forms a locally closed loop, and micro-frequency energy is injected according to the control signal. Compared with the traditional method of relying on the main pump or conventional cartridge valve group for pressure holding, this avoids the problems of large inertia, low response speed and pressure overshoot of the main hydraulic system, and achieves high-fidelity tracking of the target pressure trajectory. This provides a hardware foundation for the accurate implementation of the control algorithm and ensures the final effect of adaptive pressure holding control. Attached Figure Description

[0027] Figure 1 This is a diagram of the copper busbar bending control system architecture of the present invention;

[0028] Figure 2 This is a flowchart illustrating the copper busbar bending control system of the present invention.

[0029] Figure 3 This is a perspective view of the copper busbar bending device of the present invention.

[0030] The components include: 1. Hydraulic cylinder; 2. Extrusion plate; 3. Template; 4. Bending area; 5. Limiting plate; 6. Workbench; 7. Hydraulic pump station; 10. Multi-source status sensing module; 20. Central processing module; and 30. Precision hydraulic execution module. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see the appendix Figure 1-3 This invention provides a copper busbar bending control system, comprising:

[0033] The system includes a multi-source state perception module 10, a central processing module 20, and a precision hydraulic actuation module 30.

[0034] The working stages of the copper busbar bending control system mainly include the pressure bending stage and the adaptive pressure holding stage. The adaptive pressure holding stage includes the initial pressure holding and online identification stage and the adaptive trajectory tracking pressure holding stage.

[0035] The multi-source state sensing module 10 is used to collect physical parameters during the copper busbar bending process. The physical parameters collected by the multi-source state sensing module 10 include the initial temperature of the copper busbar to be processed. Real-time temperature of bending template 3 and the actual pressure inside the working chamber of hydraulic cylinder 1 .

[0036] The central processing module 20 has its signal input terminal electrically connected to the signal output terminal of the multi-source state sensing module 10. This central processing module 20 receives the physical parameters collected by the multi-source state sensing module 10, performs a series of calculations based on a preset algorithm model, and ultimately generates a control signal.

[0037] During the calculation, the central processing module 20 first calculates an initial estimate based on the stress relaxation time constant estimation formula. The stress relaxation time constant estimation formula is as follows:

[0038] ;

[0039] In the formula: is the initial estimate of the stress relaxation time constant; A is the material constant, also known as the pre-exponential factor; e is the base of the natural logarithm; Let be the apparent activation energy of the stress relaxation process; R is the ideal gas constant. The equivalent thermodynamic temperature is determined by the initial temperature. and real-time temperature The calculation yielded the result.

[0040] Subsequently, the central processing module 20, based on the collected pressure decay data from the initial holding stage, performs nonlinear fitting using a pressure decay fitting model formula to solve for the final precise stress relaxation time constant of the current workpiece. The pressure decay fitting model formula is as follows:

[0041] ;

[0042] In the formula: The function value of the theoretical stress model used to fit the data at time t during the identification phase; t is the relative time from the start of the identification phase. The peak pressure at the start of the identification phase; The fitting parameter represents the final steady-state pressure value to which the pressure will stabilize as time approaches infinity; The fitting parameter represents the final accurate stress relaxation time constant of the current workpiece.

[0043] In obtaining Subsequently, the central processing module 20 generates the target pressure curve for the subsequent pressure holding stage using the target pressure trajectory generation formula. The target pressure trajectory generation formula is:

[0044] ;

[0045] In the formula: In the trajectory tracking phase, The target pressure setting for the time period; The time from the start of the trajectory tracking phase; The target endpoint pressure set for the process at the end of the pressure holding period; This represents the actual pressure measurement at the start of the trajectory tracking phase.

[0046] During the trajectory tracking phase, the central processing module 20 calculates the pressure deviation in real time using the pressure error calculation formula. The pressure error calculation formula is as follows:

[0047] ;

[0048] In the formula: In the trajectory tracking phase, Pressure deviation over time; In order to enable the multi-source state perception module 10 to perform the trajectory tracking phase... The actual pressure value measured in real time.

[0049] Finally, the central processing module 20 calculates the final control output signal based on the pressure error using the PID control output formula. The PID control output formula is:

[0050] ;

[0051] In the formula: In the trajectory tracking phase, Control signals for time output; This is the proportional gain coefficient of the PID controller; This is the integral gain coefficient of the PID controller; The derivative gain coefficient of the PID controller; The definite integral operator represents the integral of a function from 0 to time. Perform integration; s is the virtual time variable in the integration operation; The differential operator represents the operation on time. Find the derivative.

[0052] The precision hydraulic actuator module 30 has its control input terminal electrically connected to the control output terminal of the central processing module 20, and its hydraulic interface fluidly connected to the hydraulic circuit of the hydraulic pump station 7. This precision hydraulic actuator module 30 is used to receive control signals generated by the central processing module 20. Based on this, the hydraulic circuit of hydraulic pump station 7 is switched and fine-tuned to control the pressure in the working chamber of hydraulic cylinder 1 to precisely follow the pressure generated by the hydraulic pump station 7. Defined target pressure trajectory.

[0053] The multi-source state sensing module 10 is the foundation for data acquisition in this control system. Its function is to provide the central processing module 20 with the environmental and state physical quantities required for calculation and decision-making. The multi-source state sensing module 10 consists of several functionally independent sensor units.

[0054] Specifically, the multi-source state sensing module 10 includes a high-precision pressure sensor unit. This high-precision pressure sensor unit is a piezoresistive pressure sensor. The piezoresistive pressure sensor is installed on the oil inlet pipe of the hydraulic cylinder 1, and its installation position is adjacent to the oil inlet of the hydraulic cylinder 1. This installation method aims to minimize the interference of pressure loss generated when hydraulic oil flows in the pipe on the measurement results, thereby ensuring that the pressure data measured by the piezoresistive pressure sensor can accurately reflect the actual operating pressure within the working chamber of the hydraulic cylinder 1. This piezoresistive pressure sensor features high-frequency response characteristics, enabling it to capture rapid pressure changes at the millisecond level, providing high-density data points for subsequent online identification and closed-loop tracking.

[0055] The multi-source state sensing module 10 also includes a workpiece initial temperature sensor unit. This workpiece initial temperature sensor unit is specifically structured as a non-contact infrared thermometer. This non-contact infrared thermometer can be installed at the loading position in the bending area 4, with its measuring optical axis aligned with the conveying path of the copper busbar to be processed. Its function is to measure the initial temperature of the copper busbar before it enters the bending station. Perform a rapid, non-contact measurement. This non-contact measurement method avoids physical contact with the workpiece, enabling online inspection without affecting the production cycle.

[0056] The multi-source state sensing module 10 further includes a mold temperature sensor unit. The specific structure of this mold temperature sensor unit is a K-type armored thermocouple. This K-type armored thermocouple is pre-embedded within the internal structure of the bending template 3. To ensure the accuracy and sensitivity of temperature measurement, its measuring endpoint is positioned near the curved working surface of the bending area 4 adjacent to the area where the template 3 and the copper busbar come into contact, for example, at a depth of 1-3 mm from this working surface. This installation method enables the mold temperature sensor unit to accurately monitor the working temperature of the mold template 3 due to heat transfer and friction during continuous production. The dynamic changes provide crucial real-time data for the central processing module 20 to perform thermodynamic compensation calculations.

[0057] The central processing module 20 is physically composed of an industrial PC or a high-performance PLC, which internally executes a series of preset calculation and control instructions. These instructions are logically divided into several functional units.

[0058] The feedforward compensation parameter calculation unit is a logical functional unit within the central processing module 20. Its function is to pre-calculate an initial estimate of the stress relaxation time constant based on temperature data provided by the multi-source state sensing module 10 before the pressure holding action of the copper busbar bending begins. The input to this feedforward compensation parameter calculation unit is the initial temperature measured by the workpiece initial temperature sensor unit. Real-time temperature measured by the mold temperature sensor unit .

[0059] Specifically, when received and Then, the feedforward compensation parameter calculation unit first calculates an equivalent thermodynamic temperature. This calculation can be performed using a weighted average method, for example:

[0060] ;

[0061] In the formula: and These are preset weighting coefficients stored in the memory of the central processing module 20, and .

[0062] The values ​​of these two weighting coefficients are determined based on the heat capacity, contact area, and other thermophysical properties of the copper busbar to be processed and the bending template 3.

[0063] Subsequently, the feedforward compensation parameter calculation unit will calculate the... Substitute the stress relaxation time constant prediction formula stored in the memory of the central processing module 20:

[0064] ;

[0065] In the formula: is the initial estimate of the stress relaxation time constant; A is the material constant, also known as the pre-exponential factor; e is the base of the natural logarithm; Let be the apparent activation energy of the stress relaxation process; R is the ideal gas constant. The equivalent thermodynamic temperature is determined by the initial temperature. and real-time temperature The calculation yielded the result.

[0066] A and These are physical constants corresponding to the grade of the copper busbar material to be processed. These two constants are calibrated by conducting offline stress relaxation experiments at different temperatures on the copper busbar material to be processed, and are pre-stored in the non-volatile memory of the central processing module 20.

[0067] The final output of the feedforward compensation parameter calculation unit is the calculated initial estimate. This value is immediately passed to the online identification algorithm unit within the central processing module 20, serving as the starting value for subsequent nonlinear fitting algorithms and providing an initial point close to the final solution for subsequent calculations.

[0068] The online identification algorithm unit is another logical functional unit within the central processing module 20. Its function is to accurately determine the final stress relaxation time constant of the copper busbar under the current working conditions by analyzing actual pressure data during the initial stage of the pressure holding phase. .

[0069] When the pressure of hydraulic cylinder 1 reaches the preset peak pressure Furthermore, after the precision hydraulic actuator 30 performs the shutdown action, the online identification algorithm unit is immediately activated. Within a preset time window after activation (e.g., 0.5 to 2 seconds), the online identification algorithm unit continuously records the sequence of actual pressure values ​​acquired by the high-precision pressure sensor unit at a high sampling frequency (e.g., 100 Hz). .

[0070] The online identification algorithm unit calls a nonlinear numerical fitting algorithm, such as the Levonburg-Marquardt algorithm, stored in the memory of the central processing module 20, to perform fitting calculations on the collected pressure data point sequence. The objective function for fitting is the pressure decay fitting model formula:

[0071] ;

[0072] In the formula: The function value of the theoretical stress model used to fit the data at time t during the identification phase; t is the relative time from the start of the identification phase. The peak pressure at the start of the identification phase is a known initial value obtained from the high-precision pressure sensor unit; , is one of the fitting parameters to be solved, representing the final steady-state pressure value to which the pressure will stabilize as time approaches infinity; The other fitting parameter to be solved represents the final accurate stress relaxation time constant of the current workpiece.

[0073] When executing the nonlinear numerical fitting algorithm, the online identification algorithm unit uses the initial estimated value calculated by the feedforward compensation parameter calculation unit in the previous stage. As a parameter The starting point for the iterative solution. Simultaneously, it can be... Multiply by an empirical coefficient less than 1 (e.g., 0.8) as a parameter. The starting point of the iteration.

[0074] Through the above fitting calculations, the online identification algorithm unit ultimately solves for a unique and accurate solution. The value is then output to the target trajectory generation unit within the central processing module 20.

[0075] The target trajectory generation unit is another logical functional unit within the central processing module 20. Its function is to ensure that the online identification algorithm unit successfully solves for the final stress relaxation time constant. Subsequently, a customized target pressure curve is dynamically generated for the subsequent trajectory tracking and pressure holding phase. .

[0076] The calculation process of this target trajectory generation unit is triggered the instant the online identification phase ends. Upon triggering, the target trajectory generation unit first acquires three key input parameters:

[0077] First, the final accurate stress relaxation time constant received from the online identification algorithm unit. ;

[0078] Second, the actual pressure measurement value at the end of the identification phase, obtained from the high-precision pressure sensor unit, is defined as the starting pressure of the trajectory tracking phase. ;

[0079] Third, the target endpoint pressure at the end of the pressure holding period, pre-set by the process procedure, is read from the non-volatile memory of the central processing module 20. .

[0080] After obtaining the above input parameters, the target trajectory generation unit calculates the target pressure value by executing the target pressure trajectory generation formula:

[0081] ;

[0082] In the formula: In the trajectory tracking phase, The target pressure setting for the time period; The time from the start of the trajectory tracking phase; The target endpoint pressure set for the process at the end of the pressure holding period; This represents the actual pressure measurement at the start of the trajectory tracking phase.

[0083] The output of the target trajectory generation unit is a time-varying variable. Continuous function of change Alternatively, it can be a sequence of target pressure setpoints within a discrete control cycle. This output is continuously and in real-time transmitted to the trajectory tracking control unit within the central processing module 20 as a reference signal for executing closed-loop control.

[0084] The trajectory tracking control unit is a logical functional unit within the central processing module 20 responsible for executing closed-loop control. Its function is to continuously compare the target pressure with the actual pressure in a high-frequency control cycle and calculate the control signal required to drive the precision hydraulic actuator module 30, thereby maintaining the actual pressure within the hydraulic cylinder 1. The target pressure curve generated by the precise target trajectory generation unit .

[0085] Within each control cycle, the trajectory tracking control unit first calculates the pressure deviation at the current moment using the pressure error calculation formula:

[0086] ;

[0087] In the formula: In the trajectory tracking phase, Pressure deviation over time; In order to enable the high-precision pressure sensor unit of the multi-source state perception module 10 to perform the trajectory tracking phase, The actual pressure value measured in real time.

[0088] Obtaining pressure error value Then, the trajectory tracking control unit immediately uses it as input to execute the PID (Proportional-Integral-Derivative) control algorithm preset in the memory of the central processing module 20. This algorithm calculates the final control signal using the PID control output formula:

[0089] ;

[0090] In the formula: In the trajectory tracking phase, The timing is output as a control signal to the precision hydraulic actuator module 30; This is the proportional gain coefficient of the PID controller; This is the integral gain coefficient of the PID controller; The derivative gain coefficient of the PID controller; The definite integral operator represents the integral of a function from 0 to time. Perform integration; s is the virtual time variable in the integration operation; The differential operator represents the operation on time. Find the derivative.

[0091] The proportional gain coefficient Integral gain coefficient With differential gain coefficient All values ​​are preset values, which are determined by mathematical modeling and simulation of the hydraulic characteristics of the system or by on-site experimental tuning, and are stored in the non-volatile memory of the central processing module 20.

[0092] The final output of this trajectory tracking control unit is a control signal. This signal is a standard industrial analog signal, such as a 0-10V voltage signal or a 4-20mA current signal. This signal is sent directly to the micro-energy compensation unit in the precision hydraulic actuator module 30 via the signal output interface of the central processing module 20, thereby driving the valve core displacement of the high-frequency response micro-flow electro-hydraulic proportional valve therein, thus precisely adjusting the flow and direction of the compensation oil circuit.

[0093] The precision hydraulic actuator module 30 is the physical actuator of this control system. Its function is to receive and execute control signals from the central processing module 20 to perform physical operations on the hydraulic circuit. The precision hydraulic actuator module 30 includes a pressure-holding isolation unit and a micro-energy compensation unit.

[0094] The pressure-holding isolation unit is specifically structured as a high-pressure two-position two-way solenoid valve. This high-pressure two-position two-way solenoid valve is installed in series on the main hydraulic pipeline from the hydraulic pump station 7 to the hydraulic cylinder 1. Its installation position is upstream of the parallel connection point between the micro-energy compensation unit and the main hydraulic pipeline, that is, closer to the side of the hydraulic pump station 7.

[0095] This high-pressure two-position two-way solenoid valve has two operating positions controlled by electrical signals. In the first operating position, its valve port is open, creating an unobstructed oil passage between the oil outlet of the hydraulic pump station 7 and the oil inlet of the hydraulic cylinder 1. This position is used during the pressure bending stage of the copper busbar, allowing the hydraulic pump station 7 to deliver a large flow of high-pressure oil to the hydraulic cylinder 1.

[0096] In the second operating position, the valve is closed, thereby cutting off the fluid connection between the hydraulic pump station 7 and the hydraulic cylinder 1. This action isolates the hydraulic cylinder 1 and its connected piping, including the micro-energy compensation unit described later, into an independent, locally closed pressure-bearing circuit independent of the main pump source. This position is used to perform subsequent pressure-holding operations.

[0097] The solenoid coil of the high-pressure two-position two-way solenoid valve is electrically connected to a switch output interface of the central processing module 20. After the pressure bending is completed and the pressure reaches the peak value, the central processing module 20 immediately changes the output level signal through this interface to drive the high-pressure two-position two-way solenoid valve to switch from the first working position to the second working position.

[0098] The micro-energy compensation unit is a unit consisting of a bladder-type accumulator and a high-frequency response micro-flow electro-hydraulic proportional valve connected in series. This micro-energy compensation unit is connected in parallel to the main hydraulic line between the pressure-holding isolation unit and hydraulic cylinder 1 via a T-joint.

[0099] One end of the bladder-type accumulator is connected to a high-frequency response micro-flow electro-hydraulic proportional valve. Its function is to pre-charge and store a certain volume of high-pressure hydraulic oil from the main hydraulic line when the main oil line is opened during the initial pressurization stage. In the subsequent adaptive pressure holding stage, which is isolated by the pressure holding isolation unit, the accumulator acts as a local and independent pressure source.

[0100] The control input terminal of the high-frequency response micro-flow electro-hydraulic proportional valve is electrically connected to the analog output interface of the central processing module 20, and its hydraulic ports are connected to a T-connector and a bladder accumulator, respectively. The function of this high-frequency response micro-flow electro-hydraulic proportional valve is to receive control signals calculated from the trajectory tracking control unit. The valve opening is adjusted accordingly to control the small flow of hydraulic oil from the bladder accumulator to the isolated hydraulic cylinder 1 circuit.

[0101] Specifically, when the control signal When the signal is positive, the valve core of the high-frequency response micro-flow electro-hydraulic proportional valve is displaced, opening a throttle orifice proportional to the signal amplitude. This allows hydraulic oil to flow from the accumulator and replenish the hydraulic cylinder circuit 1, thereby increasing the actual pressure within that circuit. Increase. When the control signal... When the value is zero, the valve core of the high-frequency response micro-flow electro-hydraulic proportional valve resets, the valve port closes, and the compensation oil circuit is cut off.

[0102] The high-frequency response characteristics of this high-frequency micro-flow electro-hydraulic proportional valve enable it to respond to dynamic control signals emitted by the central processing module 20 during high-frequency control cycles. It provides a rapid response. Its micro-flow characteristics ensure that the volume of hydraulic oil injected for each compensation is small enough, thereby achieving precise and smooth adjustment of the actual pressure and avoiding pressure overshoot caused by excessive compensation.

[0103] This invention also provides a copper busbar bending device, including a workbench 6 and a hydraulic pump station 7. A hydraulic cylinder 1, a template 3 and a limiting plate 5 are installed on the top of the workbench 6. An extrusion plate 2 is fixedly connected to the output end of the hydraulic cylinder 1. The extrusion plate 2 is slidably connected between the workbench 6 and the limiting plate 5. The position where the extrusion plate 2 and the template 3 face each other is the bending area 4. The hydraulic pump station 7 is connected to the hydraulic cylinder 1 through a hydraulic pipeline and is used to provide high-pressure hydraulic oil to the hydraulic cylinder 1 as a power source.

[0104] Specifically, the hydraulic cylinder 1 is installed on the workbench 6 with its axis pointing in the direction of bending operation. Fixed in front of the hydraulic cylinder 1 on the workbench 6 is a template 3, which serves as a forming die. The template 3 is made of mold steel that has been hardened by quenching. The side of the template facing the hydraulic cylinder 1 has a concave arc-shaped working surface with a specific radius. The contour of this arc-shaped working surface determines the final inner R angle after the copper busbar is bent.

[0105] The piston rod output end of the hydraulic cylinder 1 is fixed to a pressing plate 2, which serves as a punch, by means of a flange or thread, so as to ensure that the huge thrust generated by the hydraulic cylinder 1 can be transmitted to the pressing plate 2 without gaps or loss.

[0106] By fixing the limiting plates 5 on the worktable 6 and setting them on both sides of the extrusion plate 2, the bottom surface of the extrusion plate 2 and the top surface of the worktable 6 together form a precision guide slide, ensuring that the extrusion plate 2 can maintain linear movement and effectively preventing the extrusion plate 2 from deflecting.

[0107] The space defined between the moving front end of the extrusion plate 2 and the arc-shaped working surface of the template 3 is the bending area 4. Before the work begins, the straight copper busbar to be processed is placed in the bending area 4.

[0108] An independent hydraulic pump station 7 is set up next to the workbench 6. The hydraulic pump station 7 is connected to the oil inlet and oil return port of the hydraulic cylinder 1 through a high-pressure hydraulic pipeline. According to the instructions from the external control system, it generates and delivers high-pressure hydraulic oil to the hydraulic cylinder 1, thereby driving its piston rod to extend or retract, and thus precisely controlling the movement of the extrusion plate 2 towards the template 3, providing the core power source for the entire bending process.

[0109] Working principle: Before the pressure bending action begins, the copper busbar to be bent is placed in the bending area 4 on the worktable 6. At the same time, the initial temperature sensor unit of the workpiece and the temperature sensor unit of the mold in the multi-source state sensing module 10 collect the initial temperature of the copper busbar and the real-time temperature of the template 3, respectively, and send the data to the central processing module 20. The feedforward compensation parameter calculation unit inside the central processing module 20 calculates an initial estimate of the stress relaxation time constant based on the received temperature data.

[0110] During the pressure bending stage, the central processing module 20 controls the hydraulic pump station 7 to start and puts the pressure holding isolation unit in the precision hydraulic actuator module 30 into the open position. The high-pressure oil drives the hydraulic cylinder 1 to work, pushing the extrusion plate 2 to extrude the copper busbar in the bending area 4 until the copper busbar is formed along the inner contour of the template 3. During this process, the high-precision pressure sensor unit monitors the pressure in real time. When the monitored pressure reaches the preset peak pressure, the central processing module 20 immediately sends a shutdown command to the pressure holding isolation unit to switch it to the closed position, thereby isolating the circuit of the hydraulic cylinder 1 from the hydraulic pump station 7 and entering the adaptive pressure holding stage.

[0111] After the pressure holding isolation unit is closed, an initial pressure holding and online identification stage is entered. During this stage, the online identification algorithm unit in the central processing module 20 is activated. It uses the data of the natural decay of the initial pressure due to the stress relaxation inside the copper busbar collected by the high-precision pressure sensor unit, and combines it with the previously calculated initial estimate to accurately solve the final stress relaxation time constant of the current workpiece. After the solution is completed, the target trajectory generation unit generates a target pressure trajectory based on the final stress relaxation time constant, the current pressure and the set endpoint pressure.

[0112] After online identification and trajectory generation are completed, the adaptive trajectory tracking and pressure holding stage begins. The trajectory tracking control unit in the central processing module 20 starts working. In the control loop, it continuously compares the actual pressure measured by the high-precision pressure sensor unit with the target pressure trajectory and calculates the pressure error value. Based on the pressure error value, a control signal is generated through the PID control algorithm and sent to the micro-energy compensation unit in the precision hydraulic actuation module 30. The high-frequency response micro-flow electro-hydraulic proportional valve in the micro-energy compensation unit precisely adjusts the valve opening according to the received control signal, injecting a small amount of high-pressure oil from the bladder accumulator into the isolated hydraulic cylinder 1 circuit to compensate for the pressure drop caused by stress relaxation, so that the actual pressure accurately follows the target pressure trajectory.

[0113] When the set pressure holding time ends, the central processing module 20 stops outputting control signals to the high-frequency response micro-flow electro-hydraulic proportional valve and controls the main pressure relief circuit of the hydraulic system to open, releasing the pressure in the hydraulic cylinder 1. Finally, it controls the extrusion plate 2 to return to the initial position. At this time, the copper busbar that has been bent can be taken out, and one work cycle ends.

Claims

1. A copper bar folding control system, characterized by, The control steps include: Step S1, collecting the initial temperature of the copper bar to be processed, the real-time temperature of the bending template (3), and the actual pressure in the working cavity of the hydraulic cylinder (1) through a multi-source state perception module; Step S2, recording the actual pressure collected by the multi-source state perception module to obtain pressure decay data during the initial bending pressure maintaining stage, and solving the final accurate stress relaxation time constant of the current workpiece by using a pressure decay fitting model formula based on the pressure decay data; Step S3, generating a target pressure set value by a target pressure trajectory generation formula according to the final accurate stress relaxation time constant obtained in step S2 during the adaptive pressure maintaining stage; Step S4, calculating the deviation value between the target pressure set value generated in step S3 and the actual pressure collected in step S1 in real time through the central processing module, and calculating the control signal according to the deviation value; Step S5, receiving and adjusting the pressure in the working cavity of the hydraulic cylinder (1) according to the control signal calculated in step S4 through the precise hydraulic execution module, and making the actual pressure approach the target pressure set value by dynamically compensating for pressure loss, thereby performing bending pressure maintaining control on the copper bar.

2. The copper bar folding control system of claim 1, wherein, The central processing module includes a feedforward compensation parameter calculation unit for: receiving and calculating the initial estimated value of the stress relaxation time constant through a stress relaxation time constant estimation formula according to the initial temperature and the real-time temperature, and taking the initial estimated value as the iteration starting value for solving the final accurate stress relaxation time constant in the pressure decay fitting model formula.

3. The copper bar folding control system of claim 2, wherein, The central processing module includes an online identification algorithm unit for: continuously recording the sequence of the actual pressure collected by the multi-source state perception module through a high sampling frequency to obtain the pressure decay data; calling a nonlinear numerical fitting algorithm, and using the pressure decay fitting model formula to perform fitting calculation on the pressure decay data with the initial estimated value of the stress relaxation time constant as the iteration starting point to solve the final accurate stress relaxation time constant.

4. The copper bar folding control system of claim 3, wherein, The central processing module includes a target trajectory generation unit for: obtaining the final accurate stress relaxation time constant solved by the online identification algorithm unit, the actual pressure at the end of the initial bending pressure maintaining stage, and the target end pressure at the preset pressure maintaining end time, and generating the target pressure set value for the adaptive pressure maintaining stage by executing the target pressure trajectory generation formula; wherein the target end pressure is a value preset by a process specification.

5. The copper bar folding control system of claim 4, wherein, The central processing module includes a trajectory tracking control unit for: calculating the pressure deviation value between the target pressure set value and the actual pressure through a pressure error calculation formula in each control cycle of the adaptive pressure maintaining stage; taking the pressure deviation value as input, calculating the control signal by executing a PID control output formula, and outputting the control signal to the precise hydraulic execution module.

6. The copper bar folding control system of claim 1, wherein, The multi-source state perception module includes: A high-precision pressure sensor unit for measuring the actual pressure; A workpiece initial temperature sensor unit for measuring the initial temperature; A mold temperature sensor unit for measuring the real-time temperature.

7. The copper bar folding control system of claim 6, wherein, The high-precision pressure sensor unit is a pressure sensor installed on the pipeline of the hydraulic cylinder (1) near the oil inlet; The workpiece initial temperature sensor unit is a non-contact infrared temperature measuring instrument installed on the feeding path of the bending area (4); The mold temperature sensor unit is a thermocouple embedded in the inside of the mold plate (3) near the workpiece contact area.

8. The copper bar folding control system of claim 1, wherein, The precise hydraulic execution module comprises: A pressure maintaining isolation unit for cutting off the fluid communication between the hydraulic pump station (7) and the hydraulic cylinder (1) to form a local closed pressure bearing circuit at the beginning of the initial bending pressure maintaining stage; A micro-energy compensation unit for receiving and injecting a small amount of high-pressure oil into the local closed pressure bearing circuit according to the control signal.

9. The copper bar folding control system of claim 8, wherein, The pressure maintaining isolation unit is a high-pressure two-position two-way electromagnetic valve installed on the oil path between the hydraulic pump station (7) and the hydraulic cylinder (1); The micro-energy compensation unit is an integral body of a small-sized bladder accumulator and a micro-flow electro-hydraulic proportional valve connected in series, which is connected in parallel in the circuit between the pressure maintaining isolation unit and the hydraulic cylinder (1).

10. A copper bar folding device characterized by, The copper bar bending control system according to any one of claims 1-9, comprising a workbench (6) and a hydraulic pump station (7), wherein the top of the workbench (6) is provided with a hydraulic cylinder (1), a mold plate (3) and a limiting plate (5), the output end of the hydraulic cylinder (1) is fixedly connected with an extrusion plate (2), the extrusion plate (2) is slidingly connected between the workbench (6) and the limiting plate (5), the positions of the extrusion plate (2) and the mold plate (3) facing each other are bending areas (4), the hydraulic pump station (7) is connected with the hydraulic cylinder (1) through a hydraulic pipeline, and is used for providing high-pressure hydraulic oil as a power source for the hydraulic cylinder (1).

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