A method for linkage control of hydraulic equipment and electric injection molding equipment

Abstract

This invention relates to the field of automation control technology, and in particular to a method for the linkage control of hydraulic equipment and electric injection molding equipment, comprising the following steps: acquiring displacement and pressure signals of the hydraulic equipment cylinders and interconnecting them with the injection completion and ejection signals of the injection molding equipment; integrating the acquired signals into a controller, loading a pre-compression formula and outputting instructions according to an algorithm; controlling the hydraulic cylinders to increase pressure in stages before welding, balancing the contact force, and slightly compensating for displacement deviations during the pressure holding stage; pre-adjusting the clamping force according to the trend of feedback signal changes and performing secondary compensation during welding; correcting the pre-compression parameters according to the quality deviation after welding; interrupting welding and triggering an alarm when the displacement or pressure deviation exceeds the limit. This invention, based on the changing trend of the real-time process feedback signal from the welding equipment, pre-adjusts the clamping force before the temperature rises and performs secondary compensation during temperature rise, achieving a composite suppression of thermal deformation prediction and feedback, avoiding workpiece deformation or stress concentration caused by traditional delayed adjustments.

Description

Technical Field

[0001] This invention relates to the field of automation control technology, and in particular to a method for the linkage control of hydraulic equipment and electric injection molding equipment. Background Technology

[0002] In the field of automated manufacturing, after the electric injection molding equipment completes the injection molding, the workpiece usually needs to be transferred to the subsequent station for secondary processing such as welding and assembly. Among them, the workpiece needs to be accurately positioned and pre-clamped before the welding process to ensure the welding quality. Hydraulic equipment, due to its large output force and good rigidity, is often used as the pre-clamping actuator of the welding station.

[0003] Traditional welding pre-stressing systems mostly use constant clamping force or adjust it only according to the temperature threshold. Due to the response delay of the hydraulic system and the lag in heat conduction, the clamping force is not released in time when welding thermal expansion occurs, resulting in workpiece deformation or stress concentration. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a linkage control method for hydraulic equipment and electric injection molding equipment, which aims to improve the problem that traditional welding pre-compression systems mostly adopt constant clamping force or adjust only according to temperature threshold lag, which easily leads to the clamping force not being released in time when welding thermal expansion occurs, resulting in workpiece deformation or stress concentration.

[0005] This invention provides the following technical solution: a method for linkage control of hydraulic equipment and electric injection molding equipment, comprising the following steps: S1. Collect displacement and pressure signals of multiple sets of cylinders on the hydraulic equipment and interconnect them with multiple sets of core control signals of the electric injection molding equipment. The core control signals include injection completion signals for triggering pre-compression preparation actions and ejection signals for adjusting pre-compression timing. S2. All collected signals are fed into the controller, the corresponding pre-compression process formula is automatically loaded according to the current workpiece model, and control commands are output according to the preset collaborative logic algorithm. S3. Before the welding process, control multiple sets of hydraulic cylinders to perform graded pressure increase and pre-pressure action. First, the workpiece is contacted with low pressure and the contact force of each set of hydraulic cylinders is balanced through pressure feedback. Then, the pressure is increased in stages to the target clamping force. During the pressure holding stage, the displacement feedback value is read periodically and the displacement deviation is actively micro-compensated. S4. During the welding process, receive real-time process feedback signals from the welding equipment, and adjust the clamping force of the hydraulic cylinder near the corresponding welding area in advance according to the changing trend of the process feedback signals before the workpiece temperature rises, and perform secondary compensation adjustment when the workpiece temperature rises. S5. After welding is completed, the welding quality deviation data fed back by the testing equipment is received, the welding quality deviation is converted into pre-pressure positioning error, and the pre-pressure parameters of the workpiece of this model in the next cycle are automatically corrected. S6. When the displacement or pressure deviation of any set of hydraulic cylinders exceeds the preset safety range, the welding process is interrupted and an alarm is output.

[0006] By adopting the above technical solution, by receiving real-time process feedback signals from the welding equipment, the clamping force of the hydraulic cylinder near the corresponding welding area is pre-adjusted according to the changing trend of the process feedback signals before the workpiece temperature rises, and a secondary compensation adjustment is performed when the workpiece temperature rises. This achieves a combined prediction and feedback suppression of welding thermal deformation, thereby improving the problem that traditional welding pre-pressure systems mostly use constant clamping force or adjust only according to the temperature threshold with lag. Due to the response delay of the hydraulic system and the lag of heat conduction, the clamping force is not released in time when welding thermal expansion occurs, resulting in workpiece deformation or stress concentration.

[0007] Furthermore, in S1, the step of interconnecting multiple sets of core control signals with the electric injection molding equipment includes: Determine the type of communication protocol with the electric injection molding equipment; Complete the physical layer connection according to the communication protocol type; Configure the network parameters between the controller and the electric injection molding equipment; Establish the address mapping relationship between the displacement signal and the pressure signal and the core control signal; Perform communication integration testing and obtain real-time verification results of signal transmission.

[0008] Furthermore, in S2, the step of outputting control commands according to a preset cooperative logic algorithm includes: The collected displacement signals, pressure signals, injection completion signals, and ejection signals are aligned according to a unified timing sequence. Calculate the difference between the aligned signals at adjacent sampling times to obtain the rate of change of each signal; Detect the sign change of the rate of change of each signal; When the sign of the rate of change of any signal changes from positive to negative or from negative to positive, a corresponding predictive control command is output according to the signal type before the signal reaches its extreme point.

[0009] Furthermore, in S3, the step of contacting the workpiece with low pressure and balancing the contact force of each group of cylinders through pressure feedback includes: Send low-pressure feed commands to each group of hydraulic cylinders; Read the pressure feedback values ​​of each group of hydraulic cylinders to confirm the contact status; After all the hydraulic cylinders are in contact with the workpiece, calculate the average pressure value of each group of hydraulic cylinders. Based on the deviation between the pressure value of each group of hydraulic cylinders and the average pressure value, the drive signal of the corresponding hydraulic cylinder is adjusted independently.

[0010] Further, in S3, the step of progressively increasing the pressure to the target clamping force includes: S31. Decompose the target clamping force into multiple pressure step values; S32, issue a command to each group of hydraulic cylinders to increase the pressure to the current pressure step value; S33. Confirm that the pressure value of each group of hydraulic cylinders is stable within the allowable range of the current pressure step value; S34. Repeat steps S32 to S33 until the clamping force of each set of hydraulic cylinders reaches the target clamping force.

[0011] Furthermore, in S3, the step of periodically reading the displacement feedback value and actively micro-compensating for the displacement deviation includes: The displacement feedback values ​​of each group of hydraulic cylinders are read according to the preset sampling period; Calculate the displacement deviation between the displacement feedback value and the target displacement value; When the displacement deviation exceeds the preset allowable range, the amount of compensation oil is calculated based on the direction of the displacement deviation; The corresponding oil cylinder is controlled to perform oil replenishment or oil discharge actions based on the compensation oil quantity.

[0012] Furthermore, in S4, the step of pre-adjusting the clamping force of the hydraulic cylinder near the corresponding welding area before the workpiece temperature rises includes: The process feedback signal of the welding equipment is received in real time, and the process feedback signal is a welding power signal or a welding current signal. Calculate the rate of change of the process feedback signal per unit time; The rate of change is compared with multiple preset threshold intervals, each threshold interval corresponding to a pre-adjustment amount; Based on the comparison results, the hydraulic cylinder group corresponding to the current welding area is determined, and a clamping force reduction command is issued to the hydraulic cylinder group, with the reduction amount equal to the pre-adjustment amount.

[0013] Furthermore, in S4, the step of performing secondary compensation adjustment when a rise in workpiece temperature is detected includes: Receive workpiece surface temperature values ​​from the welding station in real time; The surface temperature value of the workpiece is compared with a first temperature threshold. When the surface temperature of the workpiece exceeds the first temperature threshold, the current clamping force of the hydraulic cylinder group corresponding to the current welding area is read. The target clamping force after secondary compensation is calculated based on the current clamping force and the preset temperature and pressure compensation coefficient. The hydraulic cylinder assembly is given a command to adjust to the target clamping force, and when the surface temperature of the workpiece is subsequently detected to be lower than the second temperature threshold, the hydraulic cylinder assembly is given a command to restore to the original target clamping force.

[0014] Furthermore, in S5, the step of automatically correcting the preload parameters of the workpiece of this model for the next cycle includes: Obtain welding quality deviation data fed back by the testing equipment; Based on the preset deviation-preload parameter mapping relationship, the welding quality deviation data is converted into preload positioning error; The correction amount of the preload position target value is calculated based on the preload positioning error, and the correction amount is limited to ensure that the correction amount does not exceed the preset maximum correction value. The correction amount after the amplitude limit is added to the corresponding parameter in the pre-compression process formula of the current workpiece model.

[0015] Furthermore, in S6, the step of interrupting the welding process and outputting an alarm when the displacement deviation or pressure deviation exceeds the preset safety range includes: Real-time reading of displacement and pressure feedback values ​​for each group of hydraulic cylinders; Calculate the displacement deviation and pressure deviation values ​​for each group of hydraulic cylinders; The displacement deviation value is compared with a preset displacement safety threshold, and the pressure deviation value is compared with a preset pressure safety threshold. When the displacement deviation of any set of hydraulic cylinders exceeds the preset displacement safety threshold or the pressure deviation exceeds the preset pressure safety threshold, an interrupt command is generated and an alarm signal is triggered, and an automatic reset attempt is performed at the same time; if the reset fails, the equipment is locked.

[0016] The present invention has the following beneficial effects: 1. In this invention, by receiving real-time process feedback signals from the welding equipment, the clamping force of the hydraulic cylinder near the corresponding welding area is pre-adjusted according to the changing trend of the process feedback signals before the workpiece temperature rises, and a secondary compensation adjustment is performed when the workpiece temperature rises. This achieves a combined prediction and feedback suppression of welding thermal deformation, thereby improving the problem that traditional welding pre-pressure systems mostly use constant clamping force or adjust only according to the temperature threshold with lag. Due to the response delay of the hydraulic system and the lag of heat conduction, the clamping force is not released in time when welding thermal expansion occurs, resulting in workpiece deformation or stress concentration.

[0017] 2. In this invention, by periodically reading the displacement feedback value and actively micro-compensating for the displacement deviation during the pressure holding stage, the position closed-loop stability during the hydraulic pressure holding stage is achieved. This improves the problem that traditional hydraulic pressure holding methods mostly adopt the method of only maintaining pressure stability. Due to the compressibility of hydraulic oil, micro-leakage of seals and pressure pulsation of the hydraulic system, the positioning fixture will produce a small displacement, which will cause a decrease in the subsequent welding accuracy.

[0018] 3. In this invention, by receiving welding quality deviation data fed back by the detection equipment, the welding quality deviation is converted into pre-pressure positioning error, and the pre-pressure parameters of the workpiece of the same model in the next cycle are automatically corrected. This achieves cross-process adaptive process parameter optimization, thereby improving the problem that traditional welding quality feedback mostly adopts manual sampling and manual adjustment. Due to the separation of detection and adjustment and the long cycle, defective products cannot be corrected in time and process parameters are difficult to continuously optimize. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating a method for the linkage control of hydraulic equipment and electric injection molding equipment proposed in this invention. Figure 2 This is a schematic diagram of the architecture of a linkage control system for hydraulic equipment and electric injection molding equipment proposed in an embodiment of the present invention. Detailed Implementation

[0020] 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.

[0021] Example 1: In the first embodiment of the present invention, a method for linkage control of hydraulic equipment and electric injection molding equipment is provided, such as... Figure 1 As shown, the process includes the following steps: S1, collecting displacement and pressure signals from multiple sets of cylinders on the hydraulic equipment and interconnecting them with multiple sets of core control signals from the electric injection molding equipment. The core control signals include an injection completion signal used to trigger the pre-compression preparation action and an ejection signal used to adjust the pre-compression timing. Furthermore, in S1, the steps for interconnecting multiple sets of core control signals with the electric injection molding equipment include: Determine the type of communication protocol with the electric injection molding equipment; Complete the physical layer connection according to the communication protocol type; Configure the network parameters between the controller and the electric injection molding equipment; Establish the address mapping relationship between displacement and pressure signals and core control signals; Perform communication integration testing and obtain real-time verification results of signal transmission.

[0022] Specifically, in implementing step S1, when acquiring displacement and pressure signals from multiple sets of cylinders on the hydraulic equipment and interconnecting them with multiple sets of core control signals from the electric injection molding equipment, it is first necessary to determine the communication protocol type used between the controller and the electric injection molding equipment. This protocol type can be selected based on the equipment's interface capabilities, choosing industrial fieldbus protocols such as PROFIBUS, Modbus RTU, or real-time industrial Ethernet protocols such as Profinet, EtherCAT. After determining the protocol type, the physical layer connection of the cable or fiber optic cable is completed according to the physical layer specifications of the selected protocol, and the network parameters between the controller and the electric injection molding equipment are configured, including setting the IP address, subnet mask, communication baud rate, and data format. Next, an address mapping relationship is established between the displacement and pressure signals of each set of cylinders on the hydraulic equipment and the core control signals output by the electric injection molding equipment, such as the injection completion signal and ejection signal. This means allocating a corresponding input / output address in the controller's memory for each physical signal, enabling the controller to obtain the signal status by reading or writing these addresses. Alternatively, control commands can be output. After address mapping is completed, communication debugging is performed. The link is verified to be normal by sending test frames or exchanging heartbeat signals. The transmission delay time and data packet loss rate from the sending end to the receiving end are recorded to obtain the real-time verification result of signal transmission. This verification result is used to determine whether the current communication link meets the system's real-time requirements, such as whether the transmission delay is less than 2 milliseconds and there are no errors. If the verification result does not meet the preset real-time requirements, the network parameters need to be adjusted or the communication medium needs to be replaced until the requirements are met, thereby ensuring that the controller can accurately and with low latency obtain the status signals of the electric injection molding equipment and output control commands to the hydraulic cylinder in subsequent steps.

[0023] S2. All collected signals are fed into the controller, the corresponding pre-compression process formula is automatically loaded according to the current workpiece model, and control commands are output according to the preset collaborative logic algorithm. Furthermore, in S2, the step of outputting control commands according to the preset cooperative logic algorithm includes: The collected displacement signals, pressure signals, injection completion signals, and ejection signals are aligned according to a unified timing sequence. Calculate the difference between the aligned signals at adjacent sampling times to obtain the rate of change of each signal; Detect the sign change of the rate of change of each signal; When the sign of the rate of change of any signal changes from positive to negative or from negative to positive, a corresponding predictive control command is output according to the signal type before the signal reaches its extreme point.

[0024] Specifically, after all the acquired signals are fed into the controller, the controller automatically loads the corresponding pre-compression process formula according to the current workpiece model and outputs control commands based on the preset collaborative logic algorithm. The specific implementation of outputting control commands based on the preset collaborative logic algorithm is as follows: First, the acquired displacement signals, pressure signals, injection completion signals, and ejection signals are aligned according to a unified timing sequence to obtain the aligned signal sequence; let the... The displacement signal of the hydraulic cylinder at the sampling time The value is The pressure signal value is The injection molding completion signal is The top-out signal is The controller uses a fixed sampling period. These signals are acquired; then, the difference between each signal at adjacent sampling times is calculated to obtain the rate of change of each signal; for example, for a displacement signal, its rate of change is... Similarly, to calculate the rate of change of the pressure signal, for digital signals such as injection completion and ejection signals, the rate of change can be equivalently calculated by detecting the signal edges; then, the sign change of the rate of change of each signal is detected, i.e., monitoring... symbols and The system checks whether the signs of the signals are opposite. When the sign of the rate of change of any signal changes from positive to negative or from negative to positive, it determines that the signal is about to reach an extreme point. At this time, before the signal actually reaches the extreme point, the system outputs the corresponding predictive control command based on the signal type. For example, if the rate of change of the injection completion signal changes from positive to negative, it indicates that the injection completion signal is about to jump from a high level to a low level, and the controller can output a pre-pressure preparation command in advance. If the rate of change of the pressure signal changes from positive to negative, it indicates that the pressure is about to reach its peak value, and the controller can output a graded pressure increase switching command in advance. The output predictive control command is used to drive the hydraulic cylinder to perform the corresponding action in advance, thereby eliminating the lag caused by the response delay of the hydraulic system and realizing advanced control. The command is then sent to the actuator, such as a servo proportional valve, to adjust the clamping force or displacement of the cylinder.

[0025] S3. Before the welding process, control multiple sets of hydraulic cylinders to perform graded pressure increase and pre-pressure action. First, the workpiece is contacted with low pressure and the contact force of each set of hydraulic cylinders is balanced through pressure feedback. Then, the pressure is increased in stages to the target clamping force. During the pressure holding stage, the displacement feedback value is read periodically and the displacement deviation is actively micro-compensated. Furthermore, in S3, the steps of contacting the workpiece with low pressure and balancing the contact force of each group of cylinders through pressure feedback include: Send low-pressure feed commands to each group of hydraulic cylinders; Read the pressure feedback values ​​of each group of hydraulic cylinders to confirm the contact status; After all the hydraulic cylinders are in contact with the workpiece, calculate the average pressure value of each group of hydraulic cylinders. Based on the deviation between the pressure value of each group of hydraulic cylinders and the average pressure value, the drive signal of the corresponding hydraulic cylinder is adjusted independently.

[0026] Specifically, before the welding process, multiple sets of hydraulic cylinders are controlled to perform graded pressure boosting and pre-pressurization actions. First, the workpiece is contacted with low pressure, and the contact force of each set of cylinders is balanced through pressure feedback. Specifically, the controller sends low-pressure feed commands to each set of cylinders, driving the cylinder piston rods to move towards the workpiece surface. The controller operates at a sampling period... Read the pressure feedback values ​​of each group of hydraulic cylinders, and set the first... The hydraulic cylinder group is at all times Pressure feedback value ;when It starts from zero and rises above the preset contact detection threshold. When the controller detects that a group of hydraulic cylinders has made contact with the workpiece, it determines that the cylinder group has made contact. The controller continuously monitors the contact status of all cylinders until each group of cylinders... All greater than At this point, it is confirmed that all hydraulic cylinders are in contact with the workpiece; subsequently, the controller calculates the average pressure value of each group of hydraulic cylinders at this time. ;in The controller determines the number of cylinder groups; next, it calculates the pressure deviation for each cylinder group. ;according to The controller independently adjusts the drive signal for the corresponding hydraulic cylinder based on the sign and magnitude of the signal; if , indicating the first If the pressure in the hydraulic cylinder is too high, reduce the opening of the servo proportional valve for that cylinder to lower the pressure; if If the valve opening is increased, the pressure will be increased; the adjustment amount uses proportional control, that is, the valve opening adjustment amount is proportional to the pressure. Proportional; by repeatedly reading and adjusting the pressure feedback value, the contact force of each group of hydraulic cylinders gradually becomes more consistent, that is... Approaching zero; this equalization adjustment process ensures that the workpiece is subjected to uniform force during the low-pressure contact stage, avoiding workpiece deformation or positioning displacement due to local overpressure; after the contact force equalization is completed, the controller enters the stage of graded pressure increase to the target clamping force.

[0027] Furthermore, in S3, the step of progressively increasing the pressure to the target clamping force includes: S31. Decompose the target clamping force into multiple pressure step values; S32, issue a command to each group of hydraulic cylinders to increase the pressure to the current pressure step value; S33. Confirm that the pressure value of each group of hydraulic cylinders is stable within the allowable range of the current pressure step value; S34. Repeat steps S32 to S33 until the clamping force of each set of hydraulic cylinders reaches the target clamping force.

[0028] Specifically, in the step of gradually increasing the pressure to the target clamping force, the controller first decomposes the target clamping force into multiple pressure step values; let the target clamping force be... The pressure step number is , No. Pressure step value ;in These pressure step values ​​are pre-stored in the pre-pressurization process formula corresponding to the current workpiece model; the controller sends pressure boosting to each group of cylinders to the current pressure step value. The controller, following the instructions, drives the servo proportional valve to gradually increase the cylinder pressure; the controller operates at a sampling period... Read the pressure feedback values ​​of each group of hydraulic cylinders ;in This refers to the cylinder group number; for the current pressure step value. The controller confirms the pressure feedback value for each group of hydraulic cylinders. Whether it is stable within the allowable range, i.e., meets the requirements. ;in The preset pressure stability tolerance; when the pressure values ​​of all cylinders are within... Within the allowable range and the duration exceeds the preset stability time threshold. Afterwards, it is determined that the current step pressure has stabilized; subsequently, the controller will... Increase by 1, and issue a boost to the next pressure step value. The instruction is given, and the process of confirming stability is repeated; the pressure is increased step by step until... Pressure feedback values ​​of all hydraulic cylinders at that time All achieved the target clamping force Within the allowable range; through this step-by-step pressurization, the pressure shock caused by applying all the clamping force at once can be avoided, so that the workpiece is subjected to force smoothly and the workpiece and mold are protected from damage; after the step-by-step pressurization is completed, the controller enters the pressure holding stage, and begins to periodically read the displacement feedback value and perform active micro-compensation.

[0029] Furthermore, in S3, the steps of periodically reading the displacement feedback value and actively micro-compensating for the displacement deviation include: The displacement feedback values ​​of each group of hydraulic cylinders are read according to the preset sampling period; Calculate the displacement deviation between the displacement feedback value and the target displacement value; When the displacement deviation exceeds the preset allowable range, the amount of compensation oil is calculated based on the direction of the displacement deviation. The corresponding oil cylinder is controlled to perform oil replenishment or oil discharge actions based on the compensation oil quantity.

[0030] Specifically, during the pressure holding phase, the controller operates according to a preset sampling period. Read the displacement feedback values ​​of each group of hydraulic cylinders; let the first group... The hydraulic cylinder group is at all times The displacement feedback value This value is directly measured by a displacement sensor installed on the piston rod of the hydraulic cylinder; the controller stores the target displacement value of this group of hydraulic cylinders. The target displacement value is determined based on the pre-pressing process formula of the current workpiece model, representing the desired position that the hydraulic cylinder needs to maintain; the controller calculates the displacement deviation. ;when Exceeding the preset allowable range At that time, the controller calculates the amount of oil that needs to be compensated based on the direction of the displacement deviation; the amount of oil to be compensated... It is proportional to the displacement deviation and can be expressed as ;in The compensation coefficient's value is related to the cylinder's cross-sectional area, the hydraulic oil's elastic modulus, and the servo proportional valve's flow gain; if A positive value indicates that the actual displacement is less than the target displacement, requiring additional oil to extend the piston rod. In this case, the controller outputs a positive valve opening command. If... A negative value indicates that the actual displacement is greater than the target displacement, requiring oil release to retract the piston rod, and outputting a negative valve opening command; the controller then calculates the compensation oil quantity... The servo proportional valve driving the corresponding hydraulic cylinder performs oil replenishment or oil release actions, thus adjusting the displacement feedback value. Revert to target displacement value Nearby; by periodically performing the above displacement deviation detection and compensation, closed-loop position control during the pressure holding stage was achieved, effectively suppressing minor displacement drift caused by hydraulic oil leakage or seal deformation, and providing a stable positioning reference for subsequent welding processes.

[0031] S4. During the welding process, receive real-time process feedback signals from the welding equipment, and adjust the clamping force of the hydraulic cylinder near the corresponding welding area in advance according to the changing trend of the process feedback signals before the workpiece temperature rises, and make secondary compensation adjustments when the workpiece temperature rises. Furthermore, in S4, the step of pre-adjusting the clamping force of the hydraulic cylinder near the corresponding welding area before the workpiece temperature rises includes: Real-time reception of process feedback signals from welding equipment, which are either welding power signals or welding current signals; Calculate the rate of change of the process feedback signal per unit time; The rate of change is compared with multiple preset threshold intervals, each threshold interval corresponding to a pre-adjustment amount; Based on the comparison results, the hydraulic cylinder group corresponding to the current welding area is determined, and a clamping force reduction command is issued to the hydraulic cylinder group, with the reduction amount equal to the pre-adjustment amount.

[0032] Specifically, during the welding process, the controller receives process feedback signals from the welding equipment in real time, which are welding power signals. or welding current signal Let the current sampling time be... The received power value is Previous sampling time The power value is The sampling period is The controller calculates the rate of change of the power signal per unit time. The controller internally stores multiple threshold ranges, for example... Each threshold interval corresponds to a pre-adjustment amount. ;in The dimensionless proportionality constant represents the percentage decrease in clamping force; the calculated rate of change... Compare with these threshold intervals in turn to determine The corresponding pre-adjustment amount is obtained by determining the relevant interval. Simultaneously, the controller determines the set of cylinder group numbers corresponding to the current welding area based on the current working position of the welding equipment or the preset welding trajectory. Then, the controller sends a command to the cylinder assembly to reduce the clamping force, the reduction being equal to the pre-adjustment amount. That is, the target clamping force is updated to ;in The current clamping force is used to reduce the clamping force of the corresponding area cylinder before the workpiece temperature actually rises, in order to counteract the additional stress caused by the upcoming welding thermal expansion. After the instruction is output, the controller continues to monitor the rate of change of the process feedback signal and makes secondary compensation adjustments based on subsequent temperature detection.

[0033] Furthermore, in S4, the step of performing secondary compensation adjustment when a rise in workpiece temperature is detected includes: Receive workpiece surface temperature values ​​from the welding station in real time; Compare the workpiece surface temperature value with a first temperature threshold. When the surface temperature of the workpiece exceeds the first temperature threshold, read the current clamping force of the hydraulic cylinder group corresponding to the current welding area. Calculate the target clamping force after secondary compensation based on the current clamping force and the preset temperature and pressure compensation coefficient; The system sends a command to the hydraulic cylinder assembly to adjust to the target clamping force, and then sends a command to the hydraulic cylinder assembly to restore the original target clamping force when the workpiece surface temperature is subsequently detected to be lower than the second temperature threshold.

[0034] Specifically, during the secondary compensation adjustment process when a rise in workpiece temperature is detected, the controller receives the workpiece surface temperature value from the welding station in real time. The temperature value is measured by a temperature sensor installed near the welding area, with a sampling period identical to the controller's control period; the controller has a preset first temperature threshold. Second temperature threshold ;in Used to trigger secondary compensation Used to restore the original clamping force, and Below The controller will display the current workpiece surface temperature value. With the first temperature threshold Compare; when When the workpiece surface temperature is determined to have risen significantly, secondary compensation is required; at this time, the controller reads the current clamping force of the hydraulic cylinder group corresponding to the current welding area. This value is obtained in real time from the pressure sensor; the controller calculates the value based on the preset temperature and pressure compensation coefficient. Calculate the target clamping force after secondary compensation The unit of 'in' is force per degree Celsius, representing the reduction in clamping force required to increase temperature by one unit. This formula indicates that when the temperature exceeds... The more cylinders there are, the greater the reduction in clamping force; the controller sends an adjustment to the target clamping force to the corresponding cylinder group. The controller receives commands to drive a servo proportional valve to adjust the cylinder pressure; in subsequent sampling cycles, the controller continuously monitors the workpiece surface temperature. When detected Below the second temperature threshold When the welding process is complete and the workpiece has cooled to a safe temperature, the controller sends a force to the hydraulic cylinder assembly to restore the original target clamping force. The instructions, in which The target clamping force is set before welding begins. Through the above-mentioned secondary compensation adjustment, the clamping force is dynamically adapted to the temperature change during the welding process, which not only avoids the workpiece deformation due to excessive pressure during high temperature periods, but also ensures the timely recovery of the clamping force after cooling.

[0035] S5. After welding is completed, the welding quality deviation data fed back by the testing equipment is received, the welding quality deviation is converted into pre-pressure positioning error, and the pre-pressure parameters of the workpiece of this model in the next cycle are automatically corrected. Furthermore, in S5, the step of automatically correcting the preload parameters of this type of workpiece for the next cycle includes: Obtain welding quality deviation data fed back by the testing equipment; Based on the preset deviation-preload parameter mapping relationship, the welding quality deviation data is converted into preload positioning error; The correction amount of the preload position target value is calculated based on the preload positioning error, and the correction amount is limited to ensure that the correction amount does not exceed the preset maximum correction value. The correction amount after the amplitude limit is added to the corresponding parameter in the pre-compression process formula of the current workpiece model.

[0036] Specifically, after welding is completed, the controller acquires welding quality deviation data fed back by the inspection equipment; the inspection equipment is an automatic optical inspection device, and its output welding quality deviation data includes the weld point's position... directional offset and directional offset The controller has a pre-set deviation-preload parameter mapping relationship, which can be represented by a linear transformation matrix; the welding quality deviation data is converted into preload positioning error, that is, the preload positioning error is within... Components of direction ,exist Components of direction ;in The mapping coefficients, pre-calibrated through experiments, represent the transmission relationship between weld point offset and cylinder positioning error; the correction amount for the preload position target value is calculated based on the preload positioning error, for the first... Hydraulic cylinder assembly, its correction amount ;in and For the first The position weighting coefficient of the hydraulic cylinder group in the workpiece coordinate system indicates the degree of influence of the hydraulic cylinder on the welding point positioning; the controller adjusts the correction amount. If amplitude limiting is applied, that is... Then let ;like Then let ;in To preset the maximum correction value and prevent excessive single correction from causing parameter oscillations; finally, the correction amount after limiting... The target preload position parameter is superimposed onto the corresponding hydraulic cylinder in the preload process formula for the current workpiece model, i.e., the updated target position. The updated formula is stored in the controller for preload control of the same type of workpiece in the next cycle. Through this self-correcting mechanism, the system can gradually optimize the preload positioning parameters based on historical welding quality, thereby improving the accuracy of subsequent welding.

[0037] S6. When the displacement or pressure deviation of any set of hydraulic cylinders exceeds the preset safety range, the welding process is interrupted and an alarm is output. Furthermore, in S6, the steps for interrupting the welding process and outputting an alarm when the displacement or pressure deviation exceeds the preset safety range include: Real-time reading of displacement and pressure feedback values ​​for each group of hydraulic cylinders; Calculate the displacement deviation and pressure deviation values ​​for each group of hydraulic cylinders; Compare the displacement deviation value with the preset displacement safety threshold, and compare the pressure deviation value with the preset pressure safety threshold; When the displacement deviation of any set of hydraulic cylinders exceeds the preset displacement safety threshold or the pressure deviation exceeds the preset pressure safety threshold, an interrupt command is generated and an alarm signal is triggered, and an automatic reset attempt is performed at the same time; if the reset fails, the equipment is locked.

[0038] Specifically, during the welding process, the controller reads the displacement feedback values ​​of each group of hydraulic cylinders in real time. and pressure feedback value The displacement feedback value is measured by a displacement sensor installed at the piston rod of the hydraulic cylinder, and the pressure feedback value is measured by a pressure sensor on the hydraulic cylinder circuit; the controller determines the target displacement value based on the pre-pressurization process formula. and target pressure value Calculate the first Displacement deviation value of hydraulic cylinder group and pressure deviation value The controller has a preset displacement safety threshold. and pressure safety threshold ; the absolute value of the displacement deviation and Compare the absolute values ​​of the pressure deviations. and Compare; when or When the system detects an abnormal state, the controller immediately generates an interrupt command and sends it to the welding equipment via the digital output port to stop the welding process. Simultaneously, it triggers an audible and visual alarm to notify the operator. After triggering the interrupt and alarm, the controller performs an automatic reset attempt, slowly unloading each group of cylinders to their initial position according to a preset reset procedure and re-executing the initial self-test program. If the reset procedure is successful, the equipment enters standby mode to await the next start command. If the reset attempt fails, for example, if the cylinder displacement or pressure still exceeds the safe range, the controller locks the equipment, prohibiting any automatic actions and continuously outputting alarm signals until manual intervention unlocks the system. This abnormal handling mechanism effectively prevents mold damage or workpiece scrap caused by hydraulic system malfunctions.

[0039] Example 2: In the second embodiment of the present invention, the present invention provides a linkage control system for hydraulic equipment and electric injection molding equipment, such as... Figure 2 As shown, it includes the following modules: The signal interconnection module is used to collect displacement and pressure signals of multiple sets of cylinders on the hydraulic equipment and interconnect with multiple sets of core control signals of the electric injection molding equipment. The core control signals include an injection completion signal for triggering the pre-compression preparation action and an ejection signal for adjusting the pre-compression timing. The collaborative decision output module is used to integrate all collected signals into the controller, automatically load the corresponding pre-compression process formula according to the current workpiece model, and output control commands according to the preset collaborative logic algorithm. The graded pre-pressure and pressure holding module is used to control multiple sets of hydraulic cylinders to perform graded pressure increase and pre-pressure actions before the welding process. First, the workpiece is contacted with low pressure and the contact force of each set of hydraulic cylinders is balanced through pressure feedback. Then, the pressure is increased in stages to the target clamping force. During the pressure holding stage, the displacement feedback value is read periodically and the displacement deviation is actively micro-compensated. The welding heat compensation module is used to receive real-time process feedback signals from the welding equipment during the welding process, adjust the clamping force of the hydraulic cylinder near the corresponding welding area in advance according to the changing trend of the process feedback signals before the workpiece temperature rises, and perform secondary compensation adjustment when the workpiece temperature rises. The quality self-correction module is used to receive welding quality deviation data fed back by the testing equipment after welding is completed, convert the welding quality deviation into pre-pressure positioning error, and automatically correct the pre-pressure parameters of the workpiece of this model in the next cycle. The safety interruption protection module is used to interrupt the welding process and output an alarm when the displacement or pressure deviation of any group of hydraulic cylinders exceeds the preset safety range.

[0040] In the mid-frame assembly and welding production line, after the electric injection molding equipment completes the injection molding of the mid-frame, it needs to go through laser marking, AOI inspection, spring assembly, ultrasonic welding, and laser welding of metal springs to complete the finished product processing. This mid-frame is an irregularly shaped thin-walled structure, requiring extremely high welding precision; a pre-pressing positioning deviation exceeding ±0.01mm will cause weld point misalignment. Under traditional control methods, the hydraulic clamps experience inaccurate positioning due to cylinder displacement drift during pre-pressing, and thermal expansion during welding causes mid-frame deformation. Furthermore, manual parameter adjustment is required when changing production of different mid-frame models, resulting in large fluctuations in welding yield and low changeover efficiency. To solve these problems, this invention provides a linkage control system for hydraulic equipment and electric injection molding equipment, the structure of which is as follows: Figure 2 As shown. The specific implementation process of this system is as follows: First, the signal interconnection module collects the displacement and pressure signals of the eight sets of cylinders on the hydraulic equipment and interconnects with the injection completion and ejection signals of the electric injection molding equipment to ensure that the hydraulic action is precisely synchronized with the injection cycle and avoid waiting or misalignment caused by signal delay. Then, the collaborative decision output module integrates all the collected signals into the controller, automatically loads the corresponding pre-compression process formula according to the current mid-frame model, and outputs control commands according to the preset collaborative logic algorithm to achieve rapid switching between different models without manual intervention. Next, the graded pre-pressure holding module controls 8 sets of hydraulic cylinders to contact the middle frame at low pressure before the welding process and balances the contact force of each set of hydraulic cylinders through pressure feedback. Then, it increases the pressure in stages to the target clamping force. At the same time, during the pressure holding stage, it periodically reads the displacement feedback value and actively performs micro-compensation for the displacement deviation, thereby eliminating the small displacement caused by hydraulic cylinder leakage and ensuring that the positioning accuracy of the middle frame before welding is at the micron level. Then, the welding heat compensation module receives the real-time power signal of the ultrasonic welding machine or laser welding machine during the welding process. Based on the trend of the power signal change, it pre-adjusts the clamping force of the oil cylinder near the corresponding welding area before the temperature rises, and performs secondary compensation adjustment when the temperature rise is detected, effectively suppressing the deformation of the middle frame caused by welding thermal expansion. Subsequently, after welding is completed, the quality self-correction module receives the weld point position deviation data fed back by the automatic optical inspection equipment, converts the deviation into preload positioning error, and automatically corrects the preload parameters of the same model frame in the next cycle, so that the welding quality is gradually optimized. Finally, the safety interruption protection module will immediately interrupt the welding process and output an alarm when the displacement or pressure deviation of any set of cylinders exceeds the preset safety range. At the same time, it will perform an automatic reset attempt. If the reset fails, the equipment will be locked to avoid damage to the mold and scrap of the workpiece.

[0041] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for linkage control of hydraulic equipment and electric injection molding equipment, characterized in that, Includes the following steps: S1. Collect displacement and pressure signals of multiple sets of cylinders on the hydraulic equipment and interconnect them with multiple sets of core control signals of the electric injection molding equipment. The core control signals include injection completion signals for triggering pre-compression preparation actions and ejection signals for adjusting pre-compression timing. S2. All collected signals are fed into the controller, the corresponding pre-compression process formula is automatically loaded according to the current workpiece model, and control commands are output according to the preset collaborative logic algorithm. S3. Before the welding process, control multiple sets of hydraulic cylinders to perform graded pressure increase and pre-pressure action. First, the workpiece is contacted with low pressure and the contact force of each set of hydraulic cylinders is balanced through pressure feedback. Then, the pressure is increased in stages to the target clamping force. During the pressure holding stage, the displacement feedback value is read periodically and the displacement deviation is actively micro-compensated. S4. During the welding process, receive real-time process feedback signals from the welding equipment, and adjust the clamping force of the hydraulic cylinder near the corresponding welding area in advance according to the changing trend of the process feedback signals before the workpiece temperature rises, and perform secondary compensation adjustment when the workpiece temperature rises. S5. After welding is completed, the welding quality deviation data fed back by the testing equipment is received, the welding quality deviation is converted into pre-pressure positioning error, and the pre-pressure parameters of the workpiece of this model in the next cycle are automatically corrected. S6. When the displacement or pressure deviation of any set of hydraulic cylinders exceeds the preset safety range, the welding process is interrupted and an alarm is output.

2. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S1, the step of interconnecting and communicating with multiple sets of core control signals of the electric injection molding equipment includes: Determine the type of communication protocol with the electric injection molding equipment; Complete the physical layer connection according to the communication protocol type; Configure the network parameters between the controller and the electric injection molding equipment; Establish the address mapping relationship between the displacement signal and the pressure signal and the core control signal; Perform communication integration testing and obtain real-time verification results of signal transmission.

3. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S2, the step of outputting control commands according to a preset cooperative logic algorithm includes: The collected displacement signals, pressure signals, injection completion signals, and ejection signals are aligned according to a unified timing sequence. Calculate the difference between the aligned signals at adjacent sampling times to obtain the rate of change of each signal; Detect the sign change of the rate of change of each signal; When the sign of the rate of change of any signal changes from positive to negative or from negative to positive, a corresponding predictive control command is output according to the signal type before the signal reaches its extreme point.

4. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S3, the step of contacting the workpiece with low pressure and balancing the contact force of each group of hydraulic cylinders through pressure feedback includes: Send low-pressure feed commands to each group of hydraulic cylinders; Read the pressure feedback values ​​of each group of hydraulic cylinders to confirm the contact status; After all the hydraulic cylinders are in contact with the workpiece, calculate the average pressure value of each group of hydraulic cylinders. Based on the deviation between the pressure value of each group of hydraulic cylinders and the average pressure value, the drive signal of the corresponding hydraulic cylinder is adjusted independently.

5. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S3, the step of progressively increasing the pressure to the target clamping force includes: S31. Decompose the target clamping force into multiple pressure step values; S32, issue a command to each group of hydraulic cylinders to increase the pressure to the current pressure step value; S33. Confirm that the pressure value of each group of hydraulic cylinders is stable within the allowable range of the current pressure step value; S34. Repeat steps S32 to S33 until the clamping force of each set of hydraulic cylinders reaches the target clamping force.

6. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S3, the step of periodically reading the displacement feedback value and actively micro-compensating for the displacement deviation includes: The displacement feedback values ​​of each group of hydraulic cylinders are read according to the preset sampling period; Calculate the displacement deviation between the displacement feedback value and the target displacement value; When the displacement deviation exceeds the preset allowable range, the amount of compensation oil is calculated based on the direction of the displacement deviation; The corresponding oil cylinder is controlled to perform oil replenishment or oil discharge actions based on the compensation oil quantity.

7. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S4, the step of pre-adjusting the clamping force of the hydraulic cylinder near the corresponding welding area before the workpiece temperature rises includes: The process feedback signal of the welding equipment is received in real time, and the process feedback signal is a welding power signal or a welding current signal. Calculate the rate of change of the process feedback signal per unit time; The rate of change is compared with multiple preset threshold intervals, each threshold interval corresponding to a pre-adjustment amount; Based on the comparison results, the hydraulic cylinder group corresponding to the current welding area is determined, and a clamping force reduction command is issued to the hydraulic cylinder group, with the reduction amount equal to the pre-adjustment amount.

8. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S4, the step of performing secondary compensation adjustment when a rise in workpiece temperature is detected includes: Receive workpiece surface temperature values ​​from the welding station in real time; The surface temperature value of the workpiece is compared with a first temperature threshold. When the surface temperature of the workpiece exceeds the first temperature threshold, the current clamping force of the hydraulic cylinder group corresponding to the current welding area is read. The target clamping force after secondary compensation is calculated based on the current clamping force and the preset temperature and pressure compensation coefficient. The hydraulic cylinder assembly is given a command to adjust to the target clamping force, and when the surface temperature of the workpiece is subsequently detected to be lower than the second temperature threshold, the hydraulic cylinder assembly is given a command to restore to the original target clamping force.

9. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S5, the step of automatically correcting the preload parameters of the workpiece of this model for the next cycle includes: Obtain welding quality deviation data fed back by the testing equipment; Based on the preset deviation-preload parameter mapping relationship, the welding quality deviation data is converted into preload positioning error; The correction amount of the preload position target value is calculated based on the preload positioning error, and the correction amount is limited to ensure that the correction amount does not exceed the preset maximum correction value. The correction amount after the amplitude limit is added to the corresponding parameter in the pre-compression process formula of the current workpiece model.

10. The method for linkage control of hydraulic equipment and electric injection molding equipment according to claim 1, characterized in that, In S6, the step of interrupting the welding process and outputting an alarm when the displacement deviation or pressure deviation exceeds the preset safety range includes: Real-time reading of displacement and pressure feedback values ​​for each group of hydraulic cylinders; Calculate the displacement deviation and pressure deviation values ​​for each group of hydraulic cylinders; The displacement deviation value is compared with a preset displacement safety threshold, and the pressure deviation value is compared with a preset pressure safety threshold. When the displacement deviation of any set of hydraulic cylinders exceeds the preset displacement safety threshold or the pressure deviation exceeds the preset pressure safety threshold, an interrupt command is generated and an alarm signal is triggered, and an automatic reset attempt is performed at the same time; if the reset fails, the equipment is locked.

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