An adaptive compensation method, system and electronic equipment for the injection end speed of a die casting machine.

Abstract

This invention discloses an adaptive compensation method, system, and electronic equipment for the injection end speed of a die-casting machine, relating to the field of die-casting machine control technology. After determining that speed compensation is needed, this invention calculates a corrected flow rate by introducing the actual pressure difference and theoretical flow rate of the servo valve. Based on the corrected flow rate, the feedforward valve opening is obtained, and combined with the closed-loop valve opening calculated based on the deviation between the actual speed and the target speed, the final servo valve compensation opening is determined. Compared to existing technologies that rely solely on speed deviation for single closed-loop adjustment, this composite control strategy comprehensively considers the pressure difference state under the current operating conditions, making the calculation of the compensation opening more accurately reflect the actual flow rate requirement. This provides a more precise compensation amount when the resistance at the injection end increases, effectively mitigating the speed drop and thus improving the casting quality.

Description

Technical Field

[0001] This invention relates to the field of die-casting machine control technology, and in particular to an adaptive compensation method, system and electronic equipment for the injection end speed of a die-casting machine. Background Technology

[0002] During the injection process in a die-casting machine, the injection rod pushes molten metal into the mold cavity from a slow to a fast rate. Towards the end of the injection, the pressure inside the injection chamber rises sharply due to the rapid compression of the molten metal. As the pressure continues to increase, the resistance during the final stroke increases, causing the injection speed to deviate rapidly from the set curve. This ultimately leads to incomplete filling, resulting in defects such as porosity or cold shuts in the product. This remains a persistent technical challenge in the industry.

[0003] In existing technologies, the conventional approach is to use closed-loop control to compensate for speed reduction. However, closed-loop control is a passive response mechanism; the controller only outputs a significant compensation signal when the speed error accumulates to a certain level. In addition, the hydraulic circuit itself has a response hysteresis, and in the extremely short time at the end of the injection, it is often impossible to restore the speed to the target value in time, resulting in quality problems such as poor casting filling, air entrapment, or cold shut. Summary of the Invention

[0004] To overcome the problem of untimely speed compensation at the injection end due to response lag and hydraulic hysteresis in existing closed-loop control, this invention proposes an adaptive speed compensation method for the injection end of a die-casting machine, comprising: The position of the injection rod during the injection of the die-casting machine is obtained, and it is determined whether the current position is in the compensation range based on the position of the injection rod. The compensation range is the end of the high-speed section. If the current position of the injection rod is within the compensation range, the actual speed of the injection rod is continuously collected at a preset control cycle. Based on the actual speed of the injection rod in multiple control cycles, the speed characteristics are calculated, and the speed drop coefficient is calculated by combining the speed characteristics. Based on the speed drop coefficient, it is determined whether compensation is needed. When compensation is required, the target speed of the current control cycle is obtained, the theoretical flow rate is calculated based on the target speed, the actual pressure difference of the servo valve is obtained, the actual pressure difference is compared with the standard pressure difference, and the corrected flow rate is calculated in combination with the theoretical flow rate. Based on the corrected flow rate, the feedforward valve opening is obtained, the speed difference between the target speed and the corresponding actual speed in the current control cycle is calculated, and closed-loop control calculation is performed based on the speed difference to obtain the corresponding closed-loop valve opening. Combining the feedforward valve opening and the closed-loop valve opening, the servo valve compensation opening is determined, and the servo valve core position is controlled based on the servo valve compensation opening.

[0005] Further, determining whether the current position is within the compensation range based on the position of the injection rod includes: Determine whether the position of the injection rod is between the starting point and the ending point of the high-speed phase; The determination of the starting point of the high-speed terminal segment includes: Obtain the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, and set the rising inflection point as the reference value of the starting point of the high-speed end segment. Based on the reference value and the preset safety margin, the starting point of the high-speed terminal segment is set; The determination of the end point of the high-speed terminal segment includes: Obtain the preset pressure threshold and minimum safe braking distance, compare the pressure curve and the pressure threshold to determine the threshold point, compare the minimum safe braking distance and the total injection stroke to determine the adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

[0006] Furthermore, the actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

[0007] Furthermore, the step of calculating the speed drop coefficient based on the comprehensive speed characteristics, and determining whether compensation is needed based on the speed drop coefficient, includes: Based on the speed drop trend, speed drop rate, speed drop magnitude and corresponding weighting coefficients, a speed drop degree coefficient is calculated, wherein the weighting coefficients are adjusted based on the injection process requirements of the die casting machine. By comparing the speed drop coefficient with the compensation activation threshold, it is determined whether compensation is needed based on the comparison results.

[0008] Further, the process of obtaining the target speed of the current control cycle, calculating the theoretical flow rate based on the target speed, obtaining the actual differential pressure of the servo valve, comparing the actual differential pressure with the standard differential pressure, and calculating the corrected flow rate in conjunction with the theoretical flow rate includes: Obtain the target speed of the current control cycle and the effective working area of ​​the injection cylinder, and calculate the theoretical flow rate based on the target speed and the effective working area; Collect the inlet and outlet pressures of the servo valve, and calculate the actual pressure difference based on the inlet and outlet pressures; Calculate the pressure difference ratio between the actual pressure difference and the standard pressure difference, take the square root of the pressure difference ratio to obtain the pressure difference coefficient, and divide the theoretical flow rate by the pressure difference coefficient to obtain the corrected flow rate.

[0009] Furthermore, the step of performing closed-loop control calculations based on this speed difference to obtain the corresponding closed-loop valve opening includes: Based on the speed difference, PID calculation is performed to obtain a preliminary correction amount, which is the increment of the valve opening. Obtain the gain coefficient, and multiply the initial correction amount by the gain coefficient to obtain the closed-loop correction amount; The closed-loop correction amount is determined as the corresponding closed-loop valve opening. The gain coefficient is dynamically adjusted based on the rate drop coefficient.

[0010] This invention also proposes an adaptive compensation system for the injection end speed of a die-casting machine, comprising: The interval determination module is used to obtain the position of the injection rod during the injection of the die-casting machine, and determine whether the current period is in the compensation interval based on the position of the injection rod. The compensation interval is the high-speed end section. The compensation determination module is used to continuously collect the actual speed of the injection rod at a preset control cycle if the current position of the injection rod is in the compensation range, calculate the speed characteristics based on the actual speed of the injection rod in multiple control cycles, calculate the speed drop coefficient based on the speed characteristics, and determine whether compensation is needed based on the speed drop coefficient. The calculation module is used to obtain the target speed of the current control cycle when it is determined that compensation is needed, calculate the theoretical flow rate based on the target speed, obtain the actual pressure difference of the servo valve, compare the actual pressure difference with the standard pressure difference, and calculate the corrected flow rate by combining the theoretical flow rate. The compensation module is used to obtain the feedforward valve opening based on the corrected flow rate, calculate the speed difference between the target speed and the corresponding actual speed in the current control cycle, perform closed-loop control calculation based on the speed difference to obtain the corresponding closed-loop valve opening, combine the feedforward valve opening and the closed-loop valve opening to determine the servo valve compensation opening, and control the servo valve core position based on the servo valve compensation opening.

[0011] Furthermore, the interval determination module includes: The judgment unit is used to determine whether the position of the injection rod is between the starting point and the ending point of the high-speed final stage; The starting point determination unit is used to acquire the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, set the rising inflection point as the reference value of the starting point of the high-speed end segment, and determine the starting point of the high-speed end segment based on the reference value and the preset safety margin. The end point determination unit is used to obtain a preset pressure threshold and a minimum safe braking distance, compare the pressure curve and the pressure threshold to determine a threshold point, compare the minimum safe braking distance and the total injection stroke to determine an adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

[0012] Furthermore, the actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

[0013] This invention also proposes an electronic device, including: a processor, and a memory storing a program, the program including instructions, which, when executed by the processor, cause the processor to perform an adaptive compensation method for the injection end speed of a die-casting machine as described above.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] (1) After determining that speed compensation is required, this invention calculates the corrected flow rate by introducing the actual differential pressure and theoretical flow rate of the servo valve, obtains the feedforward valve opening based on the corrected flow rate, and combines it with the closed-loop valve opening calculated based on the deviation between the actual speed and the target speed to jointly determine the final servo valve compensation opening. Compared with the prior art that relies solely on speed deviation for single closed-loop adjustment, this composite control strategy can comprehensively consider the differential pressure state under the current operating conditions, making the calculation of the compensation opening more accurately reflect the actual flow demand, thereby providing a more precise compensation amount when the resistance at the injection end increases, effectively reducing the speed drop, and thus improving the casting forming quality.

[0016] (2) This invention calculates a speed drop severity coefficient by comprehensively considering three dimensions of speed characteristics: speed drop trend, speed drop rate, and speed drop amplitude. This coefficient is then compared with a compensation trigger threshold to determine whether compensation is necessary. This method can more reliably distinguish between normal fluctuations and true speed drops, making a judgment at the initial stage of speed drop. This avoids unnecessary compensation actions and ensures timely intervention when truly needed, achieving intelligent and precise compensation triggering. In contrast, existing technologies typically initiate compensation directly after detecting a speed decrease, lacking a comprehensive assessment of the severity of the speed drop. This can easily lead to false triggering of compensation during normal speed fluctuations or overcompensation during slight speed drops, thus introducing new speed fluctuations.

[0017] (3) This invention continuously monitors the actual speed of the injection rod within the compensation range and calculates speed characteristics (including speed drop trend, speed drop rate, and speed drop magnitude) based on actual speed data from multiple control cycles. It then comprehensively calculates the speed drop degree coefficient to determine whether compensation is needed. Compared to the traditional method that relies solely on a single speed deviation threshold, this method can identify the speed drop trend earlier and trigger compensation determination before the speed deviation has accumulated significantly, thereby shortening the compensation response delay and providing more time for subsequent compensation control. Attached Figure Description

[0018] Figure 1 This is a flowchart of an adaptive compensation method for the injection end speed of a die-casting machine according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the compensation interval in an embodiment of the present invention; Figure 3 This is a block diagram of an adaptive compensation system for the injection end speed of a die-casting machine according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0019] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0020] To overcome the problem of untimely speed compensation caused by response lag and hydraulic hysteresis at the end of the injection phase in existing closed-loop control, such as... Figure 1 As shown, this invention proposes an adaptive compensation method for the injection end speed of a die-casting machine, comprising: The position of the injection rod during the injection of the die-casting machine is obtained, and it is determined whether the current position is in the compensation range based on the position of the injection rod. The compensation range is the end of the high-speed section. During the injection process, the position of the injection rod is acquired in real time by a position sensor (such as a magnetic grating ruler, optical grating ruler, or high-precision encoder). The position sensor can be time-triggered (e.g., sampling once every 0.1 milliseconds) or position-triggered (e.g., sampling once every 0.01 mm of movement) to obtain high-precision, high-real-time position data.

[0021] The step of determining whether the current position is within the compensation range based on the position of the injection rod includes: Determine whether the position of the injection rod is between the starting point and the ending point of the high-speed phase; The determination of the starting point of the high-speed terminal segment includes: Obtain the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, and set the rising inflection point as the reference value of the starting point of the high-speed end segment. Based on the reference value and the preset safety margin, the starting point of the high-speed terminal segment is set; The determination of the end point of the high-speed terminal segment includes: Obtain the preset pressure threshold and minimum safe braking distance, compare the pressure curve and the pressure threshold to determine the threshold point, compare the minimum safe braking distance and the total injection stroke to determine the adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

[0022] Specifically, the injection process of a die-casting machine is divided into multiple stages. For example... Figure 2 As shown in the figure (where the horizontal axis P represents the position of the injection rod and the vertical axis V represents the speed of the injection rod), a typical injection process can be divided into an acceleration phase (S1), a high-speed initial phase (S2), a high-speed final phase (S3), and a braking phase (S4). Among them, the S3 interval is the aforementioned compensation interval. During this stage, the speed drop is most significant due to the sharp increase in cavity filling resistance, which has the greatest impact on the casting quality. Therefore, it is necessary to perform servo valve opening compensation control during this critical window period.

[0023] Specifically, the high-speed final segment begins at the starting point of the high-speed final segment and ends at the ending point of the high-speed final segment. The method for determining the starting point of the high-speed final stage includes: during the die-casting machine trial molding stage, obtaining the pressure curve of the complete injection process; identifying the inflection point on the pressure curve where the pressure begins to rise significantly from a stable state; and using the injection rod position corresponding to this inflection point as a reference value for the starting point of the high-speed final stage. To improve robustness, the reference value can be averaged based on the results of multiple trial moldings, and combined with a preset safety margin (e.g., subtracting 1mm to 2mm from the reference value) to ensure that the compensation preparation state is entered before the actual pressure rises sharply, thereby obtaining the final starting point of the high-speed final stage.

[0024] The method for determining the high-speed final stage end point includes: setting a pressure threshold during mold testing; when the pressure sensor detects that the injection pressure exceeds the threshold, recording the current injection rod position as the threshold point; simultaneously, calculating the minimum safe braking distance required for the injection rod to decelerate from the current speed to a complete stop based on the current movement speed of the injection rod, the maximum deceleration capacity provided by the die-casting machine's hydraulic system, and a preset safety margin coefficient; wherein, the minimum safe braking distance is the product of the theoretical braking distance and a safety margin coefficient greater than 1, used to ensure smooth deceleration and avoid overshoot. Subsequently, retracting this minimum safe braking distance forward (i.e., towards the starting direction) from the end position of the total injection stroke to obtain the safety limit position. Finally, comparing the injection rod position corresponding to the threshold point with the safety limit position, selecting the smaller value (i.e., the position closer to the injection start point) as the high-speed final stage end point, to balance filling adequacy and braking safety.

[0025] If the current position of the injection rod is within the compensation range, the actual speed of the injection rod is continuously collected at a preset control cycle. Based on the actual speed of the injection rod in multiple control cycles, the speed characteristics are calculated, and the speed drop coefficient is calculated by combining the speed characteristics. Based on the speed drop coefficient, it is determined whether compensation is needed. The actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

[0026] Specifically, after determining that the current position of the injection lever is within the compensation range, the actual velocity value of the injection lever is continuously acquired at a preset control cycle (e.g., 1 millisecond). The actual velocity values ​​of the most recent N control cycles are stored in a circular buffer. Then, a real-time velocity curve is fitted based on the actual velocity values ​​of the most recent N control cycles, and the corresponding velocity characteristics are calculated. These velocity characteristics include, but are not limited to: Speed ​​Drop Trend P1: This detects the number of control cycles in which the injection lever speed continuously decreases, tracing back from the current control cycle. Specifically, it compares sequentially from the current control cycle backward. If the injection lever speed in the current control cycle is less than the injection lever speed in the previous cycle, it is considered a drop. The total number of control cycles that continuously meet this drop condition is counted as the value of P1. A preset threshold m for the number of consecutive drops is set. When P1 is greater than or equal to m, it indicates a continuous downward trend. A single speed fluctuation (e.g., a drop in one cycle followed by a rise in the next) will result in a small P1 value (not reaching the threshold m), thus being identified as noise or a minor disturbance. However, a continuous drop across multiple control cycles will cause the P1 value to accumulate, indicating that the speed drop trend is real and ongoing.

[0027] Speed ​​Drop Rate P2: Calculates the rate of speed change in the current control cycle relative to the previous control cycle, i.e., the degree of speed change. Specifically, it is the ratio of the speed difference between two control cycles to the time interval. When the speed difference is negative (i.e., speed decreases), the absolute value of this ratio is taken as the speed drop rate; when the speed difference is positive (i.e., speed increases), the speed drop rate is recorded as 0. A larger speed drop rate indicates a rapid decrease in the injection rod speed within a short period, requiring stronger compensation; a smaller ratio suggests a potentially slow change.

[0028] Speed ​​drop amplitude P3: This represents the deviation between the injection rod speed and the set speed in the current control cycle. The set speed is the target speed corresponding to the current control cycle, derived from a preset injection process speed curve. By reading the set speed and actual speed values ​​of the current control cycle, the speed error is calculated, and this error directly reflects the degree of speed loss at the current moment.

[0029] After determining multiple speed characteristics, the deceleration trend P1, deceleration rate P2, and deceleration amplitude P3 are first normalized to convert them into dimensionless feature scores. Specific normalization methods can employ techniques commonly used in the field, such as table lookup, linear mapping, or division by a preset threshold, mapping P1, P2, and P3 to the same order of magnitude (e.g., the 0-1 interval) to eliminate the influence of dimensional differences on the weighted results.

[0030] The calculation of the speed drop degree coefficient based on the comprehensive speed characteristics, and the determination of whether compensation is needed based on the speed drop degree coefficient, include: Based on the speed drop trend, speed drop rate, speed drop magnitude and corresponding weighting coefficients, a speed drop degree coefficient is calculated, wherein the weighting coefficients are adjusted based on the injection process requirements of the die casting machine. Among them, the weighting coefficients Q1 (speed drop trend weight), Q2 (speed drop rate weight), and Q3 (speed drop magnitude weight) corresponding to the speed drop trend P1, speed drop rate P2, and speed drop magnitude P3, respectively, range from 0.1 to 1.0. The weighting allocation reflects the sensitivity of the process to different speed characteristics. For example: If a greater focus is placed on persistent trends, Q1 can be increased; If the site is particularly sensitive to rapid changes in speed, Q2 can be increased; If more emphasis is placed on the deviation between the actual speed and the target speed, Q3 can be increased.

[0031] By comparing the speed drop coefficient with the compensation activation threshold, it is determined whether compensation is needed based on the comparison results.

[0032] Specifically: Based on the deceleration trend, deceleration rate, deceleration magnitude, and corresponding weighting coefficients, the deceleration severity coefficient is calculated as follows: Based on the normalized deceleration trend P1, deceleration rate P2, and deceleration magnitude P3, these are weighted and fused with their corresponding weighting coefficients to calculate the deceleration degree coefficient.

[0033] Thus, this embodiment fuses the features of three dimensions—speed drop trend, speed drop rate, and speed drop magnitude—to calculate a speed drop severity coefficient Z, representing the severity of the speed drop. This achieves quantification of the severity of speed drop and avoids the limitations of judging based on a single feature.

[0034] In the calculation of the deceleration degree coefficient Z, P1 plays a dominant role (i.e., it has a higher weighting coefficient Q1). This means that only when the deceleration is persistent (high P1) will the high values ​​of P2 and P3 be effectively included in the Z value; conversely, if P1 is low (non-persistent), the Z value will be significantly suppressed.

[0035] For example, in the following scenarios: Scenario A (gradual deceleration): The speed continues to decrease (P1 high, P2 low, P3 medium). Due to the high weight of P1, the Z value remains at a high level. Scenario B (Sudden speed drop): The speed drops sharply and instantaneously (medium in P1, high in P2, high in P3). With P1 reaching a medium level, the high values ​​of P2 and P3 are superimposed, and the Z value is still at a high level. Scenario C (random noise): Single random disturbance (P1 low, P2 high, P3 high). Since P1 is low, the calculation result of Z value is greatly suppressed. Even if P2 and P3 are high, Z value is still at a low level and will not trigger compensation.

[0036] This effectively filters out invalid disturbances such as high-frequency noise and single impacts, and only responds to real, continuous deceleration events, thus improving the robustness of the control.

[0037] After calculating the speed drop coefficient, it is compared with the compensation activation threshold. If the speed drop coefficient is greater than the compensation activation threshold, the current operating condition is determined to be an effective speed drop, and compensation is required. Otherwise, it is determined to be a normal fluctuation, and no subsequent compensation action is triggered. The compensation activation threshold is an adjustable parameter used to balance the sensitivity and false trigger rate of compensation. Its value can be determined through multiple experiments. A lower threshold results in earlier compensation intervention but may be overly sensitive; a higher threshold provides greater stability but may miss the optimal compensation opportunity.

[0038] This invention calculates a speed drop severity coefficient by comprehensively considering three dimensions of speed characteristics: speed drop trend, speed drop rate, and speed drop amplitude. This coefficient is then compared with a compensation trigger threshold to determine whether compensation is necessary. This method more reliably distinguishes between normal fluctuations and true speed drops, making a judgment in the early stages of speed drop. This avoids unnecessary compensation actions and ensures timely intervention when truly needed, achieving intelligent and precise compensation triggering. In contrast, existing technologies typically initiate compensation directly after detecting a speed decrease, lacking a comprehensive assessment of the severity of the speed drop. This can easily lead to false triggering of compensation during normal speed fluctuations or overcompensation during slight speed drops, introducing new speed fluctuations.

[0039] When compensation is required, the target speed of the current control cycle is obtained, the theoretical flow rate is calculated based on the target speed, the actual pressure difference of the servo valve is obtained, the actual pressure difference is compared with the standard pressure difference, and the corrected flow rate is calculated in combination with the theoretical flow rate. The process of obtaining the target speed for the current control cycle, calculating the theoretical flow rate based on the target speed, obtaining the actual differential pressure of the servo valve, comparing the actual differential pressure with the standard differential pressure, and calculating the corrected flow rate by combining the theoretical flow rate includes: Obtain the target speed of the current control cycle and the effective working area of ​​the injection cylinder, and calculate the theoretical flow rate based on the target speed and the effective working area; Collect the inlet and outlet pressures of the servo valve, and calculate the actual pressure difference based on the inlet and outlet pressures; Calculate the pressure difference ratio between the actual pressure difference and the standard pressure difference, take the square root of the pressure difference ratio to obtain the pressure difference coefficient, and divide the theoretical flow rate by the pressure difference coefficient to obtain the corrected flow rate.

[0040] Based on the corrected flow rate, the feedforward valve opening is obtained, the speed difference between the target speed and the corresponding actual speed in the current control cycle is calculated, and closed-loop control calculation is performed based on the speed difference to obtain the corresponding closed-loop valve opening. Combining the feedforward valve opening and the closed-loop valve opening, the servo valve compensation opening is determined, and the servo valve core position is controlled based on the servo valve compensation opening.

[0041] The closed-loop control calculation based on this speed difference to obtain the corresponding closed-loop valve opening includes: Based on the speed difference, PID calculation is performed to obtain a preliminary correction amount, which is the increment of the valve opening. Obtain the gain coefficient, and multiply the initial correction amount by the gain coefficient to obtain the closed-loop correction amount; The closed-loop correction amount is determined as the corresponding closed-loop valve opening. The gain coefficient is dynamically adjusted based on the rate drop coefficient.

[0042] Specifically: When compensation is determined to be needed, the system immediately activates a composite compensation algorithm to bring the injection velocity back to the set curve.

[0043] Specifically, the target speed of the current control cycle is first obtained, and the theoretical flow rate required to maintain the target speed is calculated by combining the effective working area of ​​the injection cylinder, thereby converting the speed requirement into the flow rate requirement of the hydraulic system.

[0044] Subsequently, the actual differential pressure of the servo valve is acquired. This actual differential pressure is collected in real time by two pressure sensors: one sensor is installed on the inlet side of the servo valve to detect the oil supply pressure of the servo valve; the other sensor is installed on the outlet side of the servo valve to detect the load pressure leading to the injection cylinder. The oil supply pressure of the servo valve originates from the system's high-pressure oil source and remains relatively stable during the injection process; while the outlet pressure of the servo valve continuously increases as the injection process progresses and the cavity filling resistance increases. Therefore, the actual differential pressure accurately reflects the current load state of the hydraulic system—the smaller the differential pressure, the higher the back pressure, and the larger the valve opening required to maintain the same flow rate.

[0045] To eliminate the impact of actual differential pressure deviating from calibration conditions on flow output, this embodiment introduces a differential pressure correction mechanism. The system compares the actual differential pressure with the standard differential pressure (i.e., the reference differential pressure used during the servo valve's factory calibration), calculates the ratio between the two, and performs a square root operation on this ratio to obtain the differential pressure coefficient. Subsequently, the aforementioned theoretical flow rate is divided by this differential pressure coefficient to obtain the corrected flow rate.

[0046] Based on the corrected flow rate, the corresponding feedforward valve opening is obtained by querying the servo valve's flow-opening characteristic table. This servo valve flow-opening characteristic table is a pre-established data table during the servo valve's factory calibration phase, recording the output flow rate corresponding to different valve openings under standard differential pressure conditions. It is used to convert flow commands into corresponding valve core openings. When the actual differential pressure is lower than the standard differential pressure, the differential pressure coefficient is less than 1, and the corrected flow rate is greater than the theoretical flow rate. The system uses this larger corrected flow rate to query the characteristic table to obtain a larger feedforward valve opening. Its function is to compensate for the decrease in flow capacity caused by increased back pressure by actively increasing the valve opening, thereby ensuring that the actual output flow rate is as close as possible to the theoretical requirement.

[0047] Simultaneously, the speed difference between the target speed and the corresponding actual speed in the current control cycle is calculated, and closed-loop control calculations (e.g., PID calculations) are performed based on this speed difference to obtain the corresponding closed-loop valve opening. Specifically, this includes: performing PID calculations on the speed difference to obtain a preliminary correction amount; obtaining a gain coefficient; multiplying the preliminary correction amount by the gain coefficient to obtain a closed-loop correction amount; and determining this closed-loop correction amount as the closed-loop valve opening. The gain coefficient is dynamically adjusted based on a speed drop coefficient; the larger the value of the speed drop coefficient, the more severe the deviation of the current injection speed from the set value, and the system accordingly increases the gain coefficient to strengthen the closed-loop compensation effect.

[0048] Finally, the final servo valve compensation opening is determined by combining the feedforward valve opening and the closed-loop valve opening. In one embodiment, the feedforward valve opening is multiplied by a preset feedforward weighting coefficient, the closed-loop valve opening is multiplied by a preset closed-loop weighting coefficient, and the two are then added together to obtain the servo valve compensation opening. In this way, the feedforward valve opening obtained based on differential pressure correction can quickly respond to load changes, while the closed-loop valve opening obtained based on speed error feedback can finely correct the remaining deviation. The two work together to effectively improve the stability and anti-interference capability of the injection end speed tracking.

[0049] This invention continuously monitors the actual speed of the injection rod within the compensation range and calculates speed characteristics (including speed drop trend, speed drop rate, and speed drop magnitude) based on actual speed data from multiple control cycles. A comprehensive speed drop coefficient is then calculated to determine whether compensation is needed. Compared to traditional methods that rely solely on a single speed deviation threshold, this method can identify speed drop trends earlier and trigger compensation decisions before significant speed deviations accumulate, thereby shortening the compensation response delay and allowing more time for subsequent compensation control adjustments.

[0050] like Figure 3 As shown in the figure, this invention also proposes an adaptive compensation system for the injection end speed of a die-casting machine, comprising: The interval determination module is used to obtain the position of the injection rod during the injection of the die-casting machine, and determine whether the current period is in the compensation interval based on the position of the injection rod. The compensation interval is the high-speed end section. The interval determination module includes: The judgment unit is used to determine whether the position of the injection rod is between the starting point and the ending point of the high-speed final stage; The starting point determination unit is used to acquire the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, set the rising inflection point as the reference value of the starting point of the high-speed end segment, and determine the starting point of the high-speed end segment based on the reference value and the preset safety margin. The end point determination unit is used to obtain a preset pressure threshold and a minimum safe braking distance, compare the pressure curve and the pressure threshold to determine a threshold point, compare the minimum safe braking distance and the total injection stroke to determine an adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

[0051] The compensation determination module is used to continuously collect the actual speed of the injection rod at a preset control cycle if the current position of the injection rod is in the compensation range, calculate the speed characteristics based on the actual speed of the injection rod in multiple control cycles, calculate the speed drop coefficient based on the speed characteristics, and determine whether compensation is needed based on the speed drop coefficient. The actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

[0052] The calculation module is used to obtain the target speed of the current control cycle when it is determined that compensation is needed, calculate the theoretical flow rate based on the target speed, obtain the actual pressure difference of the servo valve, compare the actual pressure difference with the standard pressure difference, and calculate the corrected flow rate by combining the theoretical flow rate. The compensation module is used to obtain the feedforward valve opening based on the corrected flow rate, calculate the speed difference between the target speed and the corresponding actual speed in the current control cycle, perform closed-loop control calculation based on the speed difference to obtain the corresponding closed-loop valve opening, combine the feedforward valve opening and the closed-loop valve opening to determine the servo valve compensation opening, and control the servo valve core position based on the servo valve compensation opening.

[0053] After determining that speed compensation is needed, this invention calculates the corrected flow rate by introducing the actual differential pressure and theoretical flow rate of the servo valve. Based on the corrected flow rate, the feedforward valve opening is obtained, and combined with the closed-loop valve opening calculated based on the deviation between the actual speed and the target speed, the final servo valve compensation opening is determined. Compared with existing technologies that rely solely on speed deviation for single closed-loop adjustment, this composite control strategy comprehensively considers the differential pressure state under the current operating conditions, making the calculation of the compensation opening more accurately reflect the actual flow rate requirement. This provides a more precise compensation amount when the resistance at the injection end increases, effectively mitigating the speed drop and thus improving the casting quality.

[0054] This invention also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, which, when executed by the at least one processor, causes the electronic device to perform the method of this invention.

[0055] The present invention also provides a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of the present invention.

[0056] This invention also provides a computer program product, including a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of this invention.

[0057] refer to Figure 4The present invention will now describe a structural block diagram of an electronic device that can serve as a server or client in embodiments of the present invention, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0058] like Figure 4 As shown, the electronic device includes a computing unit 401, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 into a random access memory (RAM) 403. The RAM 403 may also store various programs and data required for the operation of the electronic device. The computing unit 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0059] Multiple components in the electronic device are connected to I / O interface 405, including: input unit 406, output unit 407, storage unit 408, and communication unit 409. Input unit 406 can be any type of device capable of inputting information into the electronic device. Input unit 406 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of the electronic device. Output unit 407 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 408 may include, but is not limited to, disks and optical discs. Communication unit 409 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0060] The computing unit 401 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, CPUs, graphics processing units (GPUs), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The computing unit 401 performs the methods and processes described above. For example, in some embodiments, the method embodiments of the present invention may be implemented as a computer program tangibly contained in a machine-readable medium, such as storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via ROM 402 and / or communication unit 409. In some embodiments, the computing unit 401 may be configured to perform the methods described above by any other suitable means (e.g., by means of firmware).

[0061] Computer programs for implementing the methods of embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0062] In the context of embodiments of the present invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0063] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0064] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0065] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A method for adaptive compensation of the injection end speed of a die-casting machine, characterized in that, include: The position of the injection rod during the injection of the die-casting machine is obtained, and it is determined whether the current position is in the compensation range based on the position of the injection rod. The compensation range is the end of the high-speed section. If the current position of the injection rod is within the compensation range, the actual speed of the injection rod is continuously collected at a preset control cycle. Based on the actual speed of the injection rod in multiple control cycles, the speed characteristics are calculated, and the speed drop coefficient is calculated by combining the speed characteristics. Based on the speed drop coefficient, it is determined whether compensation is needed. When compensation is required, the target speed of the current control cycle is obtained, the theoretical flow rate is calculated based on the target speed, the actual pressure difference of the servo valve is obtained, the actual pressure difference is compared with the standard pressure difference, and the corrected flow rate is calculated in combination with the theoretical flow rate. Based on the corrected flow rate, the feedforward valve opening is obtained, the speed difference between the target speed and the corresponding actual speed in the current control cycle is calculated, and closed-loop control calculation is performed based on the speed difference to obtain the corresponding closed-loop valve opening. Combining the feedforward valve opening and the closed-loop valve opening, the servo valve compensation opening is determined, and the servo valve core position is controlled based on the servo valve compensation opening.

2. The adaptive compensation method for the injection end speed of a die-casting machine according to claim 1, characterized in that, The step of determining whether the current position is within the compensation range based on the position of the injection rod includes: Determine whether the position of the injection rod is between the starting point and the ending point of the high-speed phase; The determination of the starting point of the high-speed terminal segment includes: Obtain the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, and set the rising inflection point as the reference value of the starting point of the high-speed end segment. Based on the reference value and the preset safety margin, the starting point of the high-speed terminal segment is set; The determination of the end point of the high-speed terminal segment includes: Obtain the preset pressure threshold and minimum safe braking distance, compare the pressure curve and the pressure threshold to determine the threshold point, compare the minimum safe braking distance and the total injection stroke to determine the adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

3. The adaptive compensation method for the injection end speed of a die-casting machine according to claim 1, characterized in that, The actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

4. The adaptive compensation method for the injection end speed of a die-casting machine according to claim 3, characterized in that, The calculation of the speed drop degree coefficient based on the comprehensive speed characteristics, and the determination of whether compensation is needed based on the speed drop degree coefficient, include: Based on the speed drop trend, speed drop rate, speed drop magnitude and corresponding weighting coefficients, a speed drop degree coefficient is calculated, wherein the weighting coefficients are adjusted based on the injection process requirements of the die casting machine. By comparing the speed drop coefficient with the compensation activation threshold, it is determined whether compensation is needed based on the comparison results.

5. The adaptive compensation method for the injection end speed of a die-casting machine according to claim 1, characterized in that, The process of obtaining the target speed for the current control cycle, calculating the theoretical flow rate based on the target speed, obtaining the actual differential pressure of the servo valve, comparing the actual differential pressure with the standard differential pressure, and calculating the corrected flow rate by combining the theoretical flow rate includes: Obtain the target speed of the current control cycle and the effective working area of ​​the injection cylinder, and calculate the theoretical flow rate based on the target speed and the effective working area; Collect the inlet and outlet pressures of the servo valve, and calculate the actual pressure difference based on the inlet and outlet pressures; Calculate the pressure difference ratio between the actual pressure difference and the standard pressure difference, take the square root of the pressure difference ratio to obtain the pressure difference coefficient, and divide the theoretical flow rate by the pressure difference coefficient to obtain the corrected flow rate.

6. The adaptive compensation method for the injection end speed of a die-casting machine according to claim 1, characterized in that, The closed-loop control calculation based on this speed difference to obtain the corresponding closed-loop valve opening includes: Based on the speed difference, PID calculation is performed to obtain a preliminary correction amount, which is the increment of the valve opening. Obtain the gain coefficient, and multiply the initial correction amount by the gain coefficient to obtain the closed-loop correction amount; The closed-loop correction amount is determined as the corresponding closed-loop valve opening. The gain coefficient is dynamically adjusted based on the rate drop coefficient.

7. An adaptive compensation system for the injection end speed of a die-casting machine, characterized in that, include: The interval determination module is used to obtain the position of the injection rod during the injection of the die-casting machine, and determine whether the current period is in the compensation interval based on the position of the injection rod. The compensation interval is the high-speed end section. The compensation determination module is used to continuously collect the actual speed of the injection rod at a preset control cycle if the current position of the injection rod is in the compensation range, calculate the speed characteristics based on the actual speed of the injection rod in multiple control cycles, calculate the speed drop coefficient based on the speed characteristics, and determine whether compensation is needed based on the speed drop coefficient. The calculation module is used to obtain the target speed of the current control cycle when it is determined that compensation is needed, calculate the theoretical flow rate based on the target speed, obtain the actual pressure difference of the servo valve, compare the actual pressure difference with the standard pressure difference, and calculate the corrected flow rate by combining the theoretical flow rate. The compensation module is used to obtain the feedforward valve opening based on the corrected flow rate, calculate the speed difference between the target speed and the corresponding actual speed in the current control cycle, perform closed-loop control calculation based on the speed difference to obtain the corresponding closed-loop valve opening, combine the feedforward valve opening and the closed-loop valve opening to determine the servo valve compensation opening, and control the servo valve core position based on the servo valve compensation opening.

8. The adaptive compensation system for the injection end speed of a die-casting machine according to claim 7, characterized in that, The interval determination module includes: The judgment unit is used to determine whether the position of the injection rod is between the starting point and the ending point of the high-speed final stage; The starting point determination unit is used to acquire the pressure curve of the die-casting machine injection process, find the rising inflection point in the pressure curve, set the rising inflection point as the reference value of the starting point of the high-speed end segment, and determine the starting point of the high-speed end segment based on the reference value and the preset safety margin. The end point determination unit is used to obtain a preset pressure threshold and a minimum safe braking distance, compare the pressure curve and the pressure threshold to determine a threshold point, compare the minimum safe braking distance and the total injection stroke to determine an adjustment value, and determine the end point of the high-speed final stage based on the threshold point and the adjustment value.

9. The adaptive compensation system for the injection end speed of a die-casting machine according to claim 7, characterized in that, The actual velocity of the injection rod based on multiple control cycles, and the calculated velocity characteristics, include: By comparing the actual speeds collected over multiple consecutive control cycles, the speed drop trend can be determined. Calculate the rate of change of speed in the current control cycle relative to the previous control cycle and determine it as the rate of speed drop; Calculate the deviation between the actual speed and the set speed in the current control cycle to determine the speed drop magnitude.

10. An electronic device, comprising: A processor and a memory storing a program, characterized in that the program includes instructions that, when executed by the processor, cause the processor to perform an adaptive compensation method for the injection end speed of a die-casting machine according to any one of claims 1 to 6.

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