Injection flow control system and method for a die casting machine

Abstract

The application discloses a pressure injection flow control system of a die casting machine, which comprises a large flow valve group, a small flow valve group and a control module; the large flow valve group and the small flow valve group are connected with input ends and output ends of a pressure injection cylinder respectively; the control module is suitable for controlling the opening degrees of the large flow valve group and the small flow valve group according to a pressure injection mode, and simultaneously correcting the opening degrees of the large flow valve group and the small flow valve group according to an actual operation state of the pressure injection cylinder, so that starting overshoot can be effectively avoided. The application further discloses a pressure injection flow control method of a die casting machine, which comprises the following steps: selecting the opening number of the small flow valve group and the large flow valve group according to a pressure injection mode of a pressure injection cylinder; and controlling the opening degrees of the large flow valve group and / or the small flow valve group in real time through a closed loop, so as to realize pressure injection precision control of the pressure injection cylinder, thereby effectively improving the response speed of the pressure injection cylinder in a pressure injection process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of die casting equipment, in particular to a pressure injection flow control system and method of a die casting machine. BACKGROUND

[0002] The die casting machine is a machine for pressure casting, which is commonly used in the production and processing of automobile parts and the like. The die casting machine can pressurize molten metal liquid into a mold to be cooled and formed into a solid metal casting under the action of pressure.

[0003] The pressure injection process of the existing cold chamber die casting machine can be divided into three stages: the first stage is slow pressure injection, the second stage is fast pressure injection, and the third stage is pressure boosting injection. The existing cold chamber die casting machine can be divided into two mechanisms, namely a mold closing mechanism and a pressure injection mechanism. Through the joint action of the mold closing mechanism and the pressure injection mechanism, the molten alloy solution can be high-pressure cast and formed. The existing pressure injection mechanism needs to configure different types and numbers of servo valves at the input and output of the pressure injection cylinder for closed-loop control when working. However, the existing pressure injection mechanism is prone to start overshoot when slow pressure injection is performed; at the same time, the control accuracy of the pressure injection cylinder is poor during the entire pressure injection process. SUMMARY

[0004] One of the purposes of the present application is to provide a control system capable of avoiding start overshoot of the die casting machine and improving pressure injection control accuracy.

[0005] Another purpose of the present application is to provide a control method capable of avoiding start overshoot of the die casting machine and improving pressure injection control accuracy.

[0006] To achieve at least one of the above purposes, the technical solution adopted by the present application is as follows: a pressure injection flow control system of a die casting machine, comprising a large flow valve group, a small flow valve group and a control module; the large flow valve group and the small flow valve group are respectively connected with the input end and the output end of a pressure injection cylinder; the control module is adapted to control the opening degree of the large flow valve group and the small flow valve group according to the pressure injection mode, and correct the opening degree of the large flow valve group and the small flow valve group according to the actual running state of the pressure injection cylinder.

[0007] Preferably, the input end and the output end of the pressure injection cylinder are each connected with at least one large flow valve and at least one small flow valve, the large flow valve and the small flow valve are each a two-position two-way valve; the large flow valves at the input end and the output end of the pressure injection cylinder are combined in pairs to form the large flow valve group which is equivalent to a three-position four-way valve; the small flow valves at the input end and the output end of the pressure injection cylinder are combined in pairs to form the small flow valve group which is equivalent to a three-position four-way valve.

[0008] Preferably, the control module includes a controller and a detection module. The controller is adapted to be connected to the high-flow valve group and the low-flow valve group for control. The detection module is adapted to detect the motion state of the injection cylinder and feed it back to the controller.

[0009] A method for controlling the injection flow rate of a die-casting machine, specifically including the following steps:

[0010] S100: Select the number of valve groups to open for small flow and large flow based on the injection mode of the injection cylinder;

[0011] S200: Real-time closed-loop control of the opening of the large-flow valve group and / or small-flow valve group is used to achieve injection accuracy control of the injection cylinder.

[0012] Preferably, step S200 specifically includes the following process:

[0013] S210: Generate the target motion trajectory curve of the injection cylinder based on the set target speed and target position of the injection cylinder;

[0014] S220: Based on the generated target motion trajectory curve of the injection cylinder and the actual motion curve of the injection cylinder, the desired control flow rate of the injection cylinder is obtained;

[0015] S230: Based on the desired flow rate, obtain the actual opening degree of the large flow valve group and the small flow valve group and open them;

[0016] S240: Detect the trajectory of the injection cylinder, obtain the actual motion curve of the injection cylinder, and feed it back to step S220.

[0017] Preferably, in step S210, the target motion trajectory curve of the injection cylinder is obtained by inverse solving of a fifth-order polynomial based on the target position and the target velocity.

[0018] Preferably, the fifth-degree polynomial is: y = c5*x^5 + c4*x^4 + c3*x^3 + c2*x^2 + c1*x + c0; where y is the output variable, i.e., the target position; x is the input variable, i.e., the motion time; and c5, c4, c3, c2, c1, and c0 are the constant coefficients of the fifth-degree polynomial.

[0019] The preferred inverse solution process for the fifth-degree polynomial is as follows:

[0020] S211: Transform the fifth-degree polynomial into Y=X*K;

[0021] S212: Using the inverse matrix X of the input matrix X -1 Solve for the constant coefficient matrix K = X -1 *Y;

[0022] S213: Determine the values ​​of the polynomial coefficients and substitute them into the constant coefficient matrix. Calculate and generate the relationship curve between the input target position and the target velocity, i.e., the target motion trajectory curve of the injection cylinder.

[0023] Wherein, the output matrix Y = [y0dy0 / dt d 2 y0 / dt 2 y1dy1 / dt d 2 y1 / dt 2 ] T Input matrix X=[t0 5 t0 4 t0 3 t0 2 t01; 5t0 4 4t0 3 3t0 2 2t01 0; 20t0 3 12t0 2 6t02 0 0; t1 5 t1 4 t1 3 t1 2 t11; 5t1 4 4t1 3 3t1 2 2t110; 20t1 3 12t1 2 6t12 0 0];Constant coefficient matrix K=[ c5、c4、c3、c2、c1、c0] T In the formula, t represents the time corresponding to the target position and the target velocity.

[0024] Preferably, in step S210, the number of target positions and corresponding target velocities set is ten.

[0025] Preferably, in step S240, the movement position and / or movement speed of the injection cylinder are used as feedback input. By differentiating the movement position of the injection cylinder, the actual feedback value of the speed of the injection cylinder is obtained, thereby generating the actual movement curve of the injection cylinder.

[0026] Compared with the prior art, the beneficial effects of this application are as follows:

[0027] (1) In the slow injection stage of the injection cylinder, compared with the traditional outlet speed regulation method, this application adopts a small flow valve group connected to both the inlet and outlet to open, which can effectively reduce the pressure in the rod chamber during the operation of the injection cylinder, thereby ensuring that there will be no overshoot during the start-up in the slow injection stage, and also improving the stability of the slow injection stage.

[0028] (2) During the injection process of the injection cylinder, the speed control cycle of the injection cylinder is shortened by using closed-loop speed control of the large flow valve group and the small flow valve group, which can effectively improve the response speed of the control module. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection structure between the injection cylinder and the hydraulic control system in this invention.

[0030] Figure 2 This is a schematic diagram illustrating the formation of a large-flow valve group or a small-flow valve group in this invention.

[0031] Figure 3 This is a schematic diagram showing the connection between the injection cylinder and the equivalent high-flow valve group and low-flow valve group in this invention.

[0032] Figure 4 This is a schematic diagram of the workflow of the injection flow control method in this invention.

[0033] In the picture: Injection cylinder 100. Detailed Implementation

[0034] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0035] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0036] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] One aspect of this application provides an injection flow control system for a die-casting machine, such as... Figures 1 to 3As shown, one preferred embodiment includes a high-flow-rate valve group, a low-flow-rate valve group, and a control module (not shown). Both the high-flow-rate and low-flow-rate valve groups are connected to the input and output terminals of the injection cylinder 100, respectively. The control module can be connected to the high-flow-rate and low-flow-rate valve groups via signal control. Therefore, when the injection mechanism is operating, the control module can control the opening degree of the high-flow-rate and low-flow-rate valve groups according to the injection mode of the injection mechanism. Furthermore, during the operation of the injection cylinder 100, the control module can also correct the opening degree of the high-flow-rate and low-flow-rate valve groups according to the actual operating state of the injection cylinder 100 to ensure the control accuracy of the injection process, thereby avoiding overshoot during the slow injection stage and overshoot during the fast injection stage.

[0038] It is understandable that when the injection cylinder 100 is performing injection, the input end of the injection cylinder 100 is the rodless chamber, and hydraulic oil can enter the rodless chamber from the hydraulic oil source; the output end of the injection cylinder 100 is the rod chamber, and hydraulic oil can be discharged to the oil tank for recovery through the rod chamber. When the injection cylinder 100 completes the injection and resets, the input end of the injection cylinder 100 is the rod chamber, and hydraulic oil can enter the rod chamber from the hydraulic oil source; the output end of the injection cylinder 100 is the rodless chamber, and hydraulic oil can be discharged to the oil tank for recovery from the rodless chamber. For the convenience of subsequent descriptions, the following descriptions will use the input and output ends of the injection cylinder 100 during injection as examples.

[0039] In this embodiment, the injection modes of the injection cylinder 100 include slow injection, fast injection, and boosted injection. During slow injection, the injection cylinder 100 requires a smaller amount of hydraulic oil. Therefore, the control module can open the small-flow valve group and close the large-flow valve group, thereby improving the accuracy of the slow injection stage by controlling the opening degree of the small-flow valve group. Furthermore, the use and adjustment of the small-flow valve group can also prevent overshoot during the slow injection stage. During fast injection, the injection cylinder 100 requires a larger amount of hydraulic oil. Therefore, the control module can open both the small-flow and large-flow valve groups, effectively ensuring the flow requirements during the fast injection stage. Furthermore, the opening degree of the small-flow valve group can be adjusted during the fast injection stage to reduce or avoid overshoot.

[0040] It should be understood that existing die-casting machines generally control the speed of the piston rod during injection by adjusting the opening of the outlet valve connected to the rod chamber of the injection cylinder 100. When the injection cylinder 100 is operating, hydraulic oil enters the rodless chamber through the inlet valve. Since the openings of the inlet and outlet valves are different (generally, the inlet valve opening is larger than the outlet valve opening), the hydraulic oil pressure in the rod chamber will rapidly increase to approximately twice that of the rodless chamber within a short period. At this time, the hydraulic oil in the rod chamber will experience compression under pressure, causing a sudden change in the piston rod's movement speed. This is reflected in the speed curve as a "bulge," known as start-up overshoot.

[0041] The embodiment employs a method of simultaneously controlling the movement of the injection cylinder 100 at both the inlet and outlet, meaning that the large-flow valve group and / or small-flow valve group are simultaneously connected to the input and output ends of the injection cylinder 100. Therefore, the large-flow and small-flow valve groups maintain the same opening degree at both the input and output ends of the injection cylinder 100; thus, the hydraulic oil velocity entering the rodless chamber of the injection cylinder 100 is the same as the hydraulic oil velocity exiting the rod chamber of the injection cylinder 100. This ensures that the oil pressure in the rodless and rod chambers of the injection cylinder 100 remains essentially constant, effectively reducing or avoiding start-up overshoot and improving the stability of the injection mechanism. Simultaneously, during the operation of the injection cylinder 100, real-time detection of its movement state is used to feedback and adjust the opening degree of the large-flow and / or small-flow valve groups, effectively improving the real-time control accuracy of the injection process of the injection cylinder 100.

[0042] In this embodiment, as Figures 1 to 3 As shown, the input and output ends of the injection cylinder 100 are each connected to at least one high-flow valve and at least one low-flow valve. Both the high-flow valve and the low-flow valve are two-position two-way valves. The high-flow valves at the input and output ends of the injection cylinder 100 can be combined in pairs to form a high-flow valve group that is equivalent to a three-position four-way valve. The low-flow valves at the input and output ends of the injection cylinder 100 can be combined in pairs to form a low-flow valve group that is equivalent to a three-position four-way valve.

[0043] Understandably, the specific number of high-flow and low-flow valves connected to the input and output ends of the injection cylinder 100 can be determined based on the model or type of the die-casting machine. For ease of description later, we will assume that there is only one high-flow and one low-flow valve connected to both the input and output ends of the injection cylinder 100. Figure 1As shown, the high-flow valve at the input end of the injection cylinder 100 can be labeled as high-flow valve V201, and the low-flow valve as low-flow valve V202; the high-flow valve at the output end of the injection cylinder 100 can be labeled as high-flow valve V301, and the low-flow valve as low-flow valve V302. Figure 2 and Figure 3 As shown, by matching and combining the high-flow valve V201 at the input end and the high-flow valve V301 at the output end of the injection cylinder 100, an equivalent high-flow valve group of a three-position four-way valve V231 can be formed. Similarly, by matching and combining the low-flow valve V202 at the input end and the low-flow valve V302 at the output end of the injection cylinder 100, an equivalent low-flow valve group of a three-position four-way valve V232 can be formed. Compared with the individual conduction of the high-flow valves V201 and V301 and the low-flow valves V202 and V302 at the input and output ends of the traditional injection cylinder 100, the equivalent three-position four-way valves V231 and V232 can double the flow regulation range of the traditional injection cylinder 100.

[0044] Generally, the injection mechanism of a die-casting machine may include multiple injection cylinders 100, and each injection cylinder 100 has multiple large-flow valves and small-flow valves connected to its input and output ends. Taking specific parameters as an example, assuming the maximum total injection flow rate of the die-casting machine is Q, and the injection mechanism includes four injection cylinders 100, with each cylinder 100 having two large-flow valves and two small-flow valves connected to its input and output ends, then the entire injection mechanism has a total of 8 large-flow valves V201, 8 large-flow valves V301, 8 small-flow valves V202, and 8 small-flow valves V302. Through the above pairwise matching, 8 three-position four-way valves V231 and 8 three-position four-way valves V232 can be formed; the maximum total injection flow rate of the 8 three-position four-way valves V231 and 8 three-position four-way valves V232 is 2Q; that is, the flow rate adjustment range of the injection mechanism is doubled. This embodiment can reduce the number of large-flow valves and small-flow valves included in the traditional injection mechanism by up to half, thereby effectively reducing the production cost of the die-casting machine.

[0045] In this embodiment, the control module includes a controller and a detection module. The controller can be connected to all large-flow valve groups and small-flow valve groups for control. The detection module can detect the motion state of the injection cylinder 100 and feed it back to the controller. The controller then adjusts the opening of the large-flow valve group and the small-flow valve group in real time according to the feedback signal from the detection module to ensure the injection accuracy of the injection cylinder 100.

[0046] It is understood that the specific structure and working principle of the controller are well known to those skilled in the art; the specific structure and working principle of the detection module are also well known to those skilled in the art. The detection module generally includes a position detection unit and a speed detection unit, etc. The detection module can detect the displacement and / or speed of the injection cylinder 100 during the injection process and feed it back to the controller; thus, the controller can compare the real-time position and / or speed of the injection cylinder 100 with the set value and make corrections based on the comparison results to ensure the injection accuracy of the injection cylinder 100.

[0047] Another aspect of this application provides a method for controlling the injection flow of a die-casting machine, a preferred embodiment of which includes the following steps:

[0048] S100: Select the number of opening valve groups for small flow valve group and large flow valve group according to the injection mode of injection cylinder 100.

[0049] S200: Real-time closed-loop control of the opening of the large flow valve group and / or small flow valve group is used to achieve injection accuracy control of the injection cylinder 100.

[0050] It is understandable that in step S100, when the injection cylinder 100 is in slow injection, the controller only needs to control the small flow valve group to open, while keeping the large flow valve group closed; when the injection cylinder 100 is in fast injection, the controller can control both the large flow valve group and the small flow valve group to open. Furthermore, fast injection generally includes two stages: a "first fast" and a "second fast." Since the speeds of the two stages are different, the number of large flow valve groups opened can be different.

[0051] In this embodiment, as Figure 4 As shown, step S200 specifically includes the following process:

[0052] S210: Generate the target motion trajectory curve of the injection cylinder 100 based on the set target speed and target position of the injection cylinder 100.

[0053] S220: Based on the target motion trajectory curve of the injection cylinder 100 and the actual motion curve of the injection cylinder 100, the desired control flow of the injection cylinder 100 is obtained.

[0054] S230: Based on the desired flow rate, obtain the actual opening degree of the large flow rate valve group and the small flow rate valve group and open them.

[0055] S240: Detect the trajectory of the injection cylinder 100, obtain the actual motion curve of the injection cylinder 100, and feed it back to step S220.

[0056] In layman's terms, such as Figure 4As shown, at the initial moment of the injection mechanism's activation, a set target position and corresponding target speed can be input to the controller. The controller can then automatically generate the target motion trajectory curve of the injection cylinder 100 based on the input target position and target speed. Next, the controller can perform trajectory planning on the generated target motion trajectory curve to obtain the target control flow rate of the injection cylinder 100 at the current moment, i.e., the desired control flow rate at the current moment. Then, the controller sends opening control signals to the large flow valve group and the small flow valve group according to the obtained desired control flow rate, causing the large flow valve group and the small flow valve group to open accordingly. The injection cylinder 100 then operates according to the corresponding opening of the large flow valve group and the small flow valve group. Then, the detection module tracks the position of the injection cylinder 100 during its movement and feeds back the real-time operating status of the injection cylinder 100 to the controller. The controller then compares the actual motion curve of the injection cylinder 100 with the target motion trajectory curve and performs flow adaptive adjustment based on the comparison result to obtain the desired control flow rate of the injection cylinder 100 at the next moment. Finally, the controller sends opening correction signals to the large-flow and small-flow valve groups based on the obtained desired control flow rate, so that the opening of the large-flow and small-flow valve groups is compensated and corrected accordingly, thereby controlling the position and speed output by the injection cylinder 100. By feeding back the real-time operating status of the injection cylinder 100 to the controller to form a closed-loop control, the control accuracy and response speed of the injection cylinder 100 can be effectively improved.

[0057] It is understandable that when planning the target motion trajectory curve, the planned position x of the injection cylinder 100 at the current moment can be obtained. ref Planning speed v ref and planning acceleration a ref Simultaneously, the detection module can detect the actual movement position x of the injection cylinder 100 at the current moment. act Actual velocity v act and actual acceleration a act Furthermore, the detection module can detect the actual movement position x of the injection cylinder 100. act and / or actual velocity v act Feedback is sent to the controller, which can then adjust the desired control flow q required by the injection cylinder 100 based on the feedback results. exp .

[0058] Specifically, in step S240, if the movement position of the injection cylinder 100 is used as the feedback input, the actual speed feedback value of the injection cylinder 100 can be obtained by differentiating the movement position of the injection cylinder 100, thereby generating the actual motion curve of the injection cylinder 100.

[0059] In this embodiment, when performing step S210 above, the number of target positions and corresponding target velocities set is generally multiple, preferably ten.

[0060] Understandably, the target position can generally be selected as a key point in the injection process of the injection cylinder 100, and the velocity corresponding to the key point is the target velocity. Furthermore, to ensure the accuracy of the target motion trajectory curve and reduce the difficulty of establishing it, multiple target positions and velocities are required. The desired target motion trajectory curve is obtained by fitting multiple target points. When the number of target positions and velocities increases to a certain point, further increasing the number will not significantly improve the accuracy of the target motion trajectory curve and will only increase the computational load; therefore, the number of target positions and velocities should not be excessive, generally not exceeding ten.

[0061] In this embodiment, during step S210, the target motion trajectory curve of the injection cylinder 100 is obtained by inverse solving of a fifth-order polynomial based on the target position and the target velocity.

[0062] Specifically, the fifth-degree polynomial is: y = c5x^5 + c4x^4 + c3x^3 + c2x^2 + c1x + c0; where y is the output variable, i.e., the target position; x is the input variable, i.e., the motion time; and c5, c4, c3, c2, c1, and c0 are the constant coefficients of the fifth-degree polynomial. The inverse solution process for the fifth-degree polynomial is as follows:

[0063] S211: Transform the quintic polynomial into Y=X*K.

[0064] S212: Using the inverse matrix X of the input matrix X -1 Solve for the constant coefficient matrix K = X -1 *Y.

[0065] S213: Determine the values ​​of the polynomial coefficients and substitute them into the constant coefficient matrix. Calculate and generate the relationship curve between the input target position and the target velocity, i.e., the target motion trajectory curve of the injection cylinder 100.

[0066] Wherein, the output matrix Y = [y0dy0 / dt d 2 y0 / dt 2 y1dy1 / dt d 2 y1 / dt 2 ] T Input matrix X=[t0 5 t0 4 t0 3 t0 2 t01; 5t0 4 4t0 33t0 2 2t01 0; 20t0 3 12t0 2 6t02 0 0; t1 5 t1 4 t1 3 t1 2 t11; 5t1 4 4t1 3 3t1 2 2t110; 20t1 3 12t1 2 6t12 0 0];Constant coefficient matrix K=[ c5、c4、c3、c2、c1、c0] T In the formula, t represents the time corresponding to the target position and the target velocity.

[0067] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A flow control system for injection of a die-casting machine, characterized in that: It includes a high-flow valve group, a low-flow valve group, and a control module; the high-flow valve group and the low-flow valve group are respectively connected to the input end and the output end of the injection cylinder; the control module is adapted to control the opening degree of the high-flow valve group and the low-flow valve group according to the injection mode, and at the same time correct the opening degree of the high-flow valve group and the low-flow valve group according to the actual operating state of the injection cylinder; The injection cylinder is connected to at least one high-flow valve and at least one low-flow valve at both its input and output ends. Both the high-flow valve and the low-flow valve are two-position two-way valves. The high-flow valves at the input and output ends of the injection cylinder are combined in pairs to form a high-flow valve group that is equivalent to a three-position four-way valve. The low-flow valves at the input and output ends of the injection cylinder are also combined in pairs to form a low-flow valve group that is equivalent to a three-position four-way valve.

2. The injection flow control system for the die-casting machine as described in claim 1, characterized in that: The control module includes a controller and a detection module. The controller is adapted to be connected to the high-flow valve group and the low-flow valve group for control. The detection module is adapted to detect the motion state of the injection cylinder and feed it back to the controller.

3. A method for controlling the injection flow rate of a die-casting machine, applied to the injection flow rate control system of the die-casting machine as described in claim 1 or 2, characterized in that, Includes the following steps: S100: Select the number of valve groups to open for small flow and large flow based on the injection mode of the injection cylinder; S200: Real-time closed-loop control of the opening of the large-flow valve group and / or small-flow valve group is used to achieve injection accuracy control of the injection cylinder.

4. The injection flow control method for a die-casting machine as described in claim 3, characterized in that, Step S200 specifically includes the following process: S210: Generate the target motion trajectory curve of the injection cylinder based on the set target speed and target position of the injection cylinder; S220: Based on the generated target motion trajectory curve of the injection cylinder and the actual motion curve of the injection cylinder, the desired control flow rate of the injection cylinder is obtained; S230: Based on the desired flow rate, obtain the actual opening degree of the large flow valve group and the small flow valve group and open them; S240: Detect the trajectory of the injection cylinder, obtain the actual motion curve of the injection cylinder, and feed it back to step S220.

5. The injection flow control method for a die-casting machine as described in claim 4, characterized in that: In step S210, the target motion trajectory curve of the injection cylinder is obtained by inverse solution of a fifth-order polynomial based on the target position and target velocity.

6. The injection flow control method for a die-casting machine as described in claim 5, characterized in that: The fifth-degree polynomial is: y = c5x^5 + c4x^4 + c3x^3 + c2x^2 + c1x + c0; where y is the output variable, i.e., the target position; x is the input variable, i.e., the motion time; and c5, c4, c3, c2, c1, and c0 are the constant coefficients of the fifth-degree polynomial.

7. The injection flow control method for a die-casting machine as described in claim 6, characterized in that: The inverse solution process for a quintic polynomial is as follows: S211: Transform the fifth-degree polynomial into Y=X*K; S212: Using the inverse matrix X of the input matrix X -1 Solve for the constant coefficient matrix K = X -1 *Y; S213: Determine the values ​​of the polynomial coefficients and substitute them into the constant coefficient matrix to calculate the relationship curve between the input target position and the target velocity, i.e., the target motion trajectory curve of the injection cylinder; Wherein, the output matrix Y = [y0 dy0 / dt d 2 y0 / dt 2 y1 dy1 / dt d 2 y1 / dt 2 ] T Input matrix X=[t0 5 t0 4 t0 3 t0 2 t0 1; 5t0 4 4t0 3 3t0 2 2t0 1 0; 20t0 3 12t0 2 6t0 2 0 0;t1 5 t1 4 t1 3 t1 2 t1 1; 5t1 4 4t1 3 3t1 2 2t1 1 0; 20t1 3 12t1 2 6t1 2 0 0];Constant coefficient matrix K=[ c5、c4、c3、c2、c1、c0] T In the formula, t represents the time corresponding to the target position and the target velocity.

8. The injection flow control method for a die-casting machine as described in claim 4, characterized in that: In step S210, the number of target positions and corresponding target velocities set is ten.

9. The injection flow control method for a die-casting machine as described in claim 4, characterized in that: In step S240, the movement position of the injection cylinder is used as the feedback input. By differentiating the movement position of the injection cylinder, the actual feedback value of the speed of the injection cylinder is obtained, and then the actual motion curve of the injection cylinder is generated.

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