Dual injection system and synchronicity control method thereof

Abstract

A dual injection system and a synchronicity control method thereof are provided. [Solution] The dual injection system includes a main injection system and a secondary injection system, each of which includes a velocity injection oil passage and a boost oil passage, and the velocity injection oil passages of the main injection system and the secondary injection system are partially independent of each other, and the boost oil passages of both the main injection system and the secondary injection system use an A-bridge valve group structure, and work together in step with each other. The synchronism control method is used to perform synchronous control on the main injection system and the secondary injection system of the above system. The beneficial effects of the present application are as follows: In the velocity injection stage, the secondary injection system achieves synchronization by feedback tracking based on the parameters of the main injection system, and in the boost injection stage, the synchronization is achieved by changing the oil passage structure of the injection system. Compared with the conventional method, the synchronization accuracy and stability between the dual injection systems can be effectively improved.

Description

[Technical field]

[0001] The present application relates to the technical field of die casting of metal parts, and in particular to a dual injection system and its synchronization control method. [Background technology]

[0002] When processing large die castings, there is usually a distal end quality problem, that is, the die casting quality becomes worse as the distance from the injection port increases. Therefore, a double injection system is used to die cast large die castings. As the name suggests, two identical ejection systems are installed on one die casting machine, and the two machines are made to hold a certain target speed position curve and controlled to maintain the synchronism between them (synchronism in a broad sense, that is, the deviation value between the two is a certain value).

[0003] In the injection process of the double injection process, the difference value between the two positions is related to the intersection position in the mold of the metal liquids on both sides, and the two metal liquids will merge at the intersection position, and there will be defects in the quality of the product at the intersection position, so the intersection problem should be considered when designing the mold, and an independent cavity such as a slag collector should be designed at the intersection point, so as to reduce the impact of the intersection point on the die casting body as much as possible. Since the intersection positions designed in different molds are different, the synchronization of the position is very important, and the two injection systems need to follow their respective predetermined target speed-position curves, one injection system is provided as a driving cylinder, and one injection system is provided as a driven cylinder, and the driven cylinder not only needs to operate according to the predetermined target speed-position curve, but also needs to follow the driving cylinder and maintain the difference value at the set target position of the two, and the control ensures the position synchronization of the two systems.

[0004] The main method of achieving synchronism in the prior art is to match the diameters of the injection hammer heads on both sides and control the two injection systems with the same oil passage, so that the synchronous control of the hydraulic cylinders can be realized only by controlling the oil passage. However, in the actual use process, not only are the structures of the hydraulic cylinders of the two injection systems unlikely to be completely consistent, but the working conditions of the two injection systems are also not completely the same, so the synchronism of the double injection system cannot be accurately controlled only by controlling the oil passage. In order to meet the requirements of the production quality of large die castings, the traditional double injection system currently needs to be improved as soon as possible. Summary of the Invention [Problem to be solved by the invention]

[0005] One object of the present application is to provide a dual injection system that overcomes at least one of the deficiencies in the background art described above.

[0006] Another object of the present application is to provide a synchronization control method for a dual injection system that overcomes at least one of the deficiencies in the above background art. [Means for solving the problem]

[0007] In order to achieve the above object, the technical means of the present application are as follows: A dual injection system includes a main injection system and a slave injection system, each of which includes a speed injection oil passage and a boost oil passage, and the speed injection oil passages of the main injection system and the slave injection system are partially independent from each other, and the boost oil passages of the main injection system and the slave injection system both use an A-bridge valve group structure and work in step with each other.

[0008] Preferably, the velocity injection oil passages of the main injection system and the slave injection system each include an injection cylinder, a control valve V03 and an accumulator V01, and the accumulator V01 communicates with the rodless cavity of the injection cylinder through the control valve V03.

[0009] Preferably, the booster oil passages of the main injection system and the slave injection system each include a booster cylinder, a control valve V04 and a control valve V08, the control valve V04 and the control valve V08 are connected in series to form an oil passage, one end of which is connected to the rodless cavity of the injection cylinder and the other end of which is connected to a fuel tank, the rod-equipped cavity of the booster cylinder is connected between the control valve V04 and the control valve V08 via a pipeline to form the A-bridge valve group structure, the rod-equipped cavities and the rodless cavities of the booster cylinders corresponding to the main injection system and the slave injection system are both connected to each other via pipelines, and the booster accumulators to which the two booster cylinders are respectively connected are connected to each other via gas pipes.

[0010] The above-mentioned dual injection system synchronism control method sets the injection cylinder corresponding to the main injection system and the injection cylinder corresponding to the slave injection system as a driving injection cylinder and a slave injection cylinder, respectively. The specific control is as follows: In a speed injection step, a control signal is generated according to a target speed curve and a target position curve, and the speed injection oil passage controls the motion of the driving injection cylinder according to the control signal; Step S200: the driven injection cylinder is controlled by the driving injection cylinder, and then feedback-adjusted based on the position deviation between the driven injection cylinder and the driving injection cylinder during the motion process to synchronize with the driving injection cylinder; The method includes a step S300 in which, during the boost injection stage, the boost cylinder generates a corresponding opening control signal based on the target pressure and the feedback pressure of the rod-containing cavity, and the A-bridge valve group adjusts the opening based on the opening control signal to control the movement of the boost cylinder.

[0011] Preferably, based on the target velocity curve and the actual pressure of the driving injection cylinder, the equation u1=f1(p1, p2, v d1), and the feedforward signal u1 is self-adapted by the feedforward proportional curve to obtain the feedforward signal u2=f2(u1,v d1 ,v a1 ) to obtain a feedforward signal u2 of the driving injection cylinder, and control the speed of the driving injection cylinder so that the speed injection oil passage performs the corresponding valve group control based on the feedforward signal u2, where p1 represents the pressure of the rodless cavity of the driving injection cylinder, p2 represents the pressure of the rod-containing cavity of the driving injection cylinder, and v d1 represents the target velocity of the driven injection cylinder, and v a1 represents the current actual speed of the driven injection cylinder.

[0012] Preferably, the position control of the driving injection cylinder uses a PID control method, specifically, the difference value is compared based on the target position and the current position to obtain a feedback signal u3 expressed by the following formula, and the speed injection oil passage is controlled to perform corresponding valve group control based on the feedback signal u3;

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[0013] Preferably, the motion of the driven injection cylinder includes a feedforward motion and a follow-up motion, and in the feedforward motion process, the speed control and position control of the driven injection cylinder are the same as those of the driving injection cylinder, and the follow-up motion includes performing PID control according to a target position difference value and an actual position difference value of the driving injection cylinder and the driven injection cylinder, and obtaining a feedback signal u8 represented by the following formula:

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[0014] Preferably, the boost injection step includes a pressure building step and a pressure stabilization step, and the movement of the boost cylinder is adjusted based on the difference in opening control of the control valves V04 and V08 in the pressure building step and the pressure stabilization step.

[0015] Preferably, in the pressure establishment step, a current boosting speed of the boosting cylinder is obtained according to the target pressure, the current pressure of the rod-containing cavity of the boosting cylinder, and the current position of the injection cylinder; and a boosting speed identification result is calculated according to the formula u 10 =f5(p d ,p a1 ,X a1 The opening control signal u of the control valve V08 is represented by 10 At this time, the control valve V04 is in a fully closed state. In the pressure stabilization stage, the voltage proportionality between the control valves V04 and V08 is obtained through the opening proportionality identification of the A bridge valve group, and then the voltages of the two control valves are gradually reduced according to the set relationship until they reach a set value. At this time, the control signal of the control valve V04 is set to u 12 The control signal for the control valve V08 is u 11 Then, u 12 =u 11 f6(p d ), where p d represents the target pressure, and p a1represents the current actual pressure in the rodless cavity of the injection cylinder, and X a1 represents the current actual position of the injection cylinder, and f6(p d ) represents the result of proportional identification of the opening degree of the A bridge valve group.

[0016] Preferably, the pressure boosting process is subjected to pressure feedback control, and a feedback control signal u 13 to the control valve V04, the total control signal of the control valve V04 is set to u in the pressure stabilization stage. 12 +u 13 year,

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[0017] Compared with the prior art, the beneficial effects of the present application are as follows: In the velocity injection stage, the slave injection system achieves synchronization by feedback tracking based on the parameters of the master injection system, and in the pressure boost injection stage, the synchronization is achieved by changing the oil passage structure of the injection system.Compared with the conventional method, the synchronization accuracy and stability between the dual injection systems can be effectively improved. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram of the overall oil passage of the dual injection system of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing the operation process of the dual injection system of the present invention performing synchronous control in the velocity injection stage. [Diagram 3] FIG. 2 is a schematic diagram showing the operation process of the dual injection system of the present invention performing synchronous control in the boost injection stage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present application will be further described below with reference to specific embodiments. It should be noted that, provided there is no contradiction, the embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0020] In the description of the present application, it should be explained that the orientations and positional relationships indicated by the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., with respect to directional terms, are based on the orientations or positional relationships shown in the drawings, and are merely intended to facilitate and simplify the description of the present application, and do not indicate or suggest that the devices or parts shown must have a specific orientation and be configured and operated in a specific orientation, and therefore should not be understood as limiting the specific protection scope of the present application.

[0021] It should be understood that the terms "first," "second," etc. in the specification and claims of this application are intended to distinguish between similar objects and not necessarily to describe a particular order or priority.

[0022] The terms "comprises" and "having" and any variations thereof in the present specification and claims are intended to cover a non-exclusive inclusion, e.g., a process, method, system, product or apparatus that includes a series of steps or units is not limited to the steps or units expressly stated, but may include other steps or units that are not expressly stated or that are inherent to those processes, methods, products or apparatus.

[0023] One aspect of the present application provides a dual injection system, and as shown in Figure 1, one preferred embodiment includes a main injection system 1 and a slave injection system 2, each of which includes a speed injection oil passage and a boost oil passage. When specifically designing the speed injection oil passage and the boost oil passage, the main injection system 1 and the slave injection system 2 are designed such that the speed injection oil passages are independent of each other, and the boost oil passages both use an A-bridge valve group structure and work in step with each other.

[0024] It should be noted that the speed injection stage includes a low-speed injection stage, the injection speed of which is generally 0.1-0.4 m / s, and a high-speed injection stage, the injection speed of which is generally 2-5 m / s. That is, the motion curve of the speed injection stage includes the process of increasing speed and constant speed, so that the motion process of the speed injection stage is complicated. If the main injection system 1 and the slave injection system 2 are connected by the same speed injection oil passage, it is difficult to realize accurate synchronization by the structural design of the oil passage in the complex operating conditions of the two injection systems, and the accuracy requirements of the large die casting cannot be met. Therefore, in this embodiment, the speed injection oil passages of the two injection systems are designed independently, and then the synchronization is realized by performing the corresponding software control according to the operating parameters of the two injection systems, so that the accuracy and stability of the synchronous control of the complex motion of the main injection system 1 and the slave injection system 2 in different operating conditions can be effectively improved.

[0025] And in the boost injection stage, the motion process of the injection system is single, so the synchronization between the two can be realized by the design of the oil passage. That is, the main injection system 1 and the slave injection system 2 both use the boost oil passage with the same A-type valve group structure, and the two boost oil passages are coordinated through the oil passage via the pipe line, and the main injection system 1 and the slave injection system 2 have the same driving pressure during boosting, so that the output pressure of the main injection system 1 and the slave injection system 2 can be guaranteed to be the same.

[0026] In this embodiment, as shown in FIG. 1, the speed injection oil passages of the main injection system 1 and the slave injection system 2 each include an injection cylinder V05, a control valve V03, a control valve V07, and an accumulator V01. The accumulator V01 may be connected to the rodless cavity of the injection cylinder V05 through the control valve V03, and the rod-equipped cavity of the injection cylinder V05 may be connected to the fuel tank through the control valve V07. In this way, when performing low-speed injection or high-speed injection, the control valve V03 can be opened, and the accumulator V01 can supply oil to the rodless cavity of the injection cylinder V05 through the open control valve V03, and the pressure oil in the rod-equipped cavity of the injection cylinder V05 can be returned to the fuel tank along the open control valve V07. The injection speed requirements and synchronism requirements of low-speed injection or high-speed injection can be controlled by controlling the opening degree of the control valves V03 and V07.

[0027] In this embodiment, as shown in Fig. 1, the booster oil passages of the main injection system 1 and the slave injection system 2 each include a booster cylinder V02, a control valve V04, and a control valve V08. The control valve V04 and the control valve V08 communicate with each other to form a serial oil passage, one end of which is connected to the rodless cavity of the injection cylinder V05 and the other end is connected to a fuel tank. The rod-equipped cavity of the booster cylinder V02 communicates with the intermediate position of the serial oil passage formed by the control valve V04 and the control valve V08 via a pipe line, and further, the control valve V04 and the control valve V08 can form an A-bridge valve group structure at the position of the rod-equipped cavity of the booster cylinder V02. The rod-equipped cavities of the booster cylinders V02 corresponding to the main injection system 1 and the slave injection system 2 are connected to each other via a pipeline, the rod-less cavities of the booster cylinders V02 corresponding to the main injection system 1 and the slave injection system 2 are connected to each other via a pipeline, and the booster accumulators to which the two booster cylinders V02 are connected are connected to each other via a gas pipe.

[0028] It should be noted that, during boost injection, the stability of boosting the injection cylinder V05 can be achieved by adjusting the opening of the control valves V04 and V08, and the synchronization of the output flow rates of the two boost cylinders V02 can also be controlled by controlling the parameters of the opening adjustment.

[0029] Specifically, the nitrogen gas bottles of the boost accumulator corresponding to the two boost cylinders V02 are connected via gas pipes, and the rod-equipped cavities of the two boost cylinders V02 are connected via oil pipes. When the boost is stable, the gas pressure in the boosted parts of the two injection systems is the same, and the pressure in the rod-equipped cavities of the boost cylinder V02 is also the same. Meanwhile, the influence of the frictional force of the boost piston on the pressure is slight. If the frictional force is not taken into account, during boosting, the pressure in the rodless cavity is calculated as follows: (gas pressure of the boost accumulator * area of ​​the rodless cavity of the boost cylinder - pressure of the rod-equipped cavity of the boost cylinder * area of ​​the rod-equipped cavity of the boost cylinder) / area of ​​the piston rod of the boost cylinder. Because the parameters of the booster cylinders V02 of the two injection systems are completely consistent, that is, the gas pressures are the same, and the areas of the rod-equipped cavities of the booster cylinders are the same, the pressures of the rodless cavities of the two booster cylinders V02 will ultimately be the same, that is, the final booster injection force will also be the same.

[0030] If the booster nitrogen gas cylinders and the rod-equipped cavity of the booster cylinder V02 of the two injection systems are not connected and only the data collected by the pressure sensor is used for control, the actual booster pressures of the two injection systems may not match due to the accuracy of the data collected by the pressure sensor. Therefore, by connecting the two booster oil lines with gas pipes and oil pipes, the consistency of the final booster injection force can be guaranteed even if there is an error in the data collected by the sensor.

[0031] It should be further noted that the main injection system 1 and the sub injection system 2 may be simultaneously connected using the boost oil passage having the same A-type valve group structure, that is, the boost nitrogen gas cylinders of the two injection systems and the boost cylinders V02 of the two injection systems may be connected to each other, and then one A-bridge valve group may be reserved to realize the synchronous boost function of the two injection systems. However, if designed in this way, firstly, the through diameter of the A-bridge valve group becomes large, which slows down the response of the valve group, and secondly, the dimension of the oil pipe connected to the rod-containing cavity of the boost cylinder V02 becomes thick, which is disadvantageous in design and installation. In this embodiment, the booster oil passages of the two injection systems are controlled by independent A-bridge valve groups, so that the diameter of the valve group can be reduced and the corresponding speed of the valve group can be improved. In the final booster injection stabilization stage, it is only necessary to maintain the pressure consistency. Thus, the diameter of the oil pipe connecting the booster cylinder V02 corresponding to the two injection systems can be reduced. In this way, when the pressures on both sides do not match, a small amount of oil can be allowed to flow to balance the pressure.

[0032] It can be understood that the specific structures and operating principles of the control valves V03, V04, V07 and V08 are all known to those skilled in the art, and the control valves can preferably be servo control valves.

[0033] Another aspect of the present application provides a synchronization control method applied to the above-mentioned double injection system. As shown in Figures 1 to 3, the injection cylinder V05 corresponding to the main injection system 1 and the injection cylinder V05 corresponding to the slave injection system 2 are set as a driving injection cylinder and a slave injection cylinder, respectively. In one preferred embodiment, the specific control includes the following steps S100 to S300.

[0034] In step S100, in a speed injection stage, a control signal is generated according to the target speed curve and the target position curve, and the speed injection oil passage controls the motion of the driving injection cylinder according to the control signal.

[0035] In step S200, the driven injection cylinder is controlled by the driving injection cylinder, and then feedback-adjusted according to the position deviation between the two during the motion process to synchronize with the driving injection cylinder.

[0036] In step S300, during the boost injection stage, the boost cylinder generates a corresponding opening control signal based on the target pressure and the feedback pressure of the rod-containing cavity, and the A-bridge valve group further adjusts the opening based on the opening control signal to control the movement of the boost cylinder.

[0037] As can be understood, from the above, the synchronism control between the main injection system 1 and the slave injection system 2 is mainly reflected in the injection stage, that is, the injection cylinder V05 corresponding to the main injection system 1 performs the injection operation according to the set target position curve and the target speed curve, and the injection cylinder V05 corresponding to the slave injection system 2 similarly operates according to the set target position curve and the target speed curve, and can also be feedback adjusted according to the motion state information of the injection cylinder V05 corresponding to the main injection system 1, so as to ensure that the synchronous motion between the slave injection system 2 and the injection cylinder V05 corresponding to the main injection system 1 is maintained. In the boost injection stage, the boost cylinder V02 corresponding to the main injection system 1 and the slave injection system 2 only needs to perform the corresponding operation according to the set target position curve and the target speed curve, and the two are synchronized with each other in terms of the oil passage by the above-mentioned oil pipe and gas pipe. For ease of understanding, the synchronous control process of the main injection system 1 and the slave injection system 2 in the injection stage and the boosted injection stage will be described in detail below.

[0038] 1. Injection stage (1) As shown in FIG. 2, the specific operation control process of the driving injection cylinder corresponding to the main injection system 1 is as follows:

[0039] Based on the target speed corresponding to the set target speed curve and the actual pressure of the driving injection cylinder, the formula u1=f1(p1, p2, vd1 ) where p1 represents the pressure in the rodless cavity of the driving injection cylinder, p2 represents the pressure in the rod-containing cavity of the driving injection cylinder, and v d1 represents the target velocity of the driven injection cylinder.

[0040] The feedforward signal u1 is self-adapted by the feedforward proportional curve to obtain the formula u2 = f2(u1, v d1 ,v a1 ) to obtain the feedforward signal u2 of the driving injection cylinder, where v a1 represents the current actual speed of the driven injection cylinder.

[0041] As can be seen, the feedforward signal u1 of the driving injection cylinder is the feedforward proportional f2(v d1 ,v a1 After undergoing the self-adaptation process, it can better meet the requirements of actual injection and the feedforward results will be more accurate.

[0042] The above control process is a speed control process for the driving injection cylinder, in order to prevent the change of the high-speed starting point during the injection process, it is not only necessary to control the speed, but also the most important thing is to control the position. In order to prevent the influence of the external environment on the position control, in this embodiment, a PID position control method is introduced for the control of the injection position, and the specific control process is as follows:

[0043] Based on the target position corresponding to the target position curve and the current position of the driving injection cylinder, the difference value can be compared to obtain a feedback signal u3 expressed by the following equation:

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[0044] As can be seen, in the feedback signal u3, the proportional part K1(X d1 -X a1 ) can quickly output a control signal based on the difference between the target position and the actual position. When the driving injection cylinder encounters a load and an error occurs, the error becomes large. At this time, the differential part K3S(X d1 -X a1 ) can respond quickly to generate output.

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[0045] It should be noted that, as can be seen from the above, in the injection stage, the control signal u4=u2+u3 is finally output to the valve group corresponding to the driving injection cylinder, that is, the speed feedforward signal u2 and the position feedback signal u3 can be added together and then act on the control valves V03 and V07 corresponding to the main injection system 1, so that the driving injection cylinder can inject according to the set target speed curve.

[0046] It should also be noted that, as can be seen from the above, during injection, the position control of the driving injection cylinder is the most important, so in this embodiment, it is preferable to perform feedback adjustment control on the position control of the driving injection cylinder.

[0047] (2) As shown in FIG. 2, the specific operation control process of the driven injection cylinder corresponding to the driven injection system 2 is as follows:

[0048] The motion of the driven injection cylinder includes feedforward motion and follow-up motion, and in the feedforward motion process, the speed control and position control of the driven injection cylinder are the same as those of the driving injection cylinder, that is, the method of controlling the driving injection cylinder is used to follow the target position and target speed curve of the driven injection cylinder.

[0049] Specifically, based on the set target speed, the following equation is used to calculate the speed of the driven injection cylinder: u5=f3(p3,p4,v d2 ) where p2 represents the pressure in the rodless cavity of the driven injection cylinder, p3 represents the pressure in the rod-containing cavity of the driven injection cylinder, and v d2 represents the target speed of the driven injection cylinder. After the feedforward signal u5 of the driven injection cylinder is self-adapted by the feedforward proportional curve, based on the relationship between the current speed and the target speed, the formula u6=f4(u5,v d2 ,v a2 ) can be obtained. Here, v a2 represents the current actual speed of the driven injection cylinder.

[0050] As can be understood, the synchronism control between the driven injection cylinder and the driving injection cylinder can be speed synchronous control, position synchronous control, or speed and position simultaneous synchronous control. As can be seen from the above, in the injection stage, the position control of the injection cylinder is the most important, so in order to simplify the control process and reduce the difficulty of control, in this embodiment, it is preferable to realize the synchronization by position tracking of the driven injection cylinder and the driving injection cylinder.

[0051] Specifically, the driven injection cylinder has two feedback controls, one is used for the feedback control of the target position and the actual position of the driven injection cylinder, the feedback control method is the same as the position control process of the driving injection cylinder, both of which use the PID position control method, and the other feedback control is used for the tracking motion process of the driven injection cylinder, that is, the position PID control of the target position difference value and the actual position difference value of the driving injection cylinder and the driven injection cylinder.

[0052] The control signal obtained based on the position PID feedback of the target position and the actual position corresponding to the driven injection cylinder is the feedback signal u7, which is expressed by the following equation:

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[0053] Based on the above control, position PID control is performed based on the target position difference value and the actual position difference value of the driving injection cylinder and the front driven injection cylinder, and a feedback signal u8 expressed by the following equation is obtained.

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[0054] It should be noted that, as can be seen from the above, in the injection stage, the control signal u9=u6+u7+u8 is finally output to the valve group corresponding to the slave injection cylinder. That is, according to the feedback signal of the target position and the actual position of the slave injection cylinder, the speed feedforward signal and the tracking feedback signal between the driving injection cylinder and the slave injection cylinder can be added, and then the control valves V03 and V07 corresponding to the slave injection system 2 can be jointly acted on. In this way, it is not only ensured that the slave injection cylinder injects according to the set target speed curve, but also ensures that the slave injection cylinder more effectively tracks the position of the driving injection cylinder during the injection process, so as to ensure the synchronization of the injection stage of the main injection system 1 and the slave injection system 2, and further ensures the consistency of the intersection of the metal liquid in the mold every injection.

[0055] Second, boost injection stage As can be seen from the above, in the boost injection stage, the main injection system 1 and the slave injection system 2 can realize synchronization in the oil passages by the oil pipes and gas pipes connected to the boost oil passages, so the main injection system 1 and the slave injection system 2 do not need to perform synchronization control of the oil passages in the boost injection stage, and it is sufficient to boost only one side and make the time required for boosting and establishing pressure as short as possible.

[0056] At the same time, the reason why the main injection system 1 and the slave injection system 2 use two independent controls in boost injection is that when boosting starts, the pressures of the rodless cavities of the injection cylinder V05 of the two injection systems are different due to different load forces, and the volumes of the oil compressed are also different, so that when the booster cylinder V02 boosts, the displacement of the booster piston is different, and the oil discharge flow rate of the rod-equipped cavity of the booster cylinder V02 may also be different. In order to ensure that the main injection system 1 and the slave injection system 2 have the same pressure establishment time as much as possible, at this time, the opening degree of the control valve V08 corresponding to each of the two injection systems is different, so that the boosting of the two injection systems is controlled separately.

[0057] Based on this, the specific control process of the boost injection stage of one injection system will be described in detail below. The boost injection stage includes a pressure building stage and a pressure stabilization stage, and the motion of the boost cylinder is adjusted according to the difference in the opening control of the control valves V04 and V08 in the pressure building stage and the pressure stabilization stage.

[0058] In this embodiment, as shown in Fig. 3, in the pressure establishment stage, the current boosting speed of the booster cylinder V02 can be obtained based on the target pressure, the current pressure of the rod-containing cavity (annular chamber) of the booster cylinder V02, and the current position of the injection cylinder V05. Based on the boosting speed identification result, the opening control signal of the control valve V08, that is, the formula u at this time 10 =f5(p d ,p a1 ,X a1 ) The control voltage u of the control valve V08 10 Here, p d represents the target pressure, and p a1 represents the current actual pressure in the rodless cavity of injection cylinder V05, and X a1 represents the current actual position of the injection cylinder V05. When the pressure in the rodless cavity of the injection cylinder V05 rises to approach the set stable boost pressure of the boost injection stage, the pressure building stage is completed and the pressure stabilization stage is started, and the control valve V04 is in a fully closed state.

[0059] In the pressure stabilization stage, the voltage proportionality between the control valves V04 and V08 can be obtained by identifying the relationship between the voltage proportionality and the pressure, that is, the opening proportionality of the A bridge valve group. Then, the voltages of the two control valves are gradually reduced according to the set relationship until they reach a set value, so as to achieve the purpose of further stabilizing the pressure. At this time, the control signal of the control valve V04 is set to u 12 The control signal for the control valve V08 is u 11 Then, u 12 =u 11 f6(p d ), where f6(p d ) shows the results of proportional identification of the opening degree of the A bridge valve group.

[0060] As can be seen, based on the above control process, for the control valve V04, the control signal in the pressure building phase is 0, and the control signal in the pressure stabilizing phase is u 12 For the control valve V08, the control signal in the pressure building stage is u 10 and the control signal for the pressure stabilization stage is u 11 It is.

[0061] In this embodiment, the control process of the boost injection is a feedforward process, and since there is always an error in the feedforward process, pressure feedback control, such as a feedback PID control method, is introduced to ensure that the pressure of the rodless cavity of the injection cylinder V05 reaches the set value as much as possible. The feedback control mainly acts on the control valve V04, but not on the control valve V08. That is, pressure feedback control is performed for the boost process, and the feedback control signal u expressed by the following formula is obtained: 13 By applying to the control valve V04, the total control signal of the control valve V04 is set to u during the pressure stabilization stage. 12 +u 13 Let us assume that.

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[0062] As can be seen, based on the above feedback control process, for the control valve V04, the control signal in the pressure building phase is 0, and the control signal in the pressure stabilizing phase is u 12 +u 13 For the control valve V08, the control signal in the pressure building stage is u 10 and the control signal for the pressure stabilization stage is u 11 By dividing the boost injection stage into a pressure establishment stage and a pressure stabilization stage, and introducing the identification result as feedforward, the speed and accuracy of pressure establishment can be effectively improved.

[0063] The above describes the basic principle, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and the description in the specification are only for illustrating the principles of the present application, and the present application also has various changes and improvements without departing from the spirit and scope of the present application, and all of these changes and improvements are within the scope of the present application as claimed. The scope of protection of the present application is defined by the appended claims and their equivalents. [Explanation of symbols]

[0064] 1 Main ejection system 2. Sub-injection system

Claims

1. A dual injection system including a primary injection system and a secondary injection system, both of which include a velocity injection oil passage and a pressure booster oil passage, The main injection system and the secondary injection system have velocity injection oil paths that are partially independent of each other; The velocity injection oil passages of the main injection system and the slave injection system each include an injection cylinder, a control valve V03 and an accumulator V01; The booster oil passages of the main injection system and the slave injection system each include a booster cylinder, a control valve V04 and a control valve V08; The control valve V04 and the control valve V08 are connected in series to form an oil passage, one end of which is connected to the rodless cavity of the injection cylinder via the control valve V03 and communicates with the accumulator V01, and the other end of which is connected to an oil tank, and the rod-equipped cavity of the booster cylinder communicates between the control valve V04 and the control valve V08 via a pipe, The rod-equipped cavity of the booster cylinder is connected to the rodless cavity of the injection cylinder via a cartridge valve V06; The rod-equipped cavities and the rodless cavities of the booster cylinders of the main injection system and the slave injection system are connected to each other through pipelines, and each booster accumulator is connected to the rodless cavity of each booster cylinder through a gas pipe, and boosts the injection pressure of the main injection system and the slave injection system by boosting the rodless cavity of each booster cylinder. A dual injection system.

2. The accumulator V01 communicates with the rodless cavity of the injection cylinder via the control valve V03.

2. The dual injection system of claim 1.

3. 2. A method for synchronizing control of a dual injection system according to claim 1, comprising: Setting an injection cylinder corresponding to the main injection system and an injection cylinder corresponding to the slave injection system as a driving injection cylinder and a slave injection cylinder, respectively; In a speed injection step, a control signal is generated according to a target speed curve and a target position curve, and the speed injection oil passage controls the movement of the driving injection cylinder according to the control signal in step S100; Step S200: the driven injection cylinder is controlled by the driving injection cylinder, and then feedback-adjusted based on the position deviation between the driven injection cylinder and the driving injection cylinder during the motion process to synchronize with the driving injection cylinder; In the boost injection stage, the boost cylinder generates a corresponding opening control signal according to the target pressure and the feedback pressure of the rod-containing cavity, and the control valve V04 and the control valve V08 adjust their openings according to the opening control signal to control the movement of the boost cylinder. A method comprising:

4. Based on the target velocity curve and the actual pressure of the driving injection cylinder, the formula u is obtained by identification. １ = f １ (p １ , p ２ , v ｄ１ ) the feedforward signal u １ Get The feedforward signal u １ is self-adapted by a feedforward proportional curve to obtain the formula u ２ = f ２ (u １ , v ｄ１ , v ａ１ The feedforward signal u of the driving injection cylinder is represented by ２ Get The speed injection oil path is the feedforward signal u ２ Controlling the speed of the driving injection cylinder to perform corresponding valve group control based on Here, p １ represents the pressure in the rod-free cavity of the driving injection cylinder, p ２ represents the pressure in the rod-containing cavity of the driving injection cylinder, and v ｄ１ represents the target velocity of the driven injection cylinder, and v ａ１ represents the current actual speed of the driven injection cylinder; The synchronicity control method for a dual injection system according to claim 3.

5. The position control of the driving injection cylinder uses a PID control method, specifically, The difference value is compared based on the target position and the current position to obtain a feedback signal u ３ and the speed injection oil passage receives the feedback signal u ３ and performing a corresponding valve group control based on the [0010] Here, X ｄ１ represents the target position of the driving injection cylinder, and X ａ１ represents the current actual position of the driving injection cylinder, and K １ represents the proportionality coefficient, and K ２ represents the integral constant, and K ３ represents a differential constant, and S represents a sampling period. The synchronicity control method for a dual injection system according to claim 3.

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