Twin injection system and method for synchronization control thereof

Abstract

To provide a twin injection system and to provide a method for synchronization control thereof.SOLUTION: A twin injection system includes a main injection system and a sub-injection system, both of which include a velocity injection oil path and a pressurization oil path, wherein the main injection system and the sub-injection system are configured such that: the velocity injection oil paths are partially independent of each other; the pressurization oil paths both use an A-bridge valve group structure; and they cooperate in synchrony with each other. The synchronization control method is used to perform synchronization control for the main injection system and the sub-injection system of the system. The beneficial effects of the present invention are as follows: in the velocity injection stage, synchronization is achieved by the sub-injection system following the main injection system's parameters based on feedback; and in the pressurization injection stage, synchronization is achieved by changing the oil path structure of the injection system. Compared to conventional methods, this invention effectively improves the synchronization accuracy and stability between the twin injection systems.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] When processing large die castings, there is usually a problem with distal end quality, i.e., the further the distance from the injection port, the worse the die casting quality becomes. Therefore, a dual injection system is used to cast large die castings. As the name suggests, two identical ejection systems are installed on one die casting machine, and the two machines are controlled to maintain a predetermined target speed position curve and synchronize the two (synchronization in a broad sense, i.e., the deviation value between the two is a predetermined value).

[0003] During the double injection process, the difference between the two positions is related to the intersection point of the two metal liquids in the mold. The intersection point causes defects in the product quality. Therefore, the intersection issue must be considered when designing the mold, and a separate cavity, such as a slag collector, must be designed at the intersection to minimize the impact on the die casting body. Because different molds have different intersection points, position synchronization is very important. Two injection systems must follow their own predetermined target speed-position curves. One injection system is designated as the driving cylinder, and the other is designated as the driven cylinder. The driven cylinder not only operates according to the predetermined target speed-position curve, but also follows the driving cylinder, maintaining the difference between the two sets of target positions. Position synchronization between the two systems is ensured through control.

[0004] The main method for achieving synchronization 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, thereby achieving synchronization control of the hydraulic cylinders simply by controlling the oil passage. However, in actual use, not only are the hydraulic cylinder structures of the two injection systems unlikely to be perfectly identical, but the operating conditions of the two injection systems are also not exactly the same, so simply controlling the oil passage cannot accurately control the synchronization of the dual injection system. To meet the production quality requirements of large die castings, the current traditional dual injection system is urgently in need of improvement. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION It is an object of the present application to provide a dual injection system that overcomes at least one deficiency in the background art described above.

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

[0007] To achieve the above object, the technical solution of the present application is as follows: The dual injection system includes a main injection system and a secondary injection system, each of which includes a speed injection oil passage and a pressure booster oil passage, and the speed injection oil passages of the main injection system and the secondary injection system are partially independent from each other, and the pressure booster oil passages of both the main injection system and the secondary injection system use an A-bridge valve group structure and work in tandem 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 via 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, one end of an oil passage formed by connecting the control valve V04 and the control valve V08 in series communicates with the rodless cavity of the injection cylinder and the other end is connected to a fuel tank, the rod-equipped cavity of the booster cylinder communicates between the control valve V04 and the control valve V08 via a pipe line 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 communicate with each other via pipe lines, and the booster accumulators connected to the two booster cylinders communicate with each other via a gas pipe.

[0010] The synchronization control method for the dual injection system is to set 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, and 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 movement of the driving injection cylinder according to the control signal in step S100; Step S200: the driven injection cylinder synchronizes with the driving injection cylinder by using the control of the driving injection cylinder and performing feedback adjustment based on the position deviation between the two during the motion process; In 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-equipped 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, by identification, the formula u1=f1(p1, p2, v d1) and self-adapting the feedforward signal u1 according to 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 corresponding valve group control according to 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 driving injection cylinder, and v a1 represents the current actual velocity of the drive injection cylinder.

[0012] Preferably, the position control of the driving injection cylinder uses a PID control method, specifically, a 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 velocity injection oil passage is controlled to perform corresponding valve group control based on the feedback signal u3:

number

[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 equation:

number

[0014] Preferably, the boost injection step includes a pressure establishment 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 during the pressure establishment step and the pressure stabilization step.

[0015] Preferably, in the pressure establishing step, the current pressure intensifying cylinder is obtained according to the target pressure, the current pressure of the rod-containing cavity of the intensifying cylinder and the current position of the injection cylinder, and the current pressure intensifying cylinder is obtained according to the pressure intensifying cylinder speed identification result, the formula u 10 =f5(p d ,p a1 ,X a1 ) the opening control signal u of the control valve V08 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. Then, the voltages of the two control valves are gradually reduced according to the set relationship until they reach the set value. At this time, the control signal of the control valve V04 is set as u 12 The control signal of 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 rod-less 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 the 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 is given by the following equation: 13 to the control valve V04, the total control signal of the control valve V04 is set to u 12 +u 13 year,

number

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In the velocity injection phase, the secondary injection system achieves synchronization by feedback tracking based on the parameters of the primary injection system, and in the pressure boost injection phase, synchronization is achieved by changing the oil path structure of the injection system, which effectively improves the synchronization accuracy and stability between the dual injection systems compared to the conventional method. [Brief explanation 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. [Figure 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. [Figure 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 INVENTION

[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 regard to orientation 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 components shown must have a specific orientation and be configured and operate in a specific orientation, and therefore should not be understood to limit 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 specification and claims of this application are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or apparatus comprising a series of steps or units is not limited to the steps or units expressly stated, but may include other steps or units not expressly stated or 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 secondary 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 speed injection oil passages of the main injection system 1 and the secondary injection system 2 are designed to be independent of each other, and the boost oil passages both use an A-bridge valve group structure and work in tandem with each other.

[0024] It should be noted that the speed injection stage includes a low-speed injection stage, where the injection speed is generally 0.1-0.4 m / s, and a high-speed injection stage, where the injection speed is generally 2-5 m / s. That is, the motion curve of the speed injection stage includes both acceleration and constant-speed processes, making the motion process of the speed injection stage complex. If the main injection system 1 and the secondary injection system 2 are connected with the same speed injection oil passage, it is difficult to achieve accurate synchronization through the oil passage structural design under the complex operating conditions of the two injection systems, and the precision requirements for large die castings cannot be met. Therefore, in this embodiment, the speed injection oil passages of the two injection systems are designed independently, and then synchronization is achieved through corresponding software control based on the operating parameters of the two injection systems. This effectively improves the accuracy and stability of the synchronized control of the complex motion of the main injection system 1 and the secondary injection system 2 under different operating conditions.

[0025] During the boost injection stage, the motion process of the injection systems is single, so the synchronization between the two can be achieved by the oil passage design. That is, the main injection system 1 and the secondary 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 and connected through pipes, so that the main injection system 1 and the secondary injection system 2 have the same driving pressure during boosting, which further ensures that the output pressure of the main injection system 1 and the secondary injection system 2 is the same.

[0026] In this embodiment, as shown in FIG. 1, the speed injection oil passages of the main injection system 1 and the sub-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 via the control valve V03, and the rod-equipped cavity of the injection cylinder V05 may be connected to a fuel tank via the control valve V07. This allows the control valve V03 to be opened during low-speed or high-speed injection, allowing the accumulator V01 to supply oil to the rodless cavity of the injection cylinder V05 via the open control valve V03, and allowing the pressure oil in the rod-equipped cavity of the injection cylinder V05 to return to the fuel tank via the open control valve V07. The injection speed and synchronization requirements for low-speed or high-speed injection can be controlled by controlling the opening of the control valves V03 and V07.

[0027] In this embodiment, as shown in Figure 1, the booster oil passages of the main injection system 1 and the secondary injection system 2 each include a booster cylinder V02, a control valve V04, and a control valve V08. The control valves V04 and V08 communicate with each other to form a serial oil passage, one end of which communicates with the rodless cavity of the injection cylinder V05 and the other end of which 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 valves V04 and V08 via a pipe line. Furthermore, the control valves V04 and 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 subsidiary 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 subsidiary 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 boost pressure in 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 opening adjustment parameters.

[0029] Specifically, the nitrogen gas bottles of the booster accumulators corresponding to the two booster cylinders V02 are connected via gas pipes, and the rod-equipped cavities of the two booster cylinders V02 are connected via oil pipes. When the boost is stable, the gas pressure in the booster parts of the two injection systems is the same, and the pressure in the rod-equipped cavities of the booster cylinders V02 is also the same. However, the influence of the friction force of the booster piston on the pressure is slight. If the friction force is not taken into account, during boosting, the pressure in the rodless cavity = (gas pressure of the booster accumulator * area of ​​the rodless cavity of the booster cylinder - pressure of the rod-equipped cavity of the booster cylinder * area of ​​the rod-equipped cavity of the booster cylinder) / area of ​​the piston rod of the booster cylinder. Since the parameters of the booster cylinders V02 of the two injection systems are completely consistent, i.e., 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, i.e., the final booster injection force will also be the same.

[0030] If the booster nitrogen gas cylinders and the rod-equipped cavities of the booster cylinder V02 of the two injection systems are not connected and control is based solely on the data collected by the pressure sensor, the actual booster pressures of the two injection systems may not match due to the accuracy of the pressure sensor data collection. 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 secondary injection system 2 can be simultaneously connected using the same A-type valve group structure for the booster oil passage, i.e., the booster nitrogen gas cylinders of the two injection systems and the booster cylinders V02 can be connected to each other, and then one A-bridge valve group can be reserved to achieve the synchronous boosting function of the two injection systems. However, such a design would result in a slow response of the valve group due to the large diameter of the A-bridge valve group, and would also require a thick oil pipe connected to the rod-containing cavity of the booster cylinder V02, which would be 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, which reduces the diameter of the valve groups and further improves the corresponding speed of the valve groups. In the final booster injection stabilization stage, it is only necessary to maintain pressure consistency. Thus, the diameter of the oil pipe connecting the booster cylinders V02 corresponding to the two injection systems can be reduced. In this way, when the pressures on both sides are not consistent, a small amount of oil can be allowed to flow to balance the pressures.

[0032] It can be understood that the specific structures and operating principles of the control valves V03, V04, V07 and V08 are all well 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 applicable to the above-mentioned dual 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 the driving injection cylinder and the slave injection cylinder, respectively. In one preferred embodiment, the specific control includes the following steps S100 to S300:

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

[0035] In step S200, the driven injection cylinder uses the control of the driving injection cylinder, and then performs feedback adjustment based on 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-equipped 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 injection operation according to the set target position curve and 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 target speed curve, and can also perform feedback adjustment based on the motion state information of the injection cylinder V05 corresponding to the main injection system 1, thereby ensuring the synchronous motion between the slave injection system 2 and the injection cylinder V05 corresponding to the main injection system 1. In the booster injection stage, the booster cylinders V02 corresponding to the main injection system 1 and the slave injection system 2 only need to perform corresponding operations according to the set target position curve and target speed curve, and the two are synchronized with each other in terms of oil passages by the above-mentioned oil pipes and gas pipes. For ease of understanding, the synchronous control process of the main injection system 1 and the slave injection system 2 in each of 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 ) to obtain a feedforward signal u1, 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 drive 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 velocity of the drive 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-adaptive process of (1), 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, and in the injection process, in order to prevent the high-speed starting point from changing, it is necessary to control not only the speed but also the position most importantly. In order to control the injection 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, 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:

number

[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 larger. At this time, the differential part K3S(X d1 -X a1 ) can respond quickly to generate an output.

number

[0045] It should be noted that, as can be seen from the above, in the injection stage, the control signal u4 finally output to the valve group corresponding to the driving injection cylinder is u4=u2+u3, that is, the velocity feedforward signal u2 and the position feedback signal u3 may 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 velocity curve.

[0046] It should also be noted that, as can be seen from the above, the position control of the driving injection cylinder is the most important during injection, 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 driving injection cylinder is controlled to follow the target position and target speed curve according to the method of controlling the driving injection cylinder.

[0049] Specifically, based on the set target speed, the equation u5=f3(p3, p4, v d2 ) can obtain a feedforward signal u5, 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 velocity of the driven injection cylinder.

[0050] As can be seen, the synchronization control between the driven injection cylinder and the driving injection cylinder can be achieved by speed synchronization control, position synchronization control, or simultaneous synchronization control of speed and position. As can be seen from the above, since the position control of the injection cylinder is the most important in the injection stage, in order to simplify the control process and reduce the difficulty of control, in this embodiment, it is preferable to achieve 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 feedback control of the target position and actual position of the driven injection cylinder, and 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; the other is used for the tracking motion process of the driven injection cylinder, i.e., position PID control of the target position difference value and 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 actual position corresponding to the driven injection cylinder is a feedback signal u7 expressed by the following equation:

number

[0053] Based on the above control, position PID control is performed based on the target position difference value and 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.

number

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

[0055] 2. Boost injection stage As can be seen from the above, in the boosted injection stage, the main injection system 1 and the secondary injection system 2 can achieve synchronization in the oil lines by the oil pipes and gas pipes connected to the boosted oil lines, so there is no need for the main injection system 1 and the secondary injection system 2 to perform synchronous control of the oil lines in the boosted injection stage, and it is sufficient to boost the pressure on 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 for boost injection is that when boosting starts, the pressures in the rodless cavities of the injection cylinder V05 of the two injection systems are different due to different load forces, and the volumes of oil compressed are also different, so 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 build-up time as much as possible, at this time, the opening degrees of the control valves V08 corresponding to the two injection systems are different, so the booster 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 buildup stage and a pressure stabilization stage, and the movement of the boost cylinder is adjusted based on the difference in the opening control of the control valves V04 and V08 in the pressure buildup stage and the pressure stabilization stage.

[0058] In this embodiment, as shown in Figure 3, in the pressure building stage, the current boosting speed of the booster cylinder V02 can be obtained based on the target pressure, the current pressure in 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, i.e., the equation u at this time, is calculated. 10 =f5(p d ,p a1 ,X a1 ) The control voltage u of the control valve V08 10 where p d represents the target pressure, and p a1 represents the current actual pressure in the rod-less 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 system switches to the pressure stabilization stage, and at this time, the control valve V04 is in a fully closed state.

[0059] During 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, i.e., 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, thereby achieving 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 of 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 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 stage is 0, and the control signal in the pressure stabilizing stage is u 12 For the control valve V08, the control signal for the pressure build-up stage is u 10 and the control signal for the pressure stabilization stage is u 11 is.

[0061] In this embodiment, the control process for the boost injection is a feedforward process. Since there is always an error in the feedforward process, pressure feedback control, such as feedback PID control, is introduced to ensure that the pressure in the rodless cavity of injection cylinder V05 reaches the set value. The feedback control mainly acts on control valve V04, not control valve V08. That is, pressure feedback control is performed on the boost injection process, and the feedback control signal u, expressed by the following equation, is 13 By applying this 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's say.

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[0062] As can be seen, based on the above feedback control process, for control valve V04, the control signal during the pressure building phase is 0, and the control signal during the pressure stabilization phase is u 12 +u 13 For the control valve V08, the control signal for the pressure build-up 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 has described the basic principles, 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 that the above embodiments and descriptions in the specification are merely for illustrating the principles of the present application. The present application also has various modifications and improvements without departing from the spirit and scope of the present application, and all of these modifications 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, each of which includes a velocity injection oil passage and a pressure booster oil passage, The main injection system and the slave injection system have partially independent speed injection oil passages, and the booster oil passages both use an A-bridge valve group structure and cooperate with each other in step with each other; The velocity injection oil passages of the main injection system and the secondary injection system each include an injection cylinder; 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; an oil passage formed by connecting the control valve V04 and the control valve V08 in series has one end connected to a rodless cavity of the injection cylinder and the other end connected to a fuel tank, and a rod-equipped cavity of the booster cylinder is connected between the control valve V04 and the control valve V08 via a pipe line, thereby forming the A-bridge valve group structure; the rod-equipped cavities and the rod-less cavities of the booster cylinders corresponding to the main injection system and the slave injection system are all in communication with each other via pipelines, and the booster accumulators to which the two booster cylinders are respectively in communication are in communication with each other via gas pipes; A dual injection system.

2. The velocity injection oil passages of the main injection system and the slave injection system each further include 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; 2. The dual injection system of claim 1 .

3. 2. The method for synchronizing control of a dual injection system according to claim 1, comprising: setting 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; 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 synchronizes with the driving injection cylinder by using the control of the driving injection cylinder and performing feedback adjustment based on the position deviation between the two during the movement process; and step S300, in a 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. A method characterized by:

4. Based on the target velocity curve and the actual pressure of the driving injection cylinder, the equation u 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 ２ Get The velocity 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, and p ２ represents the pressure in the rod-containing cavity of the driving injection cylinder, and v ｄ１ represents the target velocity of the driving injection cylinder, and v ａ１ represents the current actual speed of the driving injection cylinder; The method for controlling synchronization of a dual injection system according to claim 3.

5. The position control of the drive injection cylinder uses a PID control method, specifically: The difference value is compared based on the target position and the current position to generate a feedback signal u ３ and the speed injection oil path receives the feedback signal u ３ and performing corresponding valve group control based on the [Equation 1] 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 method for controlling synchronization of a dual injection system according to claim 3.

6. The motion of the driven injection cylinder includes a feedforward motion and a follow-up motion; 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; The following motion is controlled by PID control based on the target position difference value and the actual position difference value of the driving injection cylinder and the driven injection cylinder, and a feedback signal u expressed by the following equation is generated: ８ obtaining the [Equation 2] A=[(X ａ１ -X ａ２ )-(X ｄ１ -X ｄ２ )] Here, X ａ１ represents the current actual position of the driving injection cylinder, and X ａ２ represents the current actual position of the driven injection cylinder, and X ｄ１ represents the target position of the driving injection cylinder, and X ｄ２ represents the target position of the driven injection cylinder, and K ７ represents the proportionality coefficient, and K ８ represents the integral constant, and K ９ represents a differential constant, and S represents a sampling period. The method for controlling synchronization of a dual injection system according to claim 3.

7. the boost injection step includes a pressure establishment step and a pressure stabilization step; adjusting the movement of the booster cylinder based on the difference in opening control of the control valves V04 and V08 during the pressure building stage and the pressure stabilizing stage; The method for controlling synchronism of a double injection system according to any one of claims 3 to 6.

8. In the pressure establishing step, a current pressure boosting speed of the booster cylinder is obtained based on the target pressure, the current pressure of the rod-containing cavity of the booster cylinder, and the current position of the injection cylinder; Based on the pressure increase speed identification result, the formula u １０ = f ５ (p ｄ , p ａ１ , X ａ１ ) the opening control signal u of the control valve V08 １０ At this time, the control valve V04 is in a fully closed state. In the pressure stabilization step, the voltage proportionality between the control valves V04 and V08 is obtained by identifying the opening proportionality of the A bridge valve group; Then, the voltages of the two control valves are gradually decreased according to the set relationship until they reach the set values, and at this time, the control signal of the control valve V04 is set to u １２ The control signal of the control valve V08 is u １１ Then, u １２ =u １１ ・f ６ (p ｄ ) and Here, p ｄ represents the target pressure, and p ａ１ represents the current actual pressure in the rodless cavity of the injection cylinder, and X ａ１ represents the current actual position of the injection cylinder, The synchronism control method for a dual injection system according to claim 7.

9. Pressure feedback control is performed on the pressure boosting process, and the feedback control signal u is expressed by the following equation: １３ is applied to the control valve V04, so that in the pressure stabilization stage, the total control signal of the control valve V04 is u １２ +u １３ year, [Equation 3] Here, K １０ represents the proportionality coefficient, and K １１ represents the integral constant, and K １２ represents a differential constant, and S represents a sampling period. The synchronization control method for a dual injection system according to claim 8.

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