High-precision follow-up valve control device

Abstract

The invention discloses a high-precision follow-up valve control device, which is characterized in that a displacement measuring device is arranged between a base and a piston rod and can measure and record the position of the piston rod at each time point when the piston rod actually moves, and the position difference value of each time point is calculated by comparing the position with each time point position set by a driving movable guide rail; according to the method, on the basis that a numerical control device drives a follow-up valve to control a piston to move, a piston movement actual position measuring device is used for obtaining set time, and the position difference values of the time points and the positions of the time points set by the driving movable guide rail are superposed, so that a new time-position numerical table of the operation of the driving movable guide rail is generated. The difference value between the displacement and the actual time displacement is obtained, the set time displacement value is changed according to the difference value to control the active guide rail to move, the set time displacement value can be approached through multiple iterations, and the structure is simple and effective.

Description

Technical Field

[0001] The present invention relates to a control device, in particular to a high-precision servo valve control device. Background Art

[0002] The hydraulic cylinder piston is driven by hydraulic pressure and can have a large driving force. Many occasions require the piston to have good timing position control accuracy while being driven, such as the injection process control of die-casting machines and injection molding machines. Many servo flow pumps and valve control methods are used to achieve this goal, but the existing technology has problems of overshoot and poor stability. CN101446308B proposes a follower valve mechanism, which uses a numerical control mechanism to control the movement of the follower valve core. The follower valve body and the piston move synchronously. By opening and closing a series of oil circuits, the piston follows the movement of the valve core. However, this solution cannot meet the needs due to the large synchronization error. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a high-precision spool valve control device, which can effectively solve the deficiencies in the prior art.

[0004] The present invention is realized through the following technical solutions: a high-precision follow-up valve control device, a hydraulic cylinder body is mounted on a base, a valve body is mounted on a piston rod, a hydraulic cylinder body and an active actuating guide rail are mounted on the base, a movement direction of the active actuating guide rail is parallel to a movement direction of the piston rod, the active actuating guide rail is controlled by a numerical control device and moves according to a set time position value, the follow-up valve body is mounted on the piston rod, the follow-up valve core and the active actuating guide rail move synchronously, two groups of oil holes are provided on the follow-up valve body, two oil grooves are provided on the follow-up valve core, the active actuating guide rail drives the follow-up valve core to move so as to open and close the oil passages of the corresponding oil holes and oil grooves and drive the movement between the piston rods, a displacement measuring device is provided between the base and the piston rod, which can measure and record the position of the time point at which the piston rod moves, compare it with the position of each time point set by the active actuating guide rail and calculate the position difference of each time point, superimpose each time difference with the position of each time point set by the active actuating guide rail, and generate a new time and position value table of the active actuating guide rail operation;

[0005] To create a time displacement table, follow these steps:

[0006] ①Set the time displacement value table

[0007]

[0008] ② Measured piston movement time displacement value table

[0009]

[0010] ③ Displacement difference

[0011] L1-L1 实1 =△L11

[0012] L2-L2 实2 =△L21

[0013] L3-L3 实3 =△L31

[0014] Ln-Ln 实n =△Ln1

[0015] ④New time displacement numerical table

[0016]

[0017] The above new numerical table data controls the movement of the active guide rail.

[0018] As a preferred technical solution, after the new numerical table is run, the piston movement is actually measured using the new numerical table, and the time displacement value and the set time displacement value table are iterated again.

[0019] As a preferred technical solution, the displacement measuring device can be a grating scale, a contact scale or an optical distance measuring device.

[0020] The beneficial effects of the present invention are as follows: based on the use of a numerical control device to drive a follower valve to control the movement of a piston, the present invention uses a piston movement actual position measurement device to obtain the difference between the set time displacement and the actual time displacement, and uses this difference to change the set time displacement value to control the movement of the active guide rail, and can iteratively approximate the set time displacement value multiple times, with a simple and effective structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the combination of the servo valve and the master cylinder of the present invention;

[0023] Figure 2 This is a schematic diagram of the combination of the servo valve and the master cylinder of the present invention, with the piston of the master cylinder being guided to move upward;

[0024] Figure 3 This is a schematic diagram of the combination of the spool valve and the master cylinder of the present invention, with the piston of the master cylinder being guided to move downward;

[0025] Figure 4 This is a schematic diagram of the opening of the pilot valve body of the present invention;

[0026] Figure 5 is a schematic diagram of a guide piston of the present invention;

[0027] Figure 6 This is a schematic diagram of the installation of the grating ruler of the present invention;

[0028] Figure 7 Schematic diagram of the relationship between the movement position and movement time of the master cylinder piston of the present invention;

[0029] 1. Base; 2. Base guide rail; 3. Guide motor; 4. Guide screw; 5. Guide rail; 6. Guide piston connector; 7. Guide piston; 71. Upward oil groove; 72. Downward oil groove; 73. Guide piston; 74. Guide piston connecting rod; 8. Guide valve body; 81. Upward oil hole; 82. Downward oil hole; 83. Guide valve inner hole; 9. Oil pump; 10. Oil return groove; 11. Oil pump 2; 12. Oil return groove 2; 13. Reversing valve; 14. Main oil cylinder body; 15. Main oil cylinder piston; 16. Grating scale seat; 17. Grating scale; 18. Grating scale slide; 19. Grating scale sliding connector; DETAILED DESCRIPTION

[0030] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0031] Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0032] like Figure 1-Figure 3 As shown, there is a base 1 equipped with a main oil cylinder body 14 and a base guide rail part 2, and a guide motor 3 is installed on the base guide rail part 2. The guide motor 3 drives the guide screw 4 to rotate, and drives the guide movable guide rail 5 to make a linear motion. The guide movable guide rail 5 is connected to the guide piston connecting rod 74 through the guide piston connecting seat 6. There is a main oil cylinder piston 15 in the main oil cylinder body 14, and the main oil cylinder piston 15 is fixedly installed with a guide valve body 8. The guide valve body 8 has a hole in the middle of the guide valve body rest inner hole 83, which contains a guide piston 7. The outer circle guide piston 73 on the guide piston 7 cooperates with the guide valve rest inner hole 83, the guide valve body 8 has an upward oil hole 81 and a downward oil hole 82, and the guide piston 7 has an upward oil groove 71 and a downward oil groove 72. Figure 2 As shown, the upward oil hole 81 and the upward oil groove 71 are aligned, and the pressure oil generated by the oil pump 9 is injected into the lower oil chamber at the bottom of the main oil cylinder piston 15 through the upward oil hole 81 and the upward oil groove 71 to raise the piston. At the same time, the reversing valve 13 connects the upper oil chamber of the main oil cylinder piston 15 with the return oil groove 12, and the oil in the upper oil chamber returns to the return oil groove 12. When it rises to Figure 1 In the state, the upward oil hole 81, the downward oil hole 82 and the upward oil groove 71 are misaligned, the oil circuit is disconnected, and the main oil cylinder piston 15 stops rising. When the guide motor 3 drives the guide screw 4 to rotate and drives the guide rail 5 to move upward to make the guide piston 7 move downward, as shown in FIG. Figure 3 As shown, when the downward oil groove 72 and the downward oil hole 82 are aligned, the oil pump 11 opens the reversing valve 13 downward to inject the pressure oil in the oil pump 11 into the upper chamber of the main oil cylinder body 14, causing the main oil cylinder piston 15 to descend, and the oil in the lower oil chamber flows back to the return oil groove 10 through the downward oil hole 82 and the downward oil groove 72. When the main oil cylinder piston 15 descends and drives the guide valve body 8 to descend synchronously, causing the downward oil hole 82 and the downward oil groove 72 to be misaligned, the reflux stops and the movement of the main oil cylinder piston 15 stops.

[0033] Example 1

[0034] like Figure 6 As shown, based on the aforementioned servo valve motion control system, a grating scale seat 16 is set on the base 1, and a grating scale 17 is installed on the grating scale 16. The grating scale slide connecting seat 19 fixedly connects the master cylinder piston 15 and the grating scale slide 18. When the master cylinder piston 15 moves, the grating scale slide 18 is driven to move by the grating scale slide connecting seat 19. The movement of the grating scale slide 18 relative to the grating scale 17 will be recorded. When the relationship between the movement position and movement time of the master cylinder piston 15 is as shown in FIG. Figure 7 When displaying the curve, a table showing the relationship between time t and motion position L can be listed:

[0035]

[0036] Numerical Table 1

[0037] This set of numbers is input into the CNC system, which controls the guide motor 3, driving the guide screw 4 to rotate and causing the guide rail 5 to move. The guide rail 5 drives the guide piston 7 and the guide rail 5 to move synchronously via the guide piston connector 6, so that the movement of the guide piston 7 conforms to the relationship determined by the above-mentioned series. Because the CNC motor and the screw guide cooperate, the motion position control of the guide piston 7 can be very precise, which can be at the filament or micron level. However, the relative position of the guide piston 7 and the guide valve body 8 changes, causing the upward oil hole 81 and the upward oil groove 71 to be misaligned. Then, the movement of the main cylinder piston 15 raised and lowered by the pressurized fluid is not synchronized with the movement of the guide piston 7. Nonlinearity and even changes in oil temperature can also cause variations in the movement synchronization between the main cylinder piston 15 and the guide piston 7. When the main cylinder piston 15 moves passively, it drives the grating scale slider 18 and the grating scale 19 to move synchronously. Real-time position signals are generated between the grating scale slider 18 and the grating scale 17. The system collects the position signals at the time to form a numerical table:

[0038]

[0039] Numerical Table 2

[0040] Compare the L and L corresponding to each t to get the difference:

[0041] L1-L1 实1 =△L11

[0042] L2-L2 实2 =△L21

[0043] L3-L3 实3 =△L31

[0044] Ln-Ln 实n =△Ln1

[0045] Numerical Table 3

[0046] Add the difference to the previous CNC system difference table to get a new value table:

[0047]

[0048] K is generally set to 1, slow iteration <1, accelerated iteration >1.

[0049] Numerical Table 4

[0050] The CNC system controls the guide motor 3 with the new numerical table 4, drives the guide screw 4 to rotate, and moves the guide rail 5 to drive the guide piston 7 to move through the guide piston connecting seat 6, and then controls the movement of the main cylinder piston 15 through the follow-up valve, so that the movement of the main cylinder piston 15 is close to the relationship determined by the numerical table 1.

[0051] Example 2

[0052] On the basis of Example 1, multiple iterations are performed to finally approximate the required numerical values ​​as determined in Table 1.

[0053] Example 3

[0054] The difference from Example 1 and Example 2 is that a linear motor is used to replace the guide motor 3 and the guide screw 4 in the figure, and the linear drive guides the movement of the guide rail 5.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A high-precision servo valve control device, wherein the hydraulic cylinder is mounted on a base, the valve body is mounted on a piston rod, the hydraulic cylinder and active actuating guide are mounted on the base, the active actuating guide moving in a direction parallel to that of the piston rod, the active actuating guide being controlled by a numerical control device and moving according to a set time and position value, the servo valve body is mounted on the piston rod, the servo valve core and the active actuating guide move synchronously, the servo valve body has two sets of oil holes, the servo valve core has two oil grooves, the active actuating guide drives the servo valve core to move, opens and closes the oil passages in the corresponding oil holes and oil grooves, and drives the piston rod to move between them, characterized by: There is a displacement measuring device between the base and the piston rod, which can measure the position of the piston rod at each time point and record it. By comparing it with the position of each time point set by the active actuating guide rail and calculating the position difference at each time point, the time difference is superimposed with the position of each time point set by the active actuating guide rail to generate a new time and position value table of the active actuating guide rail operation; To create a time displacement table, follow these steps: ①Set the time displacement value table ② Measured piston movement time displacement value table ③The difference between the set and actual displacement at each time point L1-L1 实1 =△L11 <h2 style=";text-align:left;direction:ltr">L2-L2<h2 style=";text-align:left;direction:ltr"> 实2 <h2 style=";text-align:left;direction:ltr"> =△L21 <h2 style=";text-align:left;direction:ltr">L3-L3<h2 style=";text-align:left;direction:ltr"> 实3 <h2 style=";text-align:left;direction:ltr"> =△L31 Ln-Ln 实n =△Ln1 ④New time displacement numerical table K is generally set to 1, slow iteration <1, accelerated iteration >1. The above new numerical table data controls the movement of the active guide rail.

2. The high-precision spool valve control device according to claim 1, characterized in that: After the new value table is run, the piston motion is measured again using the new value table, and the time displacement value and the set time displacement value table are iterated again.

3. The high-precision spool valve control device according to claim 1 or 2, characterized in that: The displacement measuring device can be a grating scale, a contact scale or an optical distance measuring device.

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