Method for electrolytic machining double-shaft vibration phase synchronization control

Abstract

The invention provides a phase synchronization control method for electrolytic machining double-shaft vibration, and belongs to the field of electrolytic machining. According to the method, vibration displacement of a left vibration shaft and a right vibration shaft is monitored in real time through a left displacement sensor and a right displacement sensor respectively, collected signal data of the displacement sensors are processed through a control algorithm, a real-time difference value of vibration phases of the two shafts is calculated, parameters of driving motors of the two shafts are adjusted, and synchronous control over the vibration phases of the two shafts is achieved. According to the invention, double-shaft vibration phase synchronous control in electrolytic machining is realized, and the problem of accumulative error between the motion phase of a double-shaft vibration mechanism and the rotation phase of a driving motor can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic machining, in particular to a method for synchronous control of dual-axis vibration phases. Background Art

[0002] Electrochemical machining is a machining method that uses electrochemical principles to remove materials. It has the advantages of high machining efficiency and good surface quality. However, during the electrochemical machining process, factors such as electrolyte flow, bubble generation, and uneven electric field distribution can easily lead to fluctuations in machining accuracy and surface quality. Increasing the vibration between the cathode and the workpiece can accelerate the flow and renewal of the electrolyte, making the electrolytic reaction more sufficient to reduce the accumulation of bubbles and electrolytic products in the machining gap, thereby improving production efficiency and machining accuracy. In electrochemical machining, dual-axis vibration machining technology improves machining efficiency and accuracy by introducing vibrations in two directions. However, when the phases of the dual-axis vibrations are not synchronized, it may result in poor machining results or even damage to the workpiece or tool electrode.

[0003] Currently, the design structure and manufacturing accuracy of mechanical vibration devices will affect the phase of their vibration and the rotation phase of the driving motor, resulting in a lack of synchronization. Figure 2The structure of the electrolytic machining equipment with two left and right vibration shafts is shown in FIG. 1 (CN115740664A). The structure is symmetrical and mainly includes a left vibration shaft 11, a left vibration shaft drive motor 12, a left sinusoidal surface cam device 13, a left eddy current sensor 14, a right vibration shaft 21, a right vibration shaft drive motor 22, a right sinusoidal surface cam device 23, a right eddy current sensor 24, and a workpiece 30. The left sinusoidal surface cam device 13 and the right sinusoidal surface cam device 23 are cams whose surface profile presents a sinusoidal curve shape. When the cam device is driven to rotate, the left vibration shaft 11 and the right vibration shaft 12 of each of the driven parts can continuously and smoothly perform reciprocating vibration motion according to the law of the sinusoidal curve. The left eddy current sensor 14 and the right eddy current sensor 24 are non-contact displacement detection sensors based on the principle of electromagnetic induction, which can measure the displacement of the left vibration shaft 11 and the right vibration shaft 21 during vibration. The gap between the eddy current sensor and the vibration shaft should be designed and installed according to the parameters such as the specifications of the sensor and the amplitude of the vibration shaft to ensure the stability and reliability of the measurement. In electrolytic machining, the phase synchronization of the left and right vibration shafts 11 and 21 is conducive to the flow of electrolyte, promotes the timely discharge of electrolytic products to avoid the accumulation and retention of electrolytic products in the machining area, and the phase synchronization of the two vibration shafts makes the interaction more coordinated and stable during the whole electrolytic machining process, can reduce the vibration interference inside the system, and improve the stability and reliability of the whole machining process. In actual application, it is found that the left sinusoidal curve surface cam device 13 and the right sinusoidal curve surface cam 23 can realize the sinusoidal motion law of the left vibration shaft 11 and the right vibration shaft 21 in the vibration direction respectively under the connection drive of the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22, but the phase of the left vibration shaft 11 and the right vibration shaft 21 is not an absolute corresponding relationship with the rotation phase of the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22, but there is a certain cumulative error with the increase of the number of rotations of the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22. In this case, the traditional method of using motor servo encoder feedback to control the phase synchronization of the two vibration axes cannot be well applied.

[0004] For the situation where the vibration phase of a mechanical vibration device and the rotation phase of its driving motor produce cumulative errors as the number of rotations increases due to processing or installation errors, the general method of indirectly relying on the feedback phase of the driving motor encoder to achieve phase synchronization of the two vibration axes cannot meet the control requirements. Therefore, it is of great practical significance to invent a method that can directly detect the phase of the vibration device to achieve dual-axis vibration phase synchronization control. Summary of the invention

[0005] Purpose of the invention: In view of the deficiency of the applicant's declared invention CN115740664A that the vibration phase and the rotation phase of its driving motor produce cumulative errors with the number of rotations due to processing or installation errors, the purpose of the present invention is to provide a method for synchronous control of dual-axis vibration phase in electrolytic machining to solve the problem of dual-axis vibration phase synchronization in electrolytic machining.

[0006] Technical solution: To achieve the above purpose, the present invention adopts the following technical solution:

[0007] A method for synchronous control of biaxial vibration phase of electrochemical machining, comprising the following steps:

[0008] Step 1, the left eddy current sensor 141 measures the real-time displacement S1 of the left vibration shaft 11, and the left eddy current sensor 24 measures the real-time displacement S2 of the right vibration shaft 21;

[0009] Step 2, obtaining the real-time phase φ1 of the left vibration axis 11 and the real-time phase φ2 of the right vibration axis 21 through the controller;

[0010] Step 3, the controller calculates the phases φ1 and φ2 in step 2 to obtain a real-time phase difference Δφ between the vibration axis 1 and the vibration axis 2: Δφ=φ1-φ2;

[0011] Step 4: According to the set vibration frequency Fset of the vibration shaft, the rotation speeds of the drive motor 12 of the left vibration shaft 11 and the drive motor 22 of the right vibration shaft 21 are set to Nset;

[0012] Step 5: When the value of Δφ is within the preset deviation range φ limit During the time, the rotation speeds of the drive motor 12 of the left vibration shaft 11 and the drive motor 22 of the right vibration shaft 21 both run according to the set Nset.

[0013] Step 6: When the value of Δφ exceeds the preset deviation range φ limit When the speed of the driving motor of the vibration shaft 11 and the driving motor 22 of the vibration shaft 21 are adjusted according to the set algorithm, the real-time Δφ value is gradually reduced to the preset deviation range φ limit Inside.

[0014] Furthermore, the method for measuring the real-time displacement S1 of the vibration shaft 11 and the real-time displacement S2 of the vibration shaft 21 in step 1 is as follows: the electrical signal output by the displacement sensor corresponds to the detection distance range of the displacement sensor. After the controller receives the electrical signal of the displacement sensor, it converts the collected electrical signal into actual displacements S1 and S2 according to the type of the displacement sensor and the corresponding conversion formula.

[0015] Furthermore, the method for calculating the real-time phase φ1 of the left vibration shaft 11 and the real-time phase φ2 of the right vibration shaft 21 in step 2 is as follows: according to the data of the left eddy current sensor 14 and the right eddy current sensor 24 collected by the controller, the maximum displacement S measured by the displacement sensor during the vibration process of the left vibration shaft 11 can be measured respectively. max1 and the minimum displacement S min1 and the maximum displacement S of the right vibration shaft 21 during vibration max2 and the minimum displacement S min2 .

[0016] Establish the sinusoidal motion equation of the left vibration shaft 11 S1=A1sin(φ1)+B1,

[0017] in:

[0018] A1 is the amplitude of the sinusoidal motion of the left vibration shaft 11, A1 = (S max1 -S min1 ) / 2;

[0019] B1 is the displacement of the equilibrium position of the left vibration shaft 11 when doing sinusoidal motion, B1=(S max1 +S min1 ) / 2;

[0020] Substituting A1 and B1 into the sinusoidal motion formula, we get S1=(S max1 -S min1 ) / 2*sin(φ1)+(S max1 +S min1 ) / 2,

[0021] At the same time, the controller collects and records the position value S of the left vibration shaft 11 at the last collection cycle t in real time. 1-t, By comparing the current displacement S1 with the displacement value S of the previous cycle in real time 1-t The size of can be used to determine the running direction of the vibration axis 11 in one phase cycle.

[0022] Calculated

[0023]

[0024] The range of φ1 obtained in the above calculation formula is 0 to 2π.

[0025] Similarly, the sinusoidal motion equation of the right vibration shaft 21 is established as S2=A2sin(φ2)+B2,

[0026] in:

[0027] A2 is the amplitude of the sinusoidal motion of the right vibration shaft 21, A2=(S max2 -S min2 ) / 2;

[0028] B2 is the displacement of the equilibrium position of the right vibration shaft 21 doing sinusoidal motion, B2 = (S max2 +S min2 ) / 2;

[0029] Substituting into the formula, we get S2 = (S max2 -S min2 ) / 2*sin(φ2)+(S max2 +S min2 ) / 2,

[0030] At the same time, the controller collects and records the position value S of the vibration axis 2 at the last collection cycle t in real time. 2-t, By comparing the current displacement S2 with the displacement value S of the previous cycle in real time 2-t The magnitude of can be used to determine the running direction of the vibration axis 2 in one phase cycle.

[0031] Calculated

[0032]

[0033] The range of φ2 obtained in the above calculation formula is 0 to 2π.

[0034] Furthermore, the algorithm method for adjusting the speed in step 6 is:

[0035] When the absolute value of Δφ is within the preset deviation range φ limit During the time, the speeds of the driving motor 12 of the vibration shaft 11 and the driving motor 22 of the vibration shaft 21 are both set according to the N set When the absolute value of Δφ exceeds the maximum deviation range φmax, the control alarms and stops the operation of the vibration shaft 11 drive motor and the vibration shaft 21 drive motor.

[0036] When the absolute value of Δφ exceeds the preset deviation range φ limit When the maximum deviation range φmax is within the range, the driving motors of the vibration shaft 11 and the vibration shaft 21 start to adjust the speed:

[0037] At this time, when Δφ is greater than 0, it means that the phase of the vibration shaft 11 is ahead. In order to reduce the phase difference Δφ, the speed of the driving motor of the vibration shaft 11 is reduced, while the speed of the driving motor of the vibration shaft 21 is maintained so that the phase of the vibration shaft 21 gradually catches up with the phase of the vibration shaft 11.

[0038] On the contrary, when Δφ is less than 0, it means that the phase of the vibration shaft 21 is ahead. In order to reduce the phase difference Δφ, the speed of the driving motor of the vibration shaft 21 is reduced while maintaining the speed of the driving motor of the vibration shaft 11 so that the phase of the vibration shaft 11 gradually catches up with the phase of the vibration shaft 21.

[0039] The above process of adjusting the driving motor of vibration shaft 11 and the driving motor of vibration shaft 21 will continuously monitor the phase difference Δφ, and automatically adjust the rotation speed of the driving motors of the two vibration shafts according to the real-time numerical value of Δφ to achieve the reduction of Δφ of vibration shaft 1 and vibration shaft 2 and realize phase synchronization between the two.

[0040] Beneficial effect: This method uses a displacement sensor to monitor the vibration displacement of two vibration axes in real time, uses a control algorithm to process the collected displacement sensor signal data, calculates the real-time difference between the vibration phases of the two axes, and adjusts the parameters of each drive motor to achieve synchronous control of the dual-axis vibration phase. The present invention realizes synchronous control of dual-axis vibration phases in electrolytic machining, and can solve the problem of cumulative error between the motion phase of the dual-axis vibration mechanism and the rotation phase of the drive motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A flow chart of the dual-axis vibration phase synchronization method provided by the present invention;

[0042] Figure 2 This is a schematic diagram of the dual-axis vibration phase synchronization mechanism disclosed in CN115740664A.

[0043] Markings in the figure: 11-left vibration shaft, 12-left vibration shaft driving motor, 13-left sine curve surface cam device, 14-left eddy current sensor, 21-right vibration shaft, 22-right vibration shaft driving motor, 23-right sine curve surface cam device, 24-right eddy current sensor, 30-processed workpiece. DETAILED DESCRIPTION

[0044] In order to make the purpose and technical solution of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0045] like Figure 1 The present invention provides a method for electrolytic machining dual-axis vibration phase synchronization control, which can achieve phase synchronization of the left vibration axis 11 and the right vibration axis 21. It includes the following steps:

[0046] Step 1: The displacement sensor 14 measures the real-time displacement S1 of the left vibration shaft 11, and the displacement sensor 24 measures the real-time displacement S2 of the right vibration shaft 21; in this embodiment, the displacement sensors are the left eddy current sensor 14 and the right eddy current sensor 24. The 4-20mA current signal output by the eddy current sensor corresponds to the detection distance range of the displacement sensor. After receiving the current signal of the displacement sensor, the controller converts the current signal into the actual detection distance value. The conversion formula is:

[0047] S=(I-4) / (20-4)×D

[0048] Where: S: the distance from the end face of the displacement sensor to the detected metal surface; I: the actual current value output by the eddy current sensor (unit: mA); D: the maximum detection distance of the sensor (unit: mm).

[0049] So we can ask for:

[0050] S1=(I1-4) / (20-4)×D

[0051] S2=(I2-4) / (20-4)×D

[0052] Where I1 is the current value measured and output by the displacement sensor 24 , and I2 is the current value measured and output by the displacement sensor 14 .

[0053] Step 2: The real-time phase φ1 of the left vibration shaft 11 and the real-time phase φ2 of the right vibration shaft 21 are obtained by the controller; according to the displacement sensor distance measurement formula S = (I-4) / (20-4) × D, the maximum displacement S measured by the displacement sensor during the vibration process of the left vibration shaft 11 can be measured respectively. max1 and the minimum displacement S min1 and the maximum displacement S of the right vibration shaft 21 during vibration max2 and the minimum displacement S min2 .

[0054] Therefore, the sinusoidal motion equation of the vibration of the left vibration shaft 11 can be suggested to be S1=A1sin(φ1)+B1, where A1 is the amplitude of the sinusoidal motion of the left vibration shaft 11, and A1=(S max1 -S min1 ) / 2, B1 is the displacement of the equilibrium position of the vibration axis 1 doing sinusoidal motion, it can be obtained that B1=(S max1 +S min1 ) / 2, and then put A1 and B1 into the formula to get:

[0055] S1=(S max1 -S min1 ) / 2*sin(φ1)+(S max1 +S min1 ) / 2

[0056] At the same time, the controller collects and records the position value S of the left vibration shaft 11 at the last collection cycle t in real time. 1-t, By comparing the current displacement S1 with the displacement value S of the previous cycle in real time 1-t The magnitude of can be used to derive the running direction of the left vibration axis 11 in a phase cycle, which can be calculated as:

[0057]

[0058] The range of φ1 obtained in the above calculation formula is 0 to 2π.

[0059] Similarly, the sinusoidal motion equation of the right vibration shaft 21 can be established S2=A2sin(φ2)+B2, where A2 is the amplitude of the sinusoidal motion of the right vibration shaft 21, and it can be concluded that A2=(S max2 -S min2 ) / 2; B2 is the displacement of the equilibrium position of the right vibration shaft 21 when doing sinusoidal motion, and it can be obtained that B2=(S max2 +S min2 ) / 2; Substitute A2 and B2 into the formula to get:

[0060] S2=(S max2 -S min2 ) / 2*sin(φ2)+(S max2 +S min2 ) / 2

[0061] At the same time, the controller collects and records the position value S of the right vibration shaft 21 at the last collection cycle t in real time. 2-t, By comparing the current displacement S2 with the displacement value S of the previous cycle in real time 2-t The magnitude of can be used to determine the direction of movement of the vibration axis 2 in a phase cycle.

[0062]

[0063] The range of φ2 obtained in the above calculation formula is 0 to 2π.

[0064] Step 3: Based on the calculated phase φ1 of the left vibration axis 11 and the phase φ2 of the right vibration axis 21 , the real-time phase difference Δφ=φ1-φ2 ​​between the left vibration axis 11 and the right vibration axis 21 can be calculated.

[0065] Step 4: Set the vibration frequency of the left vibration axis 11 and the right vibration axis 21 to F set In this embodiment, the frequency-to-speed ratio of the left-side sinusoidal surface cam device 13 and the right-side sinusoidal surface cam device 23 is ω. According to the formula It can be concluded that the speed setting of the drive motor 12 of the left vibration shaft and the drive motor 21 of the right vibration shaft is

[0066] Step 5: During operation, when the controller monitors and calculates in real time that the absolute value of the phase difference Δφ between the left vibration axis 11 and the right vibration axis 21 is within the preset deviation range φ limit During the time, the rotation speeds of the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22 are both set according to the program N set run.

[0067] When the absolute value of the phase difference Δφ between the left and right vibration axes exceeds the maximum deviation range φmax, the control alarm is sounded and the operation of the left vibration axis drive motor 12 and the right vibration axis drive motor 21 is stopped. limit When the maximum deviation range φmax is within the range, the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22 start to adjust the speed:

[0068] At this time, when Δφ is greater than 0, it means that the phase of the left vibration shaft 11 is ahead. In order to reduce the phase difference Δφ, the speed of the left vibration shaft drive motor 12 is controlled to be reduced to α*N. set , where α = 0.98, while keeping the speed of the right vibration shaft drive motor 22 at N set , so that the phase of the right vibration axis 21 gradually catches up with the phase of the left vibration axis 11.

[0069] On the contrary, when Δφ is less than 0, it means that the phase of the right vibration shaft 21 is ahead. In order to reduce the phase difference Δφ, the speed of the right vibration shaft driving motor 22 is reduced to β*N. set , where β = 0.98, while keeping the speed of the left vibration shaft drive motor 12 at N set , so that the phase of the left vibration axis 11 gradually catches up with the phase of the right vibration axis 21.

[0070] The above process of adjusting the left vibration shaft drive motor 12 and the right vibration shaft drive motor 22 will continuously monitor the phase difference Δφ between the left vibration shaft 11 and the right vibration shaft 21, and automatically adjust the rotation speeds of the left and right vibration shaft drive motors according to the real-time numerical value of Δφ according to the above rules, so as to reduce Δφ between the left vibration shaft 11 and the right vibration shaft 21 within a certain range, and realize synchronous control of the phases of the two within a certain error range.

[0071] The preset deviation range in this embodiment is The maximum deviation range of the setting

[0072] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A method for synchronous control of biaxial vibration phase in electrochemical machining, characterized in that: The following steps are involved: Step 1, the left displacement sensor 11 measures the real-time displacement S1 of the left vibration shaft 11, and the right displacement sensor 14 measures the real-time displacement S2 of the vibration shaft 21, and the real-time signals measured by the displacement sensors are input into the controller; Step 2, obtaining the real-time phase φ1 of the left vibration axis 11 and the real-time phase φ2 of the right vibration axis 21 through the controller; Step 3, the controller calculates the phases φ1 and φ2 in step 2 to obtain a real-time phase difference Δφ between the vibration axis 1 and the vibration axis 2: Δφ=φ1-φ2; Step 4: According to the set vibration axis vibration frequency F set , the speed of the drive motor 1 of the vibration axis 1 and the drive motor 2 of the vibration axis 2 is set to N set ; Step 5: When the value of Δφ is within the preset deviation range φ limit During the time, the speed of the drive motor of the vibration axis 1 and the drive motor 2 of the vibration axis 2 are both set according to the N set run; Step 6: When the value of Δφ exceeds the preset maximum deviation range φmax, the speeds of the drive motor of the vibration axis 1 and the drive motor 2 of the vibration axis 2 are adjusted according to the set algorithm, and the real-time Δφ value is gradually reduced to the preset deviation range φ limit Inside; Where: φ limit is the preset deviation range threshold, φ max is the maximum deviation range alarm threshold.

2. A method for electrochemical machining dual-axis vibration phase synchronization control according to claim 1, characterized in that: In step 1, the real-time displacement measurement method is: the electrical signal output by the displacement sensor corresponds to the detection distance range of the displacement sensor, the controller receives the electrical signal of the displacement sensor in real time, and converts the collected electrical signal into actual displacements S1 and S2 according to the type of the displacement sensor and the conversion formula.

3. A method for electrochemical machining dual-axis vibration phase synchronization control according to claim 1, characterized in that: In step 2, the real-time phase φ of the vibration shaft is calculated by: according to the data of the displacement sensor collected by the controller, the maximum displacement S measured by the displacement sensor during the vibration process of the vibration shaft is measured. max and the minimum displacement S min ; Establish the sinusoidal motion equation of the vibrating shaft: S=Asin(φ)+B (1) but: A= (S max -S min ) / 2 (2) B= (S max +S min ) / 2 (3) Substituting A and B in equation (2) and (3) into equation (1), we get: S=(S max -S min ) / 2*sin(φ)+ (S max +S min ) / 2 (4) Among them, A is the amplitude of the vibration axis doing sinusoidal motion, and B is the displacement of the equilibrium position of the vibration axis doing sinusoidal motion; The controller collects and records the position value S of the vibration axis at the last collection cycle t in real time. 1-t, By comparing the current displacement S with the displacement value S of the previous cycle in real time 1-t The magnitude of can be used to determine the direction of the vibration axis in a phase cycle, and the calculation results are: The range of φ obtained in the above calculation formula is 0 to 2π; According to formula (5), φ1 and φ2 are obtained respectively; and further, Δφ=φ1-φ2 ​​is obtained.

4. A method for electrochemical machining dual-axis vibration phase synchronization control according to claim 1, characterized in that: In step 6, the method for adjusting the speed is: (1) When the absolute value of Δφ is within the preset deviation range φ limit The speed of the driving motors of the left and right vibration axes is set according to the N set run; (2) When the absolute value of Δφ exceeds the maximum deviation range φmax, the control alarm is sounded and the operation of the vibration axis 1 drive motor and the vibration axis 2 drive motor is stopped; (3) When the absolute value of Δφ exceeds the preset deviation range φ limit When the maximum deviation is within the range φma, the drive motors of the left and right vibration axes begin to adjust their speed: (3-1) When Δφ is greater than 0, it indicates that the phase of the left vibration shaft 11 is ahead. In order to reduce the phase difference Δφ, the speed of the driving motor of the left vibration shaft 11 is reduced while the speed of the driving motor of the right vibration shaft 21 is maintained, so that the phase of the vibration shaft 21 gradually catches up with the phase of the vibration shaft 11; (3-2) When Δφ is less than 0, it indicates that the phase of the vibration axis 21 is ahead. In order to reduce the phase difference Δφ, the speed of the driving motor of the vibration axis 21 is reduced while the speed of the driving motor of the vibration axis 11 is maintained, so that the phase of the vibration axis 11 gradually catches up with the phase of the vibration axis 21. The above process of adjusting the driving motor of vibration axis 1 and the driving motor of vibration axis 2 will continuously monitor the phase difference Δφ, and automatically adjust the rotation speed of the driving motors of the two vibration axes according to the real-time numerical value of Δφ, so as to reduce Δφ of vibration axis 1 and vibration axis 2 and achieve phase synchronization between the two.

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