Pneumatic needling mass transfer mechanism and needling crystal vibration reduction method thereof

Abstract

The invention discloses a pneumatic needling mass transfer mechanism and a needling crystal vibration reduction method thereof, and relates to the technical field of chip mass transfer, the pneumatic needling mass transfer mechanism comprises a cross beam, a follow-up system and a needling system, the needling system comprises a sliding plate, a large-stroke motor, a camera, a voice coil motor, a needle rod and a gas circuit, the sliding plate is driven by the large-stroke motor and is in sliding connection with the front end face of the cross beam through the sliding rail, the voice coil motor and the camera are arranged in front of the sliding plate side by side, the needle rod is in linkage with an output shaft of the voice coil motor and communicated with the air path, and the follow-up system is in sliding connection with the rear end face of the cross beam and comprises a permanent magnet linear motor and a detachable mass block. According to the pneumatic needling mass transfer mechanism and the needling crystal vibration reduction method thereof, the follow-up system and the needling system do reverse synchronous movement with the same speed and the same acceleration, and cross beam torsional vibration caused by repeated starting and stopping movement of the single-side permanent magnet linear motor is reduced; and local momentum balance in the crystal stabbing process is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of chip mass transfer, and in particular to a pneumatic needle puncture mass transfer mechanism and a crystal puncture vibration reduction method thereof. Background Art

[0002] Mini / Micro LED display screens are composed of a large number of three-color micron-level LED display chips. Mini / Micro LED display chips are independently packaged to form a single pixel, and have excellent performance in terms of luminous efficiency, power consumption, contrast, response speed and lifespan, making them the best choice for the next generation of mainstream display screens. The mass transfer of LED display chips is divided into point transfer represented by precise pick-and-release transfer technology and laser peeling technology, and block transfer represented by self-assembly technology and roller transfer technology.

[0003] Point transfer has been developed for a long time, and the process flow is relatively complete. The application of point transfer is mainly divided into three types: mechanical swing arm type, laser peeling type and needle puncture type. The needle puncture type uses a needle to puncture the chip to achieve transfer. Compared with the mechanical swing arm type, the transfer stroke is shortened and the transfer mechanism is optimized. Compared with the laser peeling type, the transfer process has no thermal reaction and is friendly to the chip structure. It is currently the most promising transfer method used in production. Due to the ultra-high frequency start-stop characteristics of needle puncture transfer, there are inevitably two problems in actual working conditions: vibration caused by the high-speed start-stop movement of the platform and vibration caused by the vertical needling movement. The two vibrations will directly affect the transfer accuracy of the equipment and affect the quality of the finished Mini / Micro LED display. For the problem of vibration caused by the high-speed start-stop movement of the platform, the industry mainly adopts active vibration reduction (countering and reducing vibration force) and passive vibration reduction (optimized design) to solve it.

[0004] Patent application CN202310323917.4 describes a vibration reduction design method for damping rings for aviation gears, electronic equipment, and storage media. Software is used to perform modal analysis on the gear spokes and vibration stress calculations. The dangerous models whose calculation results do not meet the requirements are restructured and then the modal analysis is re-performed. This solution can meet the vibration reduction requirements for a single component, but is not applicable to complex assemblies. The lack of an active vibration reduction structure limits the vibration reduction effect.

[0005] Patent application CN202410888298.8 describes a control method and system for an active-passive hybrid vibration reduction system. Vibration signals at different positions are collected, processed by algorithms and controllers, to obtain optimal control signals at each position, and the electronically controlled hydraulic valve is driven to actively offset the high-frequency vibration of the experimental platform. This scheme has high control accuracy and improved response speed compared to other active vibration reduction methods. However, the vibration reduction process requires signal collection, signal processing and driving, and the vibration reduction process is relatively long. In addition, this vibration reduction method counteracts the vibration force and cannot reduce the vibration force from the source. Summary of the invention

[0006] The purpose of the present invention is to provide a pneumatic acupuncture mass transfer mechanism and its crystal puncture vibration reduction method, which utilizes the follow-up system and the acupuncture system to perform opposite synchronous motion at the same speed and acceleration, thereby reducing the torsional vibration of the beam caused by the repeated start and stop motion of the single-sided permanent magnet linear motor, and forming a local momentum balance during the crystal puncture process.

[0007] To achieve the above-mentioned purpose, the present invention provides a pneumatic acupuncture mass transfer mechanism, including a crossbeam, a follow-up system and acupuncture system, the acupuncture system including a slide plate, a long-stroke motor, a camera, a voice coil motor, a needle rod and an air path, the slide plate is driven by the long-stroke motor and is slidably connected to the front end surface of the crossbeam through a slide rail, the voice coil motor and the camera are arranged side by side in front of the slide plate, the needle rod is linked to the output shaft of the voice coil motor, the needle rod is connected to the air path, the follow-up system is slidably connected to the rear end surface of the crossbeam, and the follow-up system includes a permanent magnet linear motor and a detachable mass block.

[0008] A method for reducing vibration of a pneumatic needle-piercing mass transfer mechanism, the steps are as follows:

[0009] S1. Remove the mass block from the follow-up system, and under the initial working condition where the follow-up system is not turned on, establish a vibration dynamics model of the pneumatic acupuncture mass transfer mechanism according to Newton's second law and mechanical dynamics equations to obtain the torsional vibration dynamics equation of the beam;

[0010] S2. According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the initial disturbance equation is calculated, and then the excitation response disturbance caused by the general excitation force is superimposed to obtain the system's initial disturbance superposition amplitude ΔL0;

[0011] S3, loading the mass block onto the follow-up system, turning on the follow-up system, making the follow-up system and the acupuncture system move synchronously in opposite directions, adopting the dynamic balancing active vibration reduction method to reduce vibration, referring to the mathematical model of the rotating permanent magnet motor, modeling the permanent magnet linear motor involved in the dynamic balancing active vibration reduction, and obtaining the permanent magnet linear motor model;

[0012] S4. According to the permanent magnet linear motor model, the neural network feedforward method is used to adjust the permanent magnet linear motor current PID control parameters to obtain the minimum amplitude ΔL of the system disturbance superposition after the follow-up system is added.

[0013] Preferably, the torsional vibration dynamic equation of the beam of the acupuncture system in S1 is:

[0014]

[0015] Where M0, M1, and M2 are the mass of the beam, the mass of the acupuncture system, the mass of the needle and the voice coil motor, and the mass of the connector between the needle and the voice coil motor, respectively; F0 is the thrust of the permanent magnet linear motor of the acupuncture system; C0 and C1 are the damping of the acupuncture system and the servo system, respectively; and K0 and K1 are the stiffness of the acupuncture system and the servo system, respectively.

[0016] Preferably, in S2, the process of calculating the initial disturbance is as follows:

[0017] Substitute the initial disturbance, displacement and velocity at time t = 0 into the amplitude x(t) under the initial disturbance csrd expression:

[0018]

[0019] Where:

[0020] The general excitation force can be regarded as the integration of a series of tiny pulse excitations. According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the integral of all pulse excitations of the system in the interval 0≤τ≤t is equal to the general excitation response x(t) jlxy :

[0021]

[0022] The maximum amplitude ΔL of the beam is the superposition of the displacement response caused by the initial disturbance and the excitation state, so:

[0023]

[0024] Preferably, in S3, with reference to the mathematical model of the rotating permanent magnet motor, the voltage equation of the permanent magnet linear motor in the rotating coordinate is established as follows:

[0025]

[0026] Where U d with U q are the d-axis and q-axis voltages, I d with I q are the d-axis and q-axis currents, L d With L q are the d-axis and q-axis inductances, respectively, f is the permanent magnet flux, v is the running speed, τ e is the pole pitch, R is the winding resistance, and the power input of the permanent magnet linear motor is shown as follows:

[0027]

[0028] In the formula, Indicates the coil heating loss, represents electromagnetic potential energy, It represents the work done by thrust. By taking the derivative of the work done by thrust, we can get the total thrust F of the permanent magnet linear motor. z The expression is:

[0029]

[0030] Using surface mounted permanent magnet linear motor, L d With L q Approximately equal, let L d =L q , and obtain the tensile deformation force F of the beam of the permanent magnet linear motor ls With tensile torsion force F nz The expression is:

[0031]

[0032] Where λ is defined as the performance ratio parameter of the surface-mounted permanent magnet linear motor, and the value of λ is:

[0033]

[0034] The actual torsional force F is expressed as:

[0035] F=λI q (F 扭转 ≤F≤F 总 ).

[0036] Preferably, in S4, the BP neural network PID is used to control the movement of the acupuncture system and the servo system, and the current parameters are adjusted in real time to control the thrust of the motor. After the regulation, the actual current I s As shown below:

[0037]

[0038] In the formula, K P , K I and K D are the proportional constant, integral constant and differential constant of PID control, μ and η are intermediate operational variables. In summary, the thrust F0 of the acupuncture system motor can be obtained as follows:

[0039]

[0040] When a mass block with a weight of M3 is added to the follow-up system, the relationship between the torsional vibration amplitude of the entire beam and the current is:

[0041]

[0042] In the formula, C1 is the damping of the servo system, K1 is the stiffness of the servo system, and F1 is the thrust of the permanent magnet linear motor of the servo system. F1 is expressed as:

[0043]

[0044] The system balance equation at this time is:

[0045]

[0046] In summary, the minimum amplitude ΔL of the system disturbance superposition after the servo system starts working is obtained as:

[0047]

[0048] In the formula,

[0049] Therefore, the present invention adopts a pneumatic needling mass transfer mechanism and a crystal pricking vibration reduction method with the above-mentioned structure and steps. The crossbeam is located between the needling system and the follow-up system. It is the core component for performing alignment and the main motion medium unit of the three-degree-of-freedom platform. The linear motor with synchronous reverse motion is used to reduce the torsional amplitude of the crossbeam and the torsional vibration of the crossbeam caused by the repeated start and stop motion of the single-side linear motor. It can form a local momentum balance in the crystal pricking process, improve the crystal pricking accuracy and the stability of the whole machine transfer process, and realize pneumatic needling mass transfer under high-frequency motion.

[0050] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural schematic diagram of an embodiment of a pneumatic acupuncture mass transfer mechanism of the present invention;

[0052] Figure 2 A top view of the structure of a pneumatic acupuncture mass transfer mechanism according to an embodiment of the present invention;

[0053] Figure 3 It is a flow chart of a method for reducing vibration of a pneumatic acupuncture mass transfer mechanism according to an embodiment of the present invention;

[0054] Figure 4 Schematic diagram of theoretical model parameters and deformation of an embodiment of the present invention;

[0055] Figure 5 This is a block diagram of a neural network feedforward method PID controller according to an embodiment of the present invention;

[0056] Figure 6 A schematic diagram of a neural network feedforward method network model according to an embodiment of the present invention;

[0057] Figure 7 It is a simulation cloud diagram of equivalent deformation of beam torsion according to an embodiment of the present invention;

[0058] Figure 8 The equivalent deformation simulation data of the beam torsion according to the embodiment of the present invention;

[0059] Fig. 9 This is a real shot of the pneumatic acupuncture mass transfer device and the vibration measuring device according to an embodiment of the present invention;

[0060] Fig.10 This is a comparison diagram of the chip positions collected by the camera before and after vibration reduction using the dynamic balancing method in an embodiment of the present invention.

[0061] Reference numerals

[0062] 1. Crossbeam; 2. Acupuncture system; 21. Camera; 22. Slide rail; 23. Slide plate; 24. Long-stroke motor; 25. Voice coil motor; 26. Needle rod; 3. Follow-up system. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0064] Example

[0065] like Figure 1 and Figure 2 As shown, a pneumatic acupuncture mass transfer mechanism includes a crossbeam 1, a follow-up system 3 and acupuncture system 2. The acupuncture system 2 includes a slide plate 23, a long-stroke motor 24, a camera 21, a voice coil motor 25, a needle rod 25, and an air path. The slide plate 23 is driven by the long-stroke motor 24 and is slidably connected to the front end face of the crossbeam 1 through a slide rail 22. The voice coil motor 25 and the camera 21 are arranged side by side in front of the slide plate 23. The needle rod 25 is linked to the output shaft of the voice coil motor 25. The middle part of the needle rod 25 has a through hole, and a positive pressure air source is externally connected through the air path. During the crystal acupuncture process, an air film is formed between the "needle head-film material". There is no actual contact between the needle head and the film material, thereby avoiding the influence of the longitudinal expansion and contraction vibration of the rod, and the lateral deformation of the needle rod 25 is a high-order small amount, so it is negligible. The follow-up system 3 is slidably connected to the rear end face of the crossbeam 1. The follow-up system 3 includes a permanent magnet linear motor and a detachable mass block. The permanent magnet linear motor drives the mass block to slide along the crossbeam. The actual picture is as follows Fig. 9 shown.

[0066] Based on the above-mentioned pneumatic needle-piercing mass transfer mechanism, the crystal vibration reduction method is as follows: Figure 3 As shown, the steps are as follows:

[0067] S1, remove the mass block from the follow-up system 3, and under the initial working condition of not turning on the follow-up system 3, establish a vibration dynamics model of the pneumatic acupuncture mass transfer mechanism according to Newton's second law and mechanical dynamics equations to obtain the torsional vibration dynamics equation of the beam 1;

[0068] like Figure 4As shown, the torsional vibration dynamic equation of the acupuncture system 2 beam 1 is:

[0069]

[0070] Wherein M0, M1, and M2 are the masses of the beam 1, the acupuncture system 2, and the needle including the voice coil motor 25 and its connecting parts, respectively; F0 is the thrust of the permanent magnet linear motor of the acupuncture system 2; C0 and C1 are the damping of the acupuncture system 2 and the follow-up system 3, respectively; and K0 and K1 are the stiffness of the acupuncture system 2 and the follow-up system 3, respectively.

[0071] S2. According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the initial disturbance equation is calculated, and then the excitation response disturbance caused by the general excitation force is superimposed to obtain the system's initial disturbance superposition amplitude ΔL0;

[0072] The process of calculating the initial perturbation is as follows:

[0073] Substitute the initial disturbance, displacement and velocity at time t = 0 into the amplitude x(t) under the initial disturbance csrd expression:

[0074]

[0075] Where:

[0076] The general excitation force can be regarded as the integration of a series of tiny pulse excitations. According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the integral of all pulse excitations of the system in the interval 0≤τ≤t is equal to the general excitation response x(t) jlxy :

[0077]

[0078] The maximum amplitude ΔL of beam 1 is the superposition of the displacement response caused by the initial disturbance and the excitation state, so:

[0079]

[0080] S3. Load the mass block onto the follow-up system 3, turn on the follow-up system 3, make the follow-up system 3 and the acupuncture system 2 move in opposite directions synchronously, adopt dynamic balancing active vibration reduction to reduce vibration, refer to the mathematical model of the rotating permanent magnet motor, model the permanent magnet linear motor involved in dynamic balancing active vibration reduction, and obtain the permanent magnet linear motor model.

[0081] The voltage equation of the permanent magnet linear motor in rotating coordinates is established as follows:

[0082]

[0083] Where Ud with U q are the d-axis and q-axis voltages, I d with I q are the d-axis and q-axis currents, L d With L q are the d-axis and q-axis inductances, respectively, f is the permanent magnet flux, v is the running speed, τ e is the pole pitch, R is the winding resistance, and the power input of the permanent magnet linear motor is shown as follows:

[0084]

[0085] In the formula, Indicates the coil heating loss, represents electromagnetic potential energy, It represents the work done by thrust. By taking the derivative of the work done by thrust, we can get the total thrust F of the permanent magnet linear motor. z The expression is:

[0086]

[0087] Using surface mounted permanent magnet linear motor, L d With L q Approximately equal, let L d =L q , and obtain the tensile deformation force F of the permanent magnet linear motor beam 1 ls With tensile torsion force F nz The expression is:

[0088]

[0089] Where λ is defined as the performance ratio parameter of the surface-mounted permanent magnet linear motor, and the value of λ is:

[0090]

[0091] The actual torsional force F is expressed as:

[0092]

[0093] S4. According to the permanent magnet linear motor model, the neural network feedforward method is used to adjust the permanent magnet linear motor current PID control parameters to obtain the minimum amplitude ΔL of the system disturbance superposition after the follow-up system 3 is added.

[0094] like Figure 5As shown, the BP neural network PID is used to control the movement of the acupuncture system 2 and the servo system 3, and the current parameters are adjusted in real time to control the motor thrust. The conventional PID part can form a closed-loop feedback control for the controlled object. With the mapping ability of the BP network to nonlinear functions, the optimal solution of various nonlinear combinations of the three parameters in the PID controller can be obtained through self-learning based on the system state and a specific learning algorithm, and finally the optimal parameters of the PID controller are obtained.

[0095] like Figure 6 As shown in the figure, the BP neural network adopts a "3-5-3" structure, with 5 hidden layer nodes. It represents the nodes of the input layer, hidden layer, and output layer. The upper right subscript [i] is one of [1], [2], and [3], representing the input layer, hidden layer, and output layer, respectively. The lower right subscript j represents the number of nodes in this layer. According to the actual control requirements of the system, the hyperbolic tangent function is selected as the activation function of the hidden layer, and the non-negative hyperbolic tangent function is selected as the activation function of the output layer.

[0096] The working mode of BP neural network is as follows: process one: information is directly transmitted through the input layer, hidden layer and output layer. At this time, if the output value meets the expected value, the learning is completed, otherwise it enters process two; process two: when the output value does not meet the expected value, the error signal is fed forward and the connection weights of the output layer and the hidden layer are modified to reduce the negative gradient of the error, and the weights are adjusted to reduce the error, and then process one is entered again until all information is processed and output, and the cycle ends.

[0097] After BP neural network regulation, the actual current I s As shown below:

[0098]

[0099] In the formula, K P , K I and K D are the proportional constant, integral constant and differential constant of PID control, μ and η are intermediate operational variables. In summary, the motor thrust F0 of acupuncture system 2 is:

[0100]

[0101] When a mass block with a weight of M3 is added to the follow-up system 3, the relationship between the torsional vibration amplitude of the entire beam 1 and the current is:

[0102]

[0103] In the formula, C1 is the damping of the servo system 3, K1 is the stiffness of the servo system 3, and F1 is the thrust of the permanent magnet linear motor of the servo system 3. F1 is expressed as:

[0104]

[0105] The system balance equation at this time is:

[0106]

[0107] In summary, the minimum amplitude ΔL of the system disturbance superposition after the servo system 3 starts working is obtained as:

[0108]

[0109] In the formula,

[0110] The technical solution proposed by the present invention is simulated, and the deformation cloud diagrams under different acceleration modes are as follows: Figure 7 As shown, the vibration amplitude is Figure 8 Compare the chip positions captured by the camera 21 before and after the dynamic balancing method of the present invention is used for vibration reduction, as shown in FIG. Fig.10 As shown, the left figure shows the situation where the dynamic balancing method is not used, and the chip is offset, lost and misaligned during the transfer process; the right figure shows that after the dynamic balancing method of the present application is adopted, the chip transfer yield is improved.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A pneumatic acupuncture mass transfer mechanism, Features: It includes a crossbeam, a follow-up system and a needling system. The needling system includes a slide plate, a long-stroke motor, a camera, a voice coil motor, a needle rod and an air path. The slide plate is driven by the long-stroke motor and is slidably connected to the front end face of the crossbeam through a slide rail. The voice coil motor and the camera are arranged side by side in front of the slide plate. The needle rod is linked to the output shaft of the voice coil motor, the needle rod is connected to the air path, the follow-up system is slidably connected to the rear end face of the crossbeam, and the follow-up system includes a permanent magnet linear motor and a detachable mass block.

2. A method for reducing vibration of a pneumatic needle-piercing mass transfer mechanism as claimed in claim 1, It is characterized in that Here are the steps: S1. Remove the mass block from the follow-up system, and under the initial working condition where the follow-up system is not turned on, establish a vibration dynamics model of the pneumatic acupuncture mass transfer mechanism according to Newton's second law and mechanical dynamics equations to obtain the torsional vibration dynamics equation of the beam; S2. According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the initial disturbance equation is calculated, and then the excitation response disturbance caused by the general excitation force is superimposed to obtain the system initial disturbance superposition amplitude ΔL 0 ; S3, loading the mass block onto the servo system, turning on the servo system, making the servo system and the acupuncture system move in opposite directions synchronously, and adopting the method of dynamic balancing active vibration reduction to reduce vibration. Under the condition of turning on the servo system, refer to the mathematical model of the rotating permanent magnet motor, and conduct motor modeling for the permanent magnet linear motor involved in the dynamic balancing active vibration reduction to obtain the permanent magnet linear motor model; S4. According to the permanent magnet linear motor model, the neural network feedforward method is used to adjust the permanent magnet linear motor current PID control parameters to obtain the minimum amplitude ΔL of the system disturbance superposition after the follow-up system is added.

3. A pneumatic needle puncture mass transfer mechanism crystal vibration reduction method according to claim 2, Features: The torsional vibration dynamic equation of the beam of the acupuncture system in S1 is: Where M 0 、M 1 、M 2 are the mass of the beam, the mass of the acupuncture system, the mass of the needle and the voice coil motor, and the mass of the connection between the needle and the voice coil motor, F 0 is the thrust of the permanent magnet linear motor of the acupuncture system, C 0 , C 1 are the damping of acupuncture system and servo system, K 0 , K 1 are the stiffness of the acupuncture system and the follow-up system, respectively.

4. A pneumatic needle puncture mass transfer mechanism crystal vibration reduction method according to claim 3, Features: In S2, the process of calculating the initial disturbance is as follows: Substitute the initial disturbance, displacement and velocity at time t = 0 into the amplitude x(t) under the initial disturbance csrd expression: Where: According to the superposition principle of linear systems and the second integral form of Duhamel's formula, the integral of all pulse excitations of the system in the interval 0≤τ≤t is equal to the general excitation response x(t) jlxy : The maximum amplitude ΔL of the beam is the superposition of the displacement response caused by the initial disturbance and the excitation state, so:

5. A pneumatic needle puncture mass transfer mechanism crystal vibration reduction method according to claim 4, Features: In S3, referring to the mathematical model of the rotating permanent magnet motor, the voltage equation of the permanent magnet linear motor in the rotating coordinate is established as follows: Where U d with U q are the d-axis and q-axis voltages, I d with I q are the d-axis and q-axis currents, L d With L q are the d-axis and q-axis inductances, respectively, f is the permanent magnet flux, v is the running speed, τ e is the pole pitch, R is the winding resistance, and the power input of the permanent magnet linear motor is shown as follows: In the formula, Indicates the coil heating loss, represents electromagnetic potential energy, It represents the work done by thrust. By taking the derivative of the work done by thrust, we can get the total thrust F of the permanent magnet linear motor. z The expression is: Using surface mounted permanent magnet linear motor, L d With L q Approximately equal, let L d =L q , and obtain the tensile deformation force F of the beam of the permanent magnet linear motor 1s With tensile torsion force F nz The expression is: Where λ is defined as the performance ratio parameter of the surface-mounted permanent magnet linear motor, and the value of λ is: The actual torsional force F is expressed as: F=λI q (F 扭转 ≤F≤F 总 )。 6. A pneumatic needle puncture mass transfer mechanism crystal vibration reduction method according to claim 5, Features: In S4, BP neural network PID is used to control the movement of the acupuncture system and the servo system, and the current parameters are adjusted in real time to control the motor thrust. After regulation, the actual current I s As shown below: In the formula, K P , K I and K D are the proportional constant, integral constant and differential constant of PID control, μ and η are intermediate operational variables, and the motor thrust F of the acupuncture system can be obtained from the above. 0 for: The weight is M 3 The mass block is added to the follow-up system. At this time, the relationship between the torsional vibration amplitude of the entire beam and the current is: In the formula, C 1 is the damping of the servo system, K 1 is the stiffness of the follow-up system, F 1 is the thrust of the permanent magnet linear motor of the follow-up system, F 1 It is expressed as: The system balance equation at this time is: In summary, the minimum amplitude ΔL of the system disturbance superposition after the servo system starts working is obtained as: In the formula,

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