Valve-controlled vacuum system pressure stabilization control method

Abstract

The present application relates to the field of valve control, and particularly relates to a vacuum system pressure stabilizing control method based on valve control. The vacuum system comprises a chamber and a vacuum pump connected to the chamber through a valve. The method comprises: step S1, based on the chamber sampling pressure and the target pressure, using incremental PID to calculate the target valve opening weight of the next period; step S2, according to the relationship between the pre-calibrated valve opening and the valve opening weight, obtaining the target valve opening corresponding to the target valve opening weight; step S3, adjusting the valve to the target valve opening, returning to step S1 until the current pressure of the chamber is adjusted to the target pressure. The present application can improve the chamber pressure control precision of the vacuum system.

Description

Technical Field

[0001] This invention relates to the field of valve control, and more specifically to a valve-based pressure stabilization control method for a vacuum system. Background Technology

[0002] In industrial automation and vacuum systems, vacuum valves serve as core control components for precisely regulating and maintaining system vacuum levels. Today, in applications such as semiconductor manufacturing, electronic component assembly, and medical device manufacturing, extremely high demands are placed on the precise control and rapid response of chamber vacuum levels.

[0003] A vacuum system typically includes a chamber, a vacuum pump, valves, a vacuum gauge, and a gas flow meter. The vacuum pump is connected to the chamber via valves; by adjusting the valve opening, the amount of gas entering the vacuum pump is controlled, thereby regulating the vacuum level.

[0004] Conventional PID controllers can meet high-precision requirements within small valve opening ranges, such as 1% to 2% or 2% to 3%, but they cannot meet high-precision requirements within large opening ranges such as 0% to 100%. While fuzzy PID controllers could adjust PID parameters separately for each valve opening interval, this is cumbersome to adjust, and the correction coefficients are significantly affected by the chamber and pump speed, resulting in limited applicability.

[0005] Therefore, it is urgent to solve the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a valve-based vacuum system pressure stabilization control method that can improve the chamber pressure control accuracy of the vacuum system.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: a valve-controlled vacuum system pressure stabilization control method, wherein the vacuum system includes a chamber and a vacuum pump connected to the chamber via a valve, and the method includes:

[0008] Step S1: Based on the chamber sampling pressure and the target pressure, use incremental PID to calculate the target valve opening weight for the next cycle;

[0009] Step S2: Based on the pre-calibrated relationship between valve opening degree and valve opening degree weight, obtain the target valve opening degree corresponding to the target valve opening degree weight;

[0010] Step S3: Adjust the valve to the target valve opening, return to step S1, until the current pressure in the chamber is adjusted to the target pressure.

[0011] Furthermore, step S1 also includes:

[0012] If the proportion of chamber pressure change exceeds the preset proportion, after calculating the target valve opening weight for the next cycle using incremental PID, the target valve opening weight for the next cycle calculated by incremental PID is corrected based on the chamber pressure change rate, the cumulative value of the chamber pressure change rate, and the change in valve opening weight.

[0013] Furthermore, the relationship between valve opening degree and valve opening degree weight is calibrated, specifically including:

[0014] Record the steady-state pressure in the vacuum chamber corresponding to the opening degrees of multiple valves;

[0015] Valve opening weight U corresponding to valve opening i i =(P0-P i ) 100 / (P0-P 100 );in,

[0016] P0, P i and P 100 These are the steady-state pressures when the valve opening is 0 degrees, i degrees, and 100 degrees, respectively; the weight for intermediate openings is obtained by linear interpolation of the weights of two adjacent valve openings.

[0017] Furthermore, incremental PID is used to calculate the target valve opening weight for the next cycle; the specific formula is as follows:

[0018] ;

[0019] fp t+1 =fp(angle(t))+Δpower;

[0020] In the formula, Kp , Ki and Kd These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the difference between the target pressure within the chamber and the pressure from the t-th sampling. This is the difference between the target pressure inside the chamber and the pressure from the (t-1)th sampling. This represents the difference between the target pressure within the chamber and the pressure from the (t-2)th sampling. The output of the incremental PID controller; angle(t) and fp(angle(t)) are the actual valve opening and corresponding valve opening weights for the t-th sample; fp t+1 The target valve opening weight for the next cycle.

[0021] Furthermore, the formula for calculating the proportion of chamber pressure change is as follows:

[0022] K = (P(t) - starting pressure) / (target pressure - starting pressure);

[0023] In the formula, K represents the proportion of the chamber pressure change, and P(t) represents the pressure of the t-th sampling.

[0024] Furthermore, the formulas for calculating the cumulative rate of change of chamber pressure and the weighted change of valve opening are as follows:

[0025] sum_speed(t) = sum_speed(t-1)+[P(t)-P(t-1)] / T;

[0026] sum_move_power(t) = sum_move_power(t-1)+fp(angle(t))-fp(angle(t-1));

[0027] In the formula, sum_speed(t) and sum_speed(t-1) represent the cumulative values ​​of the chamber pressure change rate at the t-th and t-1-th sampling times, respectively; P(t) and P(t-1) represent the pressure at the t-th and t-1-th sampling times, respectively; and T represents the time interval between two adjacent sampling times.

[0028] sum_move_power(t) and sum_move_power(t-1) represent the changes in valve opening weight at the t-th and t-1-th sampling times, respectively; angle(t) and fp(angle(t)) are the actual valve opening and corresponding valve opening weight at the t-th sampling time; angle(t-1) and fp(angle(t-1)) are the actual valve opening and corresponding valve opening weight at the t-1-th sampling time.

[0029] Furthermore, the target valve opening weight for the next cycle is calculated based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight; specifically including:

[0030] Calculate the remaining number of incremental PID control cycles based on the rate of change of chamber pressure;

[0031] If the number of remaining adjustment cycles is greater than the first threshold, the target valve opening weight for the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight.

[0032] If the remaining number of adjustment cycles is less than the second threshold, the target valve opening weight for the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight; the first threshold is greater than the second threshold.

[0033] Furthermore, the formula for calculating the remaining number of adjustment cycles is as follows:

[0034] left(t) = [target pressure - P(t)] / speed(t);

[0035] speed(t) = [P(t)-P(t-1)] / T;

[0036] In the formula, left(t) represents the number of remaining adjustment cycles; P(t) and P(t-1) represent the pressure of the t-th and t-1-th samples, respectively; speed(t) represents the rate of change of chamber pressure; and T represents the time interval between two adjacent samples.

[0037] Furthermore, the target valve opening weight calculated by the incremental PID in the next cycle is adjusted; the specific formula is as follows:

[0038] fp t+1 =fp(angle(t))+Δpower+add_power(t);

[0039] If the remaining number of adjustment cycles is greater than the first threshold, the formula for calculating the correction amount is:

[0040] add_power(t) = m speed(t) sum_move_power(t) / (sum_speed(t));

[0041] If the remaining number of adjustment cycles is less than the second threshold, the formula for calculating the correction amount is:

[0042] add_power(t) = -n speed(t) sum_move_power(t) / (sum_speed(t));

[0043] In the formula, angle(t) and fp(angle(t)) are the actual valve opening degree and the corresponding valve opening degree weight of the t-th sampling. This is the output of the incremental PID controller; add_power(t) represents the correction amount; sum_move_power(t) represents the change in valve opening weight at the t-th sampling time; sum_speed(t) represents the cumulative value of the chamber pressure change rate at the t-th sampling time; m represents the acceleration coefficient, and n represents the deceleration coefficient.

[0044] By adopting the above technical solution, the present invention transforms the nonlinear relationship between valve opening degree and chamber steady-state pressure into a linear relationship between valve opening degree weight and chamber steady-state pressure, and enables incremental PID to generate valve opening degree weight increment, thereby improving the chamber pressure control accuracy. Attached Figure Description

[0045] Figure 1 This is a flowchart of the valve-controlled vacuum system pressure stabilization control method of the present invention;

[0046] Figure 2 This is a detailed flowchart of step S1 of the present invention;

[0047] Figure 3 A graph showing the pressure increase of the chamber from 20 Torr to 50 Torr.

[0048] Figure 4 A graph showing the control of chamber pressure dropping from 50 Torr to 20 Torr;

[0049] Figure 5 A graph showing the pressure increase of the chamber from 20 Torr to 70 Torr.

[0050] Figure 6 A graph showing the pressure increase in the control chamber from 70 Torr to 20 Torr. Detailed Implementation

[0051] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0052] like Figure 1 As shown, a valve-controlled vacuum system pressure stabilization control method is disclosed. The vacuum system includes a chamber and a vacuum pump connected to the chamber via valves. The method includes:

[0053] Step S0: Calibrate the relationship between valve opening degree and valve opening degree weight;

[0054] Step S1: Based on the current chamber pressure and the target pressure, use incremental PID to calculate the target valve opening weight for the next cycle;

[0055] Step S2: Based on the pre-calibrated relationship between valve opening degree and valve opening degree weight, obtain the target valve opening degree corresponding to the target valve opening degree weight;

[0056] Step S3: Adjust the valve to the target valve opening, return to step S1, until the current pressure in the chamber is adjusted to the target pressure.

[0057] Specifically, considering that PID is more suitable for linear systems, this embodiment converts the nonlinear relationship between valve opening and chamber steady-state pressure (which, according to testing, resembles an exponential function relationship) into a linear relationship between valve opening weight and chamber steady-state pressure, and enables incremental PID to generate valve opening weight increments, thereby improving the chamber pressure control accuracy.

[0058] In this embodiment, to improve the voltage regulation speed and accuracy, step S1 further includes:

[0059] When the proportion of chamber pressure change exceeds a preset proportion (pressure change takes time, and the accumulation of valve opening weight changes also takes time, resulting in relatively large errors in the early accumulated data; however, once the pressure change reaches the preset proportion, the accumulated data is relatively accurate, making it reasonable to use relatively accurate accumulated data as the basis for calculating acceleration or deceleration. This preset proportion is obtained through sufficient historical data), after calculating the target valve opening weight for the next cycle using incremental PID, the target valve opening weight for the next cycle calculated by incremental PID is corrected based on the chamber pressure change rate, the cumulative value of the chamber pressure change rate, and the change in valve opening weight.

[0060] Specifically, this embodiment also adjusts the target valve opening weight for the next cycle based on the pressure stabilization progress, which can further improve the pressure stabilization accuracy.

[0061] In this embodiment, the relationship between calibrating the valve opening degree and the valve opening degree weight can specifically include:

[0062] Record the steady-state pressure in the vacuum chamber corresponding to the opening degrees of multiple valves;

[0063] Valve opening weight U corresponding to valve opening i i =(P0-P i ) 100 / (P0-P 100 ), P0, P i and P 100 These are the steady-state pressures when the valve opening is 0 degrees, i degrees, and 100 degrees, respectively; the weight for intermediate openings is obtained by linear interpolation of the weights of two adjacent valve openings.

[0064] In this embodiment, incremental PID is used to calculate the target valve opening weight for the next cycle; the specific formula is as follows:

[0065] ;

[0066] fp t+1 =fp(angle(t))+Δpower;

[0067] The target valve opening weight for the next cycle is then:

[0068] angle(t+1) = fa(fp(angle(t))+Δpower);

[0069] In the formula, Kp , Ki and Kd These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the difference between the target pressure within the chamber and the pressure from the t-th sampling. This is the difference between the target pressure inside the chamber and the pressure from the (t-1)th sampling. This represents the difference between the target pressure within the chamber and the pressure from the (t-2)th sampling. For the output of the incremental PID; fp t+1 is the target valve opening weight for the next cycle; angle(t) and fp(angle(t)) are the actual valve opening and corresponding valve opening weight for the t-th sampling; angle(t+1) is the target valve opening for the next cycle of incremental PID control; fa(x) represents the valve opening corresponding to the valve opening weight X.

[0070] In this embodiment, the formula for calculating the proportion of chamber pressure change is:

[0071] K = (P(t) - starting pressure) / (target pressure - starting pressure);

[0072] In the formula, K represents the proportion of the chamber pressure change, and P(t) represents the pressure of the t-th sampling.

[0073] In this embodiment, the formulas for calculating the cumulative value of the chamber pressure change rate and the weighted change of the valve opening can be:

[0074] sum_speed(t) = sum_speed(t-1)+[P(t)-P(t-1)] / T;

[0075] sum_move_power(t) = sum_move_power(t-1)+fp(angle(t))-fp(angle(t-1));

[0076] In the formula, sum_speed(t) and sum_speed(t-1) represent the cumulative values ​​of the chamber pressure change rate at the t-th and t-1-th sampling times, respectively; P(t) and P(t-1) represent the pressure at the t-th and t-1-th sampling times, respectively; and T represents the time interval between two adjacent sampling times.

[0077] sum_move_power(t) and sum_move_power(t-1) represent the changes in valve opening weights at the t-th and t-1-th sampling times, respectively; angle(t-1) and fp(angle(t-1)) are the actual valve opening and the corresponding valve opening weight at the t-1-th sampling time.

[0078] In this embodiment, the target valve opening for the next cycle calculated by the incremental PID is corrected; specifically, this includes:

[0079] Calculate the remaining number of incremental PID control cycles based on the rate of change of chamber pressure;

[0080] The formula for calculating the number of remaining adjustment cycles can be:

[0081] left(t) = [target pressure - P(t)] / speed(t);

[0082] speed(t) = [P(t)-P(t-1)] / T;

[0083] In the formula, left(t) represents the number of remaining adjustment cycles; T represents the time interval between two adjacent samplings.

[0084] If the remaining number of adjustment cycles is greater than the first threshold, the target valve opening weight in the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight.

[0085] If the remaining number of adjustment cycles is less than the second threshold, the target valve opening weight in the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the decrease in the valve opening weight; the first threshold is greater than the second threshold.

[0086] Specifically, this embodiment accelerates and then decelerates according to the voltage regulation process. Acceleration achieves a fast response, while deceleration suppresses overshoot, thereby simultaneously improving voltage regulation speed and accuracy.

[0087] In this embodiment, the target valve opening weight for the next cycle calculated by the incremental PID is corrected; the specific formula is as follows:

[0088] fp t+1 =fp(angle(t))+Δpower+add_power(t);

[0089] The specific formula for the target valve opening in the next cycle is:

[0090] angle(t+1) = fa(fp(angle(t))+Δpower+add_power(t));

[0091] If the remaining number of adjustment cycles is greater than the first threshold, the formula for calculating the correction amount is:

[0092] add_power(t) = m speed(t) sum_move_power(t) / (sum_speed(t));

[0093] If the remaining number of adjustment cycles is less than the second threshold (the first threshold is greater than the second threshold), the formula for calculating the correction amount is:

[0094] add_power(t) = -n speed(t) sum_move_power(t) / (sum_speed(t));

[0095] In the formula, add_power(t) represents the correction amount; m and n represent coefficients.

[0096] Specifically, the formula for calculating the correction factor takes into account the cumulative rate of change of chamber pressure (sum_speed(t)) and the change in valve opening weight (sum_move_power(t)), which is equivalent to incorporating historical data, making it more reasonable. Furthermore, calculating the correction factor based on the current rate of pressure change means that, to a certain extent, the correction factor is inversely proportional to the cumulative rate of change of chamber pressure (sum_speed(t)) and directly proportional to the change in valve opening weight (sum_move_power(t)). (For example, based on historical data, if the change in valve opening weight is relatively small while the cumulative rate of change of chamber pressure is relatively large, then the correction factor for valve opening weight should naturally be smaller.) This allows for a more reasonable and effective approach to achieving a rapid response through acceleration and suppressing overshoot through deceleration.

[0097] The specific processes involved in the above embodiments will be described in detail below with reference to specific examples.

[0098] The first step is to establish the weighting relationship of valve opening degree.

[0099] Because the nonlinear relationship between valve opening and pressure can significantly impact the effectiveness of PID control, linearization of the valve opening is necessary. This valve is installed between the chamber and the vacuum pump; a larger opening results in a higher flow rate into the pump and a lower pressure in the chamber.

[0100] After the system is running, the controller first runs in learning mode (the vacuum pump operates at a fixed frequency, and the fluid flow rate entering the chamber is in a steady state): the valve moves from 100% opening to 50% opening in 5% increments, then moves to 0% opening in 1% increments, recording the steady-state pressure P at each opening. i ;

[0101] Valve opening P i The corresponding weight estimate is U i =(P0-P i ) 100 / (P0-P 100 The weights range from 0.00 to 100.00. The weight for each position is recorded in the table. The weight for intermediate openings is obtained by linear interpolation of the weights of adjacent positions. For example, U... 2.5 = U² + (2.5 - 2) (U3-U2)

[0102] For angle (0.00%~100.00%) and weight (0.00%~100.00%)

[0103] The function is: power = fp(angle)

[0104] By establishing an angle and weight table, the angle with the corresponding weight can be obtained through bisection lookup and linear interpolation.

[0105] If the weight is 80.0, the angle is found to be between 26 and 27 by looking up the table using the bisection method. The angle is calculated by linear interpolation as: angle = 26 + (80 - 79.681) / (81.32 - 79.681).

[0106] Let the function be: angle = fa(power).

[0107] The table is as follows:

[0108]

[0109] Step S2: Based on the set pressure and the current feedback pressure, the controller initially controls the valve opening using incremental PID control.

[0110] A discrete incremental PID algorithm is used:

[0111]

[0112] Calculate the target valve opening angle(t+1) for the next cycle: angle(t+1) = fa(fp(angle(t)) + Δpower)

[0113] The controller immediately moves to the designated position based on the target valve opening.

[0114] Step S3 involves real-time detection of the pressure change rate and correction of the PID calculation value to ensure that the pressure quickly, accurately, and stably stabilizes at the set value.

[0115] Starting from the pressure regulation, when (P(t) - starting pressure) / (target pressure - starting pressure) exceeds 10%, acceleration or deceleration is performed based on the accumulated data and the current speed.

[0116] speed(t) = [P(t) - P(t-1)] / T

[0117] Remaining adjustment cycles left(t) = [Set pressure - P(t)] / speed(t)

[0118] If left(t) > 20, accelerate based on 50% of its own speed.

[0119] add_power(t) = 50% speed(t) sum_move_power(t) / sum_speed(t);

[0120] If left(t) < 10, decelerate based on 50% of its own velocity.

[0121] add_power(t) = -50% speed(t) sum_move_power(t) / sum_speed(t);

[0122] Dividing sum_move_power(t) by sum_speed(t) yields the relationship between the valve opening weight and the rate of pressure change since startup. Multiplying this coefficient by 50% of the current speed gives the increased movement weight.

[0123] Based on the results generated by the PID controller, the target valve opening angle(t+1) for the next cycle is calculated as angle(t+1) = fa(fp(angle(t))+Δpower+add_power(t)).

[0124] The curve showing the controlled chamber pressure increase from 20 Torr to 50 Torr is as follows: Figure 3 As shown, green represents pressure and yellow represents valve opening.

[0125] The curve showing the control chamber pressure decreasing from 50 Torr to 20 Torr is as follows: Figure 4 As shown, green represents pressure and yellow represents valve opening.

[0126] The curve showing the controlled chamber pressure increase from 20 Torr to 70 Torr is as follows: Figure 5 As shown, green represents pressure and yellow represents valve opening.

[0127] The curve showing the controlled chamber pressure increase from 70 Torr to 20 Torr is as follows: Figure 6 As shown, green represents pressure and yellow represents valve opening.

[0128] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A valve-controlled pressure stabilization control method for a vacuum system, the vacuum system comprising a chamber and a vacuum pump connected to the chamber via valves, characterized in that, The methods include: Step S1: Based on the chamber sampling pressure and the target pressure, use incremental PID to calculate the target valve opening weight for the next cycle; Step S2: Based on the pre-calibrated relationship between valve opening degree and valve opening degree weight, obtain the target valve opening degree corresponding to the target valve opening degree weight; Step S3: Adjust the valve to the target valve opening, return to step S1, until the current pressure in the chamber is adjusted to the target pressure; The relationship between calibrating valve opening degree and valve opening degree weighting specifically includes: Record the steady-state pressure in the vacuum chamber corresponding to the opening degrees of multiple valves; Valve opening weight U corresponding to valve opening i i =(P0-P i ) 100 / (P0-P 100 );in, P0, P i and P 100 These represent the steady-state pressures when the valve opening is 0 degrees, i degrees, and 100 degrees, respectively; the weight for intermediate openings is obtained by linear interpolation of the weights of two adjacent valve openings. Incremental PID is used to calculate the target valve opening weight for the next cycle; the specific formula is as follows: ； fp t+1 =fp(angle(t))+ΔPower; In the formula, Kp , Ki and Kd These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the difference between the target pressure within the chamber and the pressure from the t-th sampling. This is the difference between the target pressure inside the chamber and the pressure from the (t-1)th sampling. This represents the difference between the target pressure within the chamber and the pressure from the (t-2)th sampling. The output of the incremental PID controller; angle(t) and fp(angle(t)) are the actual valve opening and corresponding valve opening weights for the t-th sample; fp t+1 The target valve opening weight for the next cycle.

2. The vacuum system voltage stabilization control method based on valve control according to claim 1, characterized in that, Step S1 also includes: If the proportion of chamber pressure change exceeds the preset proportion, after calculating the target valve opening weight for the next cycle using incremental PID, the target valve opening weight for the next cycle calculated by incremental PID is corrected based on the chamber pressure change rate, the cumulative value of the chamber pressure change rate, and the change in valve opening weight.

3. The valve-based vacuum system voltage stabilization control method according to claim 2, characterized in that, The formula for calculating the proportion of chamber pressure change is: K = (P(t) - starting pressure) / (target pressure - starting pressure); In the formula, K represents the proportion of the chamber pressure change, and P(t) represents the pressure of the t-th sampling.

4. The vacuum system voltage stabilization control method based on valve control according to claim 2, characterized in that, The formulas for calculating the cumulative rate of change of chamber pressure and the weighted change of valve opening are as follows: sum_speed(t) = sum_speed(t-1)+[P(t)-P(t-1)] / T; sum_move_power(t) = sum_move_power(t-1)+fp(angle(t))-fp(angle(t-1)); In the formula, sum_speed(t) and sum_speed(t-1) represent the cumulative values ​​of the chamber pressure change rate at the t-th and t-1-th sampling times, respectively; P(t) and P(t-1) represent the pressure at the t-th and t-1-th sampling times, respectively; and T represents the time interval between two adjacent sampling times. sum_move_power(t) and sum_move_power(t-1) represent the changes in valve opening weight at the t-th and t-1-th sampling times, respectively; angle(t) and fp(angle(t)) are the actual valve opening and corresponding valve opening weight at the t-th sampling time; angle(t-1) and fp(angle(t-1)) are the actual valve opening and corresponding valve opening weight at the t-1-th sampling time.

5. The vacuum system voltage stabilization control method based on valve control according to claim 2, characterized in that, Adjust the weight of the target valve opening for the next cycle calculated by the incremental PID; specifically including: Calculate the remaining number of incremental PID control cycles based on the rate of change of chamber pressure; If the number of remaining adjustment cycles is greater than the first threshold, the target valve opening weight for the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight. If the remaining number of adjustment cycles is less than the second threshold, the target valve opening weight for the next cycle is calculated by the incremental PID based on the rate of change of chamber pressure, the cumulative value of the rate of change of chamber pressure, and the change in valve opening weight; the first threshold is greater than the second threshold.

6. The vacuum system voltage stabilization control method based on valve control according to claim 5, characterized in that, The formula for calculating the number of remaining adjustment cycles is: left(t) = [target pressure - P(t)] / speed(t); speed(t) = [P(t)-P(t-1)] / T; In the formula, left(t) represents the number of remaining adjustment cycles; P(t) and P(t-1) represent the pressure of the t-th and t-1-th samples, respectively; speed(t) represents the rate of change of chamber pressure; and T represents the time interval between two adjacent samples.

7. The valve-based vacuum system voltage stabilization control method according to claim 6, characterized in that, Adjust the weight of the target valve opening for the next cycle calculated by the incremental PID; the specific formula is as follows: fp t+1 =fp(angle(t))+ΔPower+add_power(t); If the remaining number of adjustment cycles is greater than the first threshold, the formula for calculating the correction amount is: add_power(t) = m speed(t) sum_move_power(t) / (sum_speed(t)); If the remaining number of adjustment cycles is less than the second threshold, the formula for calculating the correction amount is: add_power(t) = -n speed(t) sum_move_power(t) / (sum_speed(t)); In the formula, angle(t) and fp(angle(t)) are the actual valve opening degree and the corresponding valve opening degree weight of the t-th sampling. This is the output of the incremental PID controller; add_power(t) represents the correction amount; sum_move_power(t) represents the change in valve opening weight at the t-th sampling time; sum_speed(t) represents the cumulative value of the chamber pressure change rate at the t-th sampling time; m represents the acceleration coefficient, and n represents the deceleration coefficient.

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