Fluid Machinery and Its Control Method

Abstract

The present invention provides a fluid machine. The fluid machine includes a controller, a controlled plant, and an observer. The controller is configured to generate a first signal based on the difference between the actual pressure value and the target pressure value of the fluid. The controlled plant generates an output signal in response to a first difference between the first signal and a second signal. The observer includes an inverse model. The inverse model is established by performing an inverse operation on the physical model of the controlled plant. The output signal passes through the inverse model to generate a third signal. The third signal is filtered to generate the aforementioned second signal.

Description

Technical Field

[0001] The present invention relates to a fluid machine, and more particularly to a fluid machine and its control method. Background Art

[0002] An air compressor is a machine used to compress air to increase gas pressure, which can provide power for various tools, transportation equipment, lifting equipment, and grasping equipment. Therefore, air compressors are widely used in fields such as machinery manufacturing, metallurgy, shipbuilding, electronics, chemical engineering, and oil and natural gas.

[0003] The air pressure in the air compressor chamber is desired to be maintained within an expected pressure band, so a pressure control mechanism is indispensable. Generally, the pressure value can be controlled by, for example, a PI controller (Proportional-Integral controller) or a PID controller (Proportional-Integral-Derivative controller). However, when the actual usage at the client suddenly changes significantly, the speed at which the PI controller or PID controller raises the working pressure to a higher target value is not fast enough, resulting in a continuous decrease in the pressure value in the chamber.

[0004] Therefore, a solution needs to be proposed to quickly reach the required target working pressure value when the actual usage at the client changes. Summary of the Invention

[0005] The present invention is directed to a fluid machine and its control method, which has the advantage of quickly reaching the required target working pressure value.

[0006] The fluid machine of the present invention includes a controller, a controlled plant, and an observer. The controller is used to generate a first signal based on the difference between the actual pressure value and the target pressure value of the fluid. The controlled plant generates an output signal in response to a first difference between the first signal and a second signal. The observer includes an inverse model. The inverse model is established by performing an inverse operation on the physical model of the controlled plant. The output signal passes through the inverse model to generate a third signal. The third signal is filtered to generate the aforementioned second signal.

[0007] The control method of the fluid machine of the present invention is applicable to an air compression device. The fluid machine includes a controller, a controlled plant, and an observer. The control method of the fluid machine includes: generating a first signal by the controller based on the difference between the actual pressure value and the target pressure value of the fluid; generating an output signal by the controlled plant in response to a first difference between the first signal and a second signal. Wherein, the output signal passes through the inverse model of the observer to generate a third signal. The inverse model is established by performing an inverse operation on the physical model of the controlled plant. And, the third signal is filtered to generate the second signal.

[0008] Based on the above, the present invention estimates the interference amount by setting an observer, and adjusts the first signal generated by the controller accordingly. Therefore, the present invention has better traceability for the target pressure value when facing external interference (such as a sudden increase in the client usage amount), and can further improve the efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A block diagram showing the control mechanism of the fluid machine of the present invention;

[0010] Figure 2 A step diagram showing the control method of the fluid machine of the present invention;

[0011] Figure 3 A block diagram showing the control mechanism of the fluid machine according to an embodiment of the present invention;

[0012] Figure 4 A block diagram showing the control mechanism of the fluid machine according to an embodiment of the present invention;

[0013] Figure 5 Continued Figure 3 With Figure 4 , a step flowchart showing the filtering process performed by the filter F;

[0014] Figure 6 Continued Figure 4 , a step flowchart showing the processing of the signal D3 by the limiter SA2;

[0015] Figure 7 A schematic diagram showing a curve of the flow rate varying with time;

[0016] Figure 8 A schematic diagram showing a curve of the pressure varying with time;

[0017] Figure 9 A schematic diagram showing a curve of the pressure varying with time. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0019] Figure 1 A block diagram showing the control mechanism of the fluid machine of the present invention. In this embodiment, the fluid machine may be an air compressor. See Figure 1, the fluid machine 100 includes a non-linear controlled plant 110, a disturbance observer 120, a controller C, an arithmetic unit 101, and an arithmetic unit 103. The non-linear controlled plant 110 includes an arithmetic unit 102 and a controlled plant G. The disturbance observer 120 includes an inverse model G*, an arithmetic unit 104, and a filter F.

[0020] In this embodiment, the controller C may be a closed-loop controller, generally a PI controller (Proportional-Integral controller) or a PID controller (Proportional-Integral-Derivative controller). The controller C is used to generate a signal S1, that is, a flow control signal, according to the difference between the actual pressure value of the fluid (such as air) and the target pressure value. The arithmetic unit 101 is used to calculate the difference between the signal S1 and the signal S2 to generate a signal S3. The arithmetic unit 102 is used to generate a signal S4, where the signal S4 is the sum of the signal S3 and an external disturbance component d (such as a sudden change in the client usage). The controlled plant G generates an output signal (corresponding to the actual pressure value P) in response to the signal S4. Figure 1 For example, the motor frequency command (i.e., the signal S3) actually presents pressure (i.e., the actual pressure value P) after passing through the non-linear controlled plant 110. Therefore, the non-linear controlled plant 110 may include the entire system. For example, the controlled plant G includes a compressor (including a compression device, an inverter, and a motor), an air cylinder, a pipeline volume, etc. The motor frequency disturbance (i.e., the disturbance component d) may include the machine's gas production equipment, all the gas-using equipment of the client, and other non-linear parts. In this embodiment, the input and output of the controlled plant G may be flow rate and pressure respectively.

[0021] The signal S5 represents the detected output signal, which includes noise, and is represented by the arithmetic unit 103 and the noise component n. The inverse model G* is established by performing an inverse operation on the physical model of the controlled plant G. The signal S5 passes through the inverse model G* to generate a signal S6. In this embodiment, the input and output of the inverse model G* may be pressure and flow rate respectively. The arithmetic unit 104 is used to calculate the difference between the signal S6 and the signal S3 to generate a signal S7. The filter F is used to perform a filtering process on the signal S7 to generate a signal S2.

[0022] Figure 2 A schematic diagram of the steps of the control method of the fluid machine of the present invention is shown, where the fluid machine may be an air compressor. Please also refer to Figure 1 and Figure 2, the fluid machine 100 may include the aforementioned controller C, the controlled plant G, and the observer 120. First, the controller C generates a first signal (equivalent to signal S1) according to the difference between the actual pressure value and the target pressure value of the fluid (step S210). Then, the controlled plant G generates an output signal in response to the difference between the first signal and the second signal (equivalent to signal S4, that is, the sum of the difference between signal S2 and signal S3 and the interference component d) (step S220). Finally, the controlled plant G outputs a signal (corresponding to the actual pressure value P). The sensed signal S5 (including the actual pressure value P and the noise component n incorporated during the sensing process) generates a third signal (equivalent to signal S6) through the inverse model G* of the observer 120. Among them, the inverse model G* is established by performing an inverse operation on the physical model of the controlled plant G, and the third signal is calculated and then filtered to generate the second signal (equivalent to signal S2) (step S230). The following will use Figure 3 to illustrate in detail the control mechanism of the fluid machine of the present invention.

[0023] Figure 3 A block diagram showing the control mechanism of the fluid machine according to an embodiment of the present invention. Please see Figure 3 , the fluid machine 300 may include a control system 310 and a physical system 320. In the control system 310, the arithmetic unit 105 is used to calculate the difference between the actual pressure value P (with the noise component n) of the sensed fluid and the target pressure value Pc to generate a signal Pe. The controller C is used to generate a signal Y1 (equivalent to Figure 1 the signal S1) according to the signal Pe. The arithmetic unit 101 is used to calculate the difference between the signal Y1 and the signal Y2 (equivalent to Figure 1 the signal S2). The calculation result of the arithmetic unit 101 is transmitted to the compression device E (i.e., signal Y) after passing through the limiter SA1. The purpose of setting the limiter SA1 is to ensure that the calculation result of the arithmetic unit 101 does not exceed the minimum and maximum values allowed by the compression device E, that is, to limit the calculation result of the arithmetic unit 101 within a numerical range. In this embodiment, the limiter SA1 may refer to a saturation limiter, and the minimum and maximum values allowed by the compression device E refer to the minimum and maximum values of the motor frequency.

[0024] The input and output of the compression device E may be the motor frequency and the flow rate respectively. However, the present invention is not limited thereto. In other embodiments, the input of the compression device E may also be the rotational speed, the flow rate, the current, etc. The controlled plant G receives the output of the compression device E. Among them, the output of the compression device E may be affected by external interference, such as changes in the usage of other machines or clients. In Figure 3 it, the output of the compression device E affected by interference (equivalent to Figure 1The signal S4) in can be represented by the arithmetic unit 102 and the interference component d. The controlled plant G can respond to the output of the compression device E (flow rate, including the interference component d) to generate an output pressure. The output pressure can be sensed by a sensor (not shown in the figure), and the sensed actual pressure value P is transmitted to the arithmetic unit 105. The arithmetic unit 105 can calculate the difference between the sensed actual pressure value P and the target pressure value Pc. The calculation result of the arithmetic unit 105 will be used as the input of the controller C.

[0025] Meanwhile, the observer 120 receives the sensed actual pressure value P (with the noise component n). The inverse model G* in the observer 120 is established by performing an inverse operation on the physical model of the controlled plant G. The sensed actual pressure value P passes through the inverse model G* to generate the signal Yd. The arithmetic unit 104 is used to subtract the signal Yd from the signal Y to generate the estimated interference quantity D1. The estimated interference quantity D1 is the quantity for estimating the interference component d in the input signal of the controlled plant G. The estimated interference quantity D1 is filtered by the filter F to generate the signal D2. It should be noted that the sensed actual pressure value P (with the noise component n) may be amplified due to the processing of the inverse model G*, so the filter F is needed to suppress the noise component in the estimated interference quantity D1. In this embodiment, the filter F can be a low-pass filter. The signal D2 is adjusted in magnitude by the gain value Kd to generate the signal Y2 (equivalent to Figure 1 the signal S2).

[0026] Figure 4 The block diagram showing the control mechanism of a fluid machine according to an embodiment of the present invention. For Figure 4 the description of the components in, reference can be made to Figure 3 the description of the components with the same name therein, which will not be elaborated here. Compared with Figure 3 , Figure 4 a limiter SA2 is added. Please refer to Figure 4 ,the signal D2 is adjusted in magnitude by the gain value Kd to generate the signal D3. The signal D3 passes through the limiter SA2 to generate the signal Y2 (equivalent to Figure 1 the signal S2). The function of the limiter SA2 is to ensure that the signal Y2 does not exceed a preset numerical range. In this embodiment, the limiter SA2 can refer to a saturation limiter.

[0027] For example, the upper limit value and the lower limit value of the limiter SA2 are 60 and -60 respectively. When the input of the limiter SA2 (i.e., the signal D3) is 10, the output of the limiter SA2 is 10. When the input of the limiter SA2 is 20, the output of the limiter SA2 is 20. That is to say, when the input value of the limiter SA2 is between the upper limit value and the lower limit value, the input and output of the limiter SA2 are the same. However, when the input of the limiter SA2 is 70, the output of the limiter SA2 is limited to the upper limit value, i.e., 60. When the input of the limiter SA2 is -70, the output of the limiter SA2 is limited to the lower limit value, i.e., -60. The function of the limiter SA1 is the same as that of the limiter SA2.

[0028] Furthermore, in an embodiment, the upper limit value and the lower limit value of the numerical range of the limiter SA2 are not fixed, but can be dynamically adjusted. For example, the upper limit value and the lower limit value of the limiter SA1 are 60 and 24 respectively, and the upper limit value and the lower limit value of the limiter SA2 are 60 and -60 respectively. The previous output of the controller C is denoted as Y1*, and the previous output of the observer 120 is denoted as Y2*. If the difference between Y1* and Y2* is higher than the upper limit value of the limiter SA1 or lower than the lower limit value of the limiter SA1, the limiter SA2 can automatically adjust its upper limit value and lower limit value. Specifically, when the difference between Y1* and Y2* is higher than the upper limit value of the limiter SA1, by adjusting the upper limit value and the lower limit value of the limiter SA2, the output Y2 of the limiter SA2 is made greater than the previous output Y2* (expecting the calculation result of Y1 - Y2 to decrease). For example, in the case where Y1* is 75 and Y2* is 10, the upper limit value and the lower limit value of the limiter SA2 can be adjusted to 60 and 10 respectively. When the difference between Y1* and Y2* is lower than the lower limit value of the limiter SA1, by adjusting the upper limit value and the lower limit value of the limiter SA2, the output Y2 of the limiter SA2 is made less than the previous output Y2* (expecting the calculation result of Y1 - Y2 to increase). For example, in the case where Y1* is 5 and Y2* is 10, the upper limit value and the lower limit value of the limiter SA2 can be adjusted to 10 and -60 respectively.

[0029] Figure 5 Carry on Figure 3 And Figure 4 , showing the step flowchart of the filtering process performed by the filter F. Please also refer to Figure 3 , Figure 4 And Figure 5, the process starts at step S401. First, the filter F reads the estimated interference amount D1 from the arithmetic unit 104 (step S402). When the control mechanism is started and the filtering process is performed for the first time (step S403), the filter F directly uses the estimated interference amount D1 as the filtered value D2 after the filtering process (step S404) and outputs the filtered value D2 (step S405). After that, the estimated interference amount D1 is stored in the first memory D1*, and the filtered value D2 is stored in the second memory D2*. This ends the first calculation (step S407).

[0030] Next, the filter F reads the estimated interference amount D1 from the arithmetic unit 104 again (step S402). In this embodiment, the arithmetic unit 104 periodically calculates the difference between the signal Yd and the signal Y according to the time interval. That is to say, the time points at which the filter F obtains the estimated interference amount D1 twice are separated by a time interval, denoted as ΔT. In the case of non-first calculation (step S403), the filter F reads its cut-off frequency f (related to the passband), the length information of the time interval, the data in the first memory D1*, and the data in the second memory D2* (step S408), and calculates the coefficient K based on the above data (step S409). Specifically, the control circuit 150 can calculate the formula (1) to obtain the coefficient K. The coefficient K is stored. The first ratio and the second ratio to be used later are determined based on the coefficient K.

[0031]

[0032] In step S410, the filter F performs an interpolation operation on the data in the first memory D1* and the data in the second memory D2* based on the coefficient K. The filter F determines the first ratio and the second ratio for the interpolation operation based on the coefficient K. In this embodiment, the first ratio is equal to the value obtained by subtracting the coefficient K from 1, and the second ratio is equal to the coefficient K. In other words, the sum of the first ratio and the second ratio is 1. The filter F can calculate the product of the data in the first memory D1* and the first ratio (1 - K), the product of the data in the second memory D2* and the second ratio (K), and sum the results of the two product operations to obtain the filtered value D2 and output it (steps S404 - S405). Then, the first memory D1* is updated with the estimated interference value D1 in the same way, and the second memory D2* is updated with the filtered value D2. This ends the second calculation (step S407).

[0033] Since the filtering value D2 is calculated based on the previously estimated interference values and the previously filtered values stored in the first memory D1* and the second memory D2*, the filter F can make the pressure control more stable (the pressure will eventually stop at a value). Specifically, the presence of the observer 120 can improve the overall traceability and robustness, and the filter F is used as an auxiliary to further improve the stability.

[0034] Figure 6 Continued Figure 4 , showing the step flowchart of processing the signal D3 by the limiter SA2. Please also refer to Figure 4 and Figure 6 , the process starts at step S501. The limiter SA2 reads in its maximum output value Y2max, minimum output value Y2min, and the signal D3 (step S502). Then, the limiter SA2 determines whether the signal D3 is less than or equal to the maximum output value Y2max (step S503). If not, the maximum output value Y2max is used as the output (signal Y2) (step S506). If so, the limiter SA2 further determines whether the signal D3 is greater than or equal to the minimum output value Y2min (step S504). If not, Y2min is used as the output (signal Y2) (step S507). If so, the signal D3 is used as the output (step S505). After the output signal Y2 (step S508), the process ends (step S509).

[0035] Figure 7 Showing a schematic diagram of the curve of flow rate changing with time. Please see Figure 7 , line 601 and line 603 represent the flow rate used by the client, that is, the change of the target flow rate (unit: CMM). Line 602 represents the change of the flow rate discharged by the air compressor over time without using the present invention. Line 604 represents the change of the flow rate discharged by the air compressor over time when using the present invention. When the flow rate discharged by the air compressor is the same as the target flow rate, the pressure of the client will stabilize at the target pressure value. From Figure 7 it can be seen that the target flow rate also rises at time point t. However, without using the present invention, the speed of the flow rate tracing back to the target flow rate is significantly slower. In contrast, when using the present invention, the speed of the flow rate tracing back to the target flow rate is significantly faster. That is to say, when the customer usage suddenly increases, the target flow rate will also be increased. However, traditional PI or PID controllers cannot handle this situation due to the slower tracing speed. On the contrary, the present invention has a better tracing speed.

[0036] Figure 8 Showing a schematic diagram of the curve of pressure changing with time. Please see Figure 8, lines 701 and 703 represent the pressure command changes from low frequency to high frequency. Line 702 represents the actual pressure response over time without using the present invention. Line 704 represents the actual pressure response over time when using the present invention. As can be seen from Figure 8 it that, in the case of low frequency, the actual pressure response can follow the pressure command. However, in the case of high frequency, line 702 shows that the pressure response cannot meet the changes in the high-frequency pressure command. On the contrary, line 704 (using the present invention) shows that the pressure response can better meet the changes in the high-frequency pressure command.

[0037] Figure 9 A schematic diagram showing the curve of pressure changing with time. Please refer to Figure 9 , lines 801 and 803 represent fixed pressure commands. Line 802 represents the pressure tracing situation in the case of facing different flow rate variations without using the present invention. Line 804 represents the pressure tracing situation in the case of facing different flow rate variations when using the present invention. Among them, the flow rate variation changes from slow to fast over time. As can be seen from Figure 9 it that, compared with the situation without using the present invention, the present invention has better pressure tracing ability in the case of facing different flow rate variations.

[0038] In summary, the present invention estimates the disturbance quantity by setting an observer and adjusts the first signal generated by the controller accordingly. Therefore, in the case of facing external disturbances (such as a sudden increase in the usage of the client), since the present invention has better tracing ability for the target pressure value, the robustness of the control system is improved and the control performance can also be improved. The present invention is not limited to pressure control applications and can also be applied to valve opening control, rotational speed control, current control and other applications.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fluid machine, characterized in that, Comprising: A controller (C) for generating a first signal (S1) based on the difference between the actual pressure value (P) and the target pressure value (Pc) of the fluid; A controlled plant (G) that generates an output signal (P) in response to a first difference (S3) between the first signal (S1) and a second signal (S2); And An observer (120) (observer), comprising: An inverse model (G*), established by performing an inverse operation on the physical model of the controlled plant (G); Wherein the observer further comprises: A first arithmetic unit (104) that periodically calculates the difference (S7) between a third signal (S6) and the first difference (S3) at time intervals to sequentially obtain a previous estimated interference amount and a current estimated interference amount of the interference component in the input signal for the controlled plant (G); and A filter (F) for: Performing filtering based on the passband, the time interval, and the previous estimated interference amount, and updating the current estimated interference amount with the processing result to generate an updated current estimated interference amount, thereby generating the second signal (S2); Wherein the output signal (P) passes through the inverse model (G*) to generate a third signal (S6), and the third signal (S6) is processed through arithmetic operations and then through filtering to generate the second signal (S2).

2. The fluid machine according to claim 1, wherein Wherein the observer further comprises: A limiter (SA2) for limiting the operation result to a numerical range after the updated current estimated interference amount undergoes gain operation to generate the second signal (S2).

3. The fluid machine according to claim 1 or 2, characterized in that Wherein the filter (F) is further used for: Performing an exponential operation on the passband and the time interval to generate a coefficient; and Based on the coefficient, performing an interpolation operation according to the previous estimated interference amount and the updated previous estimated interference amount to generate the processing result of the filtering process.

4. The fluid machine according to claim 3, characterized in that, Wherein the filter (F) is further used for: According to the mathematical formula perform the exponential operation to obtain the coefficient, where f represents the passband and ΔT represents the time interval; Performing the interpolation calculation to sum a first proportion of the previous estimated interference amount and a second proportion of the updated previous estimated interference amount, thereby obtaining the processing result of the filtering process, Wherein the second proportion is equal to the coefficient and the sum of the first proportion and the second proportion is 1.

5. A fluid machine, characterized in that, Comprising: A controller (C) for generating a first signal (S1) based on the difference between the actual pressure value (P) and the target pressure value (Pc) of the fluid; A controlled plant (G) that generates an output signal (P) in response to a first difference (S3) between the first signal (S1) and a second signal (S2); And An observer (120) (observer), comprising: An inverse model (G*), established by performing an inverse operation on the physical model of the controlled plant (G), wherein the output signal (P) passes through the inverse model (G*) to generate a third signal (S6), and the third signal (S6) is processed through arithmetic operations and then through filtering to generate the second signal (S2); A first arithmetic unit (104) for calculating a difference (S7) between the third signal (S6) and the first difference (S3) at a first time point to obtain a first estimated interference amount of an interference component in an input signal for the controlled plant (G); and A filter (F) coupled to the first arithmetic unit (104), using the first estimated interference amount as a first filtering result, wherein the first filtering result undergoes a gain operation to generate the second signal (S2), the first estimated interference amount is stored to update data in a first memory, and the first filtering result is stored to update data in a second memory, wherein the first arithmetic unit (104) is further configured to calculate a difference (S7) between the third signal (S6) and the first difference (S3) at a second time point after the first time point to obtain a second estimated interference amount of an interference component in an input signal for the controlled plant (G), wherein there is a time interval between the first time point and the second time point, wherein the filter (F) is further configured to perform a filtering process at the second time point based on a passband, the time interval, and data in the first memory and the second memory to generate a second filtering result, wherein the second filtering result undergoes the gain operation to generate the second signal (S2), the second estimated interference amount is stored to update data in the first memory, and the second filtering result is stored to update data in the second memory.

6. A control method for a fluid machine, applicable to an air compression device, characterized in that, Wherein the fluid machinery includes a controller, a controlled plant, and an observer, and a control method for the fluid machinery includes: Generating, by the controller, a first signal based on a difference between an actual pressure value and a target pressure value of a fluid; and Generating, by the controlled plant, an output signal in response to a first difference between the first signal and a second signal, wherein the output signal passes through an inverse model of the observer to generate a third signal, the inverse model is established by performing an inverse operation on a physical model of the controlled plant, and the third signal undergoes an operation and then a filtering process to generate the second signal, wherein the observer further includes a first arithmetic unit and a filter, and the control method for the fluid machinery further includes: Periodically calculating, by the first arithmetic unit, a difference between the third signal and the first difference based on a time interval to sequentially obtain a previous estimated interference amount and a current estimated interference amount of an interference component in an input signal for the controlled plant; and Performing, by the filter, the filtering process based on a passband, the time interval, and the previous estimated interference amount, and updating the current estimated interference amount with a processing result to generate an updated current estimated interference amount, thereby generating the second signal.

7. The control method of the fluid machinery according to claim 6, characterized in that, Wherein the observer further includes a limiter (SA2), and the control method for the fluid machinery further includes: Performing a gain operation on the updated current estimated interference amount, and limiting an operation result by the limiter to a numerical range to generate the second signal.

8. The control method of the fluid machine according to claim 6, characterized in that, Wherein the step of the filtering process includes: Exponentiate the passband and the time interval to generate coefficients; Based on the coefficients, perform interpolation operations according to the previous estimated interference amount and the updated previous estimated interference amount to generate the processing result of the filtering process.

9. The control method of the fluid machinery according to claim 8, characterized in that, The steps of the filtering process further include: According to the mathematical formula perform the exponential operation to obtain the coefficient, characterized in that f represents the passband and ΔT represents the time interval; Perform the interpolation calculation to sum a first proportion of the previous estimated interference amount and a second proportion of the updated previous estimated interference amount, thereby obtaining the processing result of the filtering process, wherein the second proportion is equal to the coefficient and the sum of the first proportion and the second proportion is 1.

10. A control method for a fluid machine, characterized in that, The fluid machinery includes a controller, a controlled plant, and an observer. The control method of the fluid machinery includes: Generate a first signal by the controller according to the difference between the actual pressure value and the target pressure value of the fluid; and Generate an output signal by the controlled plant in response to a first difference between the first signal and a second signal, wherein the output signal generates a third signal through the inverse model of the observer. The inverse model is established by performing an inverse operation on the physical model of the controlled plant, and the third signal is calculated and then filtered to generate the second signal, wherein the observer further includes a first arithmetic unit and a filter. The control method of the fluid machinery further includes: At a first time point: Calculate, by the first arithmetic unit, the difference between the third signal and the first difference to obtain a first estimated interference amount of the interference component in the input signal for the controlled plant; and Use the first estimated interference amount as the first filtering result by the filter, wherein the first filtering result is subjected to a gain operation to generate the second signal, the first estimated interference amount is stored to update the data in the first memory, and the first filtering result is stored to update the data in the second memory; At a second time point after the first time point: Calculate, by the first arithmetic unit, the difference between the third signal and the first difference to obtain a second estimated interference amount of the interference component in the input signal for the controlled plant, wherein there is a time interval between the first time point and the second time point; Perform filtering processing by the filter according to the passband, the time interval, and the data in the first memory and the second memory to generate a second filtering result, wherein the second filtering result is subjected to the gain operation to generate the second signal, the second estimated interference amount is stored to update the data in the first memory, and the second filtering result is stored to update the data in the second memory.

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