A method, device, system and apparatus for controlling the pressure of a gas in a controlled pneumatic circuit

Abstract

The application provides a kind of gas pressure control method, device and system and equipment of controlled pneumatic circuit.The method comprises: detecting whether the set pressure of controlled pneumatic circuit changes, if yes, the control stage of current time is set to first control stage, if no, the control stage of last time is kept;If it is the first control stage, it is judged whether the end pressure of controlled pneumatic circuit is greater than the first pressure threshold, if yes, the control stage of next time is set to second control stage;And the end pressure is used as the pressure for calculation of PID control;If it is the second control stage, it is judged whether the difference between the start end pressure and the end pressure is less than the second preset threshold, if yes, the control stage of next time is set to third control stage;And predicted pressure is used as the pressure for calculation of PID control;If it is the third control stage, the end pressure is used as the pressure for calculation of PID control. Gas pressure rapid stable control is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of gas pressure control method, device and system and equipment of controlled pneumatic circuit. BACKGROUND

[0002] There are many links using gas constant pressure control in automatic production field. In the pressure control system, the gas circuit and load placed after the pressure driver can be generally referred to as controlled pneumatic circuit. When controlling the gas pressure of the controlled pneumatic circuit of the pressure control system, the gas pressure at the beginning or end of the controlled pneumatic circuit is fed back to the pressure controller through the pressure sensor, and the pressure controller controls the pressure driver according to the set pressure of the upper computer and the gas pressure fed back by the pressure sensor, so as to realize accurate measurement and accurate control of the gas pressure of the controlled pneumatic circuit by adopting closed-loop feedback control method. The beginning of the above-mentioned controlled pneumatic circuit can be the input end of the controlled pneumatic circuit, i.e. the end of the pressure driver; while the end of the above-mentioned controlled pneumatic circuit can be the position close to the load in the controlled pneumatic circuit, which can be located inside the load or at the position close to the front end or rear end of the controlled load. The gas pressure at the beginning of the above-mentioned controlled pneumatic circuit can be referred to as the beginning pressure of the controlled pneumatic circuit, and the gas pressure at the end of the above-mentioned controlled pneumatic circuit can be referred to as the end pressure of the controlled pneumatic circuit. SUMMARY

[0003] The inventor found that, since the pressure driver and the load of the controlled pneumatic circuit are not at the same position, if the distance between the pressure driver and the load is far, the gas circuit of the controlled pneumatic circuit is relatively complex, or the cavity of the load is too large, there will be a pressure difference between the pressure driver and the load during the pressure control process, and there will be a response lag phenomenon at the load. If the pressure sensor is installed at the beginning of the controlled pneumatic circuit, due to the existence of the pressure difference between the pressure driver and the load, when the pressure driver reaches the set pressure, the load has not yet reached the set pressure, and then the load will slowly reach the set pressure, causing a long time required for the gas pressure to stabilize. If the pressure sensor is installed at the end of the controlled pneumatic circuit, due to the response lag phenomenon at the load, when the gas pressure approaches the set pressure, the pressure at the load is prone to fluctuation, which will also cause the time required for the gas pressure to stabilize to become longer. In order to at least partially solve the technical problem of the long time required for the gas pressure of the controlled pneumatic circuit to stabilize in the prior art, the inventor made the present application, and through specific embodiments, the technical solutions provided are as follows:

[0004] As a first aspect of an embodiment of the present application, the present application provides a gas pressure control method of a controlled pneumatic circuit, comprising:

[0005] detecting whether the set pressure of the controlled pneumatic circuit changes, if yes, setting the control stage at the current time as the first control stage, and if no, keeping the control stage at the last time.

[0006] If the control phase at the current time is the first control phase, it is determined whether the end pressure of the controlled pneumatic circuit is greater than a first pressure threshold, and if so, the control phase at the next time is set to the second control phase; and the end pressure of the controlled pneumatic circuit is taken as the pressure for calculation of the PID control;

[0007] If the control phase at the current time is the second control phase, it is determined whether the difference between the start pressure of the controlled pneumatic circuit and the end pressure of the controlled pneumatic circuit is less than a second preset threshold, and if so, the control phase at the next time is set to the third control phase; and the predicted pressure of the controlled pneumatic circuit is taken as the pressure for calculation of the PID control;

[0008] If the control phase at the current time is the third control phase, the end pressure of the controlled pneumatic circuit is taken as the pressure for calculation of the PID control.

[0009] In one or some optional embodiments, the predicted pressure is updated in the following manner:

[0010] The start pressure and the end pressure are obtained according to a preset sampling period;

[0011] A first pressure prediction variable is determined according to the start pressure and the end pressure;

[0012] A second pressure prediction variable is determined by using a least square method based on the previously determined predicted pressures of each data bit in a preset array;

[0013] An updated predicted pressure is determined according to the first pressure prediction variable and the second pressure prediction variable.

[0014] In one or some optional embodiments, the determination of the updated predicted pressure according to the first pressure prediction variable and the second pressure prediction variable comprises:

[0015] A third pressure prediction variable is determined based on the first pressure prediction variable and the second pressure prediction variable;

[0016] It is determined whether the third pressure prediction variable is greater than the start pressure and the end pressure;

[0017] If so, the updated predicted pressure is determined based on the start pressure and the end pressure;

[0018] If not, the updated predicted pressure is determined based on the third pressure prediction variable.

[0019] In one or some optional embodiments, the preset array comprises a preset number of data bits, each of which is filled with a previously determined predicted pressure;

[0020] The previously determined predicted pressure of each data bit in the preset array is obtained by:

[0021] The updated predicted pressure is filled into the first data bit in the preset array, and the predicted pressure of the previous data bit in the preset array is updated into the subsequent data bit in turn;

[0022] Or, the updated predicted pressure is filled into the last data bit in the preset array, and the predicted pressure of the subsequent data bit in the preset array is updated into the previous data bit in turn.

[0023] In one or some optional embodiments, the detection of whether the set pressure of the controlled pneumatic circuit changes comprises:

[0024] Based on the previously received pressure signal values of the set pressure, it is determined whether the set pressure of the controlled pneumatic circuit changes.

[0025] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises:

[0026] If it is determined that the set pressure of the controlled pneumatic circuit changes, the first pressure threshold is determined according to the changed set pressure.

[0027] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises judging the control stage at the current time according to:

[0028] If the control stage at the current time is not the first control stage, it is judged whether the control stage at the current time is the second control stage, and if both are not, it is determined that the control stage at the current time is the third control stage.

[0029] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises:

[0030] If the control stage at the current time is the first control stage, and the end pressure of the controlled pneumatic circuit is not greater than the first pressure threshold, the control stage at the next time remains the first control stage;

[0031] If the control stage at the current time is the second control stage, and the difference between the start end pressure of the controlled pneumatic circuit and the end pressure of the controlled pneumatic circuit is not less than the second preset threshold, the control stage at the next time remains the second control stage.

[0032] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises:

[0033] In the power-on initial state, the control phase at the initial time is set as the third control phase.

[0034] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises: according to the calculated pressure of the PID control, the control output signal at the current time is calculated by the following formula:

[0035]

[0036] In the formula, error(k) = A - B;

[0037] Wherein, U(k) represents the control output signal at the current time; error(k) represents the prediction error at the current time; k represents the current time; P is a proportional parameter; I is an integral parameter; D is a differential parameter; A is a set pressure, and B is a calculated pressure, and the calculated pressure is the end pressure, the predicted pressure or the initial pressure.

[0038] In one or some optional embodiments, the gas pressure control method of the controlled pneumatic circuit further comprises: judging whether the value of the control output signal at the current time is between the first preset output threshold and the second preset output threshold; the first preset output threshold is less than the second preset output threshold;

[0039] If yes, the control output signal at the current time is outputted;

[0040] If the value of the control output signal at the current time is less than the first preset output threshold, the signal of the first preset output threshold is outputted;

[0041] If the value of the control output signal at the current time is greater than the second preset output threshold, the signal with the value of the second preset output threshold is outputted.

[0042] As a second aspect of the embodiments of the present application, the embodiments of the present application provide a pressure controller of a controlled pneumatic circuit, comprising a processor and a memory, the memory stores a computer program, and the processor calls the computer program stored in the memory to execute the gas pressure control method of the controlled pneumatic circuit as described above.

[0043] As a third aspect of the embodiments of the present application, the embodiments of the present application provide a controlled pneumatic circuit system, comprising a pressure regulating valve, a pressure driver, a first pressure sensor, a controlled pneumatic circuit, a second pressure sensor and the pressure controller of the controlled pneumatic circuit as described above.

[0044] The pressure regulating valve is connected between an external gas source and the pressure driver;

[0045] The first pressure sensor is connected to the beginning end of the controlled pneumatic circuit;

[0046] The second pressure sensor is connected to the ending end of the controlled pneumatic circuit;

[0047] The pressure controller is connected to the first pressure sensor, the second pressure sensor and the pressure driver respectively.

[0048] As a fourth aspect of the embodiments of the present application, the embodiments of the present application provide a pneumatic driving device comprising the controlled pneumatic circuit system as described above.

[0049] The embodiments of the present application provide the above technical solutions with at least the following beneficial effects:

[0050] The gas pressure control method of the controlled pneumatic circuit provided by the embodiments of the present application, when determining the set pressure change, realizes the switching of the first to third control stages by judging the beginning end pressure and the ending end pressure of the controlled pneumatic circuit, reduces the influence of the pressure difference between the pressure driver and the controlled pneumatic circuit on the response lag of the controlled pneumatic circuit in the pressure control process. In the initial time period of the set pressure change, the ending end pressure of the controlled pneumatic circuit is used for feedback control, the response speed of the gas pressure of the controlled pneumatic circuit is accelerated, and when the ending end pressure of the controlled pneumatic circuit reaches the first pressure threshold, i.e. the ending end pressure of the controlled pneumatic circuit approaches the set pressure, the predicted pressure is used for feedback to perform the transition stage pressure control of the controlled pneumatic circuit, which avoids the fluctuation of the gas pressure of the controlled pneumatic circuit and saves the time required for the stabilization of the gas pressure. When the difference between the beginning end pressure and the ending end pressure of the controlled pneumatic circuit is less than the second preset threshold, i.e. the gas pressure of the controlled pneumatic circuit approaches the set pressure, the beginning end pressure of the controlled pneumatic circuit is used for feedback control, and the pressure control of the controlled pneumatic circuit enters the stable control stage, which ensures the stable control of the pressure of the controlled pneumatic circuit. The gas pressure control method of the controlled pneumatic circuit provided by the embodiments of the present application uses different pressures for PID control in different gas pressure control stages, which not only helps to improve the pressure response speed, but also ensures the pressure response accuracy. Meanwhile, according to different pressure control scenes, the first preset pressure threshold, the second pressure preset threshold and the predicted pressure parameter can be adjusted to flexibly cope with various pressure control occasions, and the method can be applied to various controlled pneumatic circuit systems facing pressure response lag. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1A schematic flowchart of a gas pressure control method for a controlled pneumatic circuit provided in an embodiment of the present invention;

[0052] Figure 2 Another schematic diagram of the gas pressure control method for the controlled pneumatic circuit provided in an embodiment of the present invention;

[0053] Figure 3 A schematic diagram of the process for determining predicted pressure provided in an embodiment of the present invention;

[0054] Figure 4 Another schematic diagram of the process for determining the predicted pressure provided in an embodiment of the present invention;

[0055] Figure 5 This is another schematic flowchart of the gas pressure control method for the controlled pneumatic circuit provided in the embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the controlled pneumatic circuit system provided in an embodiment of the present invention. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] This invention provides a gas pressure control method for a controlled pneumatic circuit, referring to... Figure 1 As shown, the gas pressure control method includes:

[0061] S101: Detect whether the set pressure of the controlled pneumatic circuit has changed. If yes, proceed to step S102; otherwise, proceed to step S103.

[0062] S102: Set the current control phase to the first control phase;

[0063] S103: Maintain the control phase from the previous moment;

[0064] S1041: If the control stage at the current moment is the first control stage, then determine whether the end pressure of the controlled pneumatic circuit is greater than the first pressure threshold. If so, then set the control stage at the next moment to the second control stage; and use the end pressure of the controlled pneumatic circuit as the pressure for PID control calculation.

[0065] S1042: If the control stage at the current moment is the second control stage, then determine whether the difference between the starting pressure of the controlled pneumatic circuit and the ending pressure of the controlled pneumatic circuit is less than the second preset threshold. If so, then set the control stage at the next moment to the third control stage; and use the predicted pressure of the controlled pneumatic circuit as the calculation pressure for PID control.

[0066] S1043: If the current control stage is the third control stage, then the end pressure of the controlled pneumatic circuit is used as the calculation pressure for PID control.

[0067] In this embodiment of the invention, by detecting a set pressure, when a change in the set pressure is detected, the control stage is set to the first control stage. The end pressure of the controlled pneumatic circuit is used as a feedback value to participate in the control calculation, and the pressure actuator is controlled to achieve a rapid response of the controlled gas pressure. At the same time, the change in the end pressure of the controlled pneumatic circuit is judged in real time. When the end pressure of the controlled pneumatic circuit reaches a first pressure threshold, the control stage is switched to the second control stage. The predicted pressure of the controlled pneumatic circuit is used as a feedback value to participate in the control calculation, and the pressure actuator is controlled to achieve a smooth transition of the controlled gas pressure. Simultaneously, the change in the beginning pressure and the end pressure of the controlled pneumatic circuit is judged in real time. When the difference between the beginning pressure and the end pressure of the controlled pneumatic circuit is less than a second preset threshold, the control stage is switched to the third control stage. The beginning pressure of the controlled pneumatic circuit is used as a feedback value for control calculation to achieve stable control of the gas pressure.

[0068] The starting pressure described in this embodiment of the invention is the starting pressure of the controlled pneumatic circuit. Similarly, the ending pressure described in this embodiment of the invention is the ending pressure of the controlled pneumatic circuit.

[0069] In this embodiment of the invention, reference is made to Figure 1 orFigure 2 As shown, the control process of the gas pressure control method for the controlled pneumatic circuit described above can be divided into three control stages: a first control stage, a second control stage, and a third control stage. The first control stage is a rapid response stage. After the set pressure of the controlled pneumatic circuit changes, the system enters this first control stage. During this stage, the pressure value used for calculation in the PID control with pressure feedback is the terminal pressure of the controlled pneumatic circuit. The second control stage is a transition control stage. This stage occurs when the control stage of the controlled pneumatic circuit is the first control stage, and the terminal pressure of the controlled pneumatic circuit is determined to be greater than a first pressure threshold. If the controlled pneumatic circuit is in the second control stage, the pressure value used for calculation in the PID control with pressure feedback is the predicted pressure of the controlled pneumatic circuit. The third control stage is the stable control stage. If the controlled pneumatic circuit is in the second control stage and the difference between the initial pressure and the final pressure of the controlled pneumatic circuit is less than the second preset threshold, the controlled pneumatic circuit will enter the third control stage. In the third control stage, the pressure value used for calculation in the PID control with pressure feedback is the initial pressure of the controlled pneumatic circuit.

[0070] In one embodiment, it can be, as referenced Figure 2 As shown, in the gas pressure control method of the controlled pneumatic circuit described above, before steps S1041, S1042 and S1043, the method further includes:

[0071] S104: Determine the current control phase;

[0072] In step S104 above, the control stage at the current moment can be determined in the following way:

[0073] Determine whether the current control stage is the first control stage. If not, further determine whether the current control stage is the second control stage. If not, determine that the current control stage is the third control stage.

[0074] In this embodiment of the invention, after determining the control stage at the current moment, if it is in the first control stage, it is determined whether the end pressure of the controlled pneumatic circuit is greater than a first pressure threshold; if it is in the second control stage, it is determined whether the difference between the beginning pressure and the end pressure of the controlled pneumatic circuit is less than a second preset threshold. By setting the execution step of comparing and judging the beginning pressure and / or end pressure of the controlled pneumatic circuit with the corresponding threshold after the determination step of the control stage, it is possible to avoid the control stage of the controlled pneumatic circuit jumping back and forth due to the fluctuation of the beginning pressure or end pressure of the controlled pneumatic circuit, which would affect the rapid response of pressure control and prolong the time required for pressure stabilization.

[0075] As a specific implementation of an embodiment of the present invention, refer to Figure 2 As shown, the gas pressure control method for the above-mentioned controlled pneumatic circuit further includes:

[0076] S100: In the initial power-on state, the control phase at the initial moment is set to the third control phase.

[0077] The aforementioned initial power-on state is the initial state of gas pressure control for the controlled pneumatic circuit. In this initial power-on state, the control stage of the controlled pneumatic circuit is set to the third control stage by default, so that the pressure of the controlled pneumatic circuit can achieve smooth start-up control.

[0078] In this embodiment of the invention, the gas pressure control method for the controlled pneumatic circuit described above further includes:

[0079] S1041A: If the current control phase is the first control phase, and the end pressure of the controlled pneumatic circuit is not greater than the first pressure threshold, then the control phase at the next moment remains the first control phase.

[0080] S1042A: If the current control stage is the second control stage, and the difference between the starting pressure and the ending pressure of the controlled pneumatic circuit is not less than the second preset threshold, then the control stage at the next moment remains the second control stage.

[0081] In one embodiment, refer to Figure 3 As shown, in the gas pressure control method of this controlled pneumatic circuit, the predicted pressure is updated in the following manner:

[0082] S201: Obtain the initial pressure and the final pressure according to a preset sampling period;

[0083] S202: Determine a first pressure prediction variable based on the initial pressure and the final pressure;

[0084] S203: Based on the previously determined predicted pressure of each data bit in the preset array, the least squares method is used to determine the second pressure prediction variable;

[0085] S204: Determine the updated predicted pressure based on the first pressure predictor variable and the second pressure predictor variable.

[0086] In this embodiment of the invention, by acquiring the initial pressure and the final pressure of the controlled pneumatic circuit, the corresponding predicted pressure is calculated based on the initial pressure and the final pressure at the current moment. This makes the predicted pressure not only predictive but also able to reflect the actual pressure situation of the controlled pneumatic circuit. If the control stage of the controlled pneumatic circuit is in the second control stage, the predicted pressure is used as a feedback value for PID control calculation to control the pressure actuator, thereby achieving a smooth transition of the control gas pressure.

[0087] In one specific embodiment, step S204 above, which determines the updated predicted pressure based on the first pressure predictor variable and the second pressure predictor variable, specifically includes:

[0088] Based on the first and second pressure predictor variables, a third pressure predictor variable is determined;

[0089] Determine whether the third pressure prediction variable is greater than the initial pressure and the final pressure;

[0090] If so, the updated predicted pressure is determined based on the initial pressure and the final pressure;

[0091] If not, the updated predicted pressure is determined based on the third pressure predictor variable.

[0092] In one specific embodiment, the aforementioned preset array may include a preset number of data bits, each data bit containing a pre-determined prediction pressure; based on this, in this embodiment of the invention, the pre-determined prediction pressure of each data bit in the aforementioned preset array can be obtained in the following manner:

[0093] The updated predicted pressure is loaded into the first data bit of the preset array, and the predicted pressure of the preceding data bits in the preset array is sequentially updated to the following data bits;

[0094] Alternatively, the updated predicted pressure can be loaded into the last data bit of the preset array, and the predicted pressure of the subsequent data bits in the preset array can be sequentially updated into the preceding data bits.

[0095] As an example of a specific implementation of the present invention, refer to Figure 4 As shown, assuming the above prediction array includes m data bits, each data bit can hold a pre-determined predicted pressure, where m is a positive integer. The size of m can be determined according to the actual application scenario of pressure control, for example, m can be 50, 60, or 100. Then the specific steps for updating and determining the predicted pressure include:

[0096] S301: Obtain the starting and ending pressures of the controlled pneumatic circuit according to the preset sampling period;

[0097] S302: Based on the initial pressure and the final pressure, the first pressure prediction variable is obtained using the following formula (1):

[0098] First pressure prediction variable = K1 * initial pressure + K2 * final pressure, formula (1);

[0099] Wherein, K1 and K2 are pressure prediction coefficients, K1≥0, K2≥0 and K1+K2=1.

[0100] In this embodiment of the invention, the magnitudes of the pressure prediction coefficients K1 and K2 can be determined according to the actual usage environment. The values ​​of K1 and K2 can be adjusted in controlled pneumatic circuit systems with different pressure response lags to flexibly cope with various pressure control situations.

[0101] S303: Based on the pre-determined predicted pressure at m data points in the preset array, the pressure prediction coefficients K3 and b are obtained by fitting a straight line using the least squares method. The second pressure prediction variable is determined using the following formula (2):

[0102] Second pressure prediction variable = K3*(m+1)+b, formula (2).

[0103] S304: Based on the first and second pressure predictors obtained above, the third pressure predictor is determined using the following formula (3):

[0104] Third pressure predictor variable = K4 * First pressure predictor variable + K5 * Second pressure predictor variable, formula (3);

[0105] Wherein, K4 and K5 are pressure prediction coefficients, K4≥0, K5≥0 and K4+K5=1;

[0106] S305: Determine whether the third pressure prediction variable is greater than the above-mentioned initial pressure and final pressure; if yes, proceed to step S306; if no, proceed to step S307.

[0107] S306: Based on the initial and final pressures, the updated predicted pressure is determined using the following formula (4):

[0108] Predicted pressure = K4 * initial pressure + K5 * final pressure, formula (4);

[0109] S307: Use the third pressure predictor variable mentioned above as the updated predicted pressure.

[0110] Similar to the pressure prediction coefficients K1 and K2 mentioned above, the values ​​of pressure prediction coefficients K4 and K5 can also be determined according to the actual usage environment. Thus, the values ​​of K4 and K5 can be adjusted in controlled pneumatic loop systems with different pressure response lags to flexibly cope with various pressure control situations.

[0111] In this embodiment of the invention, due to the noise of the controlled pneumatic circuit system itself or the influence of signal transmission, the value of the third pressure prediction variable obtained according to formulas (1) to (3) at a certain moment may exceed the starting pressure or the ending pressure. In order to eliminate or reduce the error of the predicted pressure and achieve the precision control of PID control, when determining the updated predicted pressure, it can be determined whether the third pressure prediction variable exceeds the range of the starting pressure or the ending pressure, thereby eliminating unreasonable third pressure prediction variables and making the updated predicted pressure within the range of the starting pressure or the ending pressure.

[0112] S308: After determining the updated predicted pressure, the updated predicted pressure is loaded into the last data bit of the preset array, and the predicted pressure of the later data bits in the preset array is sequentially updated to the earlier data bits, so that the above step S303 can be executed in the next loop to obtain a new second pressure prediction variable.

[0113] Assuming the prediction array has 50 data bits, the prediction pressure of the 2nd data bit in the prediction array is updated to the 1st data bit, the prediction pressure of the 3rd data bit is updated to the 2nd data bit, and so on. The prediction pressure of the 50th data bit is updated to the 49th data bit, and the updated prediction pressure is reloaded into the 50th data bit.

[0114] Of course, after determining the updated predicted pressure, the updated predicted pressure can be loaded into the first data bit of the preset array, and the predicted pressure of the preceding data bits in the preset array can be sequentially updated to the subsequent data bits. In this case, the data update method for each data bit in the prediction array can refer to the specific implementation method described in the above embodiments, and will not be repeated here.

[0115] In this embodiment of the invention, the execution step of determining the predicted pressure can be performed before step S101 or after step S104. In this embodiment, if the predicted pressure determination process is performed before step S101, then when the control stage is the second control stage and PID control is performed using predicted pressure, the predicted pressure used is the predicted pressure corresponding to the current moment, thereby improving the accuracy of gas pressure control. If the predicted pressure determination process is performed after step S104, then when the control stage is the second control stage and PID control is performed using predicted pressure, the predicted pressure used is the predicted pressure determined at the previous moment. Since the execution time of each cycle in the gas pressure control process is short, it will not affect the control accuracy of the gas pressure. Of course, the execution step of determining the predicted pressure can also be between steps S101 and S104. (Refer to...) Figure 5 As shown in the embodiment of the present invention, preferably, the step of predicting pressure determination is performed before the above step S101.

[0116] In one specific embodiment, the gas pressure control method for the controlled pneumatic circuit, specifically the detection of whether the set pressure of the controlled pneumatic circuit changes as described in step S101 above, may include:

[0117] Based on the pressure signal values ​​of multiple previously received set pressures, it is determined whether the set pressure of the controlled pneumatic circuit has changed.

[0118] In this embodiment of the invention, based on the pressure signal values ​​of multiple previously received set pressures, it can be determined whether the set pressure sent by the host computer has changed. Specifically, this can be achieved by acquiring p consecutive set pressure signal values, where p is a positive integer. For example, if there are 50 pressure signal values, with the first 25 values ​​being A1 and the last 25 values ​​being A2, it indicates that the set pressure signal value has switched from A1 to A2. Alternatively, p set pressure signals can be acquired at intervals based on time sequence, and the change in the set pressure of the controlled pneumatic circuit can be determined based on these p acquired pressure signal values. In this embodiment of the invention, the process of determining whether the set pressure of the controlled pneumatic circuit has changed can also refer to relevant technical means described in the prior art, which will not be elaborated here.

[0119] In one embodiment, the gas pressure control method for the controlled pneumatic circuit described above may further include:

[0120] If the set pressure change of the controlled pneumatic circuit is determined, the first pressure threshold is determined based on the changed set pressure.

[0121] In this embodiment of the invention, the first pressure threshold can be a value less than the set pressure received from the host computer at the current moment, such as 90% or 95% of the set pressure. Of course, the proportion of the first pressure threshold relative to the set pressure can also be determined according to the actual use environment. Thus, the first pressure threshold can be adjusted in controlled pneumatic circuit systems with different pressure response lags to flexibly cope with various pressure control situations.

[0122] Reference Figure 6 As shown, this is a controlled pneumatic circuit system provided by an embodiment of the present invention. The gas pressure control method for the controlled pneumatic circuit provided by this embodiment of the present invention can be applied to the pressure control device of the controlled pneumatic circuit system, i.e. Figure 6 The pressure controller shown in the diagram includes two sets of pressure feedback modules in the controlled pneumatic circuit system. These two sets of pressure feedback modules are respectively located at the beginning and end of the controlled pneumatic circuit. (Refer to...) Figure 6 As shown, the two pressure feedback modules employ two pressure sensors. The first pressure sensor is located at the beginning of the controlled pneumatic circuit, i.e., the end of the pressure actuator, to collect the initial pressure of the controlled pneumatic circuit. The second sensor is located at the end of the controlled pneumatic circuit to collect the final pressure of the controlled pneumatic circuit. Thus, the pressure controller obtains the initial and final pressures of the controlled pneumatic circuit and executes the gas pressure control method for the controlled pneumatic circuit. This control method uses the received analog input signal of the set pressure as the target pressure value, acquires the initial and final pressures of the controlled pneumatic circuit, and uses a PID control algorithm to calculate the control quantity, achieving rapid response pressure control.

[0123] In this embodiment of the invention, the set pressure can be an analog input signal sent by the host computer to the pressure controller via an electrical signal or a communication signal. The specific implementation method can refer to the relevant descriptions in the prior art, such as the implementation method of automatic control PLC related technology. Here, this embodiment of the invention does not make specific limitations.

[0124] In this embodiment of the invention, the controlled pneumatic circuit system provides a stable pressure to the gas source through a pressure regulating valve, and outputs a control signal to the pressure actuator through a pressure controller to control the opening and closing of the pressure actuator and adjust the valve opening of the pressure actuator, thereby realizing the gas pressure control of the controlled pneumatic circuit system.

[0125] The controlled pneumatic circuit described in this embodiment of the invention may include an air path and a load. The air path includes pipe joints and gas pipelines connecting to the load, and the load may be a chamber or other controlled load with a hysteresis response. The specific implementation of the pressure regulating valve, pressure controller, pressure actuator, first pressure sensor, and second pressure sensor described above can refer to the relevant descriptions in the prior art. Here, the embodiments of the invention are not specifically limited.

[0126] The following detailed explanation of the specific execution process of the gas pressure control method for the controlled pneumatic circuit described above is provided through a concrete example:

[0127] Reference Figure 5 As shown, in the initial power-on state, the control stage of the controlled pneumatic circuit is set as the third control stage, and the end pressure of the controlled pneumatic circuit is used as the calculation pressure for PID control.

[0128] In the gas pressure control process, the step of performing predicted pressure calculation specifically includes: acquiring the initial pressure and the final pressure according to a preset sampling period; determining a first pressure prediction variable based on the initial pressure and the final pressure; determining a second pressure prediction variable using the least squares method based on the previously determined predicted pressure of each data bit in a preset array; and determining the updated predicted pressure based on the first pressure prediction variable and the second pressure prediction variable.

[0129] Furthermore, during the gas pressure control process, the steps of detecting and judging changes in the set pressure are performed: specifically, the set pressure of the controlled pneumatic circuit is detected, and it is judged whether the set pressure of the controlled pneumatic circuit has changed. If it has, the control stage at the current moment is set to the first control stage; otherwise, the control stage at the previous moment is maintained.

[0130] Next, the control stage at the current moment is determined in the following way: determine whether the control stage at the current moment is the first control stage; if not, further determine whether the control stage at the current moment is the second control stage; if not, determine that the control stage at the current moment is the third control stage.

[0131] If the current control stage is the first control stage, it is determined whether the end pressure of the controlled pneumatic circuit is greater than the first pressure threshold. If so, the control stage of the next moment is set to the second control stage. If not, the control stage of the next moment remains the first control stage. The end pressure of the controlled pneumatic circuit is used as the pressure for PID control calculation.

[0132] If the current control stage is the second control stage, then determine whether the difference between the starting pressure and the ending pressure of the controlled pneumatic circuit is less than the second preset threshold. If yes, then set the control stage of the next moment to the third control stage. If no, then the control stage of the next moment remains the second control stage. And use the predicted pressure of the controlled pneumatic circuit as the pressure for PID control calculation.

[0133] If the current control stage is the third control stage, then the end pressure of the controlled pneumatic circuit is used as the pressure for PID control calculation.

[0134] The PID control calculation is performed based on the pressure determined under the current control stage, and the control output signal at the current moment is obtained.

[0135] In one specific embodiment, the specific execution process of performing PID control calculation to obtain the control output signal can be as follows: based on the calculation pressure of the PID control, the control output signal at the current moment is calculated using the following formula (5):

[0136]

[0137] In the formula, error(k)=AB;

[0138] Wherein, U(k) represents the control output signal at the current moment; error(k) represents the prediction error at the current moment; k represents the current moment; P is the proportional parameter; I is the integral parameter; D is the derivative parameter; A is the set pressure; B is the calculation pressure, and the calculation pressure is the end pressure, the prediction pressure, or the starting pressure.

[0139] The gas pressure control method for a controlled pneumatic circuit provided in this invention involves subtracting the set pressure from the calculated pressure value, performing PID calculations based on the deviation, obtaining a control output signal, and converting the control signal into an electrical signal to drive the controlled pressure actuator, thereby allowing gas to enter or exit and achieving gas pressure control of the controlled pneumatic circuit. After obtaining the control output signal at the current moment, preparations are made for entering the control cycle at the next moment. The predicted pressure is updated based on the collected start and end pressures of the controlled pneumatic circuit, and the set pressure is detected. Based on the obtained pressure signal value of the set pressure, it is determined whether the set pressure has changed, thus determining the control stage for the next moment and achieving gas pressure control at the next moment.

[0140] The gas pressure control method for a controlled pneumatic circuit provided in this embodiment of the invention, when applied to the pressure controller of a controlled pneumatic circuit system, further includes the following to ensure the accuracy of the control output signal, since the output signal of the pressure controller has upper and lower limits:

[0141] Determine whether the value of the control output signal at the current moment is between a first preset output threshold and a second preset output threshold; the first preset output threshold is less than the second preset output threshold.

[0142] If so, then output the control quantity output signal at the current moment;

[0143] If the value of the control output signal at the current moment is less than the first preset output threshold, then the signal of the first preset output threshold is output.

[0144] If the value of the control output signal at the current moment is greater than the second preset output threshold, then the output value is the signal of the second preset output threshold.

[0145] In this embodiment of the invention, by comparing the obtained control output signal with a first preset output threshold and a second preset output threshold, the system pressure control is prevented from malfunctioning and failing to accurately control the gas pressure when the obtained control output signal value exceeds the upper or lower limit of the pressure controller's output signal. In this embodiment, the first preset output threshold can be greater than or equal to the lower limit of the pressure controller's output signal, and the second preset output threshold can be less than or equal to the upper limit of the pressure controller's output signal.

[0146] The gas pressure control method for the controlled pneumatic circuit provided in this embodiment of the invention, when a change in the set pressure is determined, realizes the switching between the first and third control stages by judging the initial pressure and the final pressure of the controlled pneumatic circuit, thereby reducing the impact of the pressure difference between the pressure actuator and the controlled pneumatic circuit on the response lag of the controlled pneumatic circuit during the pressure control process. During the initial period of pressure change, feedback control is performed based on the terminal pressure of the controlled pneumatic circuit to accelerate the response speed of the gas pressure in the controlled pneumatic circuit. Furthermore, when the terminal pressure of the controlled pneumatic circuit reaches a first pressure threshold (i.e., when the terminal pressure approaches the set pressure), predicted pressure is used in the feedback to control the pressure during the transition phase of the controlled pneumatic circuit, avoiding gas pressure fluctuations and saving time required for pressure stabilization. When the difference between the initial and terminal pressures of the controlled pneumatic circuit is less than a second preset threshold (i.e., when the gas pressure in the controlled pneumatic circuit is critically approaching the set pressure), the initial pressure of the controlled pneumatic circuit is used in the feedback control, and the pressure control of the controlled pneumatic circuit enters the stable control phase, ensuring stable pressure control. The gas pressure control method for the controlled pneumatic circuit provided in this embodiment of the invention, by using different pressures as feedback signal values ​​in different gas pressure control stages to participate in PID control, not only improves the pressure response speed but also ensures the pressure response accuracy. Meanwhile, depending on different pressure control scenarios, the first preset pressure threshold, the second preset pressure threshold, and the predicted pressure parameters can be adjusted to flexibly cope with various pressure control occasions and are applicable to controlled pneumatic circuit systems with different pressure response lags.

[0147] Based on the same inventive concept, this embodiment of the invention also provides a pressure controller for a controlled pneumatic circuit, including a processor and a memory. The memory stores a computer program, and the processor executes the above-described gas pressure control method for the controlled pneumatic circuit by calling the computer program stored in the memory.

[0148] The specific implementation of the pressure controller for the controlled pneumatic circuit provided in this embodiment of the invention can be referred to the detailed description of the gas pressure control method for the controlled pneumatic circuit in the above embodiments. Repeated descriptions will not be repeated. Of course, those skilled in the art can also refer to the detailed descriptions in the prior art; therefore, this embodiment of the invention does not impose specific limitations on these descriptions.

[0149] Based on the same inventive concept, embodiments of the present invention also provide a controlled pneumatic circuit system, referring to... Figure 6 As shown, it includes a pressure regulating valve, a pressure actuator, a first pressure sensor, a controlled pneumatic circuit, a second pressure sensor, and a pressure controller for the aforementioned controlled pneumatic circuit; wherein:

[0150] The pressure regulating valve is connected between the external air source and the pressure actuator;

[0151] The first pressure sensor is connected to the beginning of the controlled pneumatic circuit;

[0152] The second pressure sensor is connected to the end of the controlled pneumatic circuit;

[0153] The pressure controller is connected to the first pressure sensor, the second pressure sensor, and the pressure actuator, respectively.

[0154] The controlled pneumatic circuit system provided in this invention features a separate design for the pressure controller, pressure actuator, first pressure sensor, and second pressure sensor. This allows for separate arrangement of the pneumatic and electrical circuits, making it suitable for various installation environments and enabling complex pressure control applications. The system can obtain a control output signal by subtracting the set pressure from the calculated pressure value and performing PID calculations based on the deviation. This control signal is then converted into an electrical signal to drive the controlled pressure actuator, allowing gas to enter or exit, thus achieving gas pressure control in the controlled pneumatic circuit.

[0155] The specific implementation of the controlled pneumatic circuit system provided in this embodiment of the invention can be referred to the detailed description of the controlled pneumatic circuit system and the gas pressure control method of the controlled pneumatic circuit in the above embodiments. Repeated descriptions will not be repeated. Of course, those skilled in the art can also refer to the detailed descriptions in the prior art; therefore, this embodiment of the invention does not impose specific limitations on these descriptions.

[0156] Based on the same inventive concept, embodiments of the present invention also provide a pneumatic drive device, including the above-described controlled pneumatic circuit system.

[0157] The specific implementation of the pneumatic drive device provided in the embodiments of the present invention can be referred to the detailed description of the controlled pneumatic circuit system in the above embodiments, and repeated details will not be repeated. Of course, those skilled in the art can also refer to the detailed description in the prior art, and therefore, the embodiments of the present invention do not impose specific limitations on this.

[0158] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The terms "upper," "lower," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0159] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. This invention is not limited to any single aspect, nor to any single embodiment, nor to any combination and / or substitution of these aspects and / or embodiments. Each aspect and / or embodiment of this invention can be used alone, or in combination with one or more other aspects and / or other embodiments.

[0160] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling gas pressure in a controlled pneumatic circuit, characterized in that, include: Detect whether the set pressure of the controlled pneumatic circuit has changed. If it has, set the current control stage to the first control stage. If not, maintain the control stage of the previous moment. If the current control stage is the first control stage, then it is determined whether the end pressure of the controlled pneumatic circuit is greater than the first pressure threshold. If so, the control stage of the next moment is set to the second control stage; and the end pressure of the controlled pneumatic circuit is used as the pressure for PID control calculation. If the current control stage is the second control stage, then determine whether the difference between the starting pressure and the ending pressure of the controlled pneumatic circuit is less than the second preset threshold. If so, then set the control stage of the next moment to the third control stage; and use the predicted pressure of the controlled pneumatic circuit as the calculation pressure for PID control. If the current control stage is the third control stage, then the end pressure of the controlled pneumatic circuit is used as the pressure for PID control calculation. The predicted pressure is updated in the following manner: The initial pressure and the final pressure are obtained according to a preset sampling period; Based on the initial pressure and the final pressure, a first pressure prediction variable is determined; Based on the pre-determined predicted pressure of each data bit in the preset array, the least squares method is used to determine the second pressure prediction variable; The updated predicted pressure is determined based on the first pressure predictor variable and the second pressure predictor variable.

2. The gas pressure control method for the controlled pneumatic circuit according to claim 1, characterized in that, Determining the updated predicted pressure based on the first pressure predictor variable and the second pressure predictor variable includes: Based on the first and second pressure predictor variables, a third pressure predictor variable is determined; Determine whether the third pressure prediction variable is greater than the initial pressure and the final pressure; If so, the updated predicted pressure is determined based on the initial pressure and the final pressure; If not, the updated predicted pressure is determined based on the third pressure predictor variable.

3. The gas pressure control method for the controlled pneumatic circuit according to claim 2, characterized in that, The preset array includes a preset number of data bits, each data bit containing a pre-determined predicted pressure; The pre-determined predicted pressure for each data bit in the preset array is obtained in the following manner: The updated predicted pressure is loaded into the first data bit of the preset array, and the predicted pressure of the preceding data bits in the preset array is sequentially updated to the following data bits; Alternatively, the updated predicted pressure can be loaded into the last data bit of the preset array, and the predicted pressure of the subsequent data bits in the preset array can be sequentially updated into the preceding data bits.

4. The gas pressure control method for a controlled pneumatic circuit according to any one of claims 1-3, characterized in that, The detection of whether the set pressure of the controlled pneumatic circuit changes includes: Based on the pressure signal values ​​of multiple previously received set pressures, it is determined whether the set pressure of the controlled pneumatic circuit has changed.

5. The gas pressure control method for the controlled pneumatic circuit according to claim 4, characterized in that, Also includes: If the set pressure change of the controlled pneumatic circuit is determined, the first pressure threshold is determined based on the changed set pressure.

6. The gas pressure control method for a controlled pneumatic circuit according to any one of claims 1-3, characterized in that, This also includes determining the control phase at the current moment in the following ways: Determine whether the current control stage is the first control stage. If not, determine whether the current control stage is the second control stage. If neither is true, determine that the current control stage is the third control stage.

7. The gas pressure control method for a controlled pneumatic circuit according to any one of claims 1-3, characterized in that, Also includes: If the current control phase is the first control phase, and the end pressure of the controlled pneumatic circuit is not greater than the first pressure threshold, then the control phase at the next moment remains the first control phase. If the current control phase is the second control phase, and the difference between the starting pressure and the ending pressure of the controlled pneumatic circuit is not less than the second preset threshold, then the control phase at the next moment will remain the second control phase.

8. The gas pressure control method for a controlled pneumatic circuit according to any one of claims 1-3, characterized in that, Also includes: In the initial power-on state, the control phase at the initial moment is set to the third control phase.

9. The gas pressure control method for a controlled pneumatic circuit according to any one of claims 1-3, characterized in that, Also includes: Based on the pressure used for PID control calculation, the control output signal at the current moment is obtained by calculating using the following formula: ； Wherein, U(k) represents the control output signal at the current moment; error(k) represents the prediction error at the current moment; k represents the current moment; P is the proportional parameter; I is the integral parameter; D is the derivative parameter; A is the set pressure; B is the calculation pressure, and the calculation pressure is the end pressure or the prediction pressure.

10. The gas pressure control method for the controlled pneumatic circuit according to claim 9, characterized in that, Also includes: Determine whether the value of the control output signal at the current moment is between the first preset output threshold and the second preset output threshold; The first preset output threshold is less than the second preset output threshold; If so, then output the control quantity output signal at the current moment; If the value of the control output signal at the current moment is less than the first preset output threshold, then the signal of the first preset output threshold is output. If the value of the control output signal at the current moment is greater than the second preset output threshold, then the output value is the signal of the second preset output threshold.

11. A pressure controller for a controlled pneumatic circuit, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the gas pressure control method of the controlled pneumatic circuit as described in any one of claims 1-10 by calling the computer program stored in the memory.

12. A controlled pneumatic circuit system, characterized in that, It includes a pressure regulating valve, a pressure actuator, a first pressure sensor, a controlled pneumatic circuit, a second pressure sensor, and a pressure controller for the controlled pneumatic circuit as described in claim 11; The pressure regulating valve is connected between the external air source and the pressure actuator; The first pressure sensor is connected to the beginning of the controlled pneumatic circuit; The second pressure sensor is connected to the end of the controlled pneumatic circuit; The pressure controller is connected to the first pressure sensor, the second pressure sensor, and the pressure actuator, respectively.

13. A pneumatic drive device, comprising the controlled pneumatic circuit system as described in claim 12.

Images