A fume hood controller based on modeless adaptive control and its use method

Abstract

The present invention discloses a fume hood controller based on modeless adaptive control and a method of using the same, including a fume hood, a controller, a ventilation pipe and an electric valve, wherein a cavity is provided on the top front side of the fume hood, and a cabinet door is movably installed on the front side of the cavity. The fume hood controller adopts a modeless adaptive algorithm to automatically control the fume hood, and the modeless adaptive algorithm has the characteristic of consistency. When the same sensor accessories and the same target are used, only one on-site parameter debugging is required to apply the parameters to all fume hood controllers in the same environment, thereby reducing the workload of engineers. Compared with PID control, it has the advantages of being independent of a specific model, easy to implement, online adaptive, and having a smooth control process and good effects. It can dynamically adjust the controller weight parameters according to the changes in input and output to complete closed-loop control, and has strong practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of controllers, and in particular to a fume hood controller based on modeless adaptive control and a use method thereof. Background Art

[0002] The existing fume hood controller has three 0-10V DC voltage input signals for the displacement sensor, air volume sensor and differential pressure sensor installed on the variable air volume valve to transmit signals. In addition, there is one 0-10V DC voltage output signal to control the opening of the variable air volume valve. The fume hood controller is used to realize automatic control of the fume hood. It monitors the changes in the environmental conditions of the fume hood through the connection of the displacement sensor, micro wind speed sensor and differential pressure sensor, controls the valve of the ventilation duct through the 0-10V DC voltage signal, and realizes automatic control of the opening of the valve through the automation algorithm, thereby adjusting the air intake, so that the wind speed at the fume hood operation port is always maintained at 0.5m / s, effectively preventing the leakage of harmful gases in the cabinet, thereby protecting the operator.

[0003] In the prior art, PID algorithm is used to realize automatic control. The opening amplitude of the fume hood door can be monitored by a displacement sensor, and the cross-sectional area of ​​the air flow of the fume hood door can be obtained by calculation. This value is used as a PID algorithm parameter to participate in the automatic operation, and the valve opening of the ventilation duct is controlled to adjust the wind speed to gradually approach the target value; and on this basis, the wind speed in the cabinet is monitored by a micro wind speed sensor, and the above result is corrected as a PID parameter; the valve opening is controlled by a secondary PID combination composed of signals collected by a displacement sensor and a micro wind speed sensor, and the value monitored by the pressure difference sensor is used as output feedback.

[0004] However, in the prior art, the airflow model in the fume hood has the characteristics of large lag, strong nonlinearity, slow time variation, and strong coupling. It is difficult to obtain an accurate mathematical model. After the valve opening is adjusted in real time, there is a certain time delay when the airflow is reflected on the wind speed sensor. At the same time, for fume hoods of different sizes, the lag time is different, resulting in the PID algorithm not being very universal. Changing the specifications of a cabinet requires adjusting the PID parameters once, which greatly increases the workload for on-site installation and debugging personnel.

[0005] Therefore, we propose a fume hood controller based on modeless adaptive control and its use method to solve the problems raised above. Summary of the invention

[0006] The purpose of the present invention is to provide a fume hood controller based on modeless adaptive control and a method of using the same, so as to solve the problem that the airflow model in the fume hood proposed in the above background technology has the characteristics of large lag, strong nonlinearity, slow time variation, and strong coupling, and an accurate mathematical model is difficult to obtain. After the valve opening is adjusted in real time, there is a certain time delay when the airflow is reflected on the wind speed sensor. At the same time, for fume hoods of different sizes, the lag time is different, resulting in the PID algorithm not being very universal. When changing a cabinet of a different specification, the PID parameters need to be adjusted once, which greatly increases the workload of on-site installation and debugging personnel.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fume hood controller based on modeless adaptive control, comprising a fume hood, a controller, a ventilation duct and an electric valve, a cavity is opened on the front side of the top of the fume hood, and a cabinet door is movably installed on the front side of the cavity, a displacement sensor is fixedly installed on the front side of the cavity, and a micro wind speed sensor is fixedly installed on the inner side of the cavity, the top of the fume hood is connected to the bottom of the ventilation duct, the top of the ventilation duct is movably installed with one end of the electric valve, a pressure difference sensor is fixedly installed on one side of the electric valve, and one end of the pressure difference sensor is fixedly installed with the inner side of the ventilation duct, one side of the top of the fume hood is fixedly installed with the bottom of the controller, and one end of the displacement sensor, the micro wind speed sensor and the pressure difference sensor are all fixedly connected to one side of the controller.

[0008] Preferably, the controller comprises a main body, and a first connector, a second connector and a third connector are respectively fixedly mounted on one side of the main body.

[0009] Preferably, one end of the first joint is fixedly connected to one end of the pressure difference sensor, one end of the second joint is fixedly connected to one end of the displacement sensor, and one end of the third joint is fixedly connected to one end of the micro wind speed sensor.

[0010] Preferably, the electric valve comprises a mounting ring, a motor is plugged into one side of the mounting ring, and a valve plate is movably mounted on one end of the motor.

[0011] Preferably, the inner side of the mounting ring is fixedly mounted to the outer side of the ventilation pipe, and the outer side of the valve plate is movably mounted to the inner side of the ventilation pipe.

[0012] Preferably, a mounting frame is fixedly mounted on the outer side of the electric valve, and one side of the mounting frame is fixedly mounted to the outer side of the mounting ring.

[0013] Preferably, one side of the mounting ring is fixedly mounted to the outer side of the differential pressure sensor, one end of the motor is fixedly connected to a motor connector, and the bottom of the motor connector is fixedly mounted to the top of the main body.

[0014] A method for using a fume hood controller based on modeless adaptive control comprises the following steps:

[0015] S1. Start.

[0016] S2. Initialization parameters.

[0017] S3. Obtain the opening of the fume hood door through a displacement sensor.

[0018] S4. Calculate the theoretically required air intake volume at time K.

[0019] S5. Compare the theoretical air intake volume with the current variable air volume valve air volume sensor and update the deviation of the air volume at time K.

[0020] S6. Calculate and update the target air volume and its change and pseudo-partial derivative at time K-1.

[0021] S7. Estimate the pseudo partial derivative at the Kth time according to the pseudo partial derivative identification algorithm.

[0022] S8. Calculate the driving quantity of the control system according to the control law algorithm, that is, adjust the opening of the variable air volume valve.

[0023] S9. Obtain the wind speed in front of the fume hood at time K through the surface wind speed sensor.

[0024] S10. Compare the current wind speed at time K with the target wind speed, and update the deviation of the wind volume at time K.

[0025] S11. Calculate and update the target air volume and its change and pseudo-partial derivative at time K-1 for the second time.

[0026] S12. Estimate the pseudo partial derivative at the Kth moment according to the pseudo partial derivative identification algorithm.

[0027] S13. Calculate the driving quantity of the control system according to the control law algorithm and perform secondary debugging on the valve.

[0028] Preferably, the controller dynamically controls the system output to approach the target value by performing a cyclic calculation according to steps S1-S13.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Through the setting of the controller, the controller adopts the mode-free adaptive algorithm (MFAC) to automatically control the fume hood. The mode-free adaptive algorithm has the characteristics of consistency. When using the same sensor accessories and the same target, only one on-site parameter debugging is required to apply the parameters to all fume hood controllers in the same environment, reducing the workload of engineers;

[0031] 2. Through the setting of the controller, compared with the PID control in the prior art, it has the advantages of not relying on a specific model, being easy to implement, online self-adaptation, stable control process and good effect;

[0032] 3. Through the setting of the controller, the fume hood controller using the mode-free adaptive algorithm (MFAC) does not need to be designed for a certain process compared to the controller using the PID algorithm, and is well suited for fume hoods of different specifications;

[0033] 4. Through the setting of the controller, the controller weight parameters can be dynamically adjusted according to the changes in input and output to complete closed-loop control, which is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A three-dimensional diagram of a fume hood controller based on modeless adaptive control of the present invention;

[0035] Figure 2 It is a three-dimensional structural schematic diagram of a fume hood controller based on modeless adaptive control of the present invention;

[0036] Figure 3 This is a top view of the structure of a fume hood controller based on modeless adaptive control according to the present invention;

[0037] Figure 4 The present invention is a flow chart of a method for using a fume hood controller based on modeless adaptive control.

[0038] In the figure:

[0039] 1. Fume hood; 2. Controller; 3. Ventilation duct; 4. Electric valve; 10. Cavity; 11. Cabinet door; 6. Displacement sensor; 5. Micro wind speed sensor; 7. Pressure difference sensor; 20. Main body; 21. First joint; 22. Second joint; 23. Third joint; 40. Mounting ring; 43. Motor; 41. Valve plate; 42. Mounting bracket; 24. Motor joint. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] See also Figure 1-3The present invention provides a technical solution: a fume hood controller based on modeless adaptive control, comprising a fume hood 1, a controller 2, a ventilation pipe 3 and an electric valve 4, a cavity 10 is opened on the top front side of the fume hood 1, and a cabinet door 11 is movably installed on the front side of the cavity 10, a displacement sensor 6 is fixedly installed on the front side of the cavity 10, and a micro wind speed sensor 5 is fixedly installed on the inner side of the cavity 10, the top of the fume hood 1 is connected to the bottom of the ventilation pipe 3, the top of the ventilation pipe 3 is movably installed with one end of the electric valve 4, a pressure difference sensor 7 is fixedly installed on one side of the electric valve 4, and one end of the pressure difference sensor 7 is fixedly installed with the inner side of the ventilation pipe 3, one side of the top of the fume hood 1 is fixedly installed with the bottom of the controller 2, one end of the displacement sensor 6, the micro wind speed sensor 5 and the pressure difference sensor 7 are all fixedly connected to one side of the controller 2, and the controller 2 comprises a main body 20, and one side of the main body 20 is respectively fixed A first joint 21, a second joint 22 and a third joint 23 are fixedly installed, one end of the first joint 21 is fixedly connected to one end of the differential pressure sensor 7, one end of the second joint 22 is fixedly connected to one end of the displacement sensor 6, one end of the third joint 23 is fixedly connected to one end of the micro-wind speed sensor 5, the electric valve 4 includes a mounting ring 40, one side of the mounting ring 40 is plugged with a motor 43, one end of the motor 43 is movably mounted with a valve plate 41, the inner side of the mounting ring 40 is fixedly installed with the outer side of the ventilation pipe 3, the outer side of the valve plate 41 is movably installed with the inner side of the ventilation pipe 3, a mounting frame 42 is fixedly installed on the outer side of the electric valve 4, and one side of the mounting frame 42 is fixedly installed with the outer side of the mounting ring 40, one side of the mounting ring 40 is fixedly installed with the outer side of the differential pressure sensor 7, one end of the motor 43 is fixedly connected with a motor joint 24, and the bottom of the motor joint 24 is fixedly installed with the top of the main body 20.

[0043] The working principle of this embodiment is as follows: when the cabinet door 11 of the fume hood 1 is opened, the displacement sensor 6 monitors the opening of the bottom of the cabinet door 11 in real time, and transmits the real-time data to the controller 2 through the second connector 22 to calculate the cross-sectional area of ​​the air flow of the cabinet door, and the micro-wind speed sensor 5 in the fume hood 1 will also transmit the real-time wind speed data in the cavity 10 to the controller 2 through the third connector 23 to correct the data of the control electric valve 4. After calculation, the controller 2 controls the start and stop of the motor 43 through the motor connector 24, thereby controlling the valve plate installed at the output end of the motor 43. The opening of the controller 41 in the ventilation duct 3 is controlled, thereby controlling the air intake in the ventilation duct 3, so that the wind speed at the operating port of the fume hood 1 is always maintained at 0.5m / s, effectively preventing the leakage of harmful gases in the cabinet, thereby protecting the operator. At the same time, the wind speed value monitored by the pressure difference sensor 7 at both ends of the valve plate 41 is used as output feedback to adjust the opening of the valve plate 41 in real time. When a fume hood 1 is debugged through the above steps, the parameters of this controller 2 can be applied to the controllers 2 of all fume hoods 1 in the same environment, thereby saving the workload of the debugger and improving the debugging efficiency of the fume hood 1.

[0044] Example 2

[0045] according to Figure 4 As shown, a method for using a fume hood controller based on modeless adaptive control includes the following steps:

[0046] S1, start;

[0047] S2, initialization parameters;

[0048] S3, obtaining the opening of the fume hood door through a displacement sensor;

[0049] S4. Calculate the theoretical required air intake volume at time K;

[0050] S5, compare the theoretical air intake volume with the current variable air volume valve air volume sensor, and update the deviation of the air volume at time K;

[0051] S6, calculating and updating the target air volume and its change and pseudo partial derivative at time K-1;

[0052] S7, estimating the pseudo partial derivative at the Kth time according to the pseudo partial derivative identification algorithm;

[0053] S8. Calculate the driving amount of the control system according to the control law algorithm, that is, adjust the opening of the variable air volume valve;

[0054] S9, obtain the wind speed in front of the fume hood at time K through the surface wind speed sensor;

[0055] S10, comparing the current wind speed at time K with the target wind speed, and updating the deviation of the wind volume at time K;

[0056] S11, recalculate and update the target air volume and its change and pseudo partial derivative at time K-1;

[0057] S12, estimating the pseudo partial derivative at the Kth moment according to the pseudo partial derivative identification algorithm;

[0058] S13. Calculate the driving quantity of the control system according to the control law algorithm and perform secondary debugging on the valve.

[0059] The working principle of this embodiment is as follows: the opening amplitude of the fume hood door 11 can be monitored by the displacement sensor 6, that is, the cross-sectional area of ​​the air flow of the fume hood door 11 can be obtained by calculation, and this value is used as a PID algorithm parameter to participate in the automatic operation, and the opening of the valve plate 41 of the ventilation pipe 3 is controlled to adjust the wind speed to gradually approach the target value. On this basis, the wind speed of the cavity 10 in the cabinet is monitored by the micro wind speed sensor 5, and the above result is corrected as a PID parameter. The opening of the valve plate 41 is controlled by a secondary PID combination composed of signals collected by the displacement sensor 6 and the micro wind speed sensor 6, and the value monitored by the differential pressure sensor 7 is used as output feedback. In this way, the controller 2 dynamically controls the wind speed of the ventilation pipe 3 through the electric valve 4, so that the output approaches the target value; after the debugging of a fume hood 1 on site is completed, the parameters can be applied to all fume hood controllers in the same environment, reducing the workload of engineers. Compared with PID control, it has the advantages of not relying on a specific model, easy to implement, online self-adaptation, stable control process and good effect, etc., and can dynamically adjust the controller weight parameters according to the changes in input and output to complete closed-loop control, and has strong practicality.

[0060] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fume hood controller based on modeless adaptive control, comprising a fume hood (1), a controller (2), a ventilation pipe (3) and an electric valve (4), characterized in that: A cavity (10) is provided on the front side of the top of the fume hood (1), and a cabinet door (11) is movably mounted on the front side of the cavity (10); a displacement sensor (6) is fixedly mounted on the front side of the cavity (10), and a micro-wind speed sensor (5) is fixedly mounted on the inner side of the cavity (10); the top of the fume hood (1) is connected to the bottom of the ventilation pipe (3), the top of the ventilation pipe (3) is movably mounted on one end of an electric valve (4), and a pressure difference sensor (5) is fixedly mounted on one side of the electric valve (4). 7), and one end of the differential pressure sensor (7) is fixedly mounted on the inner side of the ventilation pipe (3), one side of the top of the fume hood (1) is fixedly mounted on the bottom of the controller (2), one end of the displacement sensor (6), the micro wind speed sensor (5) and the differential pressure sensor (7) are all fixedly connected to one side of the controller (2), and the controller (2) comprises a main body (20), one side of the main body (20) is respectively fixedly mounted with a first joint (21), a second joint (22) and a third joint (23), and the first joint (21) is fixedly mounted on the second joint (22) and the third joint (23). One end of a connector (21) is fixedly connected to one end of a differential pressure sensor (7), one end of a second connector (22) is fixedly connected to one end of a displacement sensor (6), one end of a third connector (23) is fixedly connected to one end of a micro wind speed sensor (5), the electric valve (4) comprises a mounting ring (40), one side of the mounting ring (40) is plugged with a motor (43), one end of the motor (43) is movably mounted with a valve plate (41), the inner side of the mounting ring (40) is connected to the ventilation pipe (3), the outer side of the valve plate (41) is movably mounted on the inner side of the ventilation pipe (3), the outer side of the electric valve (4) is fixedly mounted with a mounting frame (42), and one side of the mounting frame (42) is fixedly mounted with the outer side of the mounting ring (40), one side of the mounting ring (40) is fixedly mounted with the outer side of the differential pressure sensor (7), one end of the motor (43) is fixedly connected with a motor connector (24), and the bottom of the motor connector (24) is fixedly mounted with the top of the main body (20).

2. A method for using a fume hood controller based on modeless adaptive control, characterized in that: A fume hood controller based on modeless adaptive control as described in claim 1 is used, comprising the following steps: S1, start; S2, initialization parameters; S3, obtaining the opening of the fume hood door through a displacement sensor; S4. Calculate the theoretical required air intake volume at time K; S5, compare the theoretical air intake volume with the current variable air volume valve air volume sensor, and update the deviation of the air volume at time K; S6, calculating and updating the target air volume and its change and pseudo partial derivative at time K-1; S7, estimating the pseudo partial derivative at the Kth time according to the pseudo partial derivative identification algorithm; S8. Calculate the driving amount of the control system according to the control law algorithm, that is, adjust the opening of the variable air volume valve; S9, obtain the wind speed in front of the fume hood at time K through the surface wind speed sensor; S10, comparing the current wind speed at time K with the target wind speed, and updating the deviation of the wind volume at time K; S11, recalculate and update the target air volume and its change and pseudo partial derivative at time K-1; S12, estimating the pseudo partial derivative at the Kth moment according to the pseudo partial derivative identification algorithm; S13. Calculate the driving quantity of the control system according to the control law algorithm and perform secondary debugging on the valve.

3. The method for using a fume hood controller based on modeless adaptive control according to claim 2, characterized in that: According to the loop calculation of steps S1-S13, the controller (2) dynamically controls the system output to approach the target value.

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