CN214011810U - Pneumatic pressure control system - Google Patents
Pneumatic pressure control system Download PDFInfo
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- CN214011810U CN214011810U CN202022080006.8U CN202022080006U CN214011810U CN 214011810 U CN214011810 U CN 214011810U CN 202022080006 U CN202022080006 U CN 202022080006U CN 214011810 U CN214011810 U CN 214011810U
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Abstract
The utility model discloses a pneumatic pressure control system, which is characterized by comprising a pressure sensor, a PLC control module preset with a target deviation calculation module, a PID control module, a PWM control module preset with a switch valve control rule and a switch valve group module, wherein the switch valve group module comprises a valve group base, a main air inlet pipe and a main air outlet pipe arranged in the valve group base, the main air inlet pipe is provided with a main air inlet communicated with an air supply port of external air supply equipment and an air outlet provided with an exhaust switch valve, the main air outlet pipe is provided with a main air outlet communicated with an air inlet port of the air supply equipment, the main air inlet pipe is communicated with the main air outlet pipe through at least seven air inlet branch pipes which are not communicated with each other, each air inlet branch pipe is provided with an air inlet switch valve, the pneumatic pressure control system has the advantages that the problem that the switch valve can not be opened when the duty ratio of a PWM control signal is lower and the switch valve is fully opened in advance when the duty ratio is higher, and the accuracy and the stability of the control air pressure are improved, and the adjustment is quick.
Description
Technical Field
The utility model relates to a pressure control system, especially a pneumatic pressure control system.
Background
At present, in pneumatic pressure control, a proportional valve or a high-speed switch valve is generally applied to form a system so as to realize continuous pressure regulation; because the proportional valve is expensive and large in size, the application of forming a pressure regulating system by using a high-speed switch valve is more and more recently, but the effect is not ideal in the actual fine adjustment control; due to the influence of the response capability of the electromagnetic valve and the movement time of the valve core, a PWM signal sent to the switch valve by the controller actually has certain lag, the switch valve has the problems that the switch valve cannot be opened when the given PWM duty ratio of the controller is lower and is fully opened in advance when the duty ratio is higher, the adjustment precision is not high, when closed-loop adjustment is carried out by receiving pressure feedback, the required pressure value can be reached through multiple times of adjustment, and the consumed time is long.
Disclosure of Invention
The utility model aims to solve the technical problem that a pneumatic pressure control system that pneumatic control precision is higher and control is comparatively stable is provided.
The utility model provides a technical scheme that above-mentioned technical problem adopted does: a pneumatic pressure control system comprises a pressure sensor, a PLC control module, a PID control module, a PWM control module and a switch valve group module, wherein the PLC control module is preset with a target deviation calculation module, the PWM control module is preset with a switch valve control rule, the pressure sensor is used for detecting the air pressure of an air inlet port of air equipment to obtain a current air pressure feedback value and sending the current air pressure feedback value to the preset target deviation calculation module in the PLC control module, the target deviation calculation module obtains a corresponding current target deviation value according to an externally input given pressure value and the current air pressure feedback value and inputs the current target deviation value into the PID control module, the PID control module obtains a corresponding current control quantity according to the current target deviation value and sends the current control quantity to the PWM control module, and the switch valve group module comprises a valve group base, a total air inlet pipe and a total air outlet pipe which are arranged in the valve group base, the total intake pipe be provided with a total air inlet and an gas vent that is provided with the air discharge switch valve with the air supply mouth intercommunication of outside air feeder, total outlet duct be provided with a total gas outlet with the inlet port intercommunication of air feeder, total intake pipe with total outlet duct between through seven at least air inlet branch pipe intercommunications that do not communicate each other, every air inlet branch pipe be provided with an air inlet switch valve, PWM control module according to current controlled quantity and predetermined switching valve control rule respectively output corresponding PWM control signal individual control every air inlet switch valve and air discharge switch valve's air output size.
The number of the air inlet branch pipes is 11. The precision is further improved, and the numerical value setting in the preset switching valve control rule is more convenient.
The preset switching valve control rule is as follows:
recording the current control quantity output by the PID control module as Q%, -Qm%≤Q%≤Qm%，Qm% represents a control amount corresponding to the ventilation amount when 10 intake switching valves are fully opened, and Q ism% of the total amount of the exhaust gas, and% of the total amount of the exhaust gas, the percentage of the dead zone duty ratio corresponding to the condition that the intake and exhaust switching valves cannot be opened by the PWM control signal are defined as 0 to (10S) =100%1) %, the range of the duty ratio corresponding to the PWM control signal completely opening the intake switching valve and the exhaust switching valve is defined as (10S)2) Percent to 100 percent of S1Is set as S1=2.0, adding S2Is set as S2=8.0；
Judging Q, if Q is greater than 0, dividing Q by 10 to obtain a quotient N and a remainder R, wherein N is greater than or equal to 0 and less than or equal to 10, R is greater than or equal to 0 and less than or equal to 10, executing a rule one when R is greater than or equal to 2.0 and less than 8.0, executing a rule two when R is less than 2.0, executing a rule three when R is greater than or equal to 8.0 and less than 10.0,
rule one is as follows: setting the duty ratio of the PWM control signals corresponding to the N air inlet switch valves to be a fixed value larger than 80%, setting the duty ratio of the PWM control signal corresponding to one air inlet switch valve in the other air inlet switch valves to be (10R)%, and setting the duty ratio of the PWM control signals corresponding to the rest air inlet switch valves to be 0%;
rule two is as follows: setting the duty ratio of PWM control signals corresponding to N air inlet switch valves to be a fixed value larger than 80%, setting the duty ratio of the PWM control signal corresponding to one air inlet switch valve in other air inlet switch valves to be (10A)%, and setting the duty ratio of the PWM control signal corresponding to an air exhaust switch valve to be (10B)%, wherein A is a preset fixed value, A is more than 5 and less than 8, A-B = R, and setting the duty ratios of the PWM control signals corresponding to the rest air inlet switch valves to be 0%;
rule three is as follows: setting the duty ratios of the PWM control signals corresponding to the N intake switching valves to a fixed value greater than 80%, and setting the duty ratios of the PWM control signals corresponding to two intake switching valves among the other intake switching valves to (10C)%, respectively, where C = R/2, and setting the duty ratios of the PWM control signals corresponding to the remaining intake switching valves to 0%;
if Q =0, rule four is implemented as follows: the PWM control signal output by the PWM control module is kept unchanged;
if Q is more than or equal to-2.0 and less than 0, the execution rule five is as follows: setting the duty ratio of a PWM control signal corresponding to one of the air inlet switch valves to be (10D)%, and setting the duty ratio of a PWM control signal corresponding to the exhaust switch valve to be (10E)%, wherein E is a preset fixed value, E is more than 5 and less than 8, and D-E = Q;
if-10.0 < Q < -2.0, the execution rule six is as follows: setting the duty ratio of a PWM control signal corresponding to the exhaust switch valve to be (-10Q)%;
if Q is less than or equal to-10.0, the execution rule seven is as follows: and setting the duty ratio of the PWM control signal corresponding to the exhaust switching valve to be a fixed value larger than 80%.
The PWM control module switches and sends a PWM control signal originally sent to the failed air inlet switch valve to one standby switch valve according to a preset switch valve control rule when one air inlet switch valve fails.
The air inlet switch valve and the standby switch valve are staggered on the valve group base to form a left row and a right row. The structure is compact, and the size of the valve group base is effectively reduced.
Compared with the prior art, the utility model has the advantages that a closed-loop PID control system is adopted, which comprises a pressure sensor, a PLC control module with a target deviation calculation module preset, a PID control module, a PWM control module with a preset switching valve control rule and a switching valve group module, wherein the switching valve group module comprises a valve group base, a main air inlet pipe and a main air outlet pipe which are arranged in the valve group base, the main air inlet pipe is provided with a main air inlet communicated with an air supply port of external air supply equipment and an air outlet provided with an exhaust switch valve, the main air outlet pipe is provided with a main air outlet communicated with an air inlet port of the air supply equipment, the main air inlet pipe is communicated with the main air outlet pipe through at least seven air inlet branch pipes which are not communicated with each other, each air inlet branch pipe is provided with an air inlet switch valve, wherein the pressure sensor detects the air pressure of the air inlet port of the air supply equipment to obtain the current air pressure feedback value and sends the current air pressure feedback value to the target deviation calculation module preset in the PLC control module, the target deviation calculation module acquires a corresponding current target deviation value according to an externally input given pressure value and a current air pressure feedback value and inputs the current target deviation value into the PID control module, the PID control module acquires a corresponding current control quantity according to the current target deviation value and sends the current control quantity to the PWM control module, and the PWM control module respectively outputs corresponding PWM control signals according to the current control quantity and a preset switching valve control rule to independently control the ventilation quantity of each air inlet switching valve and each air outlet switching valve to control the plurality of switching valves so as to follow the given pressure; wherein the quantity of inlet branch pipe is seven at least, can wholly realize the present controlled variable through setting up solitary controlled variable for every inlet switch valve and exhaust switch valve at predetermined ooff valve control rule, effectively solve the ooff valve and can't open when PWM control signal duty cycle is lower, open problem in advance when higher duty cycle to improve the precision of control atmospheric pressure, increase stability, it is comparatively quick to adjust.
Drawings
FIG. 1 is a block diagram of a system according to a first embodiment;
FIG. 2 is a schematic structural diagram of a switching valve train module according to a second embodiment;
fig. 3 is a pressure feedback curve acquired by the PLC control module during actual operation.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
The first embodiment is as follows: a pneumatic pressure control system comprises a pressure sensor 1, a PLC control module 2 preset with a target deviation calculation module, a PID control module 3, a PWM control module 4 preset with a switch valve control rule and a switch valve group module 5, wherein the pressure sensor 1 is used for detecting the air pressure of an air inlet port of an air using device 6 to obtain a current air pressure feedback value and sending the current air pressure feedback value to the target deviation calculation module preset in the PLC control module 2, the target deviation calculation module obtains a corresponding current target deviation value according to an externally input given pressure value and the current air pressure feedback value and inputs the current target deviation value to the PID control module 3, the PID control module 3 obtains a corresponding current control quantity according to the current target deviation value and sends the current control quantity to the PWM control module 4, the switch valve group module 5 comprises a valve group base 51, a main air inlet pipe (not shown) and a main air outlet pipe (not shown) which are arranged in the valve group base 51, the total air inlet pipe is provided with a total air inlet 52 communicated with an air inlet of the external air supply device 7 and an air outlet (not shown) provided with an exhaust switch valve (not shown), the total air outlet pipe is provided with a total air outlet 53 communicated with an air inlet of the air supply device 6, the total air inlet pipe is communicated with the total air outlet pipe through 11 air inlet branch pipes (not shown) which are not communicated with each other, each air inlet branch pipe is provided with an air inlet switch valve 54, the PWM control module 4 respectively outputs corresponding PWM control signals according to the current control quantity and a preset switch valve control rule to independently control the ventilation quantity of each air inlet switch valve 54 and the exhaust switch valve, and the preset switch valve control rule is specifically as follows:
the current control quantity output by the PID control module 3 is recorded as Q%, -Qm%≤Q%≤Qm%，Qm% represents a control amount corresponding to the ventilation amount when 10 intake switching valves 54 are fully opened, and Q is set tom% =100%, and the range of the duty ratio corresponding to the PWM control signal failing to open the intake switching valve 54 and the exhaust switching valve is defined as 0 to (10S)1）%，The range of the duty ratio corresponding to the PWM control signal fully opening the intake switching valve 54 and the exhaust switching valve is defined as (10S)2) Percent to 100 percent of S1Is set as S1=2.0, adding S2Is set as S2= 8.0; at this time, the opening time of the intake switch valve 54 is 10ms, the closing time is 10ms, the operating frequency is 10Hz, and the parameters of the exhaust switch valve and the intake switch valve 54 are the same;
judging Q, if Q is greater than 0, dividing Q by 10 to obtain a quotient N and a remainder R, wherein N is greater than or equal to 0 and less than or equal to 10, R is greater than or equal to 0 and less than or equal to 10, executing a rule one when R is greater than or equal to 2.0 and less than 8.0, executing a rule two when R is less than 2.0, executing a rule three when R is greater than or equal to 8.0 and less than 10.0,
rule one is as follows: setting the duty ratio of the PWM control signal corresponding to the N intake switching valves 54 to 90%, setting the duty ratio of the PWM control signal corresponding to one intake switching valve 54 of the other intake switching valves 54 to (10R)%, and setting the duty ratios of the PWM control signals corresponding to the remaining intake switching valves 54 to 0%;
rule two is as follows: setting the duty ratio of the PWM control signal corresponding to the N intake switching valves 54 to 90%, setting the duty ratio of the PWM control signal corresponding to one intake switching valve 54 of the other intake switching valves 54 to (10A)%, and setting the duty ratio of the PWM control signal corresponding to the exhaust switching valve to (10B)%, where a is a preset constant value, 5 < a <8, a-B = R, and setting the duty ratios of the PWM control signals corresponding to the remaining intake switching valves 54 to 0%; such as R =1.2, a =6.0, B = 4.8;
rule three is as follows: setting the duty ratios of the PWM control signals corresponding to the N intake switching valves 54 to 90%, and setting the duty ratios of the PWM control signals corresponding to two intake switching valves 54 among the other intake switching valves 54 to (10C)%, respectively, where C = R/2, and setting the duty ratios of the PWM control signals corresponding to the remaining intake switching valves 54 to 0%; such as R =9.2, C = 4.6;
if Q =0, rule four is implemented as follows: the PWM control signal output by the PWM control module 4 is kept unchanged;
if Q is more than or equal to-2.0 and less than 0, the execution rule five is as follows: setting the duty ratio of the PWM control signal corresponding to one of the intake switching valves 54 to (10D)%, and setting the duty ratio of the PWM control signal corresponding to the exhaust switching valve to (10E)%, where E is a preset constant value, E is greater than 5 and less than 8, and D-E = Q; such as Q = -1.3, D =4.8, E = 6.1;
if-10.0 < Q < -2.0, the execution rule six is as follows: setting the duty ratio of a PWM control signal corresponding to the exhaust switch valve to be (-10Q)%;
if Q is less than or equal to-10.0, the execution rule seven is as follows: the duty ratio of the PWM control signal corresponding to the exhaust switching valve is set to 90%. The duty ratio of the PWM control signal is set to 90%, and may be set to any value greater than 80%.
Example two: the rest of the components are the same as those in the first embodiment, and the difference is that two standby air inlet pipes (not shown) are arranged between the main air inlet pipe and the main air outlet pipe, a standby switch valve 55 for controlling the on-off state of the standby air inlet pipes is arranged in each standby air inlet pipe, the PWM control module 4 switches and sends a PWM control signal originally sent to one failed air inlet switch valve 54 to one standby switch valve 55 when one air inlet switch valve 54 fails according to a preset switch valve control rule, and the air inlet switch valves 54 and the standby switch valves 55 are staggered and arranged into left and right rows on the valve group base 51.
As shown in fig. 3, I is the PID control phase, II is the waveform of the pressure stabilization phase, and III is the system response given a negative step pressure after the pressure output is stabilized, it can be seen that the system response is fast, there is no obvious overshoot, and the control stability is good.
Claims (4)
1. A pneumatic pressure control system comprises a pressure sensor, a PLC control module, a PID control module, a PWM control module and a switch valve group module, wherein the PLC control module is preset with a target deviation calculation module, the PWM control module is preset with a switch valve control rule, the pressure sensor is used for detecting the air pressure of an air inlet port of air equipment to obtain a current air pressure feedback value and sending the current air pressure feedback value to the preset target deviation calculation module in the PLC control module, the target deviation calculation module obtains a corresponding current target deviation value according to an externally input given pressure value and the current air pressure feedback value and inputs the current target deviation value into the PID control module, the PID control module obtains a corresponding current control quantity according to the current target deviation value and sends the current control quantity to the PWM control module, and the switch valve group module is characterized by comprising a valve group base, a total air inlet pipe and a total air outlet pipe which are arranged in the valve group base, the total intake pipe be provided with a total air inlet and an gas vent that is provided with the air discharge switch valve with the air supply mouth intercommunication of outside air feeder, total outlet duct be provided with a total gas outlet with the inlet port intercommunication of air feeder, total intake pipe with total outlet duct between through seven at least air inlet branch pipe intercommunications that do not communicate each other, every air inlet branch pipe be provided with an air inlet switch valve, PWM control module according to current controlled quantity and predetermined switching valve control rule respectively output corresponding PWM control signal individual control every air inlet switch valve and air discharge switch valve's air output size.
2. A pneumatic pressure control system as claimed in claim 1 wherein the inlet manifold is 11.
3. The pneumatic pressure control system according to claim 1, wherein at least one standby air inlet pipe is arranged between the main air inlet pipe and the main air outlet pipe, a standby switch valve for controlling the on-off state of the standby air inlet pipe is arranged in the standby air inlet pipe, and the PWM control module switches and sends a PWM control signal, which is originally sent to one of the failed air inlet switch valves, to one of the standby switch valves when one of the air inlet switch valves fails according to a preset switch valve control rule.
4. A pneumatic pressure control system as claimed in claim 3 wherein said inlet switch valve and said backup switch valve are staggered in two left and right rows on said valve block base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022080006.8U CN214011810U (en) | 2020-09-21 | 2020-09-21 | Pneumatic pressure control system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022080006.8U CN214011810U (en) | 2020-09-21 | 2020-09-21 | Pneumatic pressure control system |
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| CN214011810U true CN214011810U (en) | 2021-08-20 |
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| CN202022080006.8U Active CN214011810U (en) | 2020-09-21 | 2020-09-21 | Pneumatic pressure control system |
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