Constant temperature device and system based on PID control strategy and control method

Abstract

The constant temperature device based on the PID control strategy comprises a temperature measuring unit, a heating unit, a draught fan and a control unit, the draught fan communicates with the heating unit, and the draught fan is used for extracting air of a preset object and guiding the extracted air into the heating unit to form airflow with the preset temperature; the control unit adopts a PID control strategy to continuously adjust the working states of the fan and the heating unit so as to keep the preset area of the preset object constant to a preset temperature interval, and the temperature measuring unit, the heating unit and the fan are all connected with the control unit. According to the constant temperature device based on the PID control strategy, the PID control strategy is introduced into the control unit to continuously adjust the working states of the draught fan and the heating unit, so that the preset area of the preset object is kept at the constant temperature within the preset temperature interval. The invention further comprises a constant temperature system and a control method of the constant temperature device based on the PID control strategy.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermostatic devices, and in particular relates to a thermostatic device, a system and a control method based on a PID control strategy. Background Art

[0002] The constant temperature device is a device widely used in industrial production, experimental research and other fields. Its main function is to maintain the controlled object within the set temperature range to ensure the stability of the production process and the accuracy of the experimental results. The accuracy of temperature control is crucial to many scientific experiments and industrial processes. Any slight temperature fluctuation may lead to deviation in the results or a decline in product quality.

[0003] At present, laboratories and industrial production fields usually use air thermostats to achieve constant temperature within a certain area. Air thermostats use electric heating elements, fans and temperature control systems to work together to effectively control the temperature of the target area through continuous air circulation and heating. Such equipment is usually simple in design and easy to operate, and is suitable for a variety of application scenarios, such as cell culture, material testing, chemical reactions and manufacturing.

[0004] Although air thermostats play an important role in many applications, existing thermostat strategies still have some significant defects. For example, temperature fluctuations often occur in actual operations. When the ambient temperature of the area changes, the air thermostats often do not set a buffer process in order to improve the response speed when heating the target area to the set temperature. This strategy may cause the temperature to fluctuate briefly when reaching the target value, thereby affecting the stability and reliability of the experiment or production. In addition, traditional thermostat strategies may also show slow response or inaccurate control when facing complex external environmental changes, further affecting the overall performance of the system.

[0005] Therefore, there is an urgent need for a thermostat that can monitor the deviation between the temperature and the set value in real time and accurately adjust the control signal. Summary of the invention

[0006] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a constant temperature system based on PID control strategy, which can effectively reduce temperature fluctuations and maintain the stability of the system by dynamically adjusting the control signal, while being able to quickly respond to environmental changes, provide precise temperature control, and ensure efficient experimental and production processes.

[0007] Technical solution: In order to achieve the above object, the present invention provides a constant temperature device based on PID control strategy, comprising:

[0008] A temperature measuring unit, used to measure temperature data of a preset area of ​​a preset object;

[0009] A heating unit, used for providing a heating function;

[0010] A fan, the fan is connected to the heating unit, and the fan is used to extract air of a preset object and introduce the extracted air into the heating unit to form an airflow of a preset temperature;

[0011] A control unit, wherein the control unit adopts a PID control strategy to continuously adjust the working states of the fan and the heating unit so as to keep a preset area of ​​the preset object at a constant temperature within a preset temperature range, and the temperature measuring unit, the heating unit and the fan are all connected to the control unit. A thermostatic device based on a PID control strategy described in the present invention continuously adjusts the working states of the fan and the heating unit by introducing a PID control strategy into the control unit so as to keep a preset area of ​​the preset object at a constant temperature within a preset temperature range.

[0012] Among them, the temperature measurement unit includes at least one thermocouple sensor, which is used to convert the measured temperature signal into an electrical signal and transmit it to the control unit to realize the collection of temperature data of a preset area, and at least one thermocouple sensor is installed in a preset area of ​​a preset object.

[0013] Further, the temperature measuring unit includes a plurality of thermocouple sensors, the thermocouple sensors are installed in a preset area of ​​a preset object, and the thermocouple sensors are arranged in an array along the preset area;

[0014] Several thermocouple sensors arranged in an array are used to integrate the measured temperature signals to form a temperature distribution signal, which is then converted into an electrical signal and transmitted to a control unit to realize the collection of temperature distribution data of a preset area.

[0015] Preferably, the control unit comprises a temperature comparison module, a PID controller, a fuzzy controller mode switching module and a controller, and the temperature comparison module, the PID controller and the fuzzy controller mode switching module are all connected to the controller;

[0016] The temperature comparison module is used to compare the temperature of a preset area of ​​a preset object with the target setting temperature.

[0017] Furthermore, the PID controller includes a first adjustment module, a second adjustment module, a third adjustment module and a fourth adjustment module, and the PID controller executes at least one of a first adjustment mode, a second adjustment mode, a third adjustment mode and a fourth adjustment mode according to the temperature deviation generated by the temperature comparison module;

[0018] The first adjustment module is used to execute the first working mode. If the temperature of the preset area is lower than the target set temperature, the first adjustment module controls the KA1 circuit breaker to close, and the heating unit enters the heating state. At the same time, the first adjustment module controls the KA2 circuit breaker to close, and the fan enters the air supply state. The fan introduces the extracted air into the heating unit in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object. The fan introduces the extracted air into the heating unit in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object.

[0019] The second adjustment module is used to execute the second working mode. If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the second adjustment module controls the KA1 circuit breaker to close, and the heating unit is started and stopped according to the first preset interval time, and the working state of the heating unit is adjusted to slowly adjust the preset area temperature of the preset object to within the preset temperature range;

[0020] The third adjustment module is used to execute the third working mode. If the temperature of the preset area reaches the target set temperature, the third adjustment module controls the heating unit to start and stop at a second preset interval time, and adjusts the working state of the heating unit to keep the temperature of the preset area of ​​the preset object constant within a preset temperature range;

[0021] The fourth adjustment module is used to execute the fourth working mode, and the fourth working mode is: if the temperature of the preset area is higher than the target setting temperature, the first adjustment module controls the KA1 circuit breaker to disconnect and controls the heating unit to suspend operation. At the same time, the first adjustment module controls the KA2 circuit breaker to close, and the fan enters the air supply state. The extracted air is introduced into the preset area of ​​the preset object in real time through the fan until the preset area reaches the target setting temperature.

[0022] The thermostatic device based on the PID control strategy of the present invention, the fuzzy controller includes a fuzzy adjustment module and a mode switching module, the mode switching module performs working mode switching according to the temperature deviation generated by the temperature comparison module;

[0023] The fuzzy adjustment module is used to execute a fuzzy working mode, which is: using a fuzzy control strategy to continuously adjust the working states of the fan and the heating unit, that is, if the error between the preset area temperature and the target setting temperature exceeds a second preset temperature value, the fuzzy adjustment module controls the heating unit and the fan to enter a preset power mode, and quickly adjusts the working states of the heating unit and the fan to quickly adjust the preset area temperature of the preset object to a preset temperature range;

[0024] If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the control strategy is switched from the fuzzy adjustment module to the working mode of the second adjustment module through the mode switching module. The present invention introduces a fuzzy control mode, which can respond quickly when the temperature deviation is large and quickly adjust the temperature to the target range; the fuzzy control mode is based on fuzzy logic reasoning of temperature error and change rate, dynamically adjusts the working state of the heating unit and the fan, improves the response speed and control accuracy of the system, and ensures the stable operation of the thermostat in various complex environments.

[0025] The constant temperature system of the constant temperature device based on the PID control strategy described in the present invention is characterized in that it also includes a shell, a mounting plate is provided in the shell, the mounting plate is hollowed out, a constant temperature cavity is provided on the mounting plate, a power supply is provided on one side of the constant temperature cavity, a group of circuit breakers are provided on one side of the power supply, and a handle is provided on the outside of the shell, the circuit breakers include KA1 circuit breaker and KA2 circuit breaker, the KA1 circuit breaker and KA2 circuit breaker are both installed on the mounting plate, and are both connected to the heating unit, the fan, the control unit and the power supply, and the heating unit and the fan are integrated in the constant temperature cavity.

[0026] The present invention discloses a thermostatic control method for a thermostatic system of a thermostatic device based on a PID control strategy, and the thermostatic control method comprises the following steps:

[0027] According to the preset area temperature data of the preset object measured by the temperature measuring unit, the preset area temperature is compared with the target set temperature in real time, and then the PID control mode is executed according to the comparison result. The specific control process is as follows:

[0028] If the temperature of the preset area is lower than the target set temperature, the heating unit is controlled to enter the heating state, and the extracted air is introduced into the heating unit in real time through the fan to form hot air;

[0029] If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the heating unit is controlled to start and stop at the first preset interval time, and the working state of the heating unit is adjusted to slowly adjust the preset area temperature of the preset object to within the preset temperature range;

[0030] If the temperature of the preset area reaches the target set temperature, the heating unit is controlled to start and stop at a second preset interval, and the working state of the heating unit is adjusted to keep the temperature of the preset area of ​​the preset object constant within the preset temperature range;

[0031] If the temperature of the preset area is higher than the target set temperature, the heating unit is controlled to stop working, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan.

[0032] The thermostatic control method of the thermostatic system of the thermostatic device based on the PID control strategy of the present invention, during the working process, if the error between the preset area temperature and the target set temperature exceeds the second preset temperature value, the fuzzy control mode is executed, and the fuzzy control mode includes: controlling the heating unit and the fan to enter the preset power mode, and quickly adjusting the working state of the heating unit and the fan to quickly adjust the preset area temperature of the preset object to the preset temperature range;

[0033] When the error between the preset area temperature and the target setting temperature is less than or equal to the first preset temperature value, the fuzzy control mode is switched to the PID control mode.

[0034] The thermostatic control method of the thermostatic system of the thermostatic device based on the PID control strategy of the present invention monitors the temperature of the preset area in real time through the thermocouple sensor during operation, and transmits the temperature data to the control unit. The control unit adjusts the working state of the heating unit and the fan through the PID control strategy according to the set target setting temperature and the current temperature to achieve constant temperature control.

[0035] During the PID control process, the error between the set temperature and the actual temperature is monitored in real time, and the output is adjusted according to the three parameters of proportion (P), integration (I), and differentiation (D) to achieve precise control of the temperature.

[0036] The PID control formula is as follows:

[0037]

[0038] In the equation, u(t) is the control output, e(t) is the temperature difference between the set temperature and the actual temperature, K p is the proportional gain, K i is the integral gain, K d is the differential gain.

[0039] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0040] 1. The air thermostat based on PID control strategy described in the present invention can monitor and adjust the temperature of the preset area in real time to ensure that the temperature is always maintained within the set range; through the precise adjustment of the PID controller, the temperature fluctuation can be effectively reduced, the stability and response speed of the system can be improved, and the needs of various experimental and production environments can be met.

[0041] 2. The air thermostat system based on PID control strategy described in the present invention can respond quickly when the temperature deviation is large and quickly adjust the temperature to the target range by introducing fuzzy control mode into the traditional PID control strategy; the fuzzy control mode is based on fuzzy logic reasoning of temperature error and change rate, dynamically adjusts the working state of the heating unit and the fan, improves the response speed and control accuracy of the system, and ensures the stable operation of the thermostat in various complex environments.

[0042] 3. When the fuzzy controller is executing the working mode, after the temperature comparison module recognizes that the error between the temperature of the preset area and the target set temperature is less than or equal to the first preset temperature value, the mode switching module switches the control mode from the fuzzy control mode to the PID control mode, and then the second adjustment module of the PID controller issues an instruction to control the heating unit to start and stop according to the first preset interval time and adjust the working state of the heating unit. In this way, the temperature of the preset area is gradually adjusted to the target set temperature to avoid temperature overshoot or oscillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the constant temperature system of the constant temperature device based on the PID control strategy described in the present invention;

[0044] Figure 2 A structural schematic diagram of another perspective of the constant temperature system of the constant temperature device based on the PID control strategy of the present invention;

[0045] Figure 3 It is a circuit connection diagram of the constant temperature system of the constant temperature device based on the PID control strategy in the present invention;

[0046] Figure 4 This is a schematic diagram of electrical connections of a thermostat based on a PID control strategy in the present invention;

[0047] Figure 5 It is a structural schematic diagram of the control unit in the present invention;

[0048] Figure 6 This is a schematic diagram of the connection of various modules of the control unit in the present invention;

[0049] Figure 7 It is a flow chart of a constant temperature control method of a constant temperature system PID control mode of a constant temperature device based on a PID control strategy in the present invention;

[0050] Figure 8 It is a flow chart of a constant temperature control method of a constant temperature system of a constant temperature device based on a PID control strategy in the present invention in a fuzzy control mode;

[0051] In the figure: a temperature measuring unit 11, a heating unit 12, a fan 13, a control unit 14, a temperature comparison module 141, a PID controller 142, a fuzzy controller 143, a housing 15, a mounting plate 151, a constant temperature cavity 152, a power supply 153, a KA1 circuit breaker 1541, a KA2 circuit breaker 1542, and a handle 155. DETAILED DESCRIPTION

[0052] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0053] Example

[0054] like Figures 1 to 6 A constant temperature device based on a PID control strategy is shown, comprising:

[0055] A temperature measuring unit 11 is used to measure temperature data of a preset area of ​​a preset object;

[0056] A heating unit 12, used to provide a heating function;

[0057] The fan 13 is connected to the heating unit 12, and the fan 13 is used to extract air from the preset object and introduce the extracted air into the heating unit 12 to form an airflow of a preset temperature; that is, the function of the fan 22 is to ensure the air flow in the preset object and promote uniform heat distribution;

[0058] The control unit 14 adopts a PID control strategy to continuously adjust the working states of the fan 13 and the heating unit 12 to keep a preset area of ​​a preset object at a constant temperature within a preset temperature range, and the temperature measuring unit 11, the heating unit 12 and the fan 13 are all connected to the control unit 14.

[0059] It should be noted that the heating unit 12 converts electrical energy into thermal energy to provide the required heat for the preset object, ensuring that the temperature can be quickly raised to the set temperature value; and the heating unit 12 can be any form of heating device as long as it can provide a heating function, including but not limited to electric heating wires or PTC (heating element and aluminum tube) heaters. In this application, reference is made to the electric heating wire heater, and the operator selects the appropriate heating unit 12 model and heating power according to the heating requirements of the preset object.

[0060] It should be noted that the control unit 14 uses an Omron temperature controller, and the model and quantity of the Omron temperature controller are set by the operator according to actual needs and costs.

[0061] The temperature measuring unit 11 includes at least one thermocouple sensor, which is used to convert the measured temperature signal into an electrical signal and transmit it to the control unit to collect temperature data of a preset area, and at least one thermocouple sensor is installed in a preset area of ​​a preset object.

[0062] The temperature measuring unit 11 includes a plurality of thermocouple sensors, which are installed in a preset area of ​​a preset object, and the thermocouple sensors are arranged in an array along the preset area;

[0063] Several thermocouple sensors arranged in an array are used to integrate the measured temperature signals to form a temperature distribution signal, and then convert the temperature distribution signal into an electrical signal and transmit it to the control unit to realize the collection of temperature distribution data of the preset area. During work, the operator arranges thermocouple sensors at key positions in the preset area according to the heat distribution characteristics of the preset object to ensure that the overall temperature situation can be reflected; after several thermocouple sensors collect temperature data, the control unit 14 uses existing filtering and denoising technology to process the collected temperature data to improve data quality; then, according to the location and importance of the thermocouple sensors, the data of each thermocouple sensor is weighted averaged to obtain a more accurate temperature distribution.

[0064] like Figure 6 The control unit 14 shown includes a temperature comparison module 141, a PID controller 142, a fuzzy controller 143 and a controller, and the temperature comparison module 141, the PID controller 142, and the fuzzy controller 143 are all connected to the controller;

[0065] The temperature comparison module 141 is used to compare the temperature of a preset area of ​​a preset object with the target setting temperature.

[0066] Example 2

[0067] The thermostatic system of the thermostatic device based on the PID control strategy in this embodiment. The structure of the thermostatic device based on the PID control strategy in the thermostatic system of the thermostatic device based on the PID control strategy is the same as that in the first embodiment.

[0068] The constant temperature system of the constant temperature device based on the PID control strategy also includes a shell 15, a mounting plate 151 is provided in the shell 15, the mounting plate 151 is hollowed out, a constant temperature cavity 152 is provided on the mounting plate 151, a power supply 153 is provided on one side of the constant temperature cavity 152, a group of circuit breakers 154 are provided on one side of the power supply 153, and a handle 155 is provided on the outer side of the shell 15, the circuit breaker 154 includes a KA1 circuit breaker 1541 and a KA2 circuit breaker 1542, the KA1 circuit breaker 1541 and the KA2 circuit breaker 1542 are both installed on the mounting plate 151, and are both connected to the heating unit 12, the fan 13, the control unit 14 and the power supply 153, and the heating unit 12 and the fan 13 are integrated in the constant temperature cavity 152.

[0069] like Figure 6The PID controller 142 shown includes a first adjustment module 1421, a second adjustment module 1422, a third adjustment module 1423 and a fourth adjustment module 1424, and the PID controller 142 executes at least one of the first adjustment mode 1421, the second adjustment mode 1422, the third adjustment mode 1423 and the fourth adjustment mode 1424 according to the temperature deviation generated by the temperature comparison module 141;

[0070] The first adjustment module 1421 is used to execute the first working mode. If the temperature of the preset area is lower than the target set temperature, the first adjustment module controls the KA1 circuit breaker 1541 to close, and the heating unit 12 enters the heating state. At the same time, the first adjustment module 1421 controls the KA2 circuit breaker 1542 to close, and the fan 13 enters the air supply state. The fan 13 introduces the extracted air into the heating unit 12 in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object. The fan 13 introduces the extracted air into the heating unit in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object.

[0071] The second adjustment module 1422 is used to execute the second working mode. If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the second adjustment module 1422 controls the KA1 circuit breaker 1541 to close. At this time, the heating unit 12 starts and stops according to the first preset interval time, and adjusts the working state of the heating unit 12 to slowly adjust the preset area temperature of the preset object to within the preset temperature range;

[0072] The third adjustment module 1422 is used to execute the third working mode. If the temperature of the preset area reaches the target set temperature, the third adjustment module controls the heating unit 12 to start and stop at a second preset interval time, and adjusts the working state of the heating unit 12 to keep the temperature of the preset area of ​​the preset object constant within the preset temperature range;

[0073] The fourth adjustment module 1424 is used to execute the fourth working mode, and the fourth working mode is: if the temperature of the preset area is higher than the target setting temperature, the first adjustment module 1421 controls the KA1 circuit breaker 1541 to be disconnected, and controls the heating unit 12 to stop working. At the same time, the first adjustment module 1421 controls the KA2 circuit breaker 1542 to be closed, and the fan 13 enters the air supply state, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan 13 until the preset area reaches the target setting temperature.

[0074] For example, the first working mode (i.e., heating mode) is executed, that is, if the temperature of the preset area is lower than the target set temperature, the first adjustment mode 1421 issues a command to control the heating unit 12 to enter the heating state, and at the same time starts the fan 13 to extract the air in the preset area through the pipeline and introduce it into the heating unit 12. In the heating unit 12, the heating element (such as a heating wire or a heating plate) heats the air into hot air, and the hot air is transported back to the preset area through the pipeline, so that the temperature of the preset area is adjusted to the target set temperature.

[0075] like Figure 6 The fuzzy controller 143 shown includes a fuzzy adjustment module 1431 and a mode switching module 1432, wherein the mode switching module 1432 performs a working mode switch according to the temperature deviation generated by the temperature comparison module 141;

[0076] The fuzzy adjustment module 1431 is used to execute a fuzzy working mode, which uses a fuzzy control strategy to continuously adjust the working states of the fan 13 and the heating unit 12, that is, if the error between the preset area temperature and the target set temperature exceeds the second preset temperature value, the fuzzy adjustment module 1431 controls the heating unit 12 and the fan 13 to enter a preset power mode, and quickly adjusts the working states of the heating unit 12 and the fan 13 to quickly adjust the preset area temperature of the preset object to the preset temperature range;

[0077] If the error between the preset area temperature and the target setting temperature is less than or equal to the first preset temperature value, the control strategy is switched from the fuzzy adjustment module 1431 to the working mode of the second adjustment module 1422 through the mode switching module 1432 .

[0078] The constant temperature control method of a constant temperature system of a constant temperature device based on a PID control strategy described in this embodiment comprises the following steps:

[0079] According to the preset area temperature data of the preset object measured by the temperature measuring unit 11, the preset area temperature is compared with the target setting temperature in real time, and then the PID control mode is executed according to the comparison result. The specific control process is as follows:

[0080] If the temperature of the preset area is lower than the target set temperature, the heating unit 12 is controlled to enter the heating state, and the extracted air is introduced into the heating unit in real time through the fan 13 to form hot air;

[0081] If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the heating unit 12 is controlled to start and stop at the first preset interval time, and the working state of the heating unit is adjusted to slowly adjust the preset area temperature of the preset object to within the preset temperature range;

[0082] If the temperature of the preset area reaches the target set temperature, the heating unit 12 is controlled to start and stop at a second preset interval, and the working state of the heating unit is adjusted to keep the temperature of the preset area of ​​the preset object constant within the preset temperature range;

[0083] If the temperature of the preset area is higher than the target set temperature, the heating unit 12 is controlled to stop working, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan 13.

[0084] The thermostatic control method of the thermostatic system of the thermostatic device based on the PID control strategy described in this embodiment, when working, compares the preset area temperature with the target set temperature in real time according to the measured preset area temperature data of the preset object, and if the error between the preset area temperature and the target set temperature exceeds the second preset temperature value, the fuzzy control mode is executed, and the fuzzy control mode includes: controlling the heating unit 12 and the fan 13 to enter the preset power mode, and quickly adjusting the working state of the heating unit 12 and the fan 13 to quickly adjust the preset area temperature of the preset object to the preset temperature range;

[0085] When the error between the preset area temperature and the target setting temperature is less than or equal to the first preset temperature value, the fuzzy control mode is switched to the PID control mode.

[0086] The thermostatic control method of the thermostatic system of the thermostatic device based on the PID control strategy described in this embodiment monitors the temperature of the preset area in real time through the thermocouple sensor during operation, and transmits the temperature data to the control unit 14. The control unit 14 adjusts the working state of the heating unit 12 and the fan 13 through the PID control strategy according to the set target setting temperature and the current temperature to achieve constant temperature control;

[0087] During the PID control process, the error between the set temperature and the actual temperature is monitored in real time, and the output is adjusted according to the three parameters of proportion (P), integration (I), and differentiation (D) to achieve precise control of the temperature.

[0088] The PID control formula is as follows:

[0089]

[0090] In the equation, u(t) is the control output, e(t) is the temperature difference between the set temperature and the actual temperature, K p is the proportional gain, K i is the integral gain, K d is the differential gain.

[0091] Specifically, K p e(t) is the proportional (P) control part, which adjusts the output according to the size of the error; The integral (I) control part accumulates the error and eliminates the steady-state error. is the differential (D) control part; in order to achieve the best control effect, the PID parameter K p , K i and K d Adjustment is performed, including but not limited to manual adjustment or automatic adjustment algorithm (such as particle swarm optimization method to automatically optimize PID parameters) adjustment, which is specifically set by the operator according to actual needs; among them, if the error is large, P control plays a major role, and the heating unit 12 heats quickly. If the error gradually decreases, I control is gradually adjusted to eliminate the cumulative error; if the temperature changes dramatically, D control is adjusted in advance to reduce fluctuations.

[0092] Example 3

[0093] The thermostatic system of a thermostatic device based on PID control strategy described in this embodiment has the same structure as that in Embodiment 2.

[0094] The second preset temperature value and preset power are set and adjusted by the operator according to actual needs and costs; illustratively, the second preset temperature value is referenced to 5°C, that is, the error between the preset area temperature and the target set temperature is greater than or equal to 5°C.

[0095] Specifically, the fuzzy variables are defined as:

[0096] Input variables: temperature error (difference between target set temperature and actual temperature) and temperature error change rate;

[0097] Output variable: control output (such as heating unit 12 power, fan 13 speed).

[0098] Then, construct a fuzzy rule base: According to the actual control experience and characteristics, a fuzzy rule base is established, such as "if the temperature error is large and the temperature error change rate is large, the control output is large".

[0099] Then, a fuzzy reasoning mechanism is set up: using the fuzzy reasoning algorithm (such as Mamdani reasoning), the fuzzy set of the control output is calculated according to the input variables and the fuzzy rule base; and the actual control output value is obtained by defuzzifying the fuzzy set (such as the centroid method).

[0100] Finally, the fuzzy control strategy is combined with the PID control strategy to set the control switching conditions: set the temperature error threshold, when the temperature error is greater than the second preset temperature value, enable the fuzzy control strategy; when the temperature error is less than the first preset temperature value, enable the PID control strategy.

[0101] like Figure 7As shown, a constant temperature control method for a constant temperature system based on a PID control strategy is involved, and the constant temperature control method comprises the following steps:

[0102] According to the measured temperature data of the preset area of ​​the preset object, the preset area temperature is compared with the target set temperature in real time, and then the PID control mode is executed according to the comparison result:

[0103] The specific working process of the PID control mode is as follows:

[0104] S100: If the temperature of the preset area is lower than the target set temperature, the heating unit 12 is controlled to enter a heating state, and the extracted air is introduced into the heating unit 12 in real time through the fan 13 to form hot air;

[0105] That is, the temperature measuring unit 11 measures the real-time temperature data of the preset area of ​​the preset object, and then transmits the real-time temperature data to the temperature comparison module 141, so as to compare the temperature of the preset area with the target setting temperature in real time, and then determine the temperature deviation according to the comparison result and transmit it to the PID controller 142, and the PID controller 142 executes at least one step in the PID working mode, for example, executes the first working mode (i.e., the heating mode), that is, if the temperature of the preset area is lower than the target setting temperature, the first adjustment module 1421 issues an instruction to control the heating unit 12 to enter the heating state, and at the same time starts the fan 13, and the air in the preset area is extracted through the pipeline and introduced into the heating unit 12, and the heating element (such as a heating wire or a heating plate) in the heating unit 12 heats the air into hot air, and the hot air is transported back to the preset area through the pipeline, so that the temperature of the preset area is adjusted to the target setting temperature;

[0106] S101: If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, control the heating unit 12 to start and stop at the first preset interval time, and adjust the working state of the heating unit 12 to slowly adjust the preset area temperature of the preset object to within the preset temperature range;

[0107] Among them, when the PID controller 142 is executing the working mode, the temperature comparison module 141 recognizes that the error between the temperature of the preset area and the target setting temperature is less than or equal to the first preset temperature value, and then enters the second working mode (i.e., fine adjustment mode), and the second adjustment module 1422 issues an instruction to control the heating unit 12 to start and stop according to the first preset interval time, and adjust the working state of the heating unit 12. In this way, the temperature of the preset area is gradually and slowly adjusted to the target setting temperature to avoid temperature overshoot or oscillation;

[0108] S102: If the temperature of the preset area reaches the target set temperature, the heating unit 12 is controlled to start and stop at a second preset interval, and the working state of the heating unit 12 is adjusted to keep the temperature of the preset area of ​​the preset object constant within a preset temperature range;

[0109] When the PID controller 142 is in the working mode, the temperature comparison module 141 recognizes that the temperature of the preset area reaches the target set temperature, and then enters the third working mode (i.e., constant temperature mode), and the third adjustment module 1423 issues instructions to control the heating unit 12 to start and stop at the second preset interval time, adjust the working state of the heating unit 12, and keep the temperature of the preset area constant within the target set temperature range through regular fine-tuning;

[0110] S103: If the temperature of the preset area is higher than the target set temperature, the heating unit 12 is controlled to stop working, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan 13;

[0111] Among them, when the PID controller 142 is executing the working mode, the temperature comparison module 141 recognizes that the temperature of the preset area is higher than the target set temperature, and then enters the fourth working mode (i.e., the cooling mode). The fourth adjustment module 1424 issues an instruction to control the heating unit 12 to suspend work, but continues to run the fan 13 to extract the air in the preset area and introduce it into the preset area. Through the air circulation of the fan 13, the temperature of the preset area is gradually reduced to the target temperature.

[0112] By adopting the above steps, the air thermostat 2 based on the PID control strategy can monitor and adjust the temperature of the preset area in real time to ensure that the temperature is always maintained within the set range; through the precise adjustment of the PID controller 142, the temperature fluctuation can be effectively reduced, the stability and response speed of the system can be improved, and it can adapt to the needs of various experimental and production environments.

[0113] like Figure 8 As shown in the figure, when the fuzzy control mode is executed in a constant temperature system based on the PID control strategy, the specific working process is as follows:

[0114] S201: According to the measured temperature data of the preset area of ​​the preset object, the preset area temperature is compared with the target setting temperature in real time. If the error between the preset area temperature and the target setting temperature exceeds the second preset temperature value, the fuzzy control mode is executed, and the fuzzy control mode is to control the heating unit 12 and the fan 13 to enter the preset power mode, and quickly adjust the working state of the heating unit 12 and the fan 13 to quickly adjust the preset area temperature of the preset object to the preset temperature range;

[0115] Specifically, the temperature measuring unit 11 measures the real-time temperature data of the preset area of ​​the preset object, and then transmits the real-time temperature data to the temperature comparison module 141, so as to compare the temperature of the preset area with the target set temperature in real time, and then determine the temperature deviation according to the comparison result. When the temperature deviation exceeds the second preset temperature value, it is transmitted to the fuzzy controller 232, and the fuzzy controller 232 executes the fuzzy control step. The fuzzy adjustment module 232-1 controls the heating unit 12 and the fan 13 to enter the preset power mode, and quickly adjusts the working state of the heating unit 12 and the fan 13 to quickly adjust the temperature of the preset area to the preset temperature range.

[0116] S202: When the error between the preset area temperature and the target setting temperature is less than or equal to a first preset temperature value, switching from the fuzzy control mode to the PID control mode.

[0117] Among them, when the fuzzy controller 232 is executing the working mode, after the temperature comparison module 141 recognizes that the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the mode switching module 232-2 switches the control mode from the fuzzy control mode to the PID control mode, and then the second adjustment module 1422 of the PID controller 142 issues an instruction to control the heating unit 12 to start and stop according to the first preset interval time, and adjust the working state of the heating unit 12. In this way, the temperature of the preset area is gradually adjusted to the target set temperature to avoid temperature overshoot or oscillation.

[0118] By adopting the above steps and introducing the fuzzy control mode into the traditional PID control strategy, it is possible to respond quickly when the temperature deviation is large and quickly adjust the temperature to the target range; the fuzzy control mode is based on fuzzy logic reasoning of temperature error and change rate, dynamically adjusts the working state of the heating unit 12 and the fan 13, improves the response speed and control accuracy of the system, and ensures that the constant temperature device 2 operates stably in various complex environments.

[0119] The present application also relates to a computer medium, on which a computer program is stored, and the computer program is executed by a processor to implement the above-mentioned constant temperature method based on the PID control strategy.

[0120] The present application also relates to a computer, comprising the computer medium.

[0121] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A constant temperature device based on PID control strategy, characterized in that: include: A temperature measuring unit (11), used for measuring temperature data of a preset area of ​​a preset object; A heating unit (12), used for providing a heating function; A fan (13), the fan (13) being connected to the heating unit (12), the fan (13) being used to extract air of a preset object and introduce the extracted air into the heating unit (12) to form an airflow of a preset temperature; A control unit (14), wherein the control unit (14) uses a PID control strategy to continuously adjust the working states of the fan (13) and the heating unit (12) so as to keep a preset area of ​​a preset object at a constant temperature within a preset temperature range, and the temperature measuring unit (11), the heating unit (12) and the fan (13) are all connected to the control unit (14).

2. The constant temperature device based on PID control strategy according to claim 1, characterized in that: The temperature measuring unit (11) comprises at least one thermocouple sensor, which is used to convert a measured temperature signal into an electrical signal and transmit it to a control unit to collect temperature data of a preset area, and at least one thermocouple sensor is installed in a preset area of ​​a preset object.

3. The constant temperature device based on PID control strategy according to claim 1, characterized in that: The temperature measuring unit (11) comprises a plurality of thermocouple sensors, the thermocouple sensors are installed in a preset area of ​​a preset object, and the thermocouple sensors are arranged in an array along the preset area; Several thermocouple sensors arranged in an array are used to integrate the measured temperature signals to form a temperature distribution signal, which is then converted into an electrical signal and transmitted to a control unit to realize the collection of temperature distribution data of a preset area.

4. The constant temperature device based on PID control strategy according to claim 1, characterized in that: The control unit (14) comprises a temperature comparison module (141), a PID controller (142), a fuzzy controller (143) and a controller, wherein the temperature comparison module (141), the PID controller (142) and the fuzzy controller (143) are all connected to the controller; The temperature comparison module (141) is used to compare the temperature of a preset area of ​​a preset object with the target setting temperature.

5. The constant temperature device based on PID control strategy according to claim 1, characterized in that: The PID controller (142) comprises a first adjustment module (1421), a second adjustment module (1422), a third adjustment module (1423) and a fourth adjustment module (1424); the PID controller (142) executes at least one of a first adjustment mode (1421), a second adjustment mode (1422), a third adjustment mode (1423) and a fourth adjustment mode (1424) according to the temperature deviation generated by the temperature comparison module (141); The first adjustment module (1421) is used to execute a first working mode. If the temperature of the preset area is lower than the target set temperature, the first adjustment module (1421) controls the KA1 circuit breaker (1541) in the circuit breaker (154) to close, and the heating unit (12) enters a heating state. At the same time, the first adjustment module (1421) controls the KA2 circuit breaker (1542) in the circuit breaker (154) to close, and the fan (13) enters an air supply state. The fan (13) introduces the extracted air into the heating unit (12) in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object. The fan (13) introduces the extracted air into the heating unit in real time to form hot air, thereby providing a constant temperature for the preset area of ​​the preset object. The second adjustment module (1422) is used to execute a second working mode. If the error between the preset area temperature and the target set temperature is less than or equal to the first preset temperature value, the second adjustment module (1422) controls the KA1 circuit breaker (15141) in the circuit breaker (154) to close. At this time, the heating unit (12) starts and stops according to the first preset interval time, and adjusts the working state of the heating unit (12) to slowly adjust the preset area temperature of the preset object to within the preset temperature range; The third adjustment module (1422) is used to execute a third working mode. If the temperature of the preset area reaches the target set temperature, the third adjustment module controls the heating unit (12) to start and stop at a second preset interval time, and adjusts the working state of the heating unit (12) to keep the temperature of the preset area of ​​the preset object constant within a preset temperature range; The fourth adjustment module (1424) is used to execute a fourth working mode, wherein the fourth working mode is: if the temperature of the preset area is higher than the target setting temperature, the first adjustment module (1421) controls the KA1 circuit breaker (1541) in the circuit breaker (154) to be disconnected, and controls the heating unit (12) to stop working. At the same time, the first adjustment module (1421) controls the KA2 circuit breaker (1542) in the circuit breaker (154) to be closed, and the fan (13) enters the air supply state, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan (13) until the preset area reaches the target setting temperature.

6. The constant temperature device based on PID control strategy according to claim 1, characterized in that: The fuzzy controller (143) comprises a fuzzy adjustment module (1431) and a mode switching module (1432), wherein the mode switching module (1432) performs operating mode switching according to the temperature deviation generated by the temperature comparison module (141); The fuzzy adjustment module (1431) is used to execute a fuzzy working mode, wherein the fuzzy working mode is: using a fuzzy control strategy to continuously adjust the working states of the fan (13) and the heating unit (12), that is, if the error between the preset area temperature and the target setting temperature exceeds a second preset temperature value, the fuzzy adjustment module (1431) controls the heating unit (12) and the fan (13) to enter a preset power mode, and quickly adjusts the working states of the heating unit (12) and the fan (13), so as to quickly adjust the preset area temperature of the preset object to a preset temperature range; If the error between the preset area temperature and the target setting temperature is less than or equal to the first preset temperature value, the control strategy is switched from the fuzzy adjustment module (1431) to the working mode of the second adjustment module (1422) through the mode switching module (1432).

7. A constant temperature system comprising a constant temperature device based on a PID control strategy as claimed in any one of claims 1 to 6, characterized in that: The invention also comprises a shell (15), wherein a mounting plate (151) is provided inside the shell (15), wherein the mounting plate (151) is hollowed out, wherein a constant temperature cavity (152) is provided on the mounting plate (151), wherein a power supply (153) is provided on one side of the constant temperature cavity (152), wherein a group of circuit breakers (154) is provided on one side of the power supply (153), wherein a handle (155) is provided on the outer side of the shell (15), wherein the circuit breaker (154) comprises a KA1 circuit breaker (1541) and a KA2 circuit breaker (1542), wherein the KA1 circuit breaker (1541) and the KA2 circuit breaker (1542) are both mounted on the mounting plate (151), and are both connected to the heating unit (12), the fan (13), the control unit (14) and the power supply (153), wherein the heating unit (12) and the fan (13) are integrated in the constant temperature cavity (152).

8. A constant temperature control method for a constant temperature system of a constant temperature device based on a PID control strategy, characterized in that: The method comprises the following steps: According to the preset area temperature data of the preset object measured by the temperature measuring unit (11), the preset area temperature is compared with the target set temperature in real time, and then the PID control mode is executed according to the comparison result. The specific control process is as follows: If the temperature of the preset area is lower than the target set temperature, the heating unit (12) is controlled to enter a heating state, and the extracted air is introduced into the heating unit in real time through the fan (13) to form hot air; If the error between the preset area temperature and the target set temperature is less than or equal to a first preset temperature value, the heating unit (12) is controlled to start and stop at a first preset interval time, and the working state of the heating unit is adjusted to slowly adjust the preset area temperature of the preset object to within a preset temperature range; If the temperature of the preset area reaches the target set temperature, the heating unit (12) is controlled to start and stop at a second preset interval, and the working state of the heating unit is adjusted to keep the temperature of the preset area of ​​the preset object constant within a preset temperature range; If the temperature of the preset area is higher than the target set temperature, the heating unit (12) is controlled to stop working, and the extracted air is introduced into the preset area of ​​the preset object in real time through the fan (13).

9. The constant temperature control method of the constant temperature system of the constant temperature device based on the PID control strategy according to claim 6, characterized in that: During operation, if the error between the preset area temperature and the target set temperature exceeds a second preset temperature value, a fuzzy control mode is executed, wherein the fuzzy control mode controls the heating unit (12) and the fan (13) to enter a preset power mode, and quickly adjusts the working states of the heating unit (12) and the fan (13) to quickly adjust the preset area temperature of the preset object to a preset temperature range; When the error between the preset area temperature and the target setting temperature is less than or equal to the first preset temperature value, the fuzzy control mode is switched to the PID control mode.

10. The constant temperature control method of the constant temperature system of the constant temperature device based on the PID control strategy according to claim 6, characterized in that: During operation, the temperature of the preset area is monitored in real time through a thermocouple sensor, and the temperature data is transmitted to a control unit (14). The control unit (14) adjusts the working state of the heating unit (12) and the fan (13) through a PID control strategy according to the set target temperature and the current temperature, thereby achieving constant temperature control. During the PID control process, the error between the set temperature and the actual temperature is monitored in real time, and the output is adjusted according to the three parameters of proportion (P), integration (I), and differentiation (D) to achieve precise control of the temperature. The PID control formula is as follows: In the equation, u(t) is the control output, e(t) is the temperature difference between the set temperature and the actual temperature, K p is the proportional gain, K i is the integral gain, K d is the differential gain.

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