Temperature flow rate coordinated control gas sensor baseline recovery method and system

Abstract

The application provides a gas sensor baseline recovery method and system based on temperature and flow rate cooperative control, and belongs to the technical field of gas detection. When the conditions for gas sensor baseline recovery are met, a double closed-loop temperature control and flow rate feedforward control system is started to perform PI control on the second current output resistance value, the current working temperature and the current gas flow rate of the gas sensor respectively, so that a total control amount is obtained. The total control amount is used as an input of a signal generator, the heating power of a working circuit of the gas sensor is changed by adjusting the voltage duty cycle, the working temperature of the gas sensor during baseline recovery is dynamically adjusted, and drift compensation is completed. The method suppresses baseline drift from the data acquisition source by using the cooperative control strategy of the double closed-loop temperature control and the flow rate feedforward compensation, ensures that the sensor response characteristics will not be hidden due to baseline drift, avoids the dependence on subsequent complex algorithms, reduces the algorithm power consumption, and realizes real-time compensation for baseline recovery.

Description

Technical Field

[0001] This invention belongs to the field of gas detection technology, specifically relating to a baseline recovery method and system for gas sensors with temperature and flow rate coordinated control. Background Technology

[0002] Metal-oxide-semiconductor (MOS) gas sensors have attracted widespread attention due to their advantages such as high response, small size, and low power consumption. In recent years, related research has significantly improved their selectivity, response time, and other performance characteristics, leading to their widespread application, such as in the detection of volatile organic compounds (VOCs) in gas leaks and industrial production. However, MOS gas sensors suffer from baseline drift during gas detection, meaning that the sensor's recovery resistance baseline changes over time and cannot recover to its initial value. This phenomenon can be attributed to the sensor's susceptibility to factors such as ambient temperature, humidity, difficulty in gas molecule desorption, or sensor aging. Since the sensor's sensitivity is determined by the ratio of the sensor's stable resistance in the target gas environment to its baseline resistance in the air environment, baseline drift will affect the accuracy of sensor detection. Therefore, it is necessary to investigate solutions to sensor baseline drift.

[0003] Currently, existing techniques for addressing baseline drift in gas sensors have limitations. For example, adaptive compensation methods construct source and target domains between the sensor's non-drifted and drifted data, establish a distribution adaptation model, quantify the distribution difference between the two domains using the maximum mean difference, and optimize the weights of marginal and conditional distributions to achieve adaptive compensation for sensor drift, thereby improving measurement accuracy and reliability. However, this method typically requires collecting static sensor response data after baseline drift (i.e., completing the full response and recovery process) for subsequent algorithm correction. In applications with high response time requirements, the performance of such methods is insufficient. For instance, methods based on improved empirical mode decomposition decompose the sensor response signal into multiple intrinsic mode function components and remove components containing low-frequency baseline drift to reconstruct a stable measurement signal, effectively handling both linear and nonlinear drift. Furthermore, constructing a nonlinear multi-input single-output neural network model for baseline drift compensation can improve gas concentration identification accuracy by an order of magnitude. However, both of these methods require collecting large amounts of data samples and additional correction algorithms, further increasing the computational burden, and may also suffer from problems such as "local minima" and insufficient generalization. Therefore, it is necessary to study methods to address drift recovery from the source of data acquisition in order to reduce reliance on subsequent cumbersome compensation algorithms.

[0004] In summary, traditional baseline recovery drift correction methods largely rely on algorithmic compensation at the data backend. Such strategies not only place additional demands on signal processing performance but also struggle to achieve real-time baseline recovery compensation, thus limiting gas identification speed. Given that high temperatures promote gas desorption, this invention proposes actively adjusting the baseline resistance by regulating the sensor's operating temperature during the recovery phase. This compensates for baseline drift at the data acquisition source, achieving real-time baseline compensation and improving gas detection speed, ultimately overcoming the inherent limitations of traditional algorithmic compensation methods. Therefore, this invention proposes a gas sensor baseline recovery method and system based on temperature and flow rate coordinated control. This method constructs a dual-closed-loop temperature control system and introduces a gas flow rate feedforward compensation stage. These two systems work together to precisely control the pulse width modulation (PWM) signal generator, thereby dynamically adjusting the sensor's operating temperature during baseline recovery. This effectively controls the baseline recovery process, thus solving the sensor baseline drift problem at the source of data acquisition. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a baseline recovery method and system for gas sensors based on temperature and flow rate coordinated control. The aim is to solve the baseline drift problem during gas sensor detection by accelerating baseline recovery after the measurement cycle, thereby improving overall gas detection efficiency.

[0006] In a first aspect, the present invention provides a gas sensor baseline recovery method for temperature and flow rate coordinated control, comprising:

[0007] Step S1: Determine the end of the gas sensor's measurement cycle, collect the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs; if the first resistance difference exceeds or equals a preset threshold, start the gas sensor's baseline recovery process and proceed to step S2; if the difference is less than the preset threshold, do not start the sensor's baseline recovery process and continue executing step S1.

[0008] Step S2: Initialize the baseline recovery process of the gas sensor to obtain initialization data, which includes: baseline resistance value, control parameters of all PI controllers, and baseline recovery judgment threshold. Temperature limit T max ;

[0009] Step S3: Acquire the second current output resistance value of the gas sensor in real time at a fixed sampling frequency;

[0010] Step S4: Calculate the second resistance difference between the baseline resistance value and the second current output resistance value;

[0011] Step S5: Use the outer loop PI controller in the temperature-flow-rate coordinated control system to perform PI calculation on the second resistance difference and output the outer loop control quantity;

[0012] Step S6: Use the inner loop temperature detector in the temperature-flow-rate coordinated control system to collect the current operating temperature of the gas sensor, and calculate the temperature difference between the current operating temperature and the outer loop control quantity output by the outer loop PI controller.

[0013] Step S7: Use the inner loop PI controller in the temperature flow rate coordinated control system to perform PI calculation on the temperature difference and output the inner loop control quantity;

[0014] Step S8: The current gas flow rate is collected by the flow rate detector in the feedforward control of the temperature-flow rate coordinated control system;

[0015] Step S9: Use the flow rate feedforward PI controller in the temperature-flow rate coordinated control system to perform PI calculation on the current gas flow rate and output the flow rate feedforward control quantity;

[0016] Step S10: Sum the inner loop control quantity and the flow rate feedforward control quantity to obtain the total control quantity;

[0017] Step S11: Use the obtained total control quantity as the input of the PWM signal generator. The PWM generator adjusts the voltage duty cycle to change the heating power of the gas sensor working circuit, so as to achieve dynamic control of the working temperature of the gas sensor.

[0018] Step S12: Acquire the third current output resistance value of the gas sensor in real time at a fixed sampling frequency; calculate the third resistance difference between the baseline resistance value and the third current output resistance value; if the third resistance difference is less than the baseline recovery judgment threshold, determine that the baseline has been recovered, terminate the current baseline recovery process and wait for the end of the next measurement cycle, and return to step S1; if the third resistance difference is greater than or equal to the baseline recovery judgment threshold, return to step S3, continue to acquire the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

[0019] In a second aspect, the present invention provides a gas sensor baseline recovery system for temperature and flow rate coordinated control, used to implement the gas sensor baseline recovery method for temperature and flow rate coordinated control in the first aspect, comprising:

[0020] The signal acquisition module, connected to the control module, is used to acquire the current operating temperature, current gas flow rate, first current output resistance value, second current output resistance value, and third current output resistance value of the gas sensor.

[0021] The control module is connected to the signal acquisition module and the heating drive module respectively. It is used to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor and the current gas flow rate of the temperature flow rate coordinated control system to obtain the total control quantity.

[0022] The heating drive module is connected to both the control module and the storage module, and is used to adjust the operating temperature of the gas sensor according to the total control quantity.

[0023] The storage module, connected to the heating drive module, is used to save historical data, historical initialization data, and historical control parameters of the gas sensor. The historical control parameters include: outer loop control quantity, inner loop control quantity, and flow rate feedforward control quantity.

[0024] The control module includes:

[0025] The recovery preparation unit is used to determine the end of the measurement cycle of the gas sensor, acquire the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs; if the first resistance difference exceeds or equals a preset threshold, the baseline recovery process of the gas sensor is started and the process proceeds to the initialization unit; if the difference is less than the preset threshold, the baseline recovery process of the sensor is not started and the recovery preparation unit continues to be executed.

[0026] The initialization unit, connected to the recovery preparation unit, is used to initialize the baseline recovery process of the gas sensor and obtain initialization data. This initialization data includes: baseline resistance value, control parameters of all PI controllers, and baseline recovery determination threshold. Temperature limit T max ;

[0027] The closed-loop control unit, connected to the initialization unit, includes an outer-loop PI controller, an inner-loop PI controller, and a flow rate feedforward PI controller. It is used by the temperature and flow rate coordinated control system to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor, and the current gas flow rate to obtain the total control quantity.

[0028] The baseline recovery judgment unit, connected to the closed-loop control unit, is used to calculate the third resistance difference between the baseline resistance value and the third current output resistance value. If the third resistance difference is less than the baseline recovery judgment threshold, the baseline is determined to be recovered. If the third resistance difference is greater than or equal to the baseline recovery judgment threshold, the system returns to the closed-loop control unit and continues to collect the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

[0029] Thirdly, this application proposes an electronic device comprising: one or more processors, and a memory for storing instructions that, when executed by the one or more processors, cause the one or more processors to perform the gas sensor baseline recovery method for temperature and flow rate coordinated control.

[0030] Fourthly, this application proposes a computer-readable storage medium storing executable instructions that, when executed, cause a processor to perform the gas sensor baseline recovery method for temperature and flow rate coordinated control.

[0031] Fifthly, this application proposes a computer program product, including a computer program or instructions that, when executed by a processor, implement the aforementioned gas sensor baseline recovery method for temperature and flow rate coordinated control.

[0032] Beneficial effects:

[0033] Unlike existing baseline recovery techniques that rely on backend algorithm correction, this invention proposes a gas sensor baseline recovery method and system based on temperature and flow rate coordinated control. Its advantages are threefold: First, it innovatively suppresses baseline drift at the data acquisition source, avoiding reliance on subsequent complex algorithms, reducing computational overhead, and achieving real-time baseline recovery compensation. Second, through a coordinated control strategy of dual closed-loop temperature control and flow rate feedforward compensation, it dynamically adjusts the sensor's operating temperature during baseline recovery to complete drift compensation. Third, this method solves the baseline drift problem at the data acquisition level, eliminating the need to collect complete static response data after drift, ensuring that the sensor's response characteristics are not hidden due to baseline drift, thereby fundamentally improving the overall speed of gas detection. In summary, this invention provides a new path for achieving efficient and stable sensor detection. In the future, with the integration of advanced control theory, this technology is expected to drive the development of gas sensors towards greater intelligence and speed. Attached Figure Description

[0034] Figure 1 Flowchart of the gas sensor baseline recovery method for temperature and flow rate coordinated control according to an embodiment of the present invention;

[0035] Figure 2 Block diagram of the temperature-flow-rate coordinated control system according to an embodiment of the present invention;

[0036] Figure 3 The response recovery characteristic curve of the gas sensor according to an embodiment of the present invention;

[0037] Figure 4 The response recovery characteristic curve of the gas sensor in this embodiment of the invention under the action of the temperature and flow rate coordinated control system;

[0038] Figure 5Periodic test curves of the gas sensor in this embodiment of the invention under the action of the temperature-flow rate coordinated control system;

[0039] Figure 6 Block diagram of a gas sensor baseline recovery system for temperature and flow rate coordinated control according to an embodiment of the present invention. Detailed Implementation

[0040] The specific implementation methods of this application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] This invention proposes a gas sensor baseline recovery method and system based on temperature and flow rate coordinated control. The method constructs a dual-closed-loop temperature control system and introduces a gas flow rate feedforward compensation stage. These two systems work together to precisely control the pulse width modulation (PWM) signal generator, thereby dynamically adjusting the sensor's operating temperature during baseline recovery and controlling the baseline recovery process to solve the sensor baseline drift problem. Finally, this invention provides a gas sensor baseline recovery system for implementing the above baseline recovery method, including a signal acquisition module, a control module, a heating drive module, and a storage module. These modules work together to achieve rapid baseline recovery of the sensor. In summary, this invention solves the gas sensor baseline drift problem at the source of data acquisition through a coordinated control strategy of "dual-closed-loop temperature control and flow rate feedforward compensation."

[0042] Example 1:

[0043] This embodiment provides a baseline recovery method for gas sensor with coordinated temperature and flow rate control. Figure 1 As shown, it includes:

[0044] Step S1: Determine the end of the gas sensor's measurement cycle, collect the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs; if the first resistance difference exceeds or equals a preset threshold, start the gas sensor's baseline recovery process and proceed to step S2; if the difference is less than the preset threshold, do not start the sensor's baseline recovery process and continue executing step S1.

[0045] In this embodiment, the preset threshold is 5% of the baseline resistance value.

[0046] Step S2: Initialize the baseline recovery process of the gas sensor to obtain initialization data. The initialization data includes: baseline resistance value, control parameters of all PI controllers, and baseline recovery determination threshold. Temperature limit T max ;

[0047] In this embodiment, the system is initialized, and the baseline resistance value is set. (i.e., the stable resistance value of the sensor in an air environment, used as the baseline for complete recovery), outer loop PI controller parameters. and Inner loop PI controller parameters and Flow rate feedforward PI controller parameters and Baseline recovery determination threshold Temperature limit T max (The sensor's highest operating temperature during baseline recovery shall not exceed the sensor's tolerance temperature), etc.

[0048] In this embodiment, the metal-oxide-semiconductor sensor is placed in the test gas environment for testing, and its detection resistance value is read in real time. After the test, synthetic air is used to purge the test gas, and after the sensor output stabilizes, its initial baseline resistance is read. Next, confirm the end of the measurement cycle and calculate the baseline deviation. And determine baseline recovery conditions If the conditions are not met, the baseline recovery process begins, including system initialization and PI control parameter calibration. and The baseline recovery threshold is set to the baseline resistance value. , For a range of values ​​[ , ], , Set temperature limits, T max =500°C (the sensor's tolerance limit is usually 600°C); clear the historical deviation value of PI.

[0049] Step S3: Acquire the second current output resistance value of the gas sensor in real time at a fixed sampling frequency;

[0050] In this embodiment, the data sampling frequency is set to 10 Hz. The sensor output resistance value R is acquired in real time using a resistance detector, while the sensor's operating temperature and gas flow rate are recorded in real time using a temperature detector and a flow rate detector, respectively.

[0051] Step S4: Calculate the second resistance difference between the baseline resistance value and the second current output resistance value;

[0052] Step S5: Use the outer loop PI controller in the temperature-flow-rate coordinated control system to perform PI calculation on the second resistance difference and output the outer loop control quantity;

[0053] Step S6: Use the inner loop temperature detector in the temperature-flow-rate coordinated control system to collect the current operating temperature of the gas sensor, and calculate the temperature difference between the current operating temperature and the outer loop control quantity output by the outer loop PI controller.

[0054] Step S7: Use the inner loop PI controller in the temperature flow rate coordinated control system to perform PI calculation on the temperature difference and output the inner loop control quantity;

[0055] Step S8: The current gas flow rate is collected by the flow rate detector in the feedforward control of the temperature-flow rate coordinated control system;

[0056] Step S9: Use the flow rate feedforward PI controller in the temperature-flow rate coordinated control system to perform PI calculation on the current gas flow rate and output the flow rate feedforward control quantity;

[0057] Step S10: Sum the inner loop control quantity and the flow rate feedforward control quantity to obtain the total control quantity;

[0058] In this embodiment, Figure 2 A block diagram of the temperature-flow rate coordinated control system is shown, mainly composed of a "dual closed-loop temperature control and flow rate feedforward compensation" control system. The dual closed-loop temperature control system consists of an outer loop and an inner loop. Specifically, the temperature-flow rate coordinated control system includes: a resistance detector, an outer-loop PI controller, a temperature detector, an inner-loop PI controller, a flow rate detector, a flow rate feedforward PI controller, a PWM signal generator, and a MOS gas sensor. The outer loop control loop consists of the resistance detector, the outer-loop PI controller, the PWM signal generator, and the MOS gas sensor; the inner loop control loop consists of the temperature detector, the inner-loop PI controller, the PWM signal generator, and the MOS gas sensor; and the feedforward control loop consists of the flow rate detector and the flow rate feedforward PI controller. The outer loop control loop is used for PI control of the second resistance difference; the inner loop control loop is used for PI control of the temperature difference; and the feedforward control loop is used for PI control of the current gas flow rate. Furthermore, since PI control can eliminate residual error and has good control performance, all controllers use PI control, with the control quantity being the PWM signal generator. The specific control algorithm is shown in the following three parts.

[0059] First, calculate the second resistance difference between the baseline resistance value and the second current output resistance value: ,in, This is the second resistance difference. This is the baseline resistance value. The second current output resistance value is used as the basis for the outer loop PI controller to adjust the second resistance difference according to the incremental PI control algorithm. Perform PI calculation and output the outer loop temperature control value. The specific outer-loop PI control algorithm is shown in equation (1):

[0060] (1);

[0061] in, This is the output of the outer loop PI controller, i.e., the outer loop control quantity. For the outer loop proportional control parameters, These are the outer loop integral control parameters. This is the real-time input of the second resistance difference value of the outer loop PI controller.

[0062] Secondly, the current operating temperature T of the gas sensor is collected by the inner loop temperature detector and compared with the outer loop control quantity output by the outer loop PI controller. Calculate the deviation .in, The outer loop control variable is T, where T is the current operating temperature. The temperature difference between the outer-loop control output of the outer-loop PI controller and the current operating temperature is used by the inner-loop PI controller according to the inner-loop PI control algorithm. Perform PI calculation and output control quantity P1. The specific inner-loop PI control algorithm is shown in equation (2):

[0063] (2);

[0064] in, This is the output of the inner-loop PI controller, i.e., the inner-loop control quantity. These are the proportional control parameters for the inner loop. These are the inner-loop integral control parameters. This is the real-time input for the temperature difference of the inner loop PI controller.

[0065] Third, the feedforward control reads the current gas flow rate f from the flow rate detector and performs PI calculations on the current gas flow rate according to the flow rate feedforward PI controller, outputting the flow rate feedforward control quantity P2. The specific flow rate feedforward PI control algorithm is shown in equation (3):

[0066] (3);

[0067] in, This is the output of the flow rate feedforward PI controller, i.e., the flow rate feedforward control quantity. These are the proportional control parameters for the flow velocity feedforward. These are the integral control parameters for the flow velocity feedforward. This is the real-time input of the current gas flow rate to the flow rate feedforward PI controller.

[0068] Step S11: Use the obtained total control quantity as the input of the PWM signal generator. The PWM generator adjusts the voltage duty cycle to change the heating power of the gas sensor working circuit, so as to achieve dynamic control of the working temperature of the gas sensor.

[0069] In this embodiment, the output P1 of the inner loop PI controller and the output P2 of the flow rate feedforward PI controller are superimposed, and the resulting total control quantity (P1+P2) is used as the input to the PWM signal generator. The PWM generator adjusts the voltage duty cycle to change the heating power of the sensor's operating circuit, thereby achieving dynamic control of the MOS gas sensor's operating temperature. It is understood that both the inner loop control quantity P1 and the flow rate feedforward control quantity P2 are digital signals, and can be directly summed based on their corresponding values.

[0070] Step S12: Acquire the third current output resistance value of the gas sensor in real time at a fixed sampling frequency; calculate the third resistance difference between the baseline resistance value and the third current output resistance value; if the third resistance difference is less than the baseline recovery judgment threshold, determine that the baseline has been recovered, terminate the current baseline recovery process and wait for the end of the next measurement cycle, and return to step S1; if the third resistance difference is greater than or equal to the baseline recovery judgment threshold, return to step S3, continue to acquire the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

[0071] In this embodiment, it is necessary to read the current sensor output resistance value again, i.e., the third current output resistance value R, and calculate the third resistance difference between the baseline resistance value and the third current output resistance value. Determine whether the absolute value of the third resistance difference is within the baseline recovery threshold. Within the range, that is Furthermore, based on the baseline recovery accuracy, a decision duration of t=50s is set to maintain the current sensor output resistance R at the decision threshold within time t. If the baseline is within the specified range, the current process is terminated and the process waits for the next measurement cycle; otherwise, the process returns to step S3 and continues until the difference reaches the threshold requirement.

[0072] Finally, once the sensor baseline is restored and the sensor's optimal operating temperature (250°C) is restored, the sensor can perform the next gas detection.

[0073] Specifically, Figure 3This is the response recovery characteristic curve of the gas sensor. In this embodiment of the invention, a Bi₂O₂CO₃ gas sensor is used, and 100 ppm of acetic anhydride gas is tested. The optimal operating temperature is 250°C. The baseline resistance of the sensor at the optimal operating temperature is 4560454 kΩ. At the start of the test, the sensor detects 100 ppm of acetic anhydride. After purging the gas with synthetic air, the resistance value returns to the baseline resistance. At this point, the gas valve is closed, the gas flow rate is 0, and the operating temperature remains constant at 250°C. The resistance baseline then experiences a significant drift and cannot maintain continuous stability.

[0074] Specifically, Figure 4 This is the response recovery characteristic curve of the gas sensor under the action of the temperature-flow rate coordinated control system. After blowing the resistance value back to 4560454 kΩ using synthetic air, the temperature-flow rate coordinated control system is started, executing steps S1-S12. Under the coordinated control of temperature and flow rate, the resistance value fluctuates around 4560454 kΩ and gradually tends to 4560454 kΩ. The time to meet the baseline stability judgment condition of step S12 is greater than 50 s, indicating that the sensor baseline recovery is complete and the sensor's optimal operating temperature (250°C) has been restored. The sensor can then perform the next gas detection. Figure 5 The figures show the periodic test curves of the gas sensor under the action of the temperature-flow rate coordinated control system. Three test periods were conducted, each satisfying the baseline stability determination condition of step S12 for a time greater than 50 seconds. Furthermore, as the test progressed, the control time gradually decreased, and the baseline resistance stabilized more quickly, indicating that the temperature-flow rate coordinated control system has a good effect on stabilizing the baseline resistance and effectively solves the baseline drift problem of the gas sensor.

[0075] Example 2:

[0076] This embodiment provides a gas sensor baseline recovery system for temperature and flow rate coordinated control, used to implement the gas sensor baseline recovery method for temperature and flow rate coordinated control in the first aspect, such as... Figure 6 As shown, it includes:

[0077] The signal acquisition module, connected to the control module, is used to acquire the current operating temperature, current gas flow rate, first current output resistance value, second current output resistance value, and third current output resistance value of the gas sensor.

[0078] The control module is connected to the signal acquisition module and the heating drive module respectively. It is used to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor and the current gas flow rate of the temperature flow rate coordinated control system to obtain the total control quantity.

[0079] The heating drive module is connected to both the control module and the storage module, and is used to adjust the operating temperature of the gas sensor according to the total control quantity.

[0080] The storage module, connected to the heating drive module, is used to save historical data, historical initialization data, and historical control parameters of the gas sensor. The historical control parameters include: outer loop control quantity, inner loop control quantity, and flow rate feedforward control quantity.

[0081] The control module includes:

[0082] The recovery preparation unit is used to determine the end of the measurement cycle of the gas sensor, acquire the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs; if the first resistance difference exceeds or equals a preset threshold, the baseline recovery process of the gas sensor is started and the process proceeds to the initialization unit; if the difference is less than the preset threshold, the baseline recovery process of the sensor is not started and the recovery preparation unit continues to be executed.

[0083] The initialization unit, connected to the recovery preparation unit, is used to initialize the baseline recovery process of the gas sensor and obtain initialization data. This initialization data includes: baseline resistance value, control parameters of all PI controllers, and baseline recovery determination threshold. Temperature limit T max ;

[0084] The closed-loop control unit, connected to the initialization unit, includes an outer-loop PI controller, an inner-loop PI controller, and a flow rate feedforward PI controller. It is used by the temperature and flow rate coordinated control system to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor, and the current gas flow rate to obtain the total control quantity.

[0085] The baseline recovery judgment unit, connected to the closed-loop control unit, is used to calculate the third resistance difference between the baseline resistance value and the third current output resistance value. If the third resistance difference is less than the baseline recovery judgment threshold, the baseline is determined to be recovered. If the third resistance difference is greater than or equal to the baseline recovery judgment threshold, the system returns to the closed-loop control unit and continues to collect the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

[0086] Signal Acquisition Module: Includes a temperature sensor, a flow rate sensor, and a signal conditioning circuit. The temperature sensor is attached to the gas sensor for accurate acquisition of the sensor's real-time temperature T. The flow rate sensor is connected to the blowing channel to measure the blowing gas flow rate f. The signal conditioning circuit acquires the sensor's real-time output signal R. Finally, the measured signal is synchronously transmitted to the control module. Control Module: As the core of the system, it uses embedded chips such as microcontrollers, FPGAs, or DSPs, and includes a recovery preparation unit, an initialization unit, a baseline recovery judgment unit, and a closed-loop control unit. The recovery preparation unit executes the relevant steps in step S1; the initialization unit executes the initialization operation in step S2, loading preset parameters; the baseline recovery judgment unit executes the baseline recovery status judgment in step S12, calculating the baseline deviation and determining the baseline recovery progress; the control unit includes an outer-loop PI controller, an inner-loop PI controller, and a flow rate feedforward PI controller, used to execute the control logic in steps S4–S11. Heating Drive Module: Receives the control quantity output from the control module, converts it into a corresponding drive signal (PWM signal), drives the heating unit to work, adjusts the heating power, and controls the sensor's operating temperature. Heating Unit: Integrated with the gas sensor, it can use heating elements such as thermistors, attached to the surface of the sensor's sensitive material. It receives drive signals from the heating drive module and adjusts the sensor temperature by changing the heating power, providing sufficient thermal energy for gas molecule chemical reactions. Storage Module: Employs storage media such as computers to store the initial baseline. Outer loop PI control parameters ( and Inner loop PI control parameters ( and ), flow rate feedforward PI control parameters ( and Baseline deviation threshold Temperature limits (T) max The system also collects historical sampling data from sensors, which the control module can access and update at any time to ensure the stable execution of the algorithm.

[0087] Example 4:

[0088] This embodiment proposes an electronic device, including: one or more processors, and a memory for storing instructions, which, when executed by the one or more processors, cause the one or more processors to perform the gas sensor baseline recovery method for temperature and flow rate coordinated control.

[0089] The electronic device may be a mobile phone, computer, or tablet computer, etc., and includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the gas sensor baseline recovery method for temperature and flow rate coordinated control as described in the embodiments. It is understood that the electronic device may also include input / output (I / O) interfaces and communication components.

[0090] The processor is used to execute all or part of the steps in the gas sensor baseline recovery method for temperature and flow rate coordinated control as described in the above embodiments. The memory is used to store various types of data, which may include, for example, instructions for any application or method in the electronic device, as well as application-related data.

[0091] The processor can be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic components, and is used to execute the gas sensor baseline recovery method for temperature and flow rate coordinated control described in the above embodiments.

[0092] Example 5:

[0093] This embodiment proposes a computer-readable storage medium that stores executable instructions. When these instructions are executed, if they are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0094] The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the gas sensor baseline recovery method for temperature and flow rate coordinated control described in the various embodiments of this application.

[0095] The aforementioned storage media include: flash memory, hard disk, multimedia card, card-type memory (e.g., SD (Secure Digital Memory Card) or DX (Memory Data Register, MDR) memory), random access memory (RAM), static random-access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic storage, disk, optical disk, server, APP (Application) application store, and other media capable of storing program verification codes. These media store computer programs, which, when executed by a processor, can implement the various steps of the gas sensor baseline recovery method for temperature and flow rate coordinated control described above.

[0096] Example 6:

[0097] This embodiment proposes a computer program product, including a computer program or instructions, which, when executed by a processor, implements the gas sensor baseline recovery method for temperature and flow rate coordinated control.

[0098] Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a computer program product.

[0099] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0100] The scope of protection of this application is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the scope and spirit of this disclosure. If such modifications and variations fall within the scope of equivalent technology of this disclosure, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A gas sensor baseline recovery method for temperature and flow rate coordinated control, characterized in that, include: Step S1: Determine the end of the measurement cycle of the gas sensor, collect the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs. If the first resistance difference exceeds or equals a preset threshold, the baseline recovery process of the gas sensor is started, and the process proceeds to step S2; if the difference is less than the preset threshold, the baseline recovery process of the sensor is not started, and step S1 is continued. Step S2: Initialize the baseline recovery process of the gas sensor to obtain initialization data; Step S3: Acquire the second current output resistance value of the gas sensor in real time at a fixed sampling frequency; Step S4: Calculate the second resistance difference between the baseline resistance value and the second current output resistance value; Step S5: Use the outer loop PI controller in the temperature-flow-rate coordinated control system to perform PI calculation on the second resistance difference and output the outer loop control quantity; Step S6: Use the inner loop temperature detector in the temperature-flow-rate coordinated control system to collect the current operating temperature of the gas sensor, and calculate the temperature difference between the current operating temperature and the outer loop control quantity output by the outer loop PI controller. Step S7: Use the inner loop PI controller in the temperature flow rate coordinated control system to perform PI calculation on the temperature difference and output the inner loop control quantity; Step S8: The current gas flow rate is collected by the flow rate detector in the feedforward control of the temperature-flow rate coordinated control system; Step S9: Use the flow rate feedforward PI controller in the temperature-flow rate coordinated control system to perform PI calculation on the current gas flow rate and output the flow rate feedforward control quantity; Step S10: Sum the inner loop control quantity and the flow rate feedforward control quantity to obtain the total control quantity; Step S11: Use the obtained total control quantity as the input of the PWM signal generator. The PWM generator adjusts the voltage duty cycle to change the heating power of the gas sensor working circuit, so as to achieve dynamic control of the working temperature of the gas sensor. Step S12: Acquire the third current output resistance value of the gas sensor in real time at a fixed sampling frequency; Calculate the third resistance difference between the baseline resistance value and the third current output resistance value; If the difference in the third resistance is less than the baseline recovery determination threshold, the baseline is determined to have been recovered, the current baseline recovery process is terminated and the process waits for the next measurement cycle to end before returning to step S1. If the third resistance difference is greater than or equal to the baseline recovery judgment threshold, return to step S3 and continue to collect the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

2. A gas sensor baseline recovery system with temperature and flow rate coordinated control, used to implement the gas sensor baseline recovery method with temperature and flow rate coordinated control as described in claim 1, characterized in that, include: The signal acquisition module, connected to the control module, is used to acquire the current operating temperature, current gas flow rate, first current output resistance value, second current output resistance value, and third current output resistance value of the gas sensor. The control module is connected to the signal acquisition module and the heating drive module respectively. It is used to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor and the current gas flow rate of the temperature flow rate coordinated control system to obtain the total control quantity. The heating drive module is connected to both the control module and the storage module, and is used to adjust the operating temperature of the gas sensor according to the total control quantity. The storage module, connected to the heating drive module, is used to save historical data, historical initialization data, and historical control parameters of the gas sensor. The historical control parameters include: outer loop control quantity, inner loop control quantity, and flow rate feedforward control quantity.

3. The gas sensor baseline recovery system for temperature and flow rate coordinated control according to claim 2, characterized in that, The control module includes: The recovery preparation unit is used to determine the end of the measurement cycle of the gas sensor, acquire the first current output resistance value of the gas sensor in real time at a fixed sampling frequency, and calculate the first resistance difference between the first current output resistance value and the baseline resistance when no drift occurs; if the first resistance difference exceeds or equals a preset threshold, the baseline recovery process of the gas sensor is started and the process proceeds to the initialization unit; if the difference is less than the preset threshold, the baseline recovery process of the sensor is not started and the recovery preparation unit continues to be executed. The initialization unit, connected to the recovery preparation unit, is used to initialize the baseline recovery process of the gas sensor and obtain initialization data. The closed-loop control unit, connected to the initialization unit, includes an outer-loop PI controller, an inner-loop PI controller, and a flow rate feedforward PI controller. It is used by the temperature and flow rate coordinated control system to perform PI control on the second current output resistance value of the gas sensor, the current operating temperature of the gas sensor, and the current gas flow rate to obtain the total control quantity. The baseline recovery judgment unit, connected to the closed-loop control unit, is used to calculate the third resistance difference between the baseline resistance value and the third current output resistance value. If the third resistance difference is less than the baseline recovery judgment threshold, the baseline is determined to be recovered. If the third resistance difference is greater than or equal to the baseline recovery judgment threshold, the system returns to the closed-loop control unit and continues to collect the second current output resistance value of the gas sensor in real time until the third resistance difference is less than the baseline recovery judgment threshold.

4. An electronic device, characterized in that, include: One or more processors, and a memory for storing instructions that, when executed by the one or more processors, cause the one or more processors to perform the gas sensor baseline recovery method for temperature and flow rate coordinated control as described in claim 1.

5. A computer-readable storage medium, characterized in that, It stores executable instructions that, when executed, cause the processor to perform the gas sensor baseline recovery method for temperature and flow rate coordinated control as described in claim 1.

6. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by the processor, they implement the gas sensor baseline recovery method for temperature and flow rate coordinated control as described in claim 1.

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