System and method for controlling liquid level of tipping smelting furnace

Abstract

The invention relates to the technical field of aluminum alloy production, and discloses a tipping smelting furnace liquid level control system and method, and the system comprises a liquid level measurement module which is used for carrying out the real-time measurement of the liquid level of molten aluminum in a tipping smelting furnace through a non-contact radar liquid level sensor; the signal acquisition module is used for acquiring a liquid level signal measured by the liquid level sensor and transmitting the liquid level signal to the controller; the data processing module is used for carrying out filtering processing on the collected liquid level signals and then carrying out averaging or state estimation processing to obtain processed liquid level information; and the control algorithm processing module is used for inputting the processed liquid level information into the controller. The non-contact radar liquid level sensor is used for carrying out real-time liquid level measurement on molten aluminum liquid, so that the problems that the liquid level detection precision is reduced and the liquid level control is unstable due to the fact that laser sensors are mostly adopted in traditional liquid level detection, and the laser reflectivity is unstable due to an oxidation film on the surface of the aluminum liquid in a runner groove are solved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy production technology, specifically to a tilting melting furnace liquid level control system and method. Background Technology

[0002] The tilting furnace is a core piece of equipment in aluminum and aluminum alloy production. Its main function is to heat and melt aluminum ingots or recycled aluminum materials, and then transport the molten aluminum to the runner channel via a tilting mechanism, before flowing into the subsequent casting mold. To ensure the stability of the aluminum flow rate and volume during the casting process, the aluminum level in the runner channel must be precisely controlled.

[0003] Traditional liquid level detection mostly uses laser sensors. However, the laser reflectivity is unstable due to the oxide film on the surface of the molten aluminum in the flow channel. At the same time, some oxide film adheres to the tank wall, resulting in reduced liquid level detection accuracy and unstable liquid level control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a tilting smelting furnace liquid level control system and method, which solves the problems of reduced liquid level detection accuracy and unstable liquid level control caused by the unstable laser reflectivity due to the oxide film on the surface of the aluminum liquid in the flow channel, and the fact that some oxide film adheres to the tank wall.

[0005] In a first aspect, the present invention provides the following technical solution: a tilting melting furnace liquid level control system, comprising:

[0006] The liquid level measurement module is used to measure the liquid level of molten aluminum in a tilting furnace in real time using a non-contact radar liquid level sensor.

[0007] The signal acquisition module is used to acquire the liquid level signal measured by the liquid level sensor and transmit it to the controller;

[0008] The data processing module is used to filter the collected liquid level signal, and then perform averaging or state estimation to obtain the processed liquid level information.

[0009] The control algorithm processing module is used to input the processed liquid level information into the controller and generate liquid level adjustment commands through a closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level.

[0010] The instruction execution module is used to drive the liquid level actuator to adjust the liquid level of the molten aluminum liquid according to the liquid level adjustment instruction;

[0011] The liquid level maintenance module is used to maintain the liquid level of molten aluminum through continuous cyclic measurement, control and execution.

[0012] The above technical solution utilizes a non-contact radar level sensor to measure the molten aluminum level in real time, thereby obtaining stable and reliable level information. This improves upon the traditional method of using laser sensors for level detection, where the laser reflectivity is unstable due to the oxide film on the surface of the molten aluminum in the flow channel, and some oxide film adheres to the tank wall, resulting in reduced level detection accuracy and unstable level control.

[0013] Preferably, the radar level sensor has a radar wave frequency of 24GHz to 80GHz. The radar level sensor is installed above the flow channel or melting furnace, with the emitting surface perpendicular to the liquid surface. The measurement distance is 100mm to 1000mm. The measurement error is controlled within ±2% through initial zero-point and full-scale calibration. The sensor outputs a liquid level signal with a sampling frequency of 10Hz to 100Hz. The liquid level data changes continuously in the range of 0mm to 1000mm. The data is transmitted to the controller through an analog current, analog voltage, or digital bus interface.

[0014] Preferably, the acquisition of the liquid level signal measured by the liquid level sensor includes the following steps:

[0015] Select the acquisition method according to the output type of the liquid level sensor, wherein the output type is either analog signal or digital signal;

[0016] It amplifies, filters, and isolates analog signals, and performs protocol parsing and data verification on digital signals.

[0017] The liquid level signal is acquired according to a set sampling frequency, which is 10Hz to 100Hz.

[0018] The acquired liquid level signal is converted into a data format that the controller can recognize;

[0019] The transmission to the controller includes the following steps:

[0020] The formatted liquid level signal is connected to the controller via a standard interface, which can be an analog input port or a digital bus interface.

[0021] Time synchronization and verification of transmitted data are performed to ensure data integrity;

[0022] The liquid level signal is transmitted to the controller in real time for subsequent control processing.

[0023] Preferably, the data processing module performs filtering processing on the acquired liquid level signal, including the following steps:

[0024] Choose a filtering method, wherein the method is a low-pass filter, a moving average filter, or a Kalman filter;

[0025] The filter parameters are set such that the cutoff frequency of the low-pass filter is 1Hz to 50Hz, the window length of the moving average filter is 5 to 50 sampling points, and the process noise covariance and measurement noise covariance of the Kalman filter are set according to the liquid level change amplitude and sensor characteristics.

[0026] The collected liquid level signals are filtered in real time, and the processing delay is controlled within 10% to 50% of the sampling period.

[0027] The filtered liquid level signal is used as the input for subsequent data processing or control.

[0028] Preferably, the data processing module performs averaging or state estimation processing on the filtered liquid level signal, including the following steps:

[0029] Averaging: The continuously acquired liquid level signals are arithmetically averaged over a window of 5 to 50 sampling points. The average value is recalculated after each update of the data within the window.

[0030] State estimation processing: The liquid level system is modeled as a linear or nonlinear dynamic system, and state equations and observation equations are established. The liquid level state estimate is calculated by Kalman filtering or extended Kalman filtering. The process noise covariance and measurement noise covariance of the filter are set according to the liquid level change amplitude and sensor accuracy.

[0031] Processing delay control: Ensure that the processing delay of average or state estimation is within 10% to 50% of the sampling period;

[0032] Output processed liquid level information: The liquid level information obtained by averaging or state estimation is used as the output of the data processing module for the control algorithm module.

[0033] Preferably, the step of generating the liquid level adjustment command through a closed-loop control algorithm includes the following steps:

[0034] Select a closed-loop control algorithm, wherein the algorithm is PID control, self-tuning PID control, or fuzzy adaptive control;

[0035] The liquid level information output by the data processing module is used as a feedback signal, and the deviation from the set liquid level is calculated to obtain an error signal.

[0036] The parameters of the closed-loop control algorithm are dynamically adjusted, with the proportional parameter Kp ranging from 0.1 to 10, the integral parameter Ki ranging from 0.01 to 5, and the derivative parameter Kd ranging from 0.001 to 1.

[0037] Based on the liquid level change trend or preset flow rate change, a feedforward control quantity is generated, and the feedforward control quantity is superimposed with the closed-loop regulation quantity to form the final liquid level regulation command.

[0038] The liquid level adjustment command is output to the command execution module. The command is an analog current signal or a digital control signal, which is updated in real time, and the delay is controlled within 10% to 50% of the sampling period.

[0039] Preferably, the liquid level regulation combined with prediction or feedforward strategies includes the following steps:

[0040] The future liquid level change trend is calculated based on historical liquid level data and the rate of liquid level change, and the prediction time window is 0.1 to 5 seconds.

[0041] A feedforward control quantity is generated based on the predicted liquid level deviation or preset flow rate change, and the range of the feedforward control quantity is 0% to 100% of the actuator control quantity;

[0042] The feedforward control quantity is superimposed with the adjustment quantity calculated by the closed-loop control algorithm to form the final liquid level adjustment command. The superposition weight can be adjusted within the range of 0.1 to 0.9.

[0043] The final liquid level adjustment command is output to the command execution module in real time, and the update cycle is synchronized with the sampling cycle, with the delay controlled within 10% to 50% of the sampling cycle.

[0044] Preferably, the driving liquid level actuator adjusts the liquid level of the molten aluminum by the following steps:

[0045] Select a level actuator, which is a level proportional valve or other device with continuously adjustable flow rate, and the control range is 0% to 100%;

[0046] Receive a liquid level adjustment command from the control algorithm processing module, wherein the command is an analog current signal, an analog voltage signal, or a digital control signal, and map it into a control quantity that the actuator can recognize;

[0047] The actuator is driven by the analyzed control quantity to adjust the liquid flow rate, thereby adjusting the liquid level of molten aluminum. The liquid level adjustment response time is 0.1 seconds to 5 seconds.

[0048] The liquid level sensor confirms the liquid level change and provides limit and overload protection for the actuator.

[0049] Preferably, maintaining the level of molten aluminum includes the following steps:

[0050] The non-contact radar level sensor of the liquid level measurement module is used to collect the liquid level of molten aluminum in real time, with a sampling frequency of 10Hz to 100Hz;

[0051] The collected liquid level signal is processed by the data processing module through filtering, averaging, or state estimation, and then input into the control algorithm module.

[0052] The control algorithm module generates liquid level adjustment commands based on closed-loop control and prediction or feedforward strategies.

[0053] The instruction execution module drives the liquid level actuator to adjust the liquid level according to the liquid level adjustment instruction. The liquid level adjustment response time is 0.1 seconds to 5 seconds, and limit and overload protection are provided.

[0054] The liquid level measurement, data processing, control algorithm and execution action are formed into a continuous closed loop, and the cycle period is synchronized with the sampling cycle.

[0055] The liquid level change trend and liquid level deviation are monitored in real time. If abnormal fluctuations are detected, the control algorithm automatically adjusts the parameters or feedforward strategy to maintain the liquid level stability, and the liquid level deviation is controlled within ±1.5mm.

[0056] Secondly, the present invention provides the following technical solution: a method for controlling the liquid level in a tilting smelting furnace, comprising the following steps:

[0057] The liquid level of molten aluminum in a tilting furnace is measured in real time using a non-contact liquid level sensor.

[0058] The liquid level signal measured by the liquid level sensor is collected and transmitted to the controller;

[0059] The collected liquid level signal is filtered, and then averaged or state estimated to obtain the processed liquid level information.

[0060] The processed liquid level information is input into the controller, and a liquid level adjustment command is generated through a closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level.

[0061] According to the liquid level adjustment command, the liquid level actuator is driven to adjust the liquid level of the molten aluminum liquid;

[0062] The level of molten aluminum is maintained through continuous cyclic measurement, control, and execution.

[0063] This invention provides a liquid level control system and method for a tilting melting furnace. It has the following beneficial effects:

[0064] 1. This invention utilizes a non-contact radar level sensor to measure the liquid level of molten aluminum in real time, thereby obtaining stable and reliable liquid level information. This improves upon the traditional method of using laser sensors for liquid level detection, which suffers from unstable laser reflectivity due to the oxide film on the surface of the molten aluminum in the flow channel, and the fact that some oxide film adheres to the tank wall, resulting in reduced liquid level detection accuracy and unstable liquid level control.

[0065] 2. This invention eliminates signal noise and instantaneous fluctuations by filtering, averaging, or estimating the state of the liquid level signal. This improves upon the traditional liquid level control, which mostly relies directly on the original sensor signal. Due to the large amount of noise and interference in the signal, the liquid level data is unstable and the control algorithm input is inaccurate.

[0066] 3. This invention generates liquid level adjustment commands by combining a closed-loop control algorithm with a prediction or feedforward strategy, thereby achieving dynamic and precise adjustment of the liquid level. This improves upon the problem that traditional liquid level control mostly adopts a fixed parameter control strategy, which lacks the ability to predict and compensate for changes in liquid level trends, resulting in lag in liquid level adjustment and difficulty in maintaining stable flow rate and volume. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the architecture of a tilting melting furnace liquid level control system proposed in this invention;

[0068] Figure 2 This is a schematic diagram of the process by which the data processing module of the tilting melting furnace liquid level control system of the present invention filters the collected liquid level signal.

[0069] Figure 3 This is a schematic diagram of the process for generating liquid level adjustment commands through a closed-loop control algorithm in a tilting melting furnace liquid level control system proposed in this invention.

[0070] Figure 4 This is a schematic diagram of the process for liquid level regulation in a tilting melting furnace liquid level control system proposed in this invention, which combines prediction or feedforward strategies.

[0071] Figure 5 This is a schematic diagram of the process for adjusting the molten aluminum liquid level using a driving liquid level actuator in a tilting melting furnace liquid level control system proposed in this invention.

[0072] Figure 6 This is a schematic diagram of the process for maintaining the molten aluminum liquid level in a tilting melting furnace liquid level control system proposed in this invention.

[0073] Figure 7 This is a schematic diagram of the process flow for a tilting melting furnace liquid level control method proposed in this invention. Detailed Implementation

[0074] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] Example 1:

[0076] In a first embodiment of the present invention, the present invention provides a tilting smelting furnace liquid level control system, such as... Figure 1 As shown, it includes:

[0077] The liquid level measurement module is used to measure the liquid level of molten aluminum in a tilting furnace in real time using a non-contact radar liquid level sensor.

[0078] Furthermore, the radar level sensor has a radar wave frequency of 24GHz to 80GHz. The radar level sensor is installed above the flow channel or melting furnace, with the emitting surface perpendicular to the liquid surface. The measurement distance is 100mm to 1000mm. The measurement error is controlled within ±2% through initial zero-point and full-scale calibration. The sensor outputs the liquid level signal at a sampling frequency of 10Hz to 100Hz. The liquid level data changes continuously in the range of 0mm to 1000mm. The data is transmitted to the controller through analog current, analog voltage or digital bus interface.

[0079] Specifically, the frequency range is The frequency-modulated continuous wave radar emits electromagnetic waves towards the surface of molten aluminum, receives the reflected echoes from the liquid surface, and calculates the distance to the liquid surface using the frequency-modulated beat signal to determine the liquid level height. The steps of this process include: First, the radar sensor emits a linearly modulated continuous wave signal. ;in The amplitude of the transmitted signal. Starting frequency For frequency modulation bandwidth, For the frequency modulation period: the reflected echo from the liquid surface is:

[0080] ;

[0081] in To delay the transmission time, The distance between the liquid surface and the radar emitting surface. The speed of electromagnetic wave propagation. The transmitted and received signals are mixed to obtain a beat signal, and its frequency components are extracted. According to the formula: The distance from the liquid level to the sensor was calculated. Linear compensation is performed on the measurement results through initial zero-point and full-scale calibration to control the error within a certain range. Internal. Input data includes the transmitted signal frequency. echo phase difference and time delay These parameters are acquired through sensor hardware; the output is the liquid level height. The calculation formula is as follows: ;in The height from the installation reference plane to the zero liquid level was obtained through actual measurement during installation and commissioning. The obtained liquid level height was then sampled at a specific frequency. Continuous output of liquid level signal, liquid level data in The data varies within a certain range and is transmitted via analog current signals. Analog voltage signal Alternatively, the data can be transmitted to the controller via a digital bus interface (such as RS485, CAN, Modbus) for subsequent data processing modules to perform filtering, state estimation, and closed-loop control, thereby providing a precise input basis for liquid level regulation.

[0082] This enables stable, continuous, and high-precision monitoring of the molten aluminum level, providing reliable input for subsequent signal processing and control algorithms, ensuring the timeliness and accuracy of level regulation, and improving the stability of the tilting furnace operation and the consistency of the casting process.

[0083] The signal acquisition module is used to acquire the liquid level signal measured by the liquid level sensor and transmit it to the controller;

[0084] Further, the liquid level signal measured by the liquid level sensor is acquired, including the following steps:

[0085] Select the acquisition method based on the output type of the liquid level sensor; the output type can be either analog signal or digital signal.

[0086] It amplifies, filters, and isolates analog signals, and performs protocol parsing and data verification on digital signals.

[0087] The liquid level signal is collected according to the set sampling frequency, which is 10Hz to 100Hz.

[0088] The acquired liquid level signal is converted into a data format that the controller can recognize;

[0089] The transmission to the controller includes the following steps:

[0090] The formatted liquid level signal is connected to the controller via a standard interface, which can be an analog input port or a digital bus interface.

[0091] Time synchronization and verification of transmitted data are performed to ensure data integrity;

[0092] The liquid level signal is transmitted to the controller in real time for subsequent control processing.

[0093] Specifically, the acquisition method is determined based on the output type of the liquid level sensor. When the output is an analog signal, the signal amplitude is adjusted by an operational amplifier circuit, high-frequency noise is removed by a low-pass filter, and common-mode interference is eliminated by an isolation module to obtain a stable voltage or current signal. When the output is a digital signal, the communication protocol is parsed by the controller's built-in or external communication module, and cyclic redundancy check (CRC) is performed to ensure data reliability. The signal is sampled within a set sampling frequency range, denoted as [sample frequency denoted as '[sample frequency '[sample frequency '['] ... Its value is in to Between, according to the sampling time Obtain instantaneous liquid level value The obtained data is encoded and output according to the format required by the controller to obtain a standardized liquid level data sequence. The data is then transmitted to the controller via an analog input port or digital bus interface. During transmission, time synchronization and data verification are performed to ensure the consistency and integrity of the data timing. The final output is a liquid level signal data stream that the controller can recognize. This data stream serves as the input to the control algorithm for subsequent filtering, averaging, state estimation, and PID control calculations, thereby providing accurate real-time data for liquid level regulation.

[0094] This enables stable acquisition and accurate transmission of liquid level signals, ensuring consistency of liquid level data in timing and amplitude, improving the reliability of the controller in acquiring liquid level information, and providing input for subsequent control algorithms.

[0095] Please see Figure 1 and Figure 2 The data processing module is used to filter the collected liquid level signal, and then perform averaging or state estimation to obtain the processed liquid level information.

[0096] Furthermore, the data processing module filters the acquired liquid level signal, including the following steps:

[0097] Choose a filtering method, such as a low-pass filter, a moving average filter, or a Kalman filter;

[0098] Set the filter parameters: the cutoff frequency of the low-pass filter is 1Hz to 50Hz, the window length of the moving average filter is 5 to 50 sampling points, and the process noise covariance and measurement noise covariance of the Kalman filter are set according to the liquid level change amplitude and sensor characteristics.

[0099] The collected liquid level signals are filtered in real time, and the processing delay is controlled within 10% to 50% of the sampling period.

[0100] The filtered liquid level signal is used as the input for subsequent data processing or control.

[0101] Specifically, the data processing module filters the acquired liquid level signal, including selecting an appropriate filtering method, setting filter parameters, and processing the acquired signal in real time. The low-pass filter is used to suppress high-frequency noise, and its mathematical expression is: ;in The collected liquid level signal. This is the filtered liquid level signal. Calculated based on the cutoff frequency and sampling frequency The moving average filter filters through continuous Smoothing is achieved by averaging the sampling points, using the following formula: ;in The window length, set according to the sampling frequency and the amplitude of liquid level change, is used by the Kalman filter to perform state estimation on the liquid level signal. Its state update equation is: ;in This is the filtered liquid level state estimate. These are prior estimates. The actual collected liquid level value. For the observation matrix, The Kalman gain is determined by the process noise covariance. Covariance of satellite measurement noise The calculated parameters are set based on the liquid level change amplitude and sensor accuracy. The input data is the liquid level signal output by the acquisition module, and the output is the filtered liquid level information. This result is used to provide subsequent averaging or state estimation processing and control algorithm modules to achieve liquid level control, ensuring the stability and reliability of the liquid level signal. The filtering delay is controlled within the sampling period. to Within the specified range, this ensures timely system response.

[0102] By filtering the acquired liquid level signal, noise and abnormal fluctuations can be suppressed, the liquid level data can be smoothed, and the signal stability can be improved. This provides a reliable input for subsequent state estimation and control algorithms, thereby improving the accuracy of liquid level regulation and the stability of system response.

[0103] The data processing module performs averaging or state estimation processing on the filtered liquid level signal, including the following steps:

[0104] Averaging: The continuously acquired liquid level signals are arithmetically averaged over a window of 5 to 50 sampling points. The average value is recalculated after each update of the data within the window.

[0105] State estimation processing: The liquid level system is modeled as a linear or nonlinear dynamic system, and state equations and observation equations are established. The liquid level state estimate is calculated by Kalman filtering or extended Kalman filtering. The process noise covariance and measurement noise covariance of the filter are set according to the liquid level change amplitude and sensor accuracy.

[0106] Processing delay control: Ensure that the processing delay of average or state estimation is within 10% to 50% of the sampling period;

[0107] Output processed liquid level information: The liquid level information obtained by averaging or state estimation is used as the output of the data processing module for the control algorithm module.

[0108] Specifically, the arithmetic mean of the continuously acquired liquid level signals is first calculated within a window length of 5 to 50 sampling points. The average is recalculated after each window update to obtain smoothed liquid level data. The formula is: ;in Indicates the first The liquid level value of the second sample. The window length is [value missing]. The input data is a filtered real-time liquid level signal, obtained through acquisition and filtering in the previous module. The output is a smoothed liquid level value used in subsequent control algorithms. The state estimation process models the liquid level system as a linear or nonlinear dynamic system and establishes the state equations. and observation equations ;in Liquid level status. To control the input, For observing signals, and These are process noise and measurement noise, respectively. The covariance is set based on the liquid level change amplitude and sensor accuracy. The liquid level state estimate is calculated using Kalman filtering. Gain The output is the estimated liquid level value. This is used to control the algorithm module to generate liquid level adjustment commands, and the processing delay is controlled within the sampling period. Within this range, continuous and smooth liquid level information can be used for closed-loop control to regulate the liquid level of molten aluminum.

[0109] By averaging or state estimation of the filtered liquid level signal, smooth and reliable liquid level information can be obtained, improving the stability and accuracy of the liquid level data. This provides a reference for the subsequent control algorithm to generate liquid level adjustment commands, thereby improving the problem of unstable liquid level control of molten aluminum.

[0110] Please see Figure 1 and Figure 3The control algorithm processing module is used to input the processed liquid level information into the controller and generate liquid level adjustment commands through the closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level.

[0111] Furthermore, a liquid level adjustment command is generated through a closed-loop control algorithm, including the following steps:

[0112] Select a closed-loop control algorithm, which can be PID control, self-tuning PID control, or fuzzy adaptive control.

[0113] The liquid level information output by the data processing module is used as a feedback signal, and the deviation from the set liquid level is calculated to obtain an error signal.

[0114] The parameters of the closed-loop control algorithm are dynamically adjusted, with the proportional parameter Kp ranging from 0.1 to 10, the integral parameter Ki ranging from 0.01 to 5, and the derivative parameter Kd ranging from 0.001 to 1.

[0115] Based on the liquid level change trend or preset flow rate change, a feedforward control quantity is generated, and the feedforward control quantity is superimposed with the closed-loop regulation quantity to form the final liquid level regulation command.

[0116] The liquid level adjustment command is output to the command execution module. The command is either an analog current signal or a digital control signal, and is updated in real time with a delay control within 10% to 50% of the sampling period.

[0117] Specifically, the error signal is obtained by using the liquid level information output by the data processing module as a feedback signal and calculating the deviation from the set liquid level. ;in For the processed liquid level information, To set the liquid level, a liquid level adjustment command is generated through a closed-loop control algorithm. The closed-loop control algorithm can employ proportional-integral-derivative (PID) control, fuzzy adaptive control, or self-tuning PID control. The PID control variable is... proportional parameters The range is 0.1 to 10, and the integral parameter is... The range is from 0.01 to 5, and the differential parameter is... The parameters, ranging from 0.001 to 1, were obtained through experimental debugging based on the magnitude of liquid level changes and the system response characteristics. Simultaneously, feedforward control variables were generated based on the liquid level change trend or preset flow rate changes. This is then combined with the closed-loop control quantity to form the final liquid level control command. The output is sent to the instruction execution module. This instruction can be an analog current signal or a digital control signal, used to drive the liquid level actuator to adjust the molten aluminum level to maintain the set level. This adjustment process is updated in real time, with the delay controlled within the sampling period. Within the specified range, it ensures rapid response and stability of the liquid level, while providing a control basis for the liquid level maintenance module.

[0118] By combining closed-loop control with predictive or feedforward strategies, real-time adjustment and dynamic control of the molten aluminum level can be achieved, thereby improving the accuracy of level maintenance and system response speed, and ensuring the stability of the smelting process.

[0119] Please see Figure 1 and Figure 4 Liquid level regulation, combined with prediction or feedforward strategies, includes the following steps:

[0120] The future liquid level change trend is calculated based on historical liquid level data and the rate of liquid level change, with a prediction time window of 0.1 to 5 seconds;

[0121] The feedforward control quantity is generated based on the predicted liquid level deviation or preset flow rate change, and the range of the feedforward control quantity is 0% to 100% of the actuator control quantity;

[0122] The feedforward control quantity is superimposed with the adjustment quantity calculated by the closed-loop control algorithm to form the final liquid level adjustment command. The superposition weight can be adjusted within the range of 0.1 to 0.9.

[0123] The final liquid level adjustment command is output to the command execution module in real time, and the update cycle is synchronized with the sampling cycle, with the delay controlled within 10% to 50% of the sampling cycle.

[0124] Specifically, the liquid level information output by the data processing module is used as the input signal. With set liquid level Error signals are obtained by performing deviation calculations. Error signal input closed-loop control algorithms, such as PID controllers, generate basic adjustment values:

[0125] ;

[0126] Where the proportional parameter The integral parameter ranges from 0.1 to 10. The differential parameter ranges from 0.01 to 5. The value ranges from 0.001 to 1 and can be dynamically adjusted based on changes in the liquid level; then, based on historical liquid level data... and rate of change of liquid level Calculate future liquid level prediction And generate feedforward control quantity The range of feedforward control quantity is the control quantity of the actuator. to , superimposed weight Adjustable between 0.1 and 0.9; the final liquid level adjustment command is given via formula. The output is sent to the instruction execution module for real-time liquid level control. This instruction can be an analog current signal or a digital control signal, and its update cycle is synchronized with the liquid level sampling cycle, with the delay controlled within a fraction of the sampling cycle. Within the range, the output results are used to drive the liquid level actuator to adjust the liquid level of molten aluminum, thereby achieving stable liquid level maintenance and rapid response, so that the flow rate and flow control of the smelting process meet the production requirements. All parameters are obtained through liquid level sensor data acquisition and initial calibration of the control system, and the prediction time window is set to 0.1 to 5 seconds.

[0127] By combining closed-loop control with predictive feedforward strategies, real-time response and dynamic optimization of liquid level regulation are achieved, enabling the molten aluminum liquid level to be maintained stably and improving the accuracy and consistency of flow rate and flow control.

[0128] Please see Figure 1 and Figure 5 The instruction execution module is used to drive the liquid level actuator to adjust the liquid level of the molten aluminum liquid according to the liquid level adjustment instruction;

[0129] Furthermore, the driving liquid level actuator adjusts the liquid level of the molten aluminum liquid, including the following steps:

[0130] Select a level actuator, which is a proportional level valve or other device with continuously adjustable flow rate, with a control range of 0% to 100%.

[0131] Receive level adjustment commands from the control algorithm processing module. The commands are analog current signals, analog voltage signals, or digital control signals, and map them into control quantities that can be recognized by the actuator.

[0132] The actuator is driven by the analyzed control quantity to adjust the liquid flow rate, thereby adjusting the liquid level of molten aluminum. The liquid level adjustment response time is 0.1 seconds to 5 seconds.

[0133] The liquid level sensor confirms the liquid level change and provides limit and overload protection for the actuator.

[0134] Specifically, the instruction execution module converts the liquid level adjustment instruction from the control algorithm processing module into a control quantity that the actuator can recognize. This process includes three steps: selecting the liquid level actuator, parsing the control signal, and driving the actuator. The input data is the liquid level adjustment instruction. ,in The signal can be an analog current signal, an analog voltage signal, or a digital control signal, and its value range corresponds to the control quantity of the actuator. to The control algorithm module determines the liquid level deviation. and feedforward quantity The generation formula is expressed as: ;in This is the closed-loop control quantity. To assign weights, values ​​range from 0.1 to 0.9. To set the liquid level, The processed liquid level information is provided by the data processing module; the steps include... Mapped to the actual control quantity of the actuator It also outputs a drive signal, the formula of which is: ;in This indicates the percentage opening of a proportional level valve or the flow control value of a continuous flow control device. The mapping function is determined by the actuator calibration, and the output result is the action response of the liquid level actuator. The liquid level is dynamically adjusted by changing the flow rate of molten aluminum. This liquid level change is collected again by the liquid level measurement module to form a closed-loop feedback, which is used for continuous liquid level control and to ensure liquid level stability. Each parameter, such as sampling period, control range and response time, is determined by the performance of the actuator and system design, and is obtained through experimental calibration or equipment manual.

[0135] This enables the conversion of liquid level adjustment commands generated by the control algorithm into actuator actions, achieving continuous adjustment and rapid response of the molten aluminum liquid level, thereby maintaining liquid level stability and improving the accuracy and reliability of aluminum liquid flow control.

[0136] Please see Figure 1 and Figure 6 The liquid level maintenance module is used to maintain the liquid level of molten aluminum through continuous cyclic measurement, control and execution;

[0137] Furthermore, maintaining the level of the molten aluminum liquid includes the following steps:

[0138] The non-contact radar level sensor of the liquid level measurement module is used to collect the liquid level of molten aluminum in real time, with a sampling frequency of 10Hz to 100Hz;

[0139] The collected liquid level signal is processed by the data processing module through filtering, averaging, or state estimation, and then input into the control algorithm module.

[0140] The control algorithm module generates liquid level adjustment commands based on closed-loop control and prediction or feedforward strategies.

[0141] The instruction execution module drives the liquid level actuator to adjust the liquid level according to the liquid level adjustment instruction. The liquid level adjustment response time is 0.1 seconds to 5 seconds, and limit and overload protection are provided.

[0142] The liquid level measurement, data processing, control algorithm and execution action are formed into a continuous closed loop, and the cycle period is synchronized with the sampling cycle.

[0143] The liquid level change trend and liquid level deviation are monitored in real time. If abnormal fluctuations are detected, the control algorithm automatically adjusts the parameters or feedforward strategy to maintain the liquid level stability, and the liquid level deviation is controlled within ±1.5mm.

[0144] Specifically, the liquid level maintenance module takes the molten aluminum liquid level signal collected by the liquid level measurement module as input, and first performs filtering, averaging, or state estimation processing by the data processing module to obtain the processed liquid level information. The data processing can use the Kalman filter formula:

[0145] ;

[0146] in This is the updated liquid level state estimate. These are the prior predicted values. For Kalman gain, The processed liquid level measurement value. The observation matrix and process noise covariance are given. Covariance of measurement noise The settings are based on the magnitude of liquid level changes and sensor accuracy; the processed liquid level information is input into the control algorithm module, which generates liquid level adjustment commands based on closed-loop control and feedforward strategies. :

[0147] ;

[0148] in For liquid level deviation, To predict the amount of liquid level change, For feedforward weighting, The parameters are set as closed-loop parameters, with the range determined based on the liquid level characteristics. The liquid level adjustment command is output to the command execution module, driving the liquid level actuator to adjust the molten aluminum flow rate to maintain the liquid level. The liquid level adjustment response time is 0.1 to 5 seconds, while simultaneously implementing limit and overload protection. Liquid level measurement, data processing, control calculation, and execution form a continuous closed-loop cycle, synchronized with the sampling cycle. The liquid level change trend and deviation are monitored in real time. If abnormal fluctuations are detected, the control algorithm automatically adjusts parameters and feedforward strategies to ensure liquid level stability and maintain the liquid level deviation within a specified range. Within the millimeter range, this result is used to achieve dynamic maintenance of the molten aluminum liquid level, ensuring stable flow and continuity and accuracy of the casting process. The input data includes real-time liquid level measurement values ​​and historical liquid level change information, and the output is a liquid level adjustment command signal.

[0149] By continuously measuring, processing, and adjusting the liquid level, the liquid level of molten aluminum is dynamically maintained, improving flow stability and ensuring that the casting process is continuous while keeping the liquid level deviation within a small range.

[0150] Example 2:

[0151] In aluminum alloy die-casting production lines, molten aluminum is injected into the runner channel of a tilting melting furnace. Due to insufficient accuracy in level measurement, the aluminum liquid level fluctuates significantly, leading to unstable flow rate and velocity in subsequent die-casting processes. This results in increased porosity, loose microstructure, and higher scrap rates in the castings. To address these issues, a tilting melting furnace level control method provided by this invention is employed, the process of which is as follows: Figure 7 As shown. The specific implementation process of this method is as follows:

[0152] First, by using a non-contact radar level sensor to measure the level of molten aluminum in the tilting furnace in real time, the problem of sensor damage due to direct contact with the molten aluminum under high temperature conditions can be avoided. At the same time, a continuous and stable level signal can be obtained, providing basic data for subsequent precise control.

[0153] Then, the liquid level signal measured by the liquid level sensor is collected and transmitted to the controller to ensure that the measured liquid level information can be transmitted to the control unit with low latency and high integrity, so as to realize real-time monitoring of liquid level changes.

[0154] Next, filtering, averaging, or state estimation processing of the collected liquid level signal can effectively eliminate liquid level fluctuations, sensor noise, and transient interference, resulting in smoother and more reliable liquid level information and improving the response accuracy of subsequent control algorithms.

[0155] Subsequently, the processed liquid level information is input into the controller, and a liquid level adjustment command is generated through a closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level, ensuring that the liquid level adjustment process has both fast response capability and suppression of adjustment overshoot, thereby improving the stability of liquid level control.

[0156] Then, according to the liquid level adjustment command, the liquid level actuator is driven to adjust the liquid level of the molten aluminum liquid, so that the liquid level can be adjusted quickly and accurately according to the target value, and the liquid level of the aluminum liquid in the flow channel is kept at the set height.

[0157] Finally, through continuous cyclic measurement, control, and execution, the molten aluminum liquid level is maintained, achieving long-term stable control of the liquid level. This avoids casting defects and reduced production efficiency caused by liquid level fluctuations, ensures the stability of flow rate and volume in subsequent die-casting processes, and improves the density and yield of castings.

[0158] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A liquid level control system for a tilting smelting furnace, characterized in that, include: The liquid level measurement module is used to measure the liquid level of molten aluminum in a tilting furnace in real time using a non-contact radar liquid level sensor. The signal acquisition module is used to acquire the liquid level signal measured by the liquid level sensor and transmit it to the controller; The data processing module is used to filter the collected liquid level signal, and then perform averaging or state estimation to obtain the processed liquid level information. The control algorithm processing module is used to input the processed liquid level information into the controller and generate liquid level adjustment commands through a closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level. The instruction execution module is used to drive the liquid level actuator to adjust the liquid level of the molten aluminum liquid according to the liquid level adjustment instruction; The liquid level maintenance module is used to maintain the liquid level of molten aluminum through continuous cyclic measurement, control and execution.

2. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The radar level sensor has a radar wave frequency of 24GHz to 80GHz. The radar level sensor is installed above the flow channel or melting furnace, with the emitting surface perpendicular to the liquid surface. The measurement distance is 100mm to 1000mm. The measurement error is controlled within ±2% through initial zero-point and full-scale calibration. The sensor outputs a liquid level signal with a sampling frequency of 10Hz to 100Hz. The liquid level data changes continuously in the range of 0mm to 1000mm. The data is transmitted to the controller through analog current, analog voltage or digital bus interface.

3. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The process of acquiring the liquid level signal measured by the liquid level sensor includes the following steps: Select the acquisition method according to the output type of the liquid level sensor, wherein the output type is either analog signal or digital signal; It amplifies, filters, and isolates analog signals, and performs protocol parsing and data verification on digital signals. The liquid level signal is acquired according to a set sampling frequency, which is 10Hz to 100Hz. The acquired liquid level signal is converted into a data format that the controller can recognize; The transmission to the controller includes the following steps: The formatted liquid level signal is connected to the controller via a standard interface, which can be an analog input port or a digital bus interface. Time synchronization and verification of transmitted data are performed to ensure data integrity; The liquid level signal is transmitted to the controller in real time for subsequent control processing.

4. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The data processing module filters the acquired liquid level signal, including the following steps: Choose a filtering method, wherein the method is a low-pass filter, a moving average filter, or a Kalman filter; The filter parameters are set such that the cutoff frequency of the low-pass filter is 1Hz to 50Hz, the window length of the moving average filter is 5 to 50 sampling points, and the process noise covariance and measurement noise covariance of the Kalman filter are set according to the liquid level change amplitude and sensor characteristics. The collected liquid level signals are filtered in real time, and the processing delay is controlled within 10% to 50% of the sampling period. The filtered liquid level signal is used as the input for subsequent data processing or control.

5. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The data processing module performs averaging or state estimation processing on the filtered liquid level signal, including the following steps: Averaging: The continuously acquired liquid level signals are arithmetically averaged over a window of 5 to 50 sampling points. The average value is recalculated after each update of the data within the window. State estimation processing: The liquid level system is modeled as a linear or nonlinear dynamic system, and state equations and observation equations are established. The liquid level state estimate is calculated by Kalman filtering or extended Kalman filtering. The process noise covariance and measurement noise covariance of the filter are set according to the liquid level change amplitude and sensor accuracy. Processing delay control: Ensure that the processing delay of average or state estimation is within 10% to 50% of the sampling period; Output processed liquid level information: The liquid level information obtained by averaging or state estimation is used as the output of the data processing module for the control algorithm module.

6. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The process of generating liquid level adjustment commands through a closed-loop control algorithm includes the following steps: Select a closed-loop control algorithm, wherein the algorithm is PID control, self-tuning PID control, or fuzzy adaptive control; The liquid level information output by the data processing module is used as a feedback signal, and the deviation from the set liquid level is calculated to obtain an error signal. The parameters of the closed-loop control algorithm are dynamically adjusted, with the proportional parameter Kp ranging from 0.1 to 10, the integral parameter Ki ranging from 0.01 to 5, and the derivative parameter Kd ranging from 0.001 to 1. Based on the liquid level change trend or preset flow rate change, a feedforward control quantity is generated, and the feedforward control quantity is superimposed with the closed-loop regulation quantity to form the final liquid level regulation command. The liquid level adjustment command is output to the command execution module. The command is an analog current signal or a digital control signal, which is updated in real time, and the delay is controlled within 10% to 50% of the sampling period.

7. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The method of combining prediction or feedforward strategies for liquid level regulation includes the following steps: The future liquid level change trend is calculated based on historical liquid level data and the rate of liquid level change, and the prediction time window is 0.1 to 5 seconds. A feedforward control quantity is generated based on the predicted liquid level deviation or preset flow rate change, and the range of the feedforward control quantity is 0% to 100% of the actuator control quantity; The feedforward control quantity is superimposed with the adjustment quantity calculated by the closed-loop control algorithm to form the final liquid level adjustment command. The superposition weight can be adjusted within the range of 0.1 to 0.

9. The final liquid level adjustment command is output to the command execution module in real time, and the update cycle is synchronized with the sampling cycle, with the delay controlled within 10% to 50% of the sampling cycle.

8. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, The driving liquid level actuator adjusts the liquid level of molten aluminum, including the following steps: Select a level actuator, which is a level proportional valve or other device with continuously adjustable flow rate, and the control range is 0% to 100%; Receive a liquid level adjustment command from the control algorithm processing module, wherein the command is an analog current signal, an analog voltage signal, or a digital control signal, and map it into a control quantity that the actuator can recognize; The actuator is driven by the analyzed control quantity to adjust the liquid flow rate, thereby adjusting the liquid level of molten aluminum. The liquid level adjustment response time is 0.1 seconds to 5 seconds. The liquid level sensor confirms the liquid level change and provides limit and overload protection for the actuator.

9. The tilting smelting furnace liquid level control system according to claim 1, characterized in that, Maintaining the level of molten aluminum includes the following steps: The non-contact radar level sensor of the liquid level measurement module is used to collect the liquid level of molten aluminum in real time, with a sampling frequency of 10Hz to 100Hz; The collected liquid level signal is processed by the data processing module through filtering, averaging, or state estimation, and then input into the control algorithm module. The control algorithm module generates liquid level adjustment commands based on closed-loop control and prediction or feedforward strategies. The instruction execution module drives the liquid level actuator to adjust the liquid level according to the liquid level adjustment instruction. The liquid level adjustment response time is 0.1 seconds to 5 seconds, and limit and overload protection are provided. The liquid level measurement, data processing, control algorithm and execution action are formed into a continuous closed loop, and the cycle period is synchronized with the sampling cycle. The liquid level change trend and liquid level deviation are monitored in real time. If abnormal fluctuations are detected, the control algorithm automatically adjusts the parameters or feedforward strategy to maintain the liquid level stability, and the liquid level deviation is controlled within ±1.5mm.

10. A method for controlling the liquid level in a tilting smelting furnace, characterized in that, The method, applied to a tilting smelting furnace level control system according to any one of claims 1-9, comprises: The liquid level of molten aluminum in a tilting furnace is measured in real time using a non-contact radar level sensor. The liquid level signal measured by the liquid level sensor is collected and transmitted to the controller; The collected liquid level signal is filtered, and then averaged or state estimated to obtain the processed liquid level information. The processed liquid level information is input into the controller, and a liquid level adjustment command is generated through a closed-loop control algorithm. The closed-loop control algorithm can dynamically adjust the control parameters and combine prediction or feedforward strategies to adjust the liquid level. According to the liquid level adjustment command, the liquid level actuator is driven to adjust the liquid level of the molten aluminum liquid; The level of molten aluminum is maintained through continuous cyclic measurement, control, and execution.

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