Pump speed dynamic calibration device and method based on weighing feedback

Abstract

The invention relates to a pump speed dynamic calibration device and method based on weighing feedback, which are applied to the technical field of biological pharmacy, and the method comprises the following steps: setting a weighing module to directly measure the weight change so as to calculate the actual flow speed, thereby getting rid of the dependence on inaccurate and variable empirical parameters such as flux per revolution and the like, and improving the accuracy of the calibration. And the authenticity and the accuracy of the feedback data are fundamentally ensured. The actual flow velocity is compared with the target flow velocity through a calibration algorithm built in the control module, the rotating speed of the pump is adjusted in real time based on deviation, and a closed-loop control system is constructed. The system can respond in real time and automatically compensate flow velocity deviation caused by various factors such as pump rotating speed nonlinearity, pipeline pressure fluctuation, pump and pipeline abrasion and aging and the like, the precision and stability of flow velocity control are remarkably improved, and the adaptability and the anti-jamming capability of the device are enhanced. According to the invention, automatic calibration and stable control of the flow are realized, and the method is especially suitable for a continuous production process with high requirements on precision and stability.

Description

Technical Field

[0001] This invention relates to the field of biopharmaceutical technology, specifically to a dynamic pump speed calibration device and method based on weighing feedback. Background Technology

[0002] In fields such as biopharmaceuticals and fine chemicals, which require high-precision fluid control, peristaltic pumps, diaphragm pumps, and plunger pumps are widely used. Currently, flow control of these pumps generally relies on a theoretical formula: "flow rate = rotational speed × flow rate per revolution," which assumes that the pump's flow rate per revolution is a pre-calibrated or set fixed value.

[0003] However, this open-loop or semi-open-loop control method based on fixed parameters has inherent drawbacks. First, the pump's flux per revolution (RPM) is not a constant value; it varies with the pump's operating speed. Within the rated speed range, the RPM will differ between lower and higher speeds, and the fixed value cannot adapt to the flux changes caused by speed fluctuations. Second, changes in pipeline pressure during pump operation affect the RPM (higher pressure results in lower RPM), and existing solutions do not consider this dynamic factor. Furthermore, pump or pipeline wear (such as peristaltic pump pipeline deformation or diaphragm pump diaphragm aging) can cause changes in RPM, and the fixed parameters cannot be corrected in real time, ultimately resulting in insufficient flow rate control accuracy and failing to meet the precise pump flow rate control requirements of the biopharmaceutical field. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a dynamic pump speed calibration device and method based on weighing feedback, which aims to solve the technical problem in the prior art that the flow control of the pump depends on fixed parameters, resulting in low flow control accuracy and poor stability under dynamic operating conditions.

[0005] According to a first aspect of the present invention, a dynamic pump speed calibration device based on weighing feedback is provided, the device comprising: Weighing module: Used to collect real-time data on the weight changes of the medium being transported at the pump output. Pump: Used to pump the target medium from the output end within the rated speed range; Data acquisition module: Connected to the weighing module, it is used to collect the weight data from the weighing module and send it to the control module; Control module: Connected to the data acquisition module and the pump drive unit respectively, it receives weight data sent by the data acquisition module, compares the actual speed with the target speed according to the preset built-in calibration algorithm, generates a pump speed adjustment command, and sends the pump speed adjustment command to the pump drive unit. Drive unit: Used to receive the pump speed adjustment command sent by the control module, and adjust the actual speed of the pump to the calibrated target speed according to the pump speed adjustment command, so that the actual flow rate approaches the preset target flow rate.

[0006] Preferably, The pump's output end is connected to the inlet of the medium storage container via a delivery pipeline; The weighing module collects data on the weight changes of the media storage container.

[0007] Preferably, The weighing module uses a weighing sensor.

[0008] Preferably, The control module is pre-set with the density and flow rate of the target transport medium. The control module is used to receive weight data from the data acquisition module and convert the weight change into the actual flow rate of the pump based on the preset density of the target conveying medium and the weight change within a preset time interval.

[0009] Preferably, The control module uses at least one of proportional control, proportional-integral control, or proportional-integral-derivative control algorithms to generate the speed adjustment command.

[0010] Preferably, The pump is a peristaltic pump, a diaphragm pump, or a plunger pump.

[0011] Preferably, The data acquisition module communicates with the weighing module, the control module with the data acquisition module, and the control module with the pump drive unit via wired or wireless means.

[0012] Preferably, The data acquisition module is also used to filter the weight data to eliminate the pulsation effect during the pump delivery process.

[0013] According to a second aspect of the present invention, a dynamic pump speed calibration method based on weighing feedback is provided, the method being based on the aforementioned dynamic pump speed calibration device based on weighing feedback, the method comprising: Obtain the weight change at the pump output end over a preset time period; The actual flow rate is obtained based on the preset density, weight change, and weight acquisition time interval of the target transport medium. Obtain the actual pump speed, and obtain the actual flow rate per revolution based on the actual flow velocity and the actual speed. The calibrated target rotational speed is obtained based on the actual throughput per revolution and the preset target flow rate. The pump speed is adjusted according to the calibrated target speed, and the actual pump speed is adjusted to the calibrated target speed so that the actual flow rate of the pump approaches the preset target flow rate.

[0014] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This application calculates the actual flow rate by directly measuring weight changes using a weighing module, eliminating reliance on inaccurate and volatile empirical parameters such as "flux per revolution," thus fundamentally ensuring the authenticity and accuracy of the feedback data. A closed-loop control system is constructed by comparing the actual flow rate with the target flow rate using a built-in calibration algorithm in the control module and adjusting the pump speed in real time based on the deviation. This system can respond in real time and automatically compensate for flow rate deviations caused by various factors such as pump speed nonlinearity, pipeline pressure fluctuations, and pump and pipeline wear and aging, significantly improving the accuracy and stability of flow rate control and enhancing the adaptability and anti-interference capabilities of the device. Furthermore, this application achieves automatic flow calibration and stable control, eliminating the need for frequent manual intervention to correct parameters, reducing operational complexity, and improving the automation level and ease of use of the device, making it particularly suitable for continuous production processes with high precision and stability requirements.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] Figure 1 This is a schematic diagram of a dynamic pump speed calibration device based on weighing feedback, according to an exemplary embodiment. Figure 2 This is a flowchart illustrating a dynamic pump speed calibration method based on weighing feedback, according to another exemplary embodiment. In the attached diagram: 1-pump, 2-drive unit, 3-control module, 4-data acquisition module, 5-weighing module, 6-medium storage container, 7-transport pipeline. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0019] Example 1 Figure 1 This is a schematic diagram of a pump speed dynamic calibration device based on weighing feedback, according to an exemplary embodiment. Figure 1 As shown, the device includes a pump 1, a drive unit 2, a control module 3, a data acquisition module 4, a weighing module 5, a medium storage container 6, and a delivery pipeline 7. In this embodiment, the above modules work together to form a whole to achieve precise control of the fluid delivery process.

[0020] Specifically, the weighing module 5 is the foundation for the accurate feedback of this device. As an optional implementation, the weighing module 5 can employ a high-precision strain gauge load cell, whose measuring range can be selected according to the application scenario (e.g., 10 kg), and whose static measurement accuracy can reach 0.1 g or higher. The media storage container 6 is stably placed on the bearing surface of the weighing module 5. Here, the media storage container 6 can be either a receiving tank for receiving the media delivered by the pump 1, or a source tank for supplying media to the pump 1. In the description of this embodiment, the media storage container 6 is used as a receiving tank, and its weight continuously increases as the pump 1 operates. The weighing module 5 is configured to measure the total weight of the media storage container 6 and its internal media at a preset frequency (e.g., every 100 milliseconds), and convert the measurement result into weight data in the form of a digital signal or a standard analog signal (e.g., 4-20 mA or 0-10 V) and output it to the data acquisition module 4; the pump 1 and the media storage container 6 are connected via a delivery pipeline 7. The data acquisition module 4 is electrically connected to the weighing module 5, and its core can be a microprocessor with a high-precision analog-to-digital converter. The data acquisition module 4 receives raw weight data from the weighing module 5 and acquires and buffers this data according to a preset sampling period. Furthermore, the data acquisition module 4 is also responsible for performing preliminary data processing, such as converting the acquired electrical signals into weight values ​​with defined physical units (e.g., grams or kilograms). The processed weight data is then sent to the control module 3.

[0021] Control module 3 is the core of the entire closed-loop control system. In one embodiment of this application, control module 3 can be a high-performance microcontroller unit or a single-board computer. It receives real-time weight data streams from data acquisition module 4 via a communication interface (e.g., a serial universal asynchronous transceiver or internal bus) and is simultaneously connected to drive unit 2 of pump 1 to send control commands to it. Control module 3 internally contains core calibration and control algorithm programs. Furthermore, control module 3 is typically equipped with a human-machine interface, such as a small display screen and buttons, or a touchscreen, to allow operators to set key process parameters such as target flow rate and density of the conveying medium. Drive unit 2, as part of the actuator, directly controls the operating state of pump 1. Depending on the type of motor used in pump 1, drive unit 2 can be a frequency converter, stepper motor driver, or servo driver. Drive unit 2 receives speed adjustment commands from control module 3, which can be an analog voltage signal, a pulse frequency signal, or command data transmitted via a digital bus. Accordingly, drive unit 2 precisely adjusts the power, frequency, or number of pulses supplied to the motor of pump 1 according to the command, thereby precisely controlling the speed of pump 1.

[0022] It should be noted that the connection between the data acquisition module 4 and the control module 3, and between the control module 3 and the drive unit 2, can be wired (such as RS485, Ethernet) or wireless (such as Bluetooth, LoRa), without affecting the implementation of the core calibration logic.

[0023] Pump 1 is the actuator for fluid transport. In this basic embodiment, it can be any type of positive displacement pump commonly used in fields such as biopharmaceuticals and fine chemicals, including but not limited to peristaltic pumps, diaphragm pumps, or plunger pumps. The inlet of pump 1 is connected to a medium source, and the outlet is connected to a medium storage container 6 via a transport pipeline 7.

[0024] It should be noted that in this embodiment, the data acquisition module 4 and the control module 3 are implemented as two functionally independent modules. This separate design facilitates functional decoupling and modular development. Alternatively, in another embodiment, the functions of the data acquisition module 4 and the control module 3 can be integrated into the same physical hardware, such as a more powerful programmable logic controller or industrial control computer. Such integrated units are collectively referred to as processing units in this embodiment.

[0025] The calibration algorithm built into control module 3 specifically includes: The operator inputs a desired flow rate value as the target flow rate Qt through the human-machine interface of the control module 3, for example, setting it to 50.0 ml / min. At the same time, the density ρ of the transport medium (e.g., for water, ρ ≈ 1.0 g / ml) is also pre-input as a known parameter and stored in the memory of the control module 3; After the system is started, pump 1 starts running at an initial speed to deliver the medium to the medium storage container 6, and then the system enters a continuous closed-loop control cycle. Data acquisition module 4 continuously acquires weight data from weighing module 5. To calculate the flow rate, the system needs to acquire the weight change Δm within a defined time interval Δt. For example, control module 3 can set Δt to 5 seconds. At time point t1, control module 3 records the weight value m1 reported by data acquisition module 4; 5 seconds later at time point t2, it records the weight value m2 again. Therefore, the effective weight increment within this 5-second time interval is Δm = m2 - m1. Based on the received weight change Δm, the preset time interval Δt, and the medium density ρ, control module 3 calculates the current actual volumetric flow rate Qv using the following formula: Qv = Δm / Δt*ρ; Control module 3 can obtain the actual rotational speed N0 of pump 1 through drive unit 2; using the actual rotational speed N0 of pump 1 and the current actual volumetric flow rate Qv of pump 1 calculated above, control module 3 can calculate the current actual flow rate Vt of pump 1 per revolution using the formula: Vt = Qv / N0; Control module 3, based on the pre-set target flow rate Qt and the actual throughput per revolution Vt, uses the formula: N cal = Qt / Vt, calculate the calibrated target rotational speed N. cal Because the actual speed N0 of pump 1 differs from the calibrated target speed N... cal Since this is already known, based on the difference between the two, control module 3 generates a speed control command, specifically including: In this embodiment, the control module 3 has a built-in proportional-integral-derivative control algorithm to generate the speed adjustment command U. The output U(t) of this algorithm consists of three parts: (1) Proportional term (P): This feature provides an immediate, proportional adjustment based on the current deviation; the larger the deviation, the greater the adjustment, thus ensuring a rapid system response.

[0026] (2) Integral term (I): This term accumulates the deviation over a period of time. Even if the current deviation is small, as long as it persists, the integral term will continue to increase, thus generating an adjustment force sufficient to eliminate the steady-state error. This characteristic is crucial for compensating for long-term flow rate drift caused by pump pipe aging, slow changes in pipeline back pressure, etc.

[0027] (3) Differential term (D): The rate of change of this response deviation is predictable. When the deviation rapidly approaches zero, the differential term generates a counterforce to prevent overshoot and system oscillation, thereby improving system stability.

[0028] The control module 30 substitutes the current speed deviation and historical deviation data into the proportional-integral-derivative control algorithm formula and outputs a specific speed adjustment command U, which corresponds to a speed adjustment amount that needs to be increased.

[0029] The control module 3 converts the calculated speed adjustment command U into a signal format that the drive unit 2 can recognize and sends it to the drive unit 2. After receiving the command, the drive unit 2 increases the motor speed of pump 1 accordingly.

[0030] Through the above methods, the device in this embodiment can automatically compensate for various interference factors. For example, when the elasticity of the hose of pump 1 decreases due to long-term use, resulting in a reduction in its "flow per revolution", the system will detect the decrease in the actual flow rate Qv and continuously increase the pump speed through the integral stage until the actual flow rate stabilizes again at the target flow rate Qt, thereby achieving long-term stability and high-precision control of the flow rate.

[0031] Example 2 This embodiment is an optimized variation of Embodiment 1, addressing the inherent output pulsation characteristics of a specific type of pump (such as a peristaltic pump). Due to the alternating compression and release of the tubing by its rollers, the instantaneous output flow rate of a peristaltic pump is not constant but exhibits periodic pulsation. This pulsation is directly reflected in the readings of the weighing module 5, causing high-frequency fluctuations in the calculated actual volumetric flow rate Qv, which may adversely affect the stability of the control system and trigger unnecessary frequent adjustments by the control module 3.

[0032] To address this issue, this embodiment is structurally similar to Embodiment 1, except that pump 1 is explicitly defined as a peristaltic pump. The core improvement lies in the data processing stage. Specifically, a specific digital filtering step is introduced into the software algorithm of the data acquisition module 4 or the integrated processing unit. This step, which can occur after the weight data acquisition, aims to smooth the raw weight data to extract the true weight change trend, thereby eliminating or significantly reducing noise interference caused by pulsation.

[0033] In this embodiment, a preferred filtering algorithm is a moving average filtering algorithm. Accordingly, the data acquisition module 4 can be configured with a buffer to store the most recent N (for example, N can be set to 10, 20, or higher depending on the pump's pulsation frequency and sampling frequency) consecutive weight sampling points. This buffer operates in a first-in, first-out queue manner: whenever the data acquisition module 4 obtains a new weight data sample value from the weighing module 5, the new value is pushed to the tail of the queue, while the oldest sample value at the head of the queue is discarded.

[0034] At any given moment, the current weight value used for subsequent flow rate calculations is no longer the original instantaneous sample value, but rather the arithmetic mean of all N sample values ​​in the buffer queue. The calculation formula is as follows: ,in, yes t The filtered weight value at time 10:00. yes t The moment before i One original weight sample value.

[0035] This moving average processing effectively smooths out the periodic, rapid weight fluctuations (i.e., high-frequency noise) caused by the switching of the peristaltic pump rollers. The data acquisition module 4 outputs a smoother weight change curve to the control module 3.

[0036] The working process is as follows: When the peristaltic pump is working, the raw weight data sequence output by the weighing module 5 may exhibit slight fluctuations similar to a sine wave. After receiving this raw data, the data acquisition module 4 does not directly use it to calculate Δm, but instead sends the data to a moving average filter. For example, if the sampling frequency is 20 Hz and the moving average window N is set to 20, the filter outputs the average weight reading over the past second. The resulting filtered weight data sequence will have significantly reduced fluctuations, thus better reflecting the macroscopic trend of medium accumulation.

[0037] Subsequently, when executing the internal calibration algorithm, control module 3 uses the weight change Δm (e.g., Δm = The actual volumetric flow rate Qv is calculated based on this smooth curve. Therefore, the calculated actual volumetric flow rate Qv will be very stable and will not fluctuate drastically with each pump pulsation.

[0038] In this way, the input signal (deviation) provided to the proportional-integral-derivative control algorithm of control module 3 becomes more stable and reliable. The controller will not generate frequent and unnecessary acceleration or deceleration commands due to instantaneous, pulsation-induced false deviations, thereby avoiding the "jittering" of drive unit 2 and pump 1, making the entire control process smoother, and the final output fluid flow rate more uniform.

[0039] The optimized scheme in this embodiment significantly improves the system's control robustness and stability when dealing with pulsating fluid sources, resulting in a smoother final flow output curve. This scheme is particularly suitable for applications with extremely high requirements for fluid delivery stability, such as gradient elution in high-performance liquid chromatography systems, continuous feeding in bioreactors, or precise dispensing in pharmaceutical formulations.

[0040] Example 3 Figure 2 This is a flowchart illustrating a dynamic pump speed calibration method based on weighing feedback, according to another exemplary embodiment. The method includes: S1, obtain the weight change at the pump output end over a preset time period; S2, obtain the actual flow rate based on the preset density, weight change and weight acquisition time interval of the target conveying medium; S3, obtain the actual pump speed, and obtain the actual flow rate per revolution based on the actual flow rate and the actual speed; S4, obtain the calibrated target rotational speed based on the actual throughput per revolution and the preset target flow rate; S5, adjust the pump speed according to the calibrated target speed, adjust the actual pump speed to the calibrated target speed, so that the actual flow rate of the pump approaches the preset target flow rate.

[0041] It is understood that the same or similar parts in the above embodiments can be referred to each other, and the contents not described in detail in some embodiments can be referred to the same or similar contents in other embodiments.

[0042] It should be noted that in the description of this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means at least two.

[0043] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0044] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0045] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0046] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0047] The storage media mentioned above can be read-only memory, disk, or optical disk, etc.

[0048] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A dynamic pump speed calibration device based on weighing feedback, characterized in that, The device includes: Weighing module: Used to collect real-time data on the weight changes of the medium being transported at the pump output. Pump: Used to pump the target medium from the output end within the rated speed range; Data acquisition module: Connected to the weighing module, it is used to collect the weight data from the weighing module and send it to the control module; Control module: Connected to the data acquisition module and the pump drive unit respectively, it receives weight data sent by the data acquisition module, compares the actual speed with the target speed according to the preset built-in calibration algorithm, generates a pump speed adjustment command, and sends the pump speed adjustment command to the pump drive unit. Drive unit: Used to receive the pump speed adjustment command sent by the control module, and adjust the actual speed of the pump to the calibrated target speed according to the pump speed adjustment command, so that the actual flow rate approaches the preset target flow rate.

2. The apparatus according to claim 1, characterized in that, The pump's output end is connected to the inlet of the medium storage container via a delivery pipeline; The weighing module collects data on the weight changes of the media storage container.

3. The apparatus according to claim 2, characterized in that, The weighing module uses a weighing sensor.

4. The apparatus according to claim 3, characterized in that, The control module is pre-set with the density and flow rate of the target transport medium. The control module is used to receive weight data from the data acquisition module and convert the weight change into the actual flow rate of the pump based on the preset density of the target conveying medium and the weight change within a preset time interval.

5. The apparatus according to claim 4, characterized in that, The control module uses at least one of proportional control, proportional-integral control, or proportional-integral-derivative control algorithms to generate the speed adjustment command.

6. The apparatus according to claim 5, characterized in that, The pump is a peristaltic pump, a diaphragm pump, or a plunger pump.

7. The apparatus according to claim 6, characterized in that, The data acquisition module communicates with the weighing module, the control module with the data acquisition module, and the control module with the pump drive unit via wired or wireless means.

8. The apparatus according to claim 7, characterized in that, The data acquisition module is also used to filter the weight data to eliminate the pulsation effect during the pump delivery process.

9. A method for dynamic calibration of pump speed based on weighing feedback, characterized in that, The method is based on a dynamic pump speed calibration device based on weighing feedback as described in any one of claims 1-8, and the method includes: Obtain the weight change at the pump output end over a preset time period; The actual flow rate is obtained based on the preset density, weight change, and weight acquisition time interval of the target transport medium. Obtain the actual pump speed, and obtain the actual flow rate per revolution based on the actual flow velocity and the actual speed. The calibrated target rotational speed is obtained based on the actual throughput per revolution and the preset target flow rate. The pump speed is adjusted according to the calibrated target speed, and the actual pump speed is adjusted to the calibrated target speed so that the actual flow rate of the pump approaches the preset target flow rate.

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