A low-power precision flow control device and method based on microstructure valve array

Abstract

This invention belongs to the field of flow regulation and discloses a low-power precision flow regulation device and method based on a microstructured valve array. The device includes a housing, a microstructured valve array substrate with fluid inlet and outlet channels, a controller, a drive module, and a sensor module. The substrate integrates multiple normally closed microstructured valve units with identical flow conductance characteristics arranged in a two-dimensional array. The controller pre-stores the rated flow rate values ​​of each valve, receives the target flow rate, and calculates the number of valves to be opened. When the number is greater than or equal to 2, a spatially distributed scheduling algorithm is used to select valves that are evenly distributed in position from the array as the valve group to be opened, and a pulse drive signal is sent to fully open them, while the rest remain normally closed. The method includes calibration storage, receiving the target flow rate, calculating the number of valves, spatially distributed selection, and pulse drive steps. This invention avoids local flow field concentration through spatially distributed scheduling, and has the advantages of low power consumption, high precision, and high reliability.

Description

Technical Field

[0001] This invention relates to the field of flow regulation, and in particular to a low-power precision flow regulation device and method based on a microstructure valve array. Background Technology

[0002] Microfluidics technology aims to achieve precise fluid manipulation at the micrometer scale and has shown broad application prospects in precision manufacturing, chemical analysis, reagent delivery, and micro-hydraulic control. As the core control component of a microfluidic system, the performance of a microvalve directly determines the operating characteristics of the entire system. In precision fluid delivery systems, flow control devices must simultaneously meet stringent requirements of low power consumption, high precision, and high reliability.

[0003] Existing digital microvalve array solutions regulate total flow by controlling the number of valves opened to overcome the nonlinearity problem of single valves. However, this solution only focuses on the number of valves opened, without addressing the selection of which valves to open. In actual operation, consistently opening only a few specific valves in the array leads to localized flow field concentration, causing problems such as particle deposition and single-valve fatigue failure. Summary of the Invention

[0004] The present invention aims to provide a low-power precision flow regulation device and method based on a microstructure valve array to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A low-power precision flow control device based on a microstructure valve array, comprising: The housing is provided with a fluid inlet channel and a fluid outlet channel; A microstructured valve array substrate is sealed within the housing. Multiple microstructured valve units are integrated on the microstructured valve array substrate, and the multiple microstructured valve units are arranged in a two-dimensional array. The inlet of each microstructured valve unit is connected to the fluid inlet channel, and the outlet of each microstructured valve unit is connected to the fluid outlet channel. Moreover, each microstructured valve unit is a normally closed microstructured valve with the same flow conduction characteristics. The controller is electrically connected to the microstructure valve array substrate, and the controller has pre-stored the rated flow value of each microstructure valve unit under standard operating conditions. The drive module is connected to the controller and the microstructure valve array substrate, respectively; The sensor module, installed inside the housing, is configured to collect the pressure and temperature values ​​of the fluid flowing into the fluid inlet channel in real time, and transmit the collected pressure and temperature values ​​to the controller; The controller is configured to: receive a target flow rate value, and determine the target number of microstructure valve units to be opened based on the target flow rate value and the rated flow rate value; when the target number of opening units is greater than or equal to 2, select microstructure valve units from the microstructure valve array substrate in a number equal to the target number of opening units as valve groups to be opened according to a preset spatial distribution scheduling algorithm, and the selected microstructure valve units are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate. The controller is also configured to send pulse drive signals to the drive module to control the microstructure valve unit in the valve group to be opened to switch to the fully open state, and control the remaining microstructure valve units to remain in the normally closed state.

[0006] Preferably, the controller further stores a two-dimensional pressure-temperature compensation relationship internally; The controller is also configured to: when the fluid pressure or temperature value collected by the sensor module deviates from the standard operating conditions, adjust the number of target activations according to the pressure-temperature two-dimensional compensation relationship to maintain a constant total output flow rate.

[0007] A low-power precision flow regulation method based on a microstructure valve array, used in any of the aforementioned low-power precision flow regulation devices based on a microstructure valve array, includes the following steps: S1. Obtain the rated flow value of each microstructure valve unit in the microstructure valve array substrate under standard operating conditions and store it in the controller. The microstructure valve array substrate is composed of multiple normally closed microstructure valve units with the same flow conduction characteristics connected in parallel. S2, Receive target traffic value; S3. Based on the rated flow rate and target flow rate obtained from S1 and S2, the controller determines the target number of microstructure valve units that need to be opened. The target number of openings is positively correlated with the target flow rate. S4. When the target number of openings obtained in S3 is greater than or equal to 2, the controller selects microstructure valve units from the microstructure valve array substrate in a number equal to the target number of openings as valve groups to be opened according to the preset spatial distribution scheduling algorithm, and the selected microstructure valve units are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate. S5. The controller sends pulse drive signals to each microstructure valve unit in the valve group to be opened selected in S4, so that it switches from the normally closed state to the fully open state, while the remaining microstructure valve units remain in the normally closed state.

[0008] Preferably, the controller determines the target number of activations using the following formula: in, The target flow value, The rated flow rate value, This indicates the rounding operation.

[0009] Preferably, in step S4, the uniform spatial distribution is achieved through the following methods: The controller acquires the two-dimensional coordinate positions of each microstructure valve unit in the microstructure valve array substrate; Based on the target number of valves to be opened, the target coordinates of each selected microstructure valve unit are calculated using a preset discrete distribution function, thereby maximizing the minimum distance between any two selected microstructure valve units in the valve group to be opened.

[0010] Preferably, S4 further includes time-dimensional round-robin scheduling: in multiple continuously running flow regulation cycles, for the same target number of openings, the controller selects microstructure valve units with different spatial location combinations as the valve group to be opened in different cycles, so that the cumulative opening time of each microstructure valve unit tends to be balanced.

[0011] Preferably, the time-dimensional round-robin scheduling is performed based on the cumulative opening duration record of each microstructure valve unit, and the microstructure valve unit with the shortest cumulative opening duration is preferentially selected to be included in the valve group to be opened.

[0012] Preferably, it also includes adaptive compensation: The controller collects the fluid pressure and temperature values ​​flowing into the fluid inlet channel in real time; When the fluid pressure or temperature value is detected to deviate from the standard operating condition, the controller corrects the number of target activations according to a pre-calibrated two-dimensional lookup table to maintain a constant total output flow rate; wherein, the two-dimensional lookup table is a pressure-temperature two-dimensional compensation relationship.

[0013] Preferably, the pressure-temperature two-dimensional compensation relationship is expressed through a compensation coefficient function. The controller adjusts the target activation number using the following formula: in, The fluid pressure value. The temperature value is... The number of targets to be enabled before the correction. The number of targets to open after the correction. For and The compensation coefficient function of the independent variable is determined by a pre-calibrated two-dimensional lookup table, and when... and When the values ​​are equal to the preset standard pressure and standard temperature values, .

[0014] Preferably, the pulse drive signal only consumes electrical energy at the moment when the microstructure valve unit switches states, and the power consumption is zero during the steady state when the microstructure valve unit is maintained open or closed.

[0015] The beneficial effects of this technical solution compared to existing technologies are as follows: (1) This scheme fundamentally solves the problem of local flow field concentration caused by "only controlling the number of valves opened without considering the opening position" in existing digital microvalve array schemes by introducing a spatial uniform distribution scheduling algorithm. After determining the number of microstructure valve units to be opened, this scheme does not select valves at a fixed location, but selects valve combinations with uniformly dispersed spatial positions from the two-dimensional array as valve groups to be opened through a preset spatial uniform distribution scheduling algorithm. This design ensures that the fluid is uniformly distributed in the array plane, avoiding local particle deposition, local temperature gradients, and single valve fatigue failure caused by long-term fixed opening of valves at the same position. This feature significantly improves the reliability and service life of the device during long-term operation.

[0016] (2) By introducing time-dimensional round-robin scheduling, the cumulative working time of each microstructure valve unit is balanced, giving full play to the redundancy and fault tolerance advantages of the parallel array. In multiple flow regulation cycles of continuous operation, for the same target number of valves to be opened, the controller selects valves with different spatial positions as valve groups to be opened in different cycles, and prioritizes the valves with the shortest cumulative opening time. This design makes the workload of all valves in the array tend to be balanced, avoiding the problem of some valves aging faster due to long-term frequent operation and the waste of other valves being idle for a long time. Even if individual valves in the array experience physical failure, the controller can automatically exclude them from the scheduling range and call on the remaining redundant valves to continue working, and the system has natural fault tolerance and robustness.

[0017] (3) By integrating pressure-temperature two-dimensional adaptive compensation, constant output flow control under complex operating conditions is achieved. The sensor module collects inlet fluid pressure and ambient temperature in real time. When a deviation from the calibration condition is detected, the controller automatically corrects the target number of openings according to the pre-calibrated two-dimensional lookup table. This design effectively eliminates the influence of source-end interference such as inlet pressure attenuation caused by the drop in liquid level of upstream fluid storage tank and fluid viscosity fluctuation caused by changes in ambient temperature on the output flow, ensuring that the output flow is always accurate and stable.

[0018] (4) By adopting a driving method that combines pulse triggering and bistable holding, steady-state zero-power operation is achieved. The driving module consumes power only at the moment when the microstructure valve unit switches states, and the power consumption is zero during the steady state when the valve is maintained open or closed. This design significantly reduces the overall power consumption of the device and significantly extends the battery life of portable devices.

[0019] (5) By connecting normally closed microstructure valve units with the same flow conductance characteristics in parallel to form a digital flow synthesis structure, the nonlinear dead zone problem of single valve proportional regulation is fundamentally eliminated. This scheme replaces the adjustment of the opening degree of a single valve with the control of the number of fully open valves, transforming the nonlinear throttling problem into a linear superposition problem. A linear flow response can be obtained without complex servo feedback, simplifying the complexity of the control system. Attached Figure Description

[0020] Figure 1 A flowchart of the method provided for this invention; Figure 2 This is a schematic diagram of the structure provided by the present invention; Reference numerals: 1. Housing; 2. Microstructured valve array substrate; 3. Microstructured valve unit; 4. Fluid outlet channel; 5. Fluid inlet channel. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments: like Figure 1-2 The low-power precision flow control device based on a microstructure valve array shown includes: The housing 1 has a fluid inlet channel 5 and a fluid outlet channel 4. The housing 1 is made of stainless steel or engineering plastic, with a compact overall structure and excellent sealing performance. The fluid inlet channel 5 is used to connect to the upstream fluid storage tank, and the fluid outlet channel 4 is used to connect to the downstream delivery pipeline, ensuring that there are no dead spaces or residues in the fluid delivery path.

[0022] A microstructured valve array substrate 2 is sealed within a housing 1. Multiple microstructured valve units 3 are integrated on the substrate 2, arranged in a two-dimensional array. The inlet of each microstructured valve unit 3 is connected to a fluid inlet channel 5, and the outlet of each microstructured valve unit 3 is connected to a fluid outlet channel 4. Each microstructured valve unit 3 is a normally closed microstructured valve with identical flow conductance characteristics. Specifically, the two-dimensional array arrangement is as follows: The matrix form, where, , Each microstructure valve unit 3 has a unique two-dimensional coordinate position within the plane of the microstructure valve array substrate 2. This provides a coordinate mapping basis for spatial uniform distribution scheduling algorithms.

[0023] Each individual microstructure valve unit 3 includes a valve orifice and a microchannel. The cross-sectional dimension of the microchannel is smaller than the opening size of the valve orifice, so that the rated flow rate of a single microstructure valve unit 3 is primarily determined by the flow resistance of the microchannel, rather than by the valve orifice size. This design reduces the impact of valve orifice machining tolerances on flow rate consistency, ensuring that the deviation of the rated flow rate of each microstructure valve unit 3 is controlled within ±2%. The surface roughness of the microchannel inner wall... This is to reduce fluid resistance and avoid fluid residue.

[0024] The driving mechanism of the microstructure valve unit 3 can be any one of electrostatic actuation, shape memory alloy actuation, or piezoelectric actuation. When electrostatic actuation is used, the micro-electrode plate fabricated using MEMS technology generates electrostatic force under the action of voltage pulses, driving the valve disc to open or close. When shape memory alloy actuation is used, a TiNi alloy is used, which undergoes a phase transition and generates displacement under pulsed current heating, and maintains its state by its own stiffness after cooling. Both actuation methods have bistable characteristics, consuming electrical energy only at the moment of state switching, and the power consumption is zero during steady-state maintenance.

[0025] The controller is electrically connected to the microstructure valve array substrate 2. The controller has pre-stored the rated flow rate values ​​of each microstructure valve unit 3 under standard operating conditions; standard operating conditions refer to preset standard pressure values. and standard temperature value . It is usually set at 25℃. The rated flow rate is typically set to 1 standard atmosphere, corresponding to the inlet static pressure of the upstream fluid storage tank when fully loaded. The method for obtaining the flow rate is as follows: Before the device leaves the factory or is used for the first time, under standard operating conditions, deionized water or standard calibration solution is used to sequentially and individually open each microstructure valve unit 3, measure the fluid volume flowing out per unit time, and calculate the rated flow rate value of each valve unit. and each The value is stored in the controller's non-volatile memory.

[0026] The drive module is connected to the controller and the microstructure valve array substrate 2 respectively. The drive module includes a pulse generation circuit and a signal amplification circuit, which are used to convert the low-voltage control signal output by the controller into a pulse drive signal sufficient to drive the microstructure valve unit 3.

[0027] The sensor module, installed within housing 1, is configured to acquire the fluid pressure and temperature values ​​flowing into the fluid inlet channel 5 in real time and transmit the acquired pressure and temperature values ​​to the controller. The sensor module includes a MEMS pressure sensor and a miniature temperature sensor, which are integrated on the same chip or installed independently. The pressure sensor accuracy is ≤ ±0.1 kPa, and the temperature sensor accuracy is ≤ ±0.1℃, ensuring the accuracy of adaptive compensation data.

[0028] The controller is configured to: receive the target flow rate value and determine the target number of microstructure valve units 3 to be opened based on the target flow rate value and the rated flow rate value; when the target number of openings is greater than or equal to 2, select microstructure valve units 3 from the microstructure valve array substrate 2 in a number equal to the target number of openings as valve groups to be opened according to the preset spatial distribution scheduling algorithm, and the selected microstructure valve units 3 are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate 2. The target flow rate value can be obtained in at least one of the following ways: for external portable devices, the user manually inputs it through a human-machine interface; for implantable or programmable devices, the controller has a time-series delivery curve pre-stored inside, and the system automatically extracts the corresponding target flow rate value according to the current time node; for devices with wireless communication capabilities, the controller receives the target flow rate value instruction issued by an external programmer or control system through a wireless module.

[0029] The controller is also configured to send pulse drive signals to the drive module to control the microstructure valve unit 3 in the valve group to be opened to switch to the fully open state, and to control the remaining microstructure valve units 3 to remain in the normally closed state.

[0030] The controller also has a pre-stored pressure-temperature two-dimensional compensation relationship; The controller is also configured to adjust the number of target activations based on the pressure-temperature two-dimensional compensation relationship when the fluid pressure or temperature value collected by the sensor module deviates from the standard operating conditions, so as to maintain a constant total output flow rate.

[0031] A low-power precision flow regulation method based on a microstructure valve array, used in any of the aforementioned low-power precision flow regulation devices based on a microstructure valve array, includes the following steps: S1. Obtain the rated flow rate value of each microstructure valve unit 3 in the microstructure valve array substrate 2 under standard operating conditions and store it in the controller. The microstructure valve array substrate 2 is composed of multiple normally closed microstructure valve units 3 with the same flow conduction characteristics connected in parallel. Specifically, under standard pressure and standard temperature values, each microstructure valve unit 3 is opened individually in sequence using deionized water or standard calibration solution, the fluid output per unit time is measured, the rated flow rate value of each microstructure valve unit 3 is obtained, and each rated flow rate value is stored in the non-volatile memory of the controller.

[0032] S2. Receive target flow rate value; the target flow rate value is obtained through at least one of the following methods: human-computer interaction input, preset delivery curve extraction, and external communication reception.

[0033] S3. The controller determines the target number of microstructure valve units 3 to be opened based on the rated flow value and target flow value obtained from S1 and S2. The target number of openings is positively correlated with the target flow value. The controller determines the number of targets to be activated using the following formula: in, For the target flow value, This is the rated flow rate. This indicates rounding to the nearest integer. The rated flow rate of a single microstructure valve unit 3... Extremely small (typically on the order of μL / min), and the number of targets turned on. The adjustment step size is 1, and the total output flow can achieve a step size equal to 1. Discrete high-resolution continuous equivalent adjustment.

[0034] S4. When the target number of openings obtained in S3 is greater than or equal to 2, the controller selects microstructure valve units 3 from the microstructure valve array substrate 2 in a number equal to the target number of openings as valve groups to be opened, according to the preset spatial distribution scheduling algorithm. The selected microstructure valve units 3 are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate 2. The uniform spatial distribution is achieved through the following methods: The controller acquires the two-dimensional coordinate positions of each microstructure valve unit in the microstructure valve array substrate 2; Based on the target number of valves to be opened, the target coordinates of each selected microstructure valve unit 3 are calculated using a preset discrete uniform distribution function, maximizing the minimum distance between any two selected microstructure valve units 3 in the valve group to be opened. The discrete uniform distribution function is designed based on the principle of maximizing the minimum Euclidean distance, that is, while satisfying the selection... Given three microstructured valve units, the target coordinates of each selected valve unit are determined with the objective of maximizing the minimum Euclidean distance between any two selected microstructured valve units in the valve group to be opened. Discrete uniformly distributed functions are existing technology and will not be elaborated upon here.

[0035] It also includes time-dimensional round-robin scheduling: In multiple flow regulation cycles of continuous operation, for the same target number of openings, the controller selects microstructure valve units 3 with different spatial positions as valve groups to be opened in different cycles, so that the cumulative opening time of each microstructure valve unit 3 tends to be balanced.

[0036] The time-dimensional round-robin scheduling is performed based on the cumulative opening duration record of each microstructure valve unit 3, prioritizing the microstructure valve unit 3 with the shortest cumulative opening duration to be included in the valve group to be opened. Specifically, the controller internally maintains a cumulative opening duration counter corresponding one-to-one with each microstructure valve unit 3, and updates the cumulative duration of the corresponding valve unit after each flow regulation cycle; in step S4 of the next cycle, the controller prioritizes selecting the valve group to be opened from the valve units with the shortest cumulative opening duration.

[0037] S5. The controller sends pulse drive signals to each microstructure valve unit 3 in the selected valve group to be opened in S4, causing it to switch from the normally closed state to the fully open state, while the remaining microstructure valve units 3 remain in the normally closed state. The pulse drive signal only consumes electrical energy at the moment the microstructure valve unit 3 switches states; during the steady state when the microstructure valve unit 3 remains open or closed, the power consumption is zero.

[0038] The specific form of the pulse drive signal is determined according to the driving method adopted: when electrostatic driving is used, the pulse drive signal is a voltage pulse with a duration of no more than 100 microseconds and an amplitude of 20V to 100V; when shape memory alloy driving is used, the pulse drive signal is a current pulse with a duration of no more than 100 milliseconds and an amplitude of 50mA to 200mA; when piezoelectric driving is used, the pulse drive signal is a voltage pulse with a duration of no more than 10 microseconds and an amplitude of 50V to 200V.

[0039] It also includes adaptive compensation: The controller collects the fluid pressure and temperature values ​​flowing into the fluid inlet channel 5 in real time; When a deviation from the standard operating condition is detected in the fluid pressure or temperature value, the controller adjusts the number of target activations according to a pre-calibrated two-dimensional lookup table to maintain a constant total output flow rate. The two-dimensional lookup table represents a pressure-temperature two-dimensional compensation relationship. The two-dimensional lookup table is pre-calibrated as follows: before the device leaves the factory, under different combinations of pressure and temperature values, the deviation of the actual output flow rate of the measuring device from the output flow rate under the standard operating condition is calculated, and the compensation coefficient corresponding to each operating point is obtained, forming a two-dimensional compensation relationship based on pressure value. and temperature value A two-dimensional compensation coefficient table indexed by the controller is stored in the controller.

[0040] The pressure-temperature two-dimensional compensation relationship is achieved through the compensation coefficient function. The controller adjusts the number of targets activated using the following formula: in, This represents the fluid pressure value. This is the temperature value. The number of targets to be enabled before the correction. The number of targets to open after the correction. For and The compensation coefficient function of the independent variable is determined by a pre-calibrated two-dimensional lookup table, and when... and When the values ​​are equal to the preset standard pressure and standard temperature values, .

[0041] when (For example, when the inlet pressure decreases due to a drop in the liquid level of the upstream fluid storage tank) the compensation coefficient The controller increases the number of activations to compensate for the decrease in flow rate caused by pressure decay; when (For example, when the ambient temperature decreases, causing the fluid viscosity to increase) the compensation coefficient The controller also increases the number of activations to compensate for the decrease in flow rate caused by increased viscosity.

[0042] The specific implementation process is as follows: like Figure 1 As shown, the device in this embodiment includes a housing 1, which is made of stainless steel and has overall dimensions of 30mm × 20mm × 8mm. The fluid inlet channel 5 is connected to the upstream fluid storage tank via a standard connector, and the fluid outlet channel 4 is connected to the downstream delivery pipeline.

[0043] A microstructured valve array substrate 2 is sealed inside the housing 1. The microstructured valve array substrate 2 is fabricated on a silicon substrate using MEMS technology. The microstructured valve array substrate 2 is arranged in a ring shape, with the inner side of the ring substrate forming an inlet manifold, and the outer side of the ring substrate forming an outlet manifold between it and the inner wall of the housing 1. The fluid inlet channel 5 communicates with the inlet manifold, and the fluid outlet channel 4 communicates with the outlet manifold.

[0044] Multiple microstructure valve units 3 are uniformly integrated along the circumference of the annular substrate, and these microstructure valve units 3 are arranged in a two-dimensional annular array within the plane of the annular substrate. In this embodiment, a total of 64 microstructure valve units 3 are integrated on the annular substrate, divided into four concentric rings, namely the first ring, the second ring, the third ring, and the fourth ring, from the inside out, with 16 valve units in each ring. Each microstructure valve unit 3 has a unique polar coordinate position within the plane of the annular substrate. ,in Indicates the first The radius of the ring, ; Indicates the first Each circumferential angular position, , .

[0045] The inlet of each microstructure valve unit 3 faces the inner side of the annular base plate, communicating with the inlet manifold and then in parallel with the fluid inlet channel 5; the outlet of each microstructure valve unit 3 faces the outer side of the annular base plate, communicating with the outlet manifold and then in parallel with the fluid outlet channel 4. This parallel structure is similar to the parallel arrangement of cylinders in a multi-cylinder pump, allowing multiple microstructure valve units 3 to work collaboratively for fluid delivery. The fluid diffuses evenly from the inlet manifold to each microstructure valve unit 3, with a symmetrical flow path and minimal difference in flow resistance from the inlet to each valve unit, which helps ensure the consistency of flow rate in each valve unit. Each microstructure valve unit 3 is a normally closed microstructure valve with the same flow conductance characteristics.

[0046] In this embodiment, the driving mechanism of the microstructure valve unit 3 adopts electrostatic drive. Each microstructure valve unit 3 includes a micro electrode plate fabricated by MEMS technology. Under the action of a voltage pulse, an electrostatic force is generated between the electrode plates, driving the valve disc to move and open the valve port. At the same time, the movement of the valve disc causes a change in the volume of the microcavity, pumping fluid from the inlet side to the outlet side. After the pulse ends, the valve disc resets under its own elastic restoring force, and the valve port closes. Electrostatic drive has bistable characteristics, requires only pulse triggering, and has zero power consumption during steady-state maintenance.

[0047] The controller employs a low-power microcontroller (MCU, model STM32L4 series), mounted on a PCB circuit board inside housing 1, and electrically connected to the microstructure valve array substrate 2 via a flexible circuit board. The controller integrates non-volatile memory (EEPROM) to store the rated flow values ​​of each microstructure valve unit 3. Standard operating parameters (standard pressure value) kPa, standard temperature value ) and a pressure-temperature two-dimensional lookup table.

[0048] The drive module includes a pulse generation circuit and a high-voltage amplifier circuit, which are respectively connected to the PWM output terminal of the controller and the electrode leads of the microstructure valve array substrate 2. The drive module receives the low-voltage PWM signal from the controller, boosts it, and shapes it into a voltage pulse that meets the requirements of electrostatic drive. The pulse drive signal is a voltage pulse with a duration of 80 microseconds and an amplitude of 60V.

[0049] The sensor module is mounted on the inner wall of the fluid inlet channel 5. The sensor module includes a MEMS pressure sensor (accuracy ±0.05 kPa) and a miniature PT100 temperature sensor (accuracy ±0.1℃), both integrated on the same ceramic substrate. The sensor module connects to the controller's data interface via an I2C bus, acquiring the fluid pressure value at the inlet in real time at a sampling rate of 10 times per second. and temperature value The collected values ​​are then transmitted to the controller.

[0050] Before the device leaves the factory, perform the following calibration steps: (1) Connect the fluid inlet channel 5 of the device to the standard pressure source and the constant temperature chamber, and connect the fluid outlet channel 4 to the precision flow meter. Set the standard operating conditions: pressure kPa, temperature Deionized water was used as the calibration medium.

[0051] (2) The controller sends a pulse drive signal to each of the 64 microstructure valve units 3 in sequence to fully open them. Each opening lasts for 60 seconds. The precision flow meter records the volume of fluid flowing out during this time period, and the controller calculates the rated flow rate of the valve unit. (Unit: μL / min).

[0052] (3) The 64 measured The values ​​are stored in the controller's non-volatile memory. In this embodiment, the values ​​of the 64 valve units are... The average value was 0.5 μL / min, the standard deviation was 0.008 μL / min, and the deviation was controlled within ±2%.

[0053] (4) Calibrate the pressure-temperature two-dimensional lookup table: Change the temperature setting of the constant temperature chamber (at 15℃, 20℃, 25℃, 30℃, and 35℃ respectively) and the output pressure of the pressure source (at 80kPa, 90kPa, 101.3kPa, 110kPa, and 120kPa respectively) to form 5×5=25 operating points. At each operating point, the controller opens a fixed number of microstructure valve units (e.g., 32), measures the ratio of the actual output flow rate to the output flow rate under standard operating conditions, and obtains the compensation coefficient corresponding to that operating point. The compensation coefficients for the 25 operating points are calculated using... and A two-dimensional lookup table is created for the index and stored in the controller's non-volatile memory. For values ​​not at the calibration point... and The controller calculates the corresponding compensation coefficients using a bilinear interpolation method.

[0054] The flow regulation method in this embodiment is performed according to the following steps: S1, Calibration Storage This step was completed before shipment; rated flow rate value. The μL / min and two-dimensional lookup table are stored in the controller. Each time the device is powered on, the controller automatically loads the above data from non-volatile memory into the internal RAM.

[0055] S2, Receive target traffic The user inputs the desired fluid delivery rate through an external human-machine interface connected to the controller, for example... μL / min. The controller receives this input value and stores it in an internal register.

[0056] S3, Calculate the number of targets activated. The controller reads the rated flow rate from the memory. μL / min, combined with target flow rate μL / min, perform the following calculations: Get the target number of times .

[0057] S4. Spatial uniformity selection and time-round scheduling because The controller executes a space-even distribution scheduling algorithm.

[0058] First, the controller acquires the polar coordinate positions of the 64 microstructure valve units 3 on the microstructure valve array substrate 2. ,in , .

[0059] Then, the controller invokes a preset discrete uniform distribution function, which aims to maximize the minimum distance between any two valve units in the valve group to be opened within the annular plane. For annular arrays, the minimum distance refers to the arc distance or radial distance along the annular plane. The discrete uniform distribution function satisfies the selected... Given a number of valve units, combinations of valve units with different rings and different circumferential angles are preferentially selected to ensure that the valve group to be opened is evenly distributed on the annular plane. For example, in this embodiment, the target coordinates calculated by the discrete distribution function are: three valve units are selected from each of the four rings, and the circumferential interval of the valve units selected in each ring is 120°, thereby achieving uniform dispersion in both radial and circumferential dimensions.

[0060] The controller further performs a round-robin scheduling over a time dimension. Internally, the controller maintains an array containing 64 elements representing the cumulative on-time duration. The controller records the historical cumulative opening time of each microstructure valve unit 3. In the scheduling of the current cycle, the controller prioritizes selecting the 12 valve units with the shortest cumulative opening time from the above evenly distributed candidate positions as the valve groups to be opened in this cycle.

[0061] S5, pulse drive The controller sends a command to the drive module, which then sends voltage pulses of 80 microseconds duration and 60V amplitude to each of the 12 microstructure valve units 3 in the valve group to be opened. Upon receiving the pulses, the valve discs of the 12 valve units move under electrostatic force, fully opening the valve ports. Simultaneously, the volume change caused by the valve disc movement pumps fluid from the inlet manifold to the outlet manifold, ultimately outputting from the fluid outlet channel 4. The remaining 52 valve units remain normally closed.

[0062] After the pulse ends, the drive module stops supplying power to the valve unit. The valve unit that has been opened remains open due to the electrostatic drive bistable characteristic, and the power consumption is zero during the steady state.

[0063] At this time, the total output flow of the device is: Consistent with the target flow rate.

[0064] During fluid transport, the sensor module continuously collects pressure values ​​at point 5 of the fluid inlet channel at a frequency of 10 times per second. and temperature value The data is then transmitted to the controller in real time.

[0065] Suppose that at a certain moment, due to a drop in the liquid level of the upstream fluid storage tank, the inlet pressure decreases from the standard pressure. kPa decreased to kPa; meanwhile, due to changes in ambient temperature, the fluid temperature changes from the standard temperature. ℃ rise to ℃.

[0066] The controller detected and This triggers the adaptive compensation procedure. The controller uses the current pressure value... kPa and temperature value Using ℃ as an index, a pre-stored pressure-temperature two-dimensional lookup table is consulted. Through table lookup and bilinear interpolation, the compensation coefficient corresponding to this operating condition is obtained. .

[0067] The controller adjusts the number of targets to be activated according to the following formula: Round the result to the nearest integer to obtain the corrected number of target activations. .

[0068] controller with Replace the original Steps S4 and S5 are then repeated to select 13 valve units evenly distributed in the annular array and drive them to open. Adding a microstructure valve unit compensates for the reduced flow rate, maintaining it at approximately 6.0 μL / min and eliminating flow deviations caused by pressure and temperature variations.

[0069] After the device has been running continuously for 24 hours, the controller checks the cumulative operating time array. Due to the execution of the time-based rotation scheduling strategy, the cumulative opening time of the 64 microstructure valve units 3 is evenly distributed, with the deviation of the cumulative opening time of each valve unit not exceeding 5% of the total running time. There were no cases of individual valve units aging faster due to long-term frequent operation, or individual valve units being idle for a long time.

[0070] During steady-state operation, the controller and sensor modules of this embodiment operate in low-power mode, waking up only during flow regulation and adaptive compensation; the drive module consumes power only during the 80-microsecond pulse of valve unit state switching. Actual measurements show that the average power consumption of the entire device is less than 5mW.

[0071] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A low-power precision flow control device based on a microstructure valve array, characterized in that, include: The housing (1) is provided with a fluid inlet channel (5) and a fluid outlet channel (4). A microstructured valve array substrate (2) is sealed and connected inside the housing (1). Multiple microstructured valve units (3) are integrated on the microstructured valve array substrate (2). The multiple microstructured valve units (3) are arranged in a two-dimensional array. The inlet of each microstructured valve unit (3) is connected to the fluid inlet channel (5), and the outlet of each microstructured valve unit (3) is connected to the fluid outlet channel (4). Each microstructured valve unit (3) is a normally closed microstructured valve with the same flow conduction characteristics. The controller is electrically connected to the microstructure valve array substrate (2), and the controller has pre-stored the rated flow values ​​of each microstructure valve unit (3) under standard operating conditions. The drive module is connected to the controller and the microstructure valve array substrate (2), respectively. The sensor module is installed inside the housing (1) and is configured to collect the fluid pressure and temperature values ​​flowing into the fluid inlet channel (5) in real time and transmit the collected pressure and temperature values ​​to the controller. The controller is configured to: receive a target flow rate value and determine the target number of microstructure valve units (3) to be opened based on the target flow rate value and the rated flow rate value; when the target number of openings is greater than or equal to 2, select microstructure valve units (3) from the microstructure valve array substrate (2) with a number equal to the target number of openings as valve groups to be opened according to a preset spatial distribution scheduling algorithm, and the selected microstructure valve units (3) are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate (2); The controller is also configured to send a pulse drive signal to the drive module to control the microstructure valve unit (3) in the valve group to be opened to switch to the fully open state, and control the remaining microstructure valve units (3) to remain in the normally closed state.

2. The low-power precision flow regulating device based on a microstructure valve array as described in claim 1, characterized in that: The controller further has a two-dimensional pressure-temperature compensation relationship pre-stored inside; The controller is also configured to: when the fluid pressure or temperature value collected by the sensor module deviates from the standard operating conditions, adjust the number of target activations according to the pressure-temperature two-dimensional compensation relationship to maintain a constant total output flow rate.

3. A low-power precision flow regulation method based on a microstructure valve array, used in the low-power precision flow regulation device based on a microstructure valve array as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Obtain the rated flow value of each microstructure valve unit (3) in the microstructure valve array substrate (2) under standard operating conditions and store it in the controller. The microstructure valve array substrate (2) is composed of multiple normally closed microstructure valve units (3) with the same flow conduction characteristics connected in parallel. S2, Receive target traffic value; S3. The controller determines the target number of microstructure valve units (3) to be opened based on the rated flow value and target flow value obtained from S1 and S2. The target number of openings is positively correlated with the target flow value. S4. When the number of target openings obtained in S3 is greater than or equal to 2, the controller selects microstructure valve units (3) from the microstructure valve array substrate (2) with a number equal to the number of target openings as valve groups to be opened according to the preset spatial distribution scheduling algorithm. The selected microstructure valve units (3) are evenly distributed in the two-dimensional array arrangement of the microstructure valve array substrate (2). S5. The controller sends pulse drive signals to each microstructure valve unit (3) in the valve group to be opened selected in S4, so that it switches from the normally closed state to the fully open state, while the remaining microstructure valve units (3) remain in the normally closed state.

4. The low-power precision flow regulation method based on a microstructure valve array as described in claim 3, characterized in that, The controller determines the target number of activations using the following formula: in, The target flow value, The rated flow rate value, This indicates the rounding operation.

5. The low-power precision flow regulation method based on a microstructure valve array as described in claim 3, characterized in that, In step S4, the uniform spatial distribution is achieved through the following methods: The controller acquires the two-dimensional coordinate positions of each microstructure valve unit (3) in the microstructure valve array substrate (2); Based on the target number of valves to be opened, the target coordinates of each selected microstructure valve unit (3) are calculated using a preset discrete distribution function, so that the minimum distance between any two selected microstructure valve units (3) in the valve group to be opened is maximized.

6. The low-power precision flow regulation method based on a microstructure valve array as described in claim 3, characterized in that, The S4 also includes time-dimensional round-robin scheduling: in multiple continuously running flow regulation cycles, for the same number of target openings, the controller selects microstructure valve units (3) with different spatial positions in different cycles as the valve group to be opened, so that the cumulative opening time of each microstructure valve unit (3) tends to be balanced.

7. The low-power precision flow regulation method based on a microstructure valve array as described in claim 6, characterized in that: The time-dimensional round-robin scheduling is performed based on the cumulative opening duration record of each microstructure valve unit (3), and the microstructure valve unit (3) with the shortest cumulative opening duration is preferentially selected to be included in the valve group to be opened.

8. The low-power precision flow regulation method based on a microstructure valve array as described in claim 3, characterized in that, It also includes adaptive compensation: The controller collects the fluid pressure and temperature values ​​flowing into the fluid inlet channel (5) in real time; When the fluid pressure or temperature value is detected to deviate from the standard operating condition, the controller corrects the number of target activations according to a pre-calibrated two-dimensional lookup table to maintain a constant total output flow rate; wherein, the two-dimensional lookup table is a pressure-temperature two-dimensional compensation relationship.

9. The low-power precision flow regulation method based on a microstructure valve array as described in claim 8, characterized in that, The pressure-temperature two-dimensional compensation relationship is expressed through a compensation coefficient function. The controller adjusts the target activation number using the following formula: in, The fluid pressure value. The temperature value is... The number of targets to be enabled before the correction. The number of targets to open after the correction. For and The compensation coefficient function of the independent variable is determined by a pre-calibrated two-dimensional lookup table, and when... and When the values ​​are equal to the preset standard pressure and standard temperature values, .

10. The low-power precision flow regulation method based on a microstructure valve array as described in claim 3, characterized in that: The pulse drive signal only consumes electrical energy at the moment when the microstructure valve unit (3) switches states. During the steady state when the microstructure valve unit (3) is open or closed, the power consumption is zero.

Images