A method and device for real-time control of particle position based on three-channel flow rate regulation

Abstract

The application discloses a kind of based on three channel flow velocity regulation and control micro-particle position real-time control method and device, including the following steps: micron particle is put in cyclone flow area, and micro-particle is captured using cyclone stagnation point;Real-time observation cyclone region, identify micro-particle position;The initial flow velocity size of microchannel and micro-particle target position are set;The flow velocity of microchannel is regulated and controlled by three channel cyclone flow velocity-stagnation point configuration model, control micro-particle position;Judge whether micro-particle reaches target position, if micro-particle has reached target position, regulation and control end;Otherwise, repeat step to continue regulating and controlling the flow velocity size of next stage.The device includes cyclone generation module, image analysis module and flow velocity control module, cyclone is generated by cyclone generation module, and the characteristics of low speed and low pressure of cyclone stagnation point are used to capture micro-particle, and the position of micro-particle is controlled by adjusting the position of cyclone stagnation point through image analysis module and flow velocity control module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microfluidics, and relates to a micro-particle manipulation technology, in particular to a micro-particle position real-time control method and device based on three-channel flow rate regulation. BACKGROUND

[0002] Particle manipulation technology is an important technique for precisely manipulating the motion and attitude of micro- and nano-scale objects, with applications spanning fields such as biomedicine and materials science (Stueber DD, Villanova J, Aponte I, et al. Magneticnanoparticles in biology and medicine: past, present, and future trends[J].Pharmaceutics, 2021, 13(7): 943.). Methods that manipulate particle positions through swirling flow do not cause mechanical damage to the particles and have relatively simple control systems. However, research on real-time particle position manipulation methods based on swirling flow is still immature, thus limiting its further application. In the research on methods for manipulating particles using flow field characteristics, Shenoy et al. from the University of Illinois (Shenoy A, et al. Flow topology during multiplexedparticle manipulation using a stokes trap[J]. Physical Review Applied, 2019,12(5): 054010.) designed a six-channel microfluidic chip structure that can capture particles for extended periods using fluid stagnation points and manipulate the particles to move along the trajectory of stagnation point changes. Yang Chaoyong et al. from Xiamen University (Yang Chaoyong, Liu Weizhi, Li Xingrui, et al. A microfluidic chip for precise manipulation and pairing of single particles and its application [P]. CN109722385A, 2019.) designed a microfluidic chip capable of precisely controlling single particles, comprising a channel layer and a control layer. The channel layer includes multiple units for capturing and transferring single particles. Each unit consists of a capture channel, a capture chamber, a capture slit, a transfer channel, a pairing chamber, and a pairing slit. The control layer is located below the capture and pairing channels, perpendicular to them, and separated by a diaphragm. This chip can efficiently and precisely manipulate the capture and transfer of single particles. After different rounds of single particle capture and transfer, it can achieve manipulation of the position of a single particle and also realize high-throughput single particle pairing. The swirl-based particle manipulation method was proposed by Professor Zhang Qin et al. of South China University of Technology (Zhang Q, Fan J, Aoyama H. ​​Manipulation of particles based on swirl[J]. Japanese Journal of Applied Physics, 2018, 57(1):017202.). By controlling the stagnation point position in the swirl region, the capture, movement, and rotation of particles can be achieved. Summary of the Invention

[0003] To address the limitations of non-destructive manipulation techniques in current particle position control technologies and the immaturity of research on swirling-based particle manipulation methods, this invention proposes a real-time particle position control method and device based on three-channel flow rate regulation. The device includes a swirling flow generation module, an image analysis module, and a flow rate control module. The swirling flow generation module generates a swirling flow, utilizing the low-speed, low-pressure characteristics of the stagnation point to capture particles. The image analysis module identifies the particle position, and the flow rate control module adjusts the position of the stagnation point to control the position of the captured particles. This device and method can be used for the directional transport of particles, providing a new approach for particle manipulation technology research.

[0004] The present invention is achieved by at least one of the following technical solutions.

[0005] A real-time particle position control method based on three-channel flow velocity regulation includes the following steps:

[0006] (1) Micron-sized particles are released into the swirling flow domain and captured by the stagnation point of the swirling flow; (2) Observe the swirling area in real time and identify the position of particles; (3) Set the initial flow rate of the microchannel and the target position of the particles; (4) The flow velocity of the microchannel is controlled by the velocity-stagnation configuration model of the three-channel swirl to control the position of the particles; (5) Determine whether the particles have reached the target position. If the particles have reached the target position, the control ends; otherwise, repeat the steps to continue controlling the flow rate in the next stage.

[0007] Furthermore, in step (4), the establishment of the velocity-stagnation configuration model of the three-channel vortex includes the following steps: 1) The velocity of the three-channel vortex flow has a quantitative relationship with the location of the stagnation point, as shown in the following formula:

[0008] in, 、 These are the x and y coordinates of the station location, respectively. , , These represent the flow rates of the first, second, and third microchannels, respectively. , , , , , , , , , , , The coefficients are known. 2) A first-order Taylor expansion of the velocity-stagnation point quantitative relationship of the three-channel swirling flow yields the following relationship:

[0009] remember , , This is the combination of flow rate magnitudes for the three microchannels in the next stage. This will serve as the location for the next phase of deployment. This is a combination of the flow rates of the three microchannels from the previous stage. , , These represent the flow rates of the first, second, and third microchannels in the previous stage, respectively. This is the location of the previous station. The expression is:

[0010] 3) The actual location of the particles identified in the previous stage Alternative This allows us to determine the combination of flow velocities in the three microchannels for the next stage. Its expression is:

[0011] in, for The generalized inverse matrix; 4) Target location of particles Alternative The expression becomes:

[0012] in, In order to enable the particles to reach the target location The combination of flow rates in the three microchannels.

[0013] Furthermore, the actual position of the particles was obtained by continuously identifying the position of multiple frames of particles and calculating the average position of these frames when the particles were captured and stably maintained in the swirling low-pressure region. At the same time, the flow rate combination of the three microchannels was recorded.

[0014] Furthermore, in step (4), controlling the particle position includes the following steps: When the particles were observed to be captured and stably maintained in the swirling low-pressure region, the positions of the particles in multiple frames were continuously identified using image processing and the average value of these particle positions was calculated. The flow rate combination of the three microchannels at this time was recorded. Substituting the average value, the current combination of flow velocities in the three microchannels, and the target position of the particle into the velocity-stagnation configuration model, we can solve for the next stage's combination of flow velocities in the three microchannels. Under the new flow velocities, the particle will move to a new position.

[0015] Furthermore, the steps to determine whether a particle has reached its target location are as follows: Calculate the Euclidean distance between the actual position of the particle and the target position of the particle. If the Euclidean distance is less than or equal to the threshold, it is considered that the particle has reached the target position and the control ends; otherwise, continue to calculate the flow velocity combination for the next stage, and finally the particle reaches the target position of the particle and rotates stably in the vicinity.

[0016] Furthermore, the size range of the micron-sized particles deployed is 50~300 μm.

[0017] Furthermore, the range of flow rate variation of the microchannel flow pump and the peak value of the flow rate increment for each speed adjustment are set.

[0018] The apparatus for implementing the real-time particle position control method based on three-channel flow velocity regulation includes a swirl generation module, an image analysis module, and a flow velocity control module. The swirl generation module includes three microchannels, wherein the endpoints of the inner walls of the first microchannel, the second microchannel, and the third microchannel are connected in pairs to form a swirl domain; The image analysis module includes an inverted microscope equipped with a high-definition CMOS microscope camera; The flow rate control module includes three flow pumps; The three microchannels are mounted and fixed in the clamping platform. The microscope is connected to the computer via a USB serial port. The flow output ends of the first, second, and third flow pumps are connected to the first, second, and third microchannels respectively via circular flexible tubes. The recovery ends of the first, second, and third flow pumps are all connected to the clamping platform via circular flexible tubes. The programmable controllers of the first, second, and third flow pumps are all connected to the computer via USB serial ports.

[0019] A computer device according to the present invention includes a memory and a processor, the memory being electrically connected to the processor, the memory storing a computer program, which, when executed by the processor, causes the processor to implement the method described herein.

[0020] The present invention provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor implements the method described herein.

[0021] Compared with the prior art, the present invention has the following advantages: 1. This invention utilizes the swirling properties to manipulate microparticles without direct contact with them, thus avoiding damage to the microparticles during manipulation. 2. This invention establishes a three-channel vortex velocity-stagnation configuration model to regulate the velocity of microchannels, enabling directional and quantitative closed-loop control of particle positions and improving control accuracy. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the installation of a real-time particle position control device based on three-channel flow rate regulation during the implementation process. Figure 2 This is a schematic diagram of the vortex flow domain of the vortex generation module during implementation; Figure 3 This is a flowchart of a real-time particle position control method based on three-channel flow velocity regulation during implementation. Figure 4 This is an experimental microscope image based on real-time particle position control using three-channel flow rate regulation. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0025] This section will describe specific embodiments of the present invention in detail. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, enabling a visual and intuitive understanding of each technical feature and the overall technical solution of the present invention. However, they should not be construed as limiting the scope of protection of the present invention. In the description of the present invention, unless otherwise explicitly limited, terms such as "setting," "installation," and "connection" should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in the present invention in conjunction with the specific content of the technical solution.

[0026] like Figure 1As shown, this embodiment provides a real-time particle position control device based on three-channel flow rate regulation, including a vortex generation module, an image analysis module, and a flow rate control module. The vortex generation module generates a vortex, utilizing the low-speed, low-pressure characteristics of the vortex stagnation point to capture particles. The image analysis module identifies the particle position, and the flow rate control module adjusts the position of the vortex stagnation point to control the position of the particles captured by the stagnation point.

[0027] like Figure 2 As shown, the swirl generation module includes three rectangular cross-section microchannels (1, 2, 3) with identical dimensions. The endpoints of the inner walls of the first microchannel 1, the second microchannel 2, and the third microchannel 3 are connected in pairs to form a swirl domain abc.

[0028] The image analysis module includes an inverted microscope 5 equipped with a 4K high-definition CMOS microscope camera, which is connected to a personal computer 18 via a USB serial port.

[0029] The flow rate control module includes three integrated injection-suction flow pumps (7, 11, 15).

[0030] The microchannels (1, 2, 3) of the cyclone generation module are fixed in the clamping platform 4. The microscope 5 is connected to the personal computer 18 via a USB serial port. The flow output end 6 of the first flow pump 7, the flow output end 10 of the second flow pump 11, and the flow output end 14 of the third flow pump 15 are respectively connected to the first microchannel 1, the second microchannel 2, and the third microchannel 3 via circular hoses. The recovery end 8 of the first flow pump 7, the recovery end 12 of the second flow pump 11, and the recovery end 16 of the third flow pump 15 are all connected to the clamping platform 4 via circular hoses. The programmable controller 9 of the first flow pump 7, the programmable controller 13 of the second flow pump 11, and the programmable controller 17 of the third flow pump 15 are all connected to the personal computer 18 via a USB serial port.

[0031] like Figure 3 As shown, the real-time particle position control method based on three-channel flow rate regulation in this embodiment includes the following steps: 1. Install and fix the vortex generation module on the clamping platform, and use the flow rate control module to deliver fluid to generate vortices.

[0032] 2. Micron-sized particles are introduced into the swirling flow area ABC. The particle size range is 50~300 μm. The swirling area is observed in real time through an image analysis module to identify the particle position. In one embodiment, particles with a diameter of 200 micrometers are introduced.

[0033] 3. Given the target position of the particle , , These are the x-coordinate and y-coordinate of the target location, respectively. This represents the x-coordinate of the particle target position in this embodiment. The vertical coordinate of the particle target position is used. The range of flow rate variation of the flow pump and the peak value of the flow rate increment for each speed adjustment are set. In this embodiment, the range of flow rate variation of the flow pump is set to 25 mm / s to 60 mm / s, and the peak value of the flow rate increment for each speed adjustment is 3 mm / s. 4. Given a combination of initial flow rates for three microchannels. And generate swirling flow through the output of the flow pump. , , These are designated as first microchannel 1, second microchannel 2, and third microchannel 3, respectively. In one embodiment, the initial flow velocity of each of the three microchannels is [missing information]. .

[0034] 5. By observing through the image analysis module that the particles are captured and stably maintain their rotation in the swirling low-pressure region, image processing is used to continuously identify the particle positions across multiple frames and calculate the average of these frame positions as the actual particle position. , , These are the x and y coordinates of the average position of particles across multiple frames.

[0035] 6. The combined flow rate of the three microchannels at this time is denoted as... , , , These represent the flow rates of the first microchannel 1, the second microchannel 2, and the third microchannel 3 at this time. and in step 5 and the information given in step 3 Substituting into the velocity-stagnation configuration model, the velocity combination of the three microchannels in the next stage is solved as follows: And it is output through a flow pump. , , These represent the flow rates of the first microchannel 1, the second microchannel 2, and the third microchannel 3 in the next stage, respectively.

[0036] 7. New flow velocity combination in step 6 Next, the particles move to a new location, and then step 5 is repeated to update. And seek and European distance d ,like dIf the particle size is <= 5 μm, it is considered that the particle has reached the target position, and the adjustment ends; otherwise, repeat step 6 to continue calculating the next stage of flow rate combination. Finally, after 5 speed adjustments, the particle reaches the target position given in step 3. It then rotates stably in the vicinity of that location.

[0037] like Figure 4 The experimental microscope image shown is based on real-time control of particle position using three-channel flow rate regulation. It includes the initial stage, the stage after the first speed adjustment, the stage after the second speed adjustment, the stage after the third speed adjustment, the stage after the fourth speed adjustment, and the stage after the fifth speed adjustment. The cross in the figure represents the target position of the particle.

[0038] In the above method, a swirling flow is generated by jetting fluid through three microchannels, and a velocity-stagnation point configuration model is established. By adjusting the velocity of the three microchannels using this model, the position of the stagnation point can be controlled, enabling real-time regulation of the position of particles of different sizes. Establishing the velocity-stagnation point configuration model for the three-channel swirling flow includes the following steps: 1) There is a quantitative relationship between the velocity of a three-channel swirling flow and the location of the stagnation point (Zhang Q, Hu S, Dang Y, et al. Controlling Stagnation Point of Swirl Based on Jet Velocity[C]. 2022 IEEE International Conference on Mechatronics and Automation (ICMA). IEEE, 2022: 1593-1598.), as follows:

[0039] in, 、 These are the x and y coordinates of the station location, respectively. , , These represent the flow rates of the first microchannel 1, the second microchannel 2, and the third microchannel 3, respectively. , , , , , , , , , , , The coefficients are known. 2) A first-order Taylor expansion of the velocity-stagnation point quantitative relationship of the three-channel swirling flow yields the following relationship:

[0040] remember , , This is the combination of flow rate magnitudes for the three microchannels in the next stage. This will serve as the location for the next phase of deployment. This is a combination of the flow rates of the three microchannels from the previous stage. This is the location of the previous station. The expression is:

[0041] 3) The actual location of the particles identified in the previous stage Alternative This allows us to determine the combination of flow velocities in the three microchannels for the next stage. Its expression is:

[0042] in, for The generalized inverse matrix.

[0043] 4) Target location of particles Alternative The expression becomes:

[0044] in, In order to enable the particles to reach the target location The combination of flow rates in the three microchannels.

[0045] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A real-time particle position control method based on three-channel flow velocity regulation, characterized in that, Includes the following steps: (1) Micron-sized particles are released into the swirling flow domain and captured by the stagnation point of the swirling flow; (2) Observe the swirling area in real time and identify the position of particles; (3) Set the initial flow rate of the microchannel and the target position of the particles; (4) The flow velocity of the microchannel is controlled by the velocity-stagnation configuration model of the three-channel swirl to control the position of the particles; (5) Determine whether the particles have reached the target position. If the particles have reached the target position, the control ends; otherwise, repeat the steps to continue controlling the flow rate in the next stage.

2. The real-time particle position control method based on three-channel flow velocity regulation according to claim 1, characterized in that, In step (4), the establishment of the velocity-stagnation configuration model of the three-channel vortex includes the following steps: 1) The velocity of the three-channel vortex flow has a quantitative relationship with the location of the stagnation point, as shown in the following formula: in, 、 These are the x and y coordinates of the station location, respectively. , , These represent the flow rates of the first, second, and third microchannels, respectively. , , , , , , , , , , , The coefficients are known. 2) A first-order Taylor expansion of the velocity-stagnation point quantitative relationship of the three-channel swirling flow yields the following relationship: remember , , This is the combination of flow rate magnitudes for the three microchannels in the next stage. This will serve as the location for the next phase of deployment. This is a combination of the flow rates of the three microchannels from the previous stage. , , These represent the flow rates of the first, second, and third microchannels in the previous stage, respectively. This is the location of the previous station. The expression is: 3) The actual location of the particles identified in the previous stage Alternative This allows us to determine the combination of flow velocities in the three microchannels for the next stage. Its expression is: in, for The generalized inverse matrix; 4) Target location of particles Alternative The expression becomes: in, In order to enable the particles to reach the target location The combination of flow rates in the three microchannels.

3. The real-time particle position control method based on three-channel flow velocity regulation according to claim 2, characterized in that, The actual position of the particles was obtained by continuously identifying the position of the particles in multiple frames and calculating the average position of these frames when the particles were captured and stably maintained in the swirling low-pressure zone. At the same time, the flow rate combination of the three microchannels was recorded.

4. The real-time particle position control method based on three-channel flow velocity regulation according to claim 1, characterized in that, In step (4), controlling the particle position includes the following steps: When the particles were observed to be captured and stably maintained in the swirling low-pressure region, the positions of the particles in multiple frames were continuously identified using image processing and the average value of these particle positions was calculated. The flow rate combination of the three microchannels at this time was recorded. Substituting the average value, the current combination of flow velocities in the three microchannels, and the target position of the particle into the velocity-stagnation configuration model, we can solve for the next stage's combination of flow velocities in the three microchannels. Under the new flow velocities, the particle will move to a new position.

5. A real-time particle position control method based on three-channel flow velocity regulation according to any one of claims 1 to 4, characterized in that, The steps to determine whether a particle has reached its target location are as follows: Calculate the Euclidean distance between the actual position of the particle and the target position of the particle. If the Euclidean distance is less than or equal to the threshold, it is considered that the particle has reached the target position and the control ends; otherwise, continue to calculate the flow velocity combination for the next stage, and finally the particle reaches the target position of the particle and rotates stably in the vicinity.

6. The real-time particle position control method based on three-channel flow velocity regulation according to claim 1, characterized in that, The size range of the micron-sized particles deployed is 50~300 μm.

7. The real-time particle position control method based on three-channel flow velocity regulation according to claim 1, characterized in that, Set the range of flow rate variation for the microchannel flow pump and the peak value of the flow rate increment for each speed adjustment.

8. An apparatus for implementing the real-time particle position control method based on three-channel flow velocity regulation as described in claim 1, characterized in that, It includes a swirl generation module, an image analysis module, and a flow rate control module; The vortex generation module includes three microchannels (1, 2, 3), wherein the endpoints of the inner walls of the first microchannel (1), the second microchannel (2), and the third microchannel (3) are connected in pairs to form a vortex flow domain; The image analysis module includes an inverted microscope (5) equipped with a high-definition CMOS microscope camera; The flow control module includes three flow pumps (7, 11, 15). The three microchannels (1, 2, 3) are installed and fixed in the clamping platform (4). The microscope (5) is connected to the computer (18) via a USB serial port. The flow output end (6) of the first flow pump (7), the flow output end (10) of the second flow pump (11) and the flow output end (14) of the third flow pump (15) are respectively connected to the first microchannel (1), the second microchannel (2) and the third microchannel (3) via a circular hose. The recovery end (8) of the first flow pump (7), the recovery end (12) of the second flow pump (11) and the recovery end (16) of the third flow pump (15) are all connected to the clamping platform (4) via a circular hose. The programmable controller (9) of the first flow pump (7), the programmable controller (13) of the second flow pump (11) and the programmable controller (17) of the third flow pump (15) are all connected to the computer (18) via a USB serial port.

9. A computer device comprising a memory and a processor, the memory being electrically connected to the processor, the memory storing a computer program, characterized in that: When the computer program is executed by the processor, it causes the processor to implement the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor implements the method as described in any one of claims 1 to 7.

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