Automatic pipetting device gun head precise positioning structure

Abstract

The utility model discloses automatic pipette equipment gun head precision positioning structure, including mounting seat, positioning subassembly, sensing detection subassembly and control module, the mounting seat top is equipped with slide rail, is equipped with the sliding seat on the slide rail, the sliding seat is connected with the slide rail slidingly, is equipped with linear motor between sliding seat and mounting seat, the lifting cylinder is equipped with on the sliding seat upside, the output of lifting cylinder is fixedly connected with the lifting seat, the gun head installation main part is installed through the bolt on the lifting seat, the lifting seat is equipped with the guide bushing, and the guide bushing is slidably connected with the guide rod, the bottom of guide rod is fixedly connected with the top of sliding seat. The utility model provides the basic mechanical positioning with the precision cooperation of guide bushing and guide rod, and realizes double position detection with laser displacement sensor and CCD visual sensor, and control module fuses the processing to detection data through positioning algorithm, can real -time correction positioning deviation.

Description

Technical Field

[0001] This utility model relates to the field of automated experimental equipment technology, specifically to a precise positioning structure for pipette tips in automated liquid handling equipment. Background Technology

[0002] In experimental fields such as biology and chemistry, automated pipetting equipment is widely used due to its efficient and stable pipetting capabilities. The positioning accuracy of the pipette tip directly determines the accuracy of the pipetting operation and is one of the key factors affecting the reliability of experimental results. Existing automated pipetting equipment often uses a single mechanical guide or photoelectric sensor positioning method, which suffers from problems such as insufficient positioning accuracy, weak anti-interference ability, and poor adaptability.

[0003] Specifically, traditional mechanical guiding and positioning structures rely on the precise fit between guide posts and guide holes for positioning. However, after long-term use, mechanical wear can lead to increased clearance and accumulated positioning errors, failing to meet the requirements of high-precision experiments. Single photoelectric sensor positioning structures are easily affected by factors such as changes in light levels and dirt on the nozzle surface in the experimental environment, leading to misinterpretation of positioning signals and problems such as nozzle misalignment, missed suction, and missed addition. Furthermore, most existing positioning structures are designed for specific nozzle models, resulting in poor compatibility. Changing to different nozzle specifications requires readjusting positioning parameters, which is cumbersome and reduces experimental efficiency.

[0004] Therefore, there is an urgent need for a precision positioning structure for the tip of an automated pipetting device with high positioning accuracy, strong anti-interference ability, and good compatibility, in order to overcome the shortcomings of existing technologies. Utility Model Content

[0005] The purpose of this invention is to provide a precise positioning structure for the pipette tip of an automated pipetting device, in order to solve the problems currently found in the market as described in the background.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a precise positioning structure for the tip of an automated pipetting device, comprising a mounting base, a positioning component, a sensing and detection component, and a control module; the mounting base has a slide rail on its top, a sliding seat on the slide rail, the sliding seat being slidably connected to the slide rail, a linear motor between the sliding seat and the mounting base, a lifting cylinder on the upper side of the sliding seat, the output end of the lifting cylinder being fixedly connected to the lifting seat, a tip mounting body being bolted onto the lifting seat, a guide sleeve being provided on the lifting seat, the guide sleeve being slidably engaged with a guide rod, the bottom of the guide rod being fixedly connected to the top of the sliding seat; the positioning component includes a positioning boss, a positioning pin, a pin hole, a tip insertion rod, an elastic clamping piece, and a tip connector, a tip being connected to the lower end of the tip mounting body, a positioning boss being provided on the outer side of the tip, and a positioning boss being fixedly mounted on the positioning boss. The gun head mounting body has a positioning pin with a pin hole at its lower end, and the positioning pin is adapted to the pin hole. The lower end of the gun head mounting body also has an insertion hole with an elastic clamping piece inside. The gun head end has a gun head insertion rod, which is inserted into the insertion hole at the lower end of the gun head mounting body. The outer side of the insertion rod is in contact with the elastic clamping piece. A gun head connector is located in the insertion hole at the lower end of the gun head mounting body and mates with the gun head insertion rod. The sensing and detection components include a laser displacement sensor and a CCD vision sensor. The laser displacement sensor is mounted on the end of the mounting base, with its detection direction facing the gun head mounting body. The CCD vision sensor is mounted on the lower side of the lifting base, and its imaging range covers the gun head mounting body and the gun head. The control module is electrically connected to the linear motor, lifting cylinder, laser displacement sensor, and CCD vision sensor.

[0007] Preferably, the inner wall of the guide sleeve on the lifting seat is provided with an aluminum nitride ceramic coating with a coating thickness of 0.05-0.1mm, and the fitting clearance between the guide sleeve and the guide rod is 0.005-0.01mm.

[0008] Preferably, the elastic clamping piece is made of titanium alloy and has anti-slip texture on its surface. The number of elastic clamping pieces is 3-4 pieces, which are evenly distributed along the inner wall of the insertion hole at the lower end of the gun head mounting body.

[0009] Preferably, the laser displacement sensor has a measurement accuracy of ±0.001mm, the CCD vision sensor has a resolution of not less than 12 million pixels, and the CCD vision sensor is equipped with a ring light.

[0010] Preferably, the control module includes a microcontroller, a signal amplification circuit, an A / D conversion module, and a communication module.

[0011] Preferably, the end of the positioning pin is provided with a tapered positioning head.

[0012] Preferably, the lifting seat is provided with reinforcing ribs, and multiple reinforcing ribs are evenly distributed on the lifting seat.

[0013] Compared with the prior art, the beneficial effects of this utility model are: (1) High positioning accuracy: The basic mechanical positioning is provided by the precise fit of the guide sleeve and the guide rod, and the fit gap is controlled within 0.005-0.01mm. At the same time, the laser displacement sensor (measurement accuracy ±0.001mm) and the CCD vision sensor (resolution not less than 12 million pixels) realize dual position detection. The control module performs fusion processing on the detection data through the positioning algorithm, which can correct the positioning deviation in real time and ensure that the positioning accuracy of the gun head reaches within 0.005mm. (2) Strong anti-interference ability: The laser displacement sensor achieves non-contact detection through the laser ranging principle, and is not affected by dirt on the surface of the gun head. The CCD vision sensor is equipped with a ring light, which can eliminate the interference of ambient light changes on the detection results. (3) Good compatibility: The elastic clamping plate is made of titanium alloy, which has good elastic deformation ability and can be adapted to gun heads of different diameters. The combination of positioning pin and pin hole can enhance the fixing effect of gun heads of different specifications. There is no need to replace the positioning component when replacing the gun head. Attached Figure Description

[0014] Figure 1 This is a three-dimensional top view of the structure of this utility model; Figure 2 This is a three-dimensional upward view of the structure of this utility model; Figure 3 This is a schematic diagram of the slide rail and sliding seat structure of this utility model; Figure 4 This is a schematic diagram of the connection structure between the gun head mounting body and the gun head of this utility model; Figure 5 This is a cross-sectional view of the connection between the gun head mounting body and the gun head of this utility model.

[0015] In the diagram: 1. Mounting base; 2. Slide rail; 3. Sliding seat; 4. Linear motor; 5. Lifting cylinder; 6. Guide rod; 7. Lifting seat; 8. Reinforcing rib; 9. Gun head mounting body; 10. Gun head; 11. Laser displacement sensor; 12. CCD vision sensor; 13. Positioning boss; 14. Positioning pin; 15. Pin hole; 16. Gun head insertion rod; 17. Elastic clamping piece; 18. Gun head connector. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-5 This utility model provides a technical solution: a precision positioning structure for the tip of an automated pipetting device, including a mounting base 1, a positioning component, a sensing and detection component, and a control module; the top of the mounting base 1 is provided with a slide rail 2, and a sliding seat 3 is provided on the slide rail 2. The sliding seat 3 is slidably connected to the slide rail 2. A linear motor 4 is provided between the sliding seat 3 and the mounting base 1. A lifting cylinder 5 is provided on the upper side of the sliding seat 3. The output end of the lifting cylinder 5 is fixedly connected to the lifting seat 7. The tip mounting body 9 is installed on the lifting seat 7 by bolts. A guide sleeve is provided on the lifting seat 7. The guide sleeve is slidably engaged with a guide rod 6. The bottom of the guide rod 6 is fixedly connected to the top of the sliding seat 3.

[0018] Furthermore, the inner wall of the guide sleeve on the lifting seat 7 is coated with aluminum nitride ceramic coating. The aluminum nitride ceramic coating has high hardness and low coefficient of friction. The coating thickness is 0.05-0.1mm. The fit clearance between the guide sleeve and the guide rod 6 is 0.005-0.01mm, which can effectively reduce the relative wear between the guide rod 6 and the guide sleeve, avoid lifting deviation caused by the increase of the fit clearance after long-term use, and ensure stable vertical repeatability positioning accuracy.

[0019] Furthermore, the lifting seat 7 is provided with reinforcing ribs 8, and multiple reinforcing ribs 8 are evenly distributed on the lifting seat 7. Among them, the position of the reinforcing rib 8 is opposite to the position of the guide sleeve. The setting of the reinforcing rib 8 forms a rigid support structure between the lifting seat 7 and the nozzle mounting body 9, which can disperse the gravity of the nozzle mounting body 9 and the impact force during the liquid transfer process, and avoid positioning deviation caused by deformation of the lifting seat 7 or the nozzle mounting body 9 due to force. It is especially suitable for high-frequency, high-load automated liquid transfer scenarios.

[0020] The positioning assembly includes a positioning boss 13, a positioning pin 14, a pin hole 15, a gun head insertion rod 16, an elastic clamping piece 17, and a gun head connector 18. A gun head 10 is connected to the lower end of the gun head mounting body 9. A positioning boss 13 is provided on the outer side of the gun head 10, and a positioning pin 14 is fixedly mounted on the positioning boss 13. The gun head 10, positioning boss 13, and positioning pin 14 are integrally formed. A pin hole 15 is provided at the lower end of the gun head mounting body 9, and the positioning pin 14 is adapted to the pin hole 15 for gun head mounting. The lower end of the main body 9 has an insertion hole, and an elastic clamping piece 17 is provided in the insertion hole. The end of the pipette tip 10 is provided with a pipette tip insertion rod 16. The pipette tip insertion rod 16 is inserted into the insertion hole at the lower end of the pipette tip mounting body 9. The outer side of the pipette tip insertion rod 16 is pressed and connected to the elastic clamping piece 17. The lower end of the pipette tip mounting body 9 has a pipette tip connector 18. The pipette tip connector 18 and the pipette tip insertion rod 16 are sealed and connected by a rubber sleeve to ensure normal pipetting operation of the pipette tip 10.

[0021] Furthermore, the elastic clamping piece 17 is made of titanium alloy, which has both high strength and excellent elasticity. It can maintain its elastic deformation ability under long-term compression, avoiding the problem of fatigue and breakage of ordinary metal clamping pieces 17. The surface is provided with anti-slip texture, which can increase the friction with the nozzle insertion rod 16 and prevent the nozzle 10 from loosening or falling off due to vibration or negative pressure during the liquid transfer process. There are 3-4 elastic clamping pieces 17, which are evenly distributed along the inner wall of the insertion hole at the lower end of the nozzle mounting body 9 to form a "multi-point encircling" clamping, which can adapt to nozzle insertion rods 16 with different outer diameters.

[0022] Furthermore, the end of the positioning pin 14 is provided with a tapered positioning head, which has an automatic centering guide function. When the gun head 10 is installed, it can guide the positioning pin 14 to be quickly inserted into the pin hole 15 without the need for precise manual alignment, thereby reducing the assembly difficulty and improving the replacement efficiency of the gun head 10.

[0023] The sensing and detection components include a laser displacement sensor 11 and a CCD vision sensor 12. The laser displacement sensor 11 is mounted on the end of the mounting base 1 and is model KEYENCEGT2-A12K. Its detection direction is towards the gun head mounting body 9. The CCD vision sensor 12 is mounted on the lower side of the lifting base 7 and is model BasleracA2500-14gm. Its imaging range covers the gun head mounting body 9 and the gun head 10.

[0024] Furthermore, the laser displacement sensor 11 has a measurement accuracy of ±0.001mm, which can capture minute positional changes of the pipette tip mounting body 9. The CCD vision sensor 12 has a resolution of no less than 12 million pixels, which can clearly identify the outline position of the pipette tip 10, meeting the stringent requirements for pipetting accuracy in biological and chemical experiments. The CCD vision sensor 12 is equipped with a ring light, which can provide a uniform and stable light source, avoiding the influence of changes in light intensity in the experimental environment on the imaging effect of the CCD vision sensor 12.

[0025] The control module is electrically connected to the linear motor 4, lifting cylinder 5, laser displacement sensor 11, and CCD vision sensor 12. The control module includes a microcontroller, a signal amplification circuit, an A / D conversion module, and a communication module. The microcontroller is an STM32H743, which can quickly process the massive amounts of data from the laser displacement sensor 11 and the CCD vision sensor 12, and generate adjustment commands for the linear motor 4 and lifting cylinder 5 in real time, avoiding positioning lag caused by computation delay. The signal amplification circuit uses an OPA227 operational amplifier, the A / D conversion module uses an ADS1256 chip, and the communication module uses RS485 or Ethernet communication protocols to support stable data interaction between the control module and the main system of the automated pipetting equipment, facilitating collaborative operation of multiple devices.

[0026] The working principle of this automated pipetting device's precise positioning structure is based on a collaborative mechanism of "mechanical positioning + dual-sensor detection + real-time electronic control correction" to achieve high-precision, anti-interference, and multi-specification-compatible positioning of the pipette tip. The details are as follows: First, insert the gun head connector 16 at the end of the gun head 10 into the connector hole at the lower end of the gun head mounting body 9. At this time, the positioning boss 13, which is integrally formed on the outer side of the gun head 10, moves synchronously with the gun head. The positioning pin 14 (with a tapered positioning head at the end) on the positioning boss 13 is automatically guided and accurately inserted into the corresponding pin hole 15 of the gun head mounting body 9, completing the initial alignment of the gun head and avoiding large offsets during installation. The elastic clamping pieces 17 (3-4 pieces of titanium alloy with anti-slip texture) in the connector hole of the gun head mounting body 9 are elastically deformed by the pressure of the gun head connector 16, and the gun head connector 16 is firmly fixed by friction. At the same time, it is compatible with gun heads of different diameters (0.1-10mm) without the need to replace the positioning components.

[0027] The control module drives the linear motor 4 to operate, which in turn drives the sliding seat 3 connected to it to slide along the slide rail 2 on the top of the mounting base 1, thereby moving the nozzle 10 in the horizontal direction. The lifting cylinder 5 on the upper side of the sliding seat 3 outputs power to push the lifting seat 7 fixed at its end to move up and down, thereby driving the nozzle mounting body 9 and nozzle 10, which are bolted to the lifting seat 7, to move vertically. The guide sleeve (with an inner wall of 0.05-0.1mm aluminum nitride ceramic coating) on ​​the lifting seat 7 and the guide rod 6 (fixed to the top of the sliding seat 3 at the bottom) are precisely slidably engaged, with a clearance of only 0.005-0.01mm, reducing shaking during vertical movement. At the same time, the reinforcing ribs 8 (equally spaced) on the lifting seat 7 disperse the gravity and liquid transfer impact force of the nozzle mounting body 9, preventing structural deformation from causing positioning deviation.

[0028] The laser displacement sensor 11 (measurement accuracy ±0.001mm) installed at the end of the mounting base 1 detects the gun head mounting body 9. Through non-contact laser ranging, it captures the minute positional changes of the gun head mounting body 9 in the horizontal / vertical direction in real time, unaffected by dirt on the surface of the gun head 10. The CCD vision sensor 12 (resolution ≥12 million pixels) installed on the lower side of the lifting base 7 captures a range that completely covers the gun head mounting body 9 and the gun head 10. The matching ring light eliminates the influence of ambient light changes and clearly identifies the actual contour position of the gun head 10. The detection signals from the two types of sensors are amplified by the signal amplification circuit (OPA227 operational amplifier) ​​of the control module, digitized by the A / D conversion module (ADS1256 chip), and then transmitted to the core of the control module.

[0029] The STM32H743 microcontroller in the control module receives the pre-processed detection data and compares it with the preset positioning coordinates of the pipette tip to calculate the horizontal / vertical position deviation value. Based on the deviation value, the microcontroller sends adjustment commands to the linear motor 4 and the lifting cylinder 5. If there is a horizontal deviation, the linear motor 4 is adjusted to drive the sliding seat 3 for fine adjustment. If there is a vertical deviation, the lifting cylinder 5 is controlled to push the lifting seat 7 to correct it, ultimately controlling the positioning accuracy of the pipette tip 10 within 0.005mm. The communication module (RS485 or Ethernet protocol) of the control module interacts with the main system of the automated pipetting equipment to support the accuracy maintenance of multi-tip synchronous positioning or continuous pipetting operations.

[0030] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precision positioning structure for the tip of an automated pipetting device, characterized in that, The system includes a mounting base (1), a positioning component, a sensing and detection component, and a control module. The mounting base (1) has a slide rail (2) on top, and a sliding seat (3) is provided on the slide rail (2). The sliding seat (3) is slidably connected to the slide rail (2). A linear motor (4) is provided between the sliding seat (3) and the mounting base (1). A lifting cylinder (5) is provided on the upper side of the sliding seat (3). The output end of the lifting cylinder (5) is fixedly connected to the lifting seat (7). A gun head mounting body (9) is installed on the lifting seat (7) by bolts. A guide sleeve is provided on the lifting seat (7). The guide sleeve is slidably engaged with the guide rod (6). The bottom of the guide rod (6) is fixedly connected to the top of the sliding seat (3). The positioning assembly includes a positioning boss (13), a positioning pin (14), a pin hole (15), a gun head insertion rod (16), an elastic clamping piece (17), and a gun head connector (18). The lower end of the gun head mounting body (9) is connected to a gun head (10). The gun head (10) has a positioning boss (13) on its outer side. The positioning boss (13) is fixedly mounted on the positioning boss (13). The lower end of the gun head mounting body (9) has a pin hole (15). The positioning pin (14) and the pin hole (15) are aligned. The gun head mounting body (9) is provided with a plug hole at the lower end, and an elastic clamping piece (17) is provided in the plug hole. The gun head (10) is provided with a gun head plug rod (16) at the end. The gun head plug rod (16) is inserted into the plug hole at the lower end of the gun head mounting body (9). The outer side of the gun head plug rod (16) is pressed and contacted with the elastic clamping piece (17). The gun head mounting body (9) is provided with a gun head connector (18) in the plug hole at the lower end. The gun head connector (18) is connected to the gun head plug rod (16). The sensing and detection components include a laser displacement sensor (11) and a CCD vision sensor (12). The laser displacement sensor (11) is installed at the end of the mounting base (1) with the detection direction facing the gun head mounting body (9). The CCD vision sensor (12) is installed on the lower side of the lifting base (7) and the shooting range covers the gun head mounting body (9) and the gun head (10). The control module is electrically connected to the linear motor (4), the lifting cylinder (5), the laser displacement sensor (11), and the CCD vision sensor (12), respectively.

2. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The inner wall of the guide sleeve on the lifting seat (7) is provided with an aluminum nitride ceramic coating with a coating thickness of 0.05-0.1mm, and the fit clearance between the guide sleeve and the guide rod (6) is 0.005-0.01mm.

3. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The elastic clamping piece (17) is made of titanium alloy and has anti-slip texture on its surface. There are 3-4 elastic clamping pieces (17) and they are evenly distributed along the inner wall of the insertion hole at the lower end of the gun head mounting body (9).

4. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The laser displacement sensor (11) has a measurement accuracy of ±0.001mm, the CCD vision sensor (12) has a resolution of not less than 12 million pixels, and the CCD vision sensor (12) is equipped with a ring light.

5. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The control module includes a microcontroller, a signal amplification circuit, an A / D conversion module, and a communication module.

6. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The end of the positioning pin (14) is provided with a tapered positioning head.

7. The precision positioning structure for the tip of an automated pipetting device according to claim 1, characterized in that: The lifting seat (7) is provided with reinforcing ribs (8), and multiple reinforcing ribs (8) are evenly distributed on the lifting seat (7).

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