A high-precision miniature Z-axis positioning platform

Abstract

This invention discloses a high-precision miniature Z-axis positioning platform for use in the field of precision platforms. By integrating an encoder, displacement sensor, and reader to construct a multi-level displacement monitoring system, it can compare the matching relationship between the voice coil motor command, the middle plate displacement, and the stage displacement under normal load conditions. When jamming occurs, it can assist in locating the fault source based on the displacement error and displacement curve status among the three. Furthermore, a clamping and tilting roller mechanism controlled by a miniature electric actuator and a drive motor is introduced. At the moment jamming is detected, the sample is actively clamped and lifted, causing it to disengage from the abnormally vibrating stage. This reduces the shaking and displacement of the sample caused by stage jamming, ensuring the stability of the sample during precision operations.

Description

Technical Field

[0001] This invention relates to the field of precision, and in particular to a high-precision miniature Z-axis positioning platform. Background Technology

[0002] With continuous breakthroughs in cutting-edge technologies such as micro-nano fabrication, precision optical inspection, and biomedical engineering, the performance requirements for miniaturized positioning systems are constantly increasing. In submicron or even nanometer-level operation scenarios, such as micro-nano repair of integrated circuits, cell-level microinjection, or fiber-optic coupling alignment, not only is extremely high positioning accuracy required, but the equipment must also achieve multi-degree-of-freedom motion control within a limited space.

[0003] The existing technology CN202023299596.X discloses a small dual-axis high-precision positioning platform based on fiber alignment. By counting square wave pulses through a grating reading head, the displacement and velocity of the grating ruler can be obtained, thereby improving the accuracy of the equipment.

[0004] The prior art CN202110718796.4 discloses a high-response, high-balance working platform. When the horizontal motion component moves horizontally, it uses an inclined plane to drive the vertical motion component to move vertically. The balancing component is placed on one or both sides of the vertical motion component and uses guides to provide vertical guidance and balancing force for the vertical motion component. It can meet the requirements of high response speed and high balance, and has a compact structure and is easy to use.

[0005] The aforementioned existing technologies can all achieve miniaturization of the micro positioning platform. However, in actual operation, due to insufficient lubrication of the guide rail or other reasons, the stage is prone to jamming during vertical lifting and lowering, causing the stage and the sample placed on its surface to shake. This shaking causes changes in the state of the sample, affecting the detection results. Therefore, it is necessary to improve the positioning platform. Summary of the Invention

[0006] The core of this invention lies in its clamping and tilting roller mechanism, controlled by a miniature electric actuator and a drive motor. This mechanism solves the problem in existing technologies where vibrations caused by stage jamming lead to sample jitter on small platforms, resulting in insufficient sample stability during precision operations. Furthermore, the flexible winding and unwinding mechanism, combined with an inflatable clamping sleeve, allows for adaptability to sample plates of different sizes, achieving stable clamping of sheet-like or flat samples.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A high-precision miniature Z-axis positioning platform includes a base plate and a display mounted on one side of the base plate. Two voice coil motors are mounted on the top surface of the base plate. A first cross roller guide rail is mounted on the top surface of the base plate, and a middle plate with a displacement sensor mounted on its surface is slidably connected to the top of the first cross roller guide rail. A second cross roller guide rail is connected to the top of the middle plate, and a stage is slidably connected to the top surface of the second cross roller guide rail. Two guide plates symmetrically arranged about the first cross roller guide rail are mounted on the top surface of the base plate. Annular spring pieces are connected to the surface of the guide plates through pressure plates, and the surface of the annular spring pieces contacts the side surface of the stage. The output of the voice coil motor is connected to an integrated encoder, and the output of the voice coil motor is connected to the surface of the middle plate through a magnetic coupling. Both sides of the base plate are equipped with reaction components. Each reaction component includes support columns arranged on both sides of the outer shell. A miniature electric actuator is installed on the top of each support column. The power end of each miniature electric actuator is connected to a bracket. A clamping roller is rotatably installed on the inner side of each bracket. A rubber sleeve is fitted on the surface of the clamping roller. A drive motor with its output end connected to the end of the clamping roller is installed on the surface of each bracket.

[0009] Furthermore, the top of the middle plate, the second cross roller guide rail, and the bottom of the stage are all arranged in a parallel wedge shape, with the guide plate located inside the voice coil motor.

[0010] Furthermore, a housing is installed on the top of the base plate, and the top of the housing has a through groove with the same vertical projection section as the stage. Half of the clamping rollers are located on the outside of the bracket.

[0011] Furthermore, a reader is embedded in the top surface of the base plate, which consists of a reading head and a grating ruler.

[0012] Furthermore, the display is internally equipped with a control system, which includes a data monitoring module, an execution module, and a correction module. The data monitoring module is connected to the integrated encoder, displacement sensor, voice coil motor, and reader to monitor whether the voice coil motor is driving the stage to move up and down normally. The execution module is connected to the miniature electric actuator, drive motor, and voice coil motor to control their opening and closing states. The correction module is connected to the voice coil motor and the data monitoring module to perform test operations after the stage moves up and down abnormally.

[0013] Furthermore, the base plate has an internal cavity filled with a cooling medium, and the base plate is made of a high thermal conductivity material.

[0014] Optionally, the surface of the rubber sleeve is provided with an adjustment groove, and the surface of the clamping roller is equipped with a winding rope symmetrically arranged with respect to the rubber sleeve. The winding rope is made of a non-elastic material, and the tail end of the winding rope is connected to a micro suction cup. A snap-fit ​​air sleeve is fitted inside the adjustment groove.

[0015] Furthermore, the cross-sectional height of the adjustment groove is greater than the diameter of the coiled rope, an inflation port is installed on the surface of the snap-fit ​​air sleeve, and the cross-sectional height of the adjustment groove is greater than the initial thickness of the snap-fit ​​air sleeve in its non-inflated state.

[0016] Compared with the prior art, the advantages of this invention are: (1) This scheme constructs a multi-level displacement monitoring system by integrating encoders, displacement sensors and readers. Under normal load conditions, it can compare the matching relationship between voice coil motor commands, middle plate displacement and stage displacement. When jamming occurs, it can help locate the source of the fault based on the displacement error and displacement curve status between the three. It can also help locate the source of the fault as the No. 1 cross roller guide, the No. 2 cross roller guide or the ring spring. On this basis, a clamping and flipping roller mechanism controlled by a micro electric push rod and a drive motor is introduced. At the moment jamming is detected, the sample is actively clamped and lifted so that it is disengaged from the abnormally vibrating stage, thereby reducing the shaking and displacement of the sample caused by stage jamming and ensuring the stability of the sample during precision operation.

[0017] (2) This solution can adapt to sample plates of different sizes by combining flexible winding and inflatable snap-fit ​​air sleeve, and achieve stable clamping of sheet or flat sample, thereby realizing a comprehensive protection strategy from three-dimensional block sample to two-dimensional planar sample. In this way, when the platform is stuck, the sample can be reliably lifted by winding the winding or flipping the rubber sleeve to achieve isolation protection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the outer casing of the present invention; Figure 3 This is a schematic diagram of the structure of the base plate and cavity of the present invention; Figure 4 This is a schematic diagram of the state of the clamping and flipping roller-assisted sample lifting isolation stage of the present invention; Figure 5 This is an installation diagram of the rubber roller, adjusting groove, winding rope, micro suction cup, and snap-fit ​​air sleeve of the present invention; Figure 6 This is a schematic diagram illustrating the lifting and isolation of a plate-shaped sample using a coiled rope, as per the present invention. Figure 7 This is a schematic diagram illustrating the lifting and isolation of samples dispersed on a sample plate using a spiral cable, as per the present invention. Figure 8 This is a schematic diagram illustrating the state in which the sample plate, whose length is less than that of the clamping roller, is lifted and isolated according to the present invention. Figure 9This is a diagram showing the arrangement of the winding cable in the adjustment groove when its length is less than that of the clamping roller.

[0019] Explanation of the labels in the diagram: 1. Base plate; 2. Display; 3. Support column; 4. Miniature electric actuator; 5. Support; 6. Clamping roller; 61. Rubber sleeve; 62. Winding rope; 63. Adjustment groove; 64. Snap-fit ​​air sleeve; 65. Miniature suction cup; 7. Drive motor; 8. Housing; 9. Stage; 10. Annular spring; 11. No. 1 cross roller guide rail; 12. Middle plate; 13. Voice coil motor; 14. Pressure plate; 15. Guide plate; 16. Reader; 17. No. 2 cross roller guide rail; 18. Cavity. Detailed Implementation

[0020] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0021] Please see Figures 1-2 A high-precision miniature Z-axis positioning platform includes a base plate 1 and a display 2 mounted on one side of the base plate 1. Two voice coil motors 13 are mounted on the top surface of the base plate 1. A first cross roller guide rail 11 is mounted on the top surface of the base plate 1, and a middle plate 12 with a displacement sensor mounted on its surface is slidably connected to the top of the first cross roller guide rail 11. A second cross roller guide rail 17 is connected to the top of the middle plate 12. A stage 9 is slidably connected to the top surface of the second cross roller guide rail 17. Two guide plates 15 are mounted on the top surface of the base plate 1, which are symmetrically arranged about the first cross roller guide rail 11. The surface of the guide plate 15 is connected to an annular spring piece 10 through a pressure plate 14, and the surface of the annular spring piece 10 is in contact with the side surface of the stage 9.

[0022] The top of the middle plate 12, the second cross roller guide rail 17, and the bottom of the stage 9 are all arranged in a wedge shape that is parallel to each other. The guide plate 15 is located inside the voice coil motor 13. The top of the bottom plate 1 is equipped with a housing 8, and the top of the housing 8 is provided with a through groove that is the same as the vertical projection section of the stage 9. Half of the clamping rollers 6 are located close to each other on the outside of the bracket 5. The top surface of the bottom plate 1 is inlaid with a reader 16, which consists of a reading head and a grating ruler.

[0023] Specifically, during vertical lifting, the voice coil motor 13 is activated, causing the middle plate 12 to slide on the base plate 1 while mounted on the first cross roller guide rail 11. The first cross roller guide rail 11 constrains the middle plate 12, ensuring it moves strictly in the preset direction without deviation or warping. The wedge-shaped surfaces of the stage 9 and the middle plate 12 are both precision-machined matching inclined surfaces, and these two inclined surfaces are slidably connected by the second cross roller guide rail 17.

[0024] When the voice coil motor 13 pushes the middle plate 12 to move along its inclined plane, a relative displacement occurs between the bottom of the stage 9 and the wedge-shaped surface at the top of the middle plate 12. Due to the geometric constraints of the inclined plane and the vertical guiding and pre-tightening force applied to the stage 9 by the annular spring 10 (fixed by the guide plate 15 and the pressure plate 14, and the non-arc part of the pressure plate 14, the guide plate 15 and the annular spring 10 are fixed and constrained by bolts), the inclined plane displacement of the middle plate 12 is forcibly converted into the vertical (Z-direction) lifting motion of the stage 9. During the lifting process, the lifting displacement of the stage 9 can be monitored by the reader 16 to achieve high-precision lifting control.

[0025] The wedge-shaped design at the top of the middle plate 12 has an angle that is the transmission ratio coefficient for displacement conversion between the middle plate 12 and the stage 9.

[0026] The output end of the voice coil motor 13 is connected to an integrated encoder (not shown in the figure, which is prior art), and the output end of the voice coil motor 13 is connected to the surface of the middle plate 12 through a magnetic coupling coupling (not shown in the figure, which is prior art). Please see Figure 1 Both sides of the base plate 1 are equipped with reaction components. Each reaction component includes support columns 3 arranged on both sides of the outer shell 8. A miniature electric actuator 4 is installed on the top of each support column 3. The power end of each miniature electric actuator 4 is connected to a bracket 5. A clamping roller 6 is rotatably installed on the inner side of each bracket 5. A rubber sleeve 61 is fitted on the surface of the clamping roller 6. A drive motor 7 with its output end connected to the end of the clamping roller 6 is installed on the surface of each bracket 5.

[0027] Specifically, the support column 3 and the corresponding clamping rollers 6 are detachable from the platform, mainly used in situations where sample stability is required. The sample placed on the stage 9 is within a suitable load range. Then, the extension of the micro electric actuator 4 causes the surface of the clamping rollers 6 to come into contact with the sample surface. If jamming occurs during the lifting and lowering of the stage 9, the current of the voice coil motor 13 will increase sharply. At this time, the micro electric actuator 4 and the drive motor 7 start simultaneously, clamping the sample and lifting it off the surface of the stage 9 using the two rotating clamping rollers 6 (e.g., ...). Figure 4 As shown), this isolates the sample state from the interference caused by the vibration of the stage 9 due to jamming.

[0028] The display 2 is equipped with a control system, which includes a data monitoring module, an execution module, and a correction module. The data monitoring module is connected to the integrated encoder, displacement sensor, voice coil motor 13, and reader 16 to monitor whether the voice coil motor 13 is driving the stage 9 to move up and down normally. The execution module is connected to the miniature electric actuator 4, drive motor 7, and voice coil motor 13 to control their opening and closing states. The correction module is connected to the voice coil motor 13 and the data monitoring module to perform test operations after the stage 9 experiences abnormal up and down movement.

[0029] In the above process, if the top of the stage 9 carries a sample, but the voice coil motor 13 cannot drive the middle plate 12 to move after being powered on (specifically, the integrated encoder on the surface of the voice coil motor 13 has a detection value, but the displacement value of the middle plate 12 is zero), the sample needs to be removed first. If the stage 9 can be raised and lowered normally after the sample is removed, and the error between the raising and lowering displacement and the theoretical output value of the voice coil motor 13 is within the allowable range, it indicates that the sample load is too large. At this time, the voice coil motor 13 is in an overload state, and the display 2 will show that the voice coil motor 13 is overloaded. At the same time, the execution module in the control system reduces the current of the voice coil motor 13, thereby reducing the heat of the voice coil motor 13, achieving the purpose of heat control inside the platform, and removing the sample with a large load, switching to a sample within a suitable load range onto the stage 9.

[0030] In this embodiment, the data monitoring module is connected to the voice coil motor 13 by signal and is mainly used to monitor the current value of the voice coil motor 13 when it is working. The module determines whether the current value of the voice coil motor 13 changes abruptly during the lifting and lowering of the platform 9 (compared with the current value when the platform 9 starts to lift and lower; if there is lubrication failure or particulate matter on the surface of the first cross roller guide 11 and the second cross roller guide 17, the voice coil motor 13 will automatically increase the output current to generate greater thrust to overcome the sudden resistance in order to maintain the preset motion trajectory). This serves as the basis for determining whether a jam has occurred.

[0031] After the jamming occurred, the displacement of the middle plate 12 during the time period after the voice coil motor 13 was powered on was marked as A, the theoretical displacement of the voice coil motor 13 was marked as B, and the actual displacement of the stage 9 was marked as D. The analysis of the location of the abnormality is shown in the table below: After the first cross roller guide 11 and the second cross roller guide 17 malfunction, while maintaining the sample lifting state, the correction module is activated, and the voice coil motor 13 continues to start, causing the stage 9 to continue lifting to check if the jamming continues. If it does not continue and the lifting speed of the stage 9 is normal, the stage 9 is reset to the position where the jamming occurred. Then, the drive motor 7 rotates in the opposite direction, slowly releasing the sample onto the surface of the stage 9. Afterward, the micro electric push rod 4 retracts, so that the clamping roller 6 is in zero-pressure contact with the sample surface. Otherwise, the lifting of the stage 9 needs to be paused and the platform needs to be adjusted.

[0032] Please see Figure 3 The base plate 1 has a cavity 18 inside, and the cavity 18 is filled with a cooling medium. The base plate 1 is made of a high thermal conductivity material.

[0033] Specifically, during the above-mentioned lifting process, the heat generated by the voice coil motor 13 can be transferred to the cavity 18 through the base plate 1, and then exchanged with the cooling medium in the cavity 18 to achieve cooling treatment inside the outer shell 8.

[0034] Example 2: Please see Figure 5 The surface of the rubber sleeve 61 is provided with an adjustment groove 63. The surface of the clamping roller 6 is provided with a winding rope 62 symmetrically arranged about the rubber sleeve 61. The winding rope 62 is made of non-elastic material. The tail end of the winding rope 62 is connected to a micro suction cup 65. The inside of the adjustment groove 63 is fitted with a snap-fit ​​air sleeve 64.

[0035] The cross-sectional height of the adjusting groove 63 is greater than the diameter of the coil 62, the surface of the snap-fit ​​air sleeve 64 is equipped with an inflation port, and the cross-sectional height of the adjusting groove 63 is greater than the initial thickness of the snap-fit ​​air sleeve 64 in the non-inflated state.

[0036] Specifically, in Example 1, if the sample is dispersed on a flat plate or the sample itself is a relatively thin flat plate (for ease of description, the flat plate involved in these two cases will be referred to as the sample plate in the following text), then the rotation of the clamping roller 6 cannot effectively clamp and lift the sample plate. In order to address this phenomenon, this example is adopted to improve the treatment.

[0037] In this embodiment, when encountering a sample plate, adjustments can be made based on the sample plate's dimensions. If the sample plate's dimensions are greater than or equal to the length of the rubber sleeve 61, the micro suction cup 65 can be directly attached to the top four corners of the sample plate, leaving sufficient slack in the winding cable 62 (this slack is greater than the maximum displacement lifting value of the stage 9, so that the winding cable 62 remains slack during the lifting process of the stage 9 and will not interfere with the lifting of the sample plate). If jamming is detected, the micro electric actuator 4 does not start, but the drive motor 7 starts to wind up the winding cable 62, indirectly lifting and isolating the sample plate (e.g., Figures 6-7 (as shown) If the sample plate is smaller than the length of the rubber sleeve 61, directly stretching the coil 62 past the end of the rubber sleeve 61 and using the micro suction cup 65 to attach the sample plate to its top four corners would cause friction between the coil 62 and the surface of the rubber sleeve 61 during subsequent winding, affecting the uniformity of the rubber sleeve 61's surface thickness. Therefore, it is necessary to stretch the coil 62, arranging it along the adjustment groove 63, and maintaining a margin before the coil 62 enters and after it extends out of the adjustment groove 63 (wherein...). The allowance before entering the adjustment groove 63 is mainly to prevent the winding cable 62 from moving relative to the cable 62 located in the adjustment groove 63. The allowance after exiting the adjustment groove 63 is to prevent interference when the stage 9 lifts the sample plate. Then, the snap-fit ​​air sleeve 64 is inserted into the adjustment groove 63. Because the sum of the initial thickness of the adjustment groove 63 and the diameter of the cable 62 is less than the width of the adjustment groove 63, the snap-fit ​​air sleeve 64 cannot restrain the cable 62 in the adjustment groove 63 after it is inserted (e.g., Figure 9 As shown), air is injected into the snap-fit ​​air sleeve 64 through the air inlet. The expanded snap-fit ​​air sleeve 64 constrains the coiled rope 62 in the adjustment groove 63. Then, when jamming occurs, the micro electric actuator 4 does not start. The drive motor 7 drives the clamping roller 6 to rotate, which in turn drives the rubber sleeve 61 to rotate in the opposite direction, indirectly driving the sample plate to be lifted and isolated (as shown). Figure 8 (As shown).

[0038] The above description is merely a preferred embodiment of the present invention; it encompasses all the protection scope of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A high-precision miniature Z-axis positioning platform, comprising a base plate (1) and a display (2) mounted on one side of the base plate (1), characterized in that: Two voice coil motors (13) are installed on the top surface of the base plate (1). A first cross roller guide rail (11) is installed on the top surface of the base plate (1). A middle plate (12) with a displacement sensor is slidably connected to the top of the first cross roller guide rail (11). A second cross roller guide rail (17) is connected to the top of the middle plate (12). A stage (9) is slidably connected to the top surface of the second cross roller guide rail (17). Two guide plates (15) are installed on the top surface of the base plate (1) symmetrically arranged about the first cross roller guide rail (11). A ring spring (10) is connected to the surface of the guide plate (15) through a pressure plate (14). The surface of the ring spring (10) is in contact with the side surface of the stage (9). The output end of the voice coil motor (13) is connected to an integrated encoder, and the output end of the voice coil motor (13) is connected to the surface of the middle plate (12) through a magnetic coupling coupling. Both sides of the base plate (1) are equipped with reaction components. Each reaction component includes a support column (3) arranged on both sides of the outer shell (8). A micro electric push rod (4) is installed on the top of each support column (3). A support (5) is connected to the power end of each micro electric push rod (4). A clamping roller (6) is rotatably installed on the inner side of each support (5). A rubber sleeve (61) is sleeved on the surface of the clamping roller (6). A drive motor (7) with its output end connected to the end of the clamping roller (6) is installed on the surface of each support (5).

2. The high-precision miniature Z-axis positioning platform according to claim 1, characterized in that: The top of the middle plate (12), the second cross roller guide rail (17) and the bottom of the platform (9) are all arranged in a wedge shape that is parallel to each other, and the guide plate (15) is located inside the voice coil motor (13).

3. The high-precision miniature Z-axis positioning platform according to claim 1, characterized in that: The top of the base plate (1) is equipped with a shell (8), and the top of the shell (8) is provided with a through groove that is the same as the vertical projection section of the platform (9). Half of the clamping rollers (6) are located on the outside of the bracket (5).

4. The high-precision miniature Z-axis positioning platform according to claim 1, characterized in that: A reader (16) is embedded in the top surface of the base plate (1), and the reader (16) consists of a reading head and a grating ruler.

5. A high-precision miniature Z-axis positioning platform according to claim 4, characterized in that: The display (2) is equipped with a control system, which includes a data monitoring module, an execution module and a correction module. The data monitoring module is connected to the integrated encoder, displacement sensor, voice coil motor (13) and reader (16) to monitor whether the voice coil motor (13) drives the stage (9) to move up and down normally. The execution module is connected to the micro electric actuator (4), the drive motor (7) and the voice coil motor (13) to control their opening and closing states; the correction module is connected to the voice coil motor (13) and the data monitoring module to perform test operations after abnormal lifting and lowering of the stage (9).

6. The high-precision miniature Z-axis positioning platform according to claim 1, characterized in that: The base plate (1) has a cavity (18) inside, and the cavity (18) is filled with a cooling medium. The base plate (1) is made of a high thermal conductivity material.

7. A high-precision miniature Z-axis positioning platform according to claim 1, characterized in that: The surface of the rubber sleeve (61) is provided with an adjustment groove (63), and the surface of the clamping roller (6) is provided with a winding rope (62) symmetrically arranged about the rubber sleeve (61). The winding rope (62) is made of non-elastic material, and the tail end of the winding rope (62) is connected to a micro suction cup (65). The inside of the adjustment groove (63) is fitted with a snap-fit ​​air sleeve (64).

8. A high-precision miniature Z-axis positioning platform according to claim 7, characterized in that: The cross-sectional height of the adjustment groove (63) is greater than the diameter of the coil (62), the surface of the snap-fit ​​air sleeve (64) is equipped with an air inlet, and the cross-sectional height of the adjustment groove (63) is greater than the initial thickness of the snap-fit ​​air sleeve (64) in the non-inflated state.

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