A device for achieving force and vibration balance based on a linear motor and its application in magnetic tweezers

Abstract

This invention discloses a device for achieving force and vibration balance based on linear motors and its application in magnetic tweezers. The device includes a vertical support, a T-shaped cantilever connecting plate, an L-shaped support, a first linear motor, a second linear motor, a linear spring, a first connecting terminal, a second connecting terminal, a permanent magnet, and a control unit. Two linear motors are fixed back-to-back vertically on the T-shaped cantilever connecting plate. The motion axis of the first linear motor is connected to the T-shaped cantilever connecting plate sequentially via the first connecting terminal, the linear spring, and the L-shaped support. The motion axis of the second linear motor is connected to the permanent magnet via the second connecting terminal and acts as the working motor, applying magnetic attraction through a magnetic field. The first linear motor acts as an auxiliary motor, generating opposite motion and vibration through a common control unit, thereby counteracting the vibration generated by the second linear motor's motion. This invention ensures precise control of the permanent magnet's motion by fixing the two motors back-to-back.

Description

Technical Field

[0001] This invention relates to the field of precision control, specifically to a device based on a linear motor to achieve force and vibration balance and its application in magnetic tweezers. Background Technology

[0002] In the field of single-molecule manipulation (such as magnetic tweezers), the motion accuracy of permanent magnets directly affects the reliability of experimental results. Traditional single-motor driven permanent magnet devices have the following drawbacks: 1. The vibration generated during the movement of a linear motor can cause the permanent magnet to displace in multiple directions. Especially at the micro-nano scale, non-axial vibration (such as lateral sway) can cause manipulation errors. 2. Single-motor control struggles to balance the inertial torque during motion, resulting in insufficient motion stability; 3. In complex environments (such as liquid environments), vibration interference is further amplified, making it difficult to meet the micron-level precision requirements for single-molecule manipulation.

[0003] In existing technologies, passive vibration reduction schemes (such as spring dampers) have slow response speeds and large sizes, while active vibration control mostly uses single-axis compensation, which cannot achieve complete decoupling of multi-directional vibrations. Therefore, there is an urgent need for a vibration cancellation scheme with a compact structure and fast response. Summary of the Invention

[0004] To address the problem that existing single-motor driven permanent magnet devices generate vibrations due to their own movement, resulting in low positioning accuracy and poor stability of the permanent magnet and other end actuators, this invention provides a device based on a linear motor to achieve force and vibration balance and its application in magnetic tweezers. This device can actively counteract vibrations and reaction forces during the movement process, thereby achieving pure, high-precision one-dimensional linear motion.

[0005] The objective of this invention is achieved through the following technical solution: A device for achieving force and vibration balance based on a linear motor, the device comprising a vertical support, a T-shaped cantilever connecting plate, an L-shaped support, a first linear motor, a second linear motor, a linear spring, a first connecting terminal, a second connecting terminal, a permanent magnet, and a control unit; The vertical bracket is used to fix it to the external support platform. The T-shaped cantilever connecting plate includes a horizontal plate and a vertical plate. One end of the horizontal plate is fixed to the vertical bracket, and the other end is fixed to the vertical plate. The first linear motor and the second linear motor are fixed back to back on the vertical plate of the T-shaped cantilever connecting plate in the vertical direction, with the exposed end of the motion shaft of the first linear motor facing upward and the exposed end of the motion shaft of the second linear motor facing downward. The exposed end of the motion shaft of the first linear motor is connected to the lower end of the first connecting terminal. The upper end of the first connecting terminal is connected to the horizontal end of the L-shaped bracket through a linear spring. The vertical end of the L-shaped bracket is fixed to the vertical plate of the T-shaped cantilever connecting plate. The exposed end of the motion shaft of the second linear motor is connected to the upper end of the second connecting terminal. The lower end of the second connecting terminal is connected to the permanent magnet, which is used to generate a controllable magnetic attraction force. The first linear motor and the second linear motor have identical specifications and their motion axes are on the same axis, but their motion directions are opposite. Both the first linear motor and the second linear motor are connected to the control unit, which controls the first linear motor and the second linear motor to move synchronously, with the same magnitude but in opposite directions.

[0006] Furthermore, the first linear motor and the second linear motor are voice coil motors.

[0007] Furthermore, the motion shafts of the first and second linear motors are made of aluminum alloy.

[0008] Application of a device based on a linear motor to achieve force and vibration balance in magnetic tweezers.

[0009] The beneficial effects of this invention are as follows: 1. High-precision vibration cancellation: Because the specifications, loads (motion axes), and motion parameters (displacement, speed) of the two linear motors are exactly the same, but in completely opposite directions, the lateral vibrations, reaction torques, and internal inertial forces generated by the drive motors during their movement will be equal in magnitude and opposite in direction to the corresponding forces generated by the compensation motors at the same time and space point, thus achieving perfect cancellation. This fundamentally eliminates the vibration source, allowing the permanent magnet to perform pure linear motion only in the set axis, greatly improving positioning accuracy to the micrometer or even sub-micrometer level.

[0010] 2. Enhanced System Stability: Because the reaction forces generated by the two motors cancel each other out, the impact force of the entire device on the external support structure is almost zero. This significantly improves the stability of the entire system (including the microscope, sample stage, etc.), making it particularly suitable for precision measurement environments that are extremely sensitive to vibration.

[0011] 3. Compact structure and fast response: The "back-to-back" integrated design of this invention results in a compact structure that is easy to integrate into existing equipment (such as inverted microscopes). Due to the use of electrical synchronous control, the system has an extremely fast response speed, enabling real-time and dynamic compensation for vibrations caused by high-speed motion, thus meeting the needs of dynamic experiments requiring rapid application and change of force.

[0012] 4. Wide range of applications: This device is not only suitable for magnetic tweezers technology, but can also be widely used in any scenario that requires high-precision one-dimensional linear motion, such as probe scanning in atomic force microscopy (AFM), sample stage positioning in optical tweezers, and precision alignment in the field of microelectronics. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a device for single-molecule manipulation based on a linear motor to achieve force and vibration balance, according to one embodiment of the present invention.

[0014] Figure 2 A detailed diagram showing the connection between the T-shaped cantilever and two voice coil motors.

[0015] Figure 3 The graphs show the results of stretching DNA (bp) at different speeds (500 μm / s, 5000 μm / s, 10000 μm / s, 2000 μm / s) under constant force for single-molecule manipulation using a device based on a linear motor to achieve force and vibration balance, and a device with only a single motor, according to embodiments of the present invention. The horizontal axis represents time, and the vertical axis represents the position of the magnetic ball relative to the lower surface of the sample well. Figure 3 Figure A is a result diagram of the dual-motor system of the present invention, Figure C is a partial enlarged view of Figure A, Figure B is a result diagram using a single motor, and Figure D is a partial enlarged view of Figure B.

[0016] In the figure, L-shaped bracket 1, first linear motor 2, second linear motor 3, linear spring 4, first connecting terminal 5, T-shaped cantilever connecting plate 6, second connecting terminal 7, permanent magnet 8, vertical bracket 9, and control unit 10. Detailed Implementation

[0017] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become clearer. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0018] like Figure 1 The diagram shown illustrates one embodiment of the present invention, demonstrating the application of the linear motor-based force and vibration balance device in a single-molecule manipulation scenario. The linear motor-based force and vibration balance device of this embodiment is as follows: Figure 1 and Figure 2As shown, it includes a vertical bracket 9, a T-shaped cantilever connecting plate 6, an L-shaped bracket 1, a first linear motor 2, a second linear motor 3, a linear spring 4, a first connecting terminal 5, a second connecting terminal 7, a permanent magnet 8, and a control unit 10.

[0019] The vertical bracket 9 is used to fix it to the external support platform, and one end of the T-shaped cantilever connecting plate 6 is fixed to the vertical bracket 9. Figure 2 As shown, the T-shaped cantilever connecting plate 6 includes a horizontal plate and a vertical plate. The right end of the horizontal plate is fixedly connected to the vertical bracket 9, and the left end of the horizontal plate is connected to the vertical plate. The first linear motor 2 and the second linear motor 3 are fixed back-to-back on the vertical plate of the T-shaped cantilever connecting plate 6 along the vertical direction. The exposed end of the motion shaft of the first linear motor 2 faces upward and is connected to the lower end of the first connecting terminal 5. The upper end of the first connecting terminal 5 is connected to the horizontal end of the L-shaped bracket 1 through a linear spring 4, and the vertical end of the L-shaped bracket 1 is fixedly connected to the vertical plate of the T-shaped cantilever connecting plate 6. The exposed end of the motion shaft of the second linear motor 3 faces downward and is connected to the upper end of the second connecting terminal 7. The lower end of the second connecting terminal 7 is connected to the permanent magnet 8. The end of the permanent magnet 8 is suspended above the sample cell, generating a controllable magnetic attraction force on the paramagnetic ball in the sample cell.

[0020] The first linear motor 2 and the second linear motor 3 have identical structures and specifications, with their motion axes on the same axis, only their motion directions are opposite. Both the first linear motor 2 and the second linear motor 3 are connected to the control unit 10, which controls their synchronous, identical-amplitude but opposite-direction motion. The second linear motor 3 is the main motor, used to drive the permanent magnet to generate a controllable magnetic attraction force on the paramagnetic spheres in the sample cell. The first linear motor 2 serves as an auxiliary motor, used to balance the lateral vibration, reaction torque, and internal inertial force generated by the movement of the second linear motor 3. Because the two motors are fixed together, they can be considered as a whole, and their relative motion is canceled out internally, avoiding random motion in other directions, thus ensuring the precision of the permanent magnet motion control, and consequently ensuring the precision of single-molecule manipulation.

[0021] The second linear motor 3 also integrates a high-resolution grating ruler for real-time and accurate feedback of the position information of its exposed end of the motion axis, thereby forming a closed-loop control to ensure positioning accuracy. To avoid signal conflicts and drive errors that may be caused by the dual feedback system, the first linear motor 2 does not connect to position feedback. Instead, through a spring reset mechanism, after each motion cycle, the linear spring 4 can reliably pull back the motion axis of the first linear motor 2 and stabilize it at a preset mechanical balance position, preventing it from moving to its limit stroke due to several types of errors.

[0022] The first linear motor 2 and the second linear motor 3 are preferably voice coil motors. The motion shafts of both the first linear motor 2 and the second linear motor 3 are made of lightweight aluminum alloy.

[0023] The device based on a linear motor to achieve force and vibration balance in this embodiment was used to stretch a 785bp DNA segment. The permanent magnet (and the lower motor shaft) were moved at speeds of 500µm / s, 5000µm / s, 10000µm / s, and 2000µm / s, respectively, resulting in a very smooth and relatively narrow peak pattern. Figure 3 As shown in Figures A and C; it can be seen from the figure that, under the condition of two linear motors, the movement of the superparamagnetic ball is very smooth and without fluctuation as the controller command is issued. For comparison, a control experiment was conducted using only the lower second linear motor without the upper first linear motor, resulting in a very sharp and relatively broad peak plot, as shown in Figures A and C. Figure 3 As shown in Figures B and D, when only the lower working motor is present and the upper auxiliary motor is absent, the vibration and amplitude of the superparamagnetic ball due to its movement increase with increasing speed. This demonstrates the advantage of the back-to-back dual motors used in this invention.

[0024] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A device for achieving force and vibration balance based on a linear motor, characterized in that, The device includes a vertical support, a T-shaped cantilever connecting plate, an L-shaped support, a first linear motor, a second linear motor, a linear spring, a first connecting terminal, a second connecting terminal, a permanent magnet, and a control unit; The vertical bracket is used to fix it to the external support platform. The T-shaped cantilever connecting plate includes a horizontal plate and a vertical plate. One end of the horizontal plate is fixed to the vertical bracket, and the other end is fixed to the vertical plate. The first linear motor and the second linear motor are fixed back to back on the vertical plate of the T-shaped cantilever connecting plate in the vertical direction, with the exposed end of the motion shaft of the first linear motor facing upward and the exposed end of the motion shaft of the second linear motor facing downward. The exposed end of the motion shaft of the first linear motor is connected to the lower end of the first connecting terminal. The upper end of the first connecting terminal is connected to the horizontal end of the L-shaped bracket through a linear spring. The vertical end of the L-shaped bracket is fixed to the vertical plate of the T-shaped cantilever connecting plate. The exposed end of the motion shaft of the second linear motor is connected to the upper end of the second connecting terminal. The lower end of the second connecting terminal is connected to the permanent magnet, which is used to generate a controllable magnetic attraction force. The first linear motor and the second linear motor have identical specifications and their motion axes are on the same axis, but their motion directions are opposite. Both the first linear motor and the second linear motor are connected to the control unit, which controls the first linear motor and the second linear motor to move synchronously, with the same magnitude but in opposite directions.

2. The device for achieving force and vibration balance based on a linear motor according to claim 1, characterized in that, The first linear motor and the second linear motor are voice coil motors.

3. The device for achieving force and vibration balance based on a linear motor according to claim 2, characterized in that, The motion shafts of the first and second linear motors are made of aluminum alloy.

4. The application of a device for achieving force and vibration balance based on a linear motor as described in any one of claims 1 to 3 in magnetic tweezers.

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