A small-angle generating system and method based on magneto-rheological fluid and fine-tuning motor

Abstract

The present application relates to the field of precision instruments and control technology, and particularly relates to a small-angle generating system and method based on magneto-rheological fluid and fine adjustment motor. The present application comprises two capacitive angular displacement sensors for measuring the relative rotation angle between the inner shaft and the outer shaft; an angle sensor signal acquisition module is used for acquiring the relative rotation angle measured by the two capacitive angular displacement sensors, and the two relative rotation angles are subtracted, and the angle difference is transmitted to the feedback controller; the feedback controller is used for comparing the angle difference with the preset target angle, calculating the angle error, and the signal processing and analysis unit is used for analyzing and processing the angle error through a closed-loop control strategy, so that the motor drive control unit and the magnetic field control unit are controlled according to the angle error, so that the relative rotation angle between the inner shaft and the outer shaft is stabilized within the target angle. The present application combines the motor micro-step subdivision drive with the vibration suppression characteristics of magneto-rheological fluid damping, and achieves high-accuracy small-angle generation.

Description

Technical Field

[0001] This invention relates to the field of precision instruments and control technology, and more specifically, to a small-angle generation system and method based on magnetorheological fluid and fine-tuning motor. Background Technology

[0002] Currently, small angle adjustments (such as machining and precision instrument calibration) mostly rely on purely mechanical structures (such as worm gears and lead screw drives), which have problems such as insufficient accuracy, slow response speed, and complex structure. Magnetorheological fluid, as a smart material, can have its rheological properties quickly adjusted by an external magnetic field (millisecond-level response), and has been widely used in sensors, damping control, power transmission and other fields. Although magnetorheological fluid technology has made progress, the following problems still exist in the field of small angle generation and control: (1) Insufficient active control capability: Existing technologies are mostly used for passive detection or power transmission (such as sensors and flexible motors), lacking the ability to actively generate and maintain small angles; (2) Limited linearity and accuracy: The relationship between the viscosity and magnetic field of magnetorheological fluid is easily affected by factors such as temperature and particle sedimentation, resulting in poor linearity and repeatability of angle adjustment; (3) Structural complexity and cost: Some systems need to be combined with capacitance detection, multi-stage transmission or complex control circuits (such as servo motors and frequency converters), resulting in large size and high cost.

[0003] In the prior art, patent CN201120144392 proposes a tilt sensor based on magnetorheological fluid, which detects angles through capacitance changes, but it is only used for passive measurement and cannot actively generate angles. Patent CN201420326129 describes a magnetorheological flexible motor that achieves flexible power output, but its core is overload protection and does not involve precise control of small angles. Patent CN201310712684's continuously variable transmission system relies on complex control circuits and is difficult to directly transfer to small-angle scenarios. Therefore, there is a need to provide a small-angle generation system and method based on magnetorheological fluid and a fine-tuning motor. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the purpose of this invention is to propose a small-angle generation system and method based on magnetorheological fluid and a fine-tuning motor, to solve the trade-off between accuracy, response speed, and reliability in small-angle generation using traditional methods, and to achieve high-accuracy small-angle generation.

[0005] To achieve the above and other related objectives, the present invention provides a small-angle generation system based on magnetorheological fluid and a fine-tuning motor, comprising:

[0006] Two capacitive angular displacement sensors are used to measure the relative rotation angle between the inner and outer shafts;

[0007] An angle sensor signal acquisition module is used to acquire the relative rotation angle measured by the two capacitive angular displacement sensors, calculate the difference between the two relative rotation angles, and transmit the angle difference value to the feedback controller.

[0008] A feedback controller is used to compare the angle difference with a preset target angle and calculate the angle error. The feedback controller is used to perform feedback control on the motor drive control unit.

[0009] The motor drive control unit is used to output the control signal of the angle error to the signal processing and analysis unit;

[0010] The signal processing and analysis unit is used to analyze and process the angle error through a closed-loop control strategy, so as to control the motor drive control unit and the magnetic field control unit according to the angle error, so that the relative rotation angle between the inner shaft and the outer shaft is stabilized within the target angle.

[0011] A computer is used to display and output the relative rotation angle between the inner and outer shafts.

[0012] In one embodiment of the present invention, it further includes:

[0013] A frustum for carrying a material is mounted on the upper part of the inner shaft, and the frustum for carrying the material is fixed to the inner shaft and rotates together with it.

[0014] An inner shaft base is installed at the lower part of the inner shaft, and the inner shaft base is fixed to the outer shaft, allowing the inner shaft and the inner shaft base to rotate relative to each other;

[0015] An outer shaft is disposed outside the inner shaft and surrounds the inner shaft;

[0016] A magnetic field generating unit is disposed on the outside of the outer shaft, and the bottom of the magnetic field generating unit is disposed on the device base;

[0017] A device base is installed at the lower part of the inner shaft base, and the inner shaft base rotates relative to the device base;

[0018] The outer wall of the device is fixedly installed on the upper part of the device base, and the outer wall of the device is located on the outside of the magnetic field generating unit, with a gap between it and the magnetic field generating unit. The capacitive angular displacement sensor is installed on the outer side of the upper edge of the loading frustum and the outer shaft, and on the inner side of the outer wall of the device.

[0019] In one embodiment of the present invention, it further includes:

[0020] A magnetorheological fluid is disposed between the inner shaft and the outer shaft.

[0021] In one embodiment of the present invention, the capacitive angular displacement sensor includes a first capacitor plate, a second capacitor plate, a third capacitor plate, a fourth capacitor plate, a fifth capacitor plate, a sixth capacitor plate, a seventh capacitor plate, and an eighth capacitor plate. The first and second capacitor plates are arranged opposite to each other; the third and fourth capacitor plates are arranged opposite to each other; the fifth and sixth capacitor plates are arranged opposite to each other; and the seventh and eighth capacitor plates are arranged opposite to each other. The first and fifth capacitor plates are mounted on the side of the frustum; the third and seventh capacitor plates are mounted on the side of the outer shaft. The second, fourth, sixth, and eighth capacitor plates are fixedly mounted on the inner side of the outer wall of the device. The first, second, fifth, and sixth capacitor plates are used to measure the rotation angle of the frustum relative to the inner shaft; the third, fourth, seventh, and eighth capacitor plates are used to measure the rotation angle of the outer shaft relative to the device base.

[0022] In one embodiment of the present invention, it further includes:

[0023] A magnetorheological fluid microsphere array is disposed on the lower part of the frustum of the carrier, and the magnetorheological fluid microsphere array is disposed on the upper surface of the outer shaft.

[0024] In one embodiment of the present invention, a plurality of pit arrays are etched on the upper surface substrate of the outer shaft, and a magnetorheological fluid microsphere is placed in each pit array, which together constitute the magnetorheological fluid microsphere array.

[0025] In one embodiment of the present invention, the magnetic field generating unit includes: a first vertical electromagnetic coil, a second vertical electromagnetic coil, a third vertical electromagnetic coil, a fourth vertical electromagnetic coil, and a first horizontal electromagnetic coil.

[0026] The first vertical electromagnetic coil and the second vertical electromagnetic coil are opposite each other and are respectively disposed on both sides of the magnetorheological fluid;

[0027] The third vertical electromagnetic coil is opposite to the fourth vertical electromagnetic coil, and the third vertical electromagnetic coil is disposed on the upper part of the frustum; the fourth vertical electromagnetic coil is disposed on the lower part of the inner shaft base.

[0028] The first horizontal electromagnetic coil is disposed outside the outer shaft.

[0029] This invention also provides a method for generating small angles based on magnetorheological fluid and a fine-tuning motor, including the aforementioned small angle generation system based on magnetorheological fluid and a fine-tuning motor, wherein the method for generating small angles based on magnetorheological fluid and a fine-tuning motor includes:

[0030] S1. The relative rotation angle between the inner and outer shafts is measured using two capacitive angular displacement sensors;

[0031] S2. The relative rotation angle measured by the two capacitive angular displacement sensors is acquired by the angle sensor signal acquisition module, and the difference between the two relative rotation angles is calculated and transmitted to the feedback controller.

[0032] S3. The feedback controller compares the angle difference with the preset target angle and calculates the angle error. The feedback controller performs feedback control on the motor drive control unit.

[0033] S4. The motor drive control unit outputs the control signal for the angle error to the signal processing and analysis unit;

[0034] S5. The signal processing and analysis unit analyzes and processes the angle error through a closed-loop control strategy, and controls the motor drive control unit and the magnetic field control unit according to the angle error, so that the relative rotation angle between the inner shaft and the outer shaft is stabilized within the target angle.

[0035] S6. Display and output the relative rotation angle between the inner and outer shafts via computer.

[0036] In one embodiment of the present invention, the signal processing and analysis unit in step S5 analyzes and processes the angle error using a closed-loop control strategy, and controls the motor drive control unit and the magnetic field control unit according to the angle error, so that the relative rotation angle between the inner shaft and the outer shaft is stabilized within the target angle, including:

[0037] For the first, second, third, fourth, fifth, sixth, seventh, and eighth capacitor plates, assuming the initial overlap area is A0, the dielectric constant between the plates is ε, and the distance between the plates is d, when the angle changes by Δθ, the change in the overlap area is ΔA. Then, the relationship between the change in capacitance ΔC and the change in angle Δθ is approximately:

[0038]

[0039] Assuming the radius of the sector-shaped plate is r, the overlapping area caused by the angle change is approximately:

[0040]

[0041] The change in angle Δθ can then be expressed as:

[0042]

[0043] The small-angle generation system operates in shear mode, in which the magnetorheological fluid is confined between two relatively rotating cylinders. In this mode, the shear rate ω is related to the force F, which is expressed as:

[0044]

[0045] Formula (4) simplifies to:

[0046]

[0047] Among them, F 屈服 (H) is the static yield force related to the magnetic field, which is independent of the angle; It is the viscous damping coefficient; η is the angular velocity; A is the shear area; r is the radius of rotation; d is the gap thickness; η is the zero-field viscosity; F in the formula is the force caused by shear stress. When subjected to external torque, the angle generated is divided into two modes: stable rotation and dynamic response.

[0048] In one embodiment of the present invention, the stable rotation mode is as follows:

[0049] Assuming the small-angle generating system reaches a steady state, at which point the external torque and the damping torque of the magnetorheological fluid are balanced, the resulting steady-state angle change is:

[0050]

[0051] Where θ0 is the initial angle value, T ext The torque generated by the fine-tuning motor is given by t, which is the time of angle change.

[0052] The dynamic response mode:

[0053] Assuming the small angle generation system is a transient change, the obtained transient angle change is:

[0054]

[0055] C1 and C2 are determined by the initial conditions, and l is the total length of the magnetorheological fluid flow path.

[0056] As described above, the small-angle generation system and method based on magnetorheological fluid and fine-tuning motor of the present invention has the following beneficial effects:

[0057] The present invention discloses a small angle generation system and method based on magnetorheological fluid and fine-tuning motor. It utilizes the rapid solidification characteristics of magnetorheological fluid under magnetic field (millisecond-level response) and combines it with the stepping drive of fine-tuning motor to achieve instantaneous locking after angle adjustment, avoiding the lag and loosening of traditional mechanical locking.

[0058] This invention discloses a small-angle generation system and method based on magnetorheological fluid and a fine-tuning motor. It employs a closed-loop adaptive algorithm, fusing motor encoder signals and magnetorheological fluid damping feedback to achieve dynamic compensation for angle fine-tuning. By combining the microstepping drive of the motor with the vibration suppression characteristics of magnetorheological fluid damping, it achieves highly accurate small-angle generation.

[0059] The present invention discloses a small angle generation system and method based on magnetorheological fluid and fine-tuning motor. It adopts a high-resolution fine-tuning motor and combines the damping compensation technology of magnetorheological fluid to eliminate mechanical transmission gaps and achieve milliarcsecond-level angle resolution, which far exceeds the angle resolution of traditional mechanical fine-tuning devices.

[0060] The present invention discloses a small angle generation system and method based on magnetorheological fluid and fine-tuning motor. The magnetorheological fluid completes the liquid to semi-solid state switching within 1-5ms under the action of a magnetic field. Combined with the fine-tuning motor drive, the angle is adjusted in real time and there is no drift after locking.

[0061] The present invention discloses a small angle generation system and method based on magnetorheological fluid and fine-tuning motor. By replacing the traditional mechanical locking mechanism with magnetorheological fluid, the number of components is reduced and the size is compact, which has significant effects in high-precision manufacturing, angle and attitude control and other fields. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of a small-angle generation system based on magnetorheological fluid and a fine-tuning motor according to an embodiment of the present invention;

[0063] Figure 2 This is a top view of the main structure of a small-angle generation system based on magnetorheological fluid and a fine-tuning motor according to an embodiment of the present invention;

[0064] Figure 3 This is a flowchart of a method for generating small angles based on magnetorheological fluid and a fine-tuning motor, according to an embodiment of the present invention.

[0065] The components are as follows: 1-Frustum; 2-Inner shaft; 3-Inner shaft base; 4-Outer shaft; 5-Magnetorheological fluid; 6-Magnetorheological fluid microsphere array; 7-Magnetic field generating unit (701-First vertical electromagnetic coil; 702-Second vertical electromagnetic coil; 703-Third vertical electromagnetic coil; 704-Fourth vertical electromagnetic coil; 705-First horizontal electromagnetic coil); 8-Device base; 9-Device outer wall; 10-Capacitive angular displacement sensor (101-First capacitor plate; 102-Second capacitor plate; 103-Third capacitor plate; 104-Fourth capacitor plate; 105-Fifth capacitor plate; 106-Sixth capacitor plate; 107-Seventh capacitor plate; 108-Eighth capacitor plate); 11-Angle sensor signal acquisition module; 12-Feedback controller; 13-Motor drive control unit; 14-Fine-tuning motor; 15-Signal processing and analysis unit; 16-Magnetic field control unit; 17-Computer. Detailed Implementation

[0066] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0067] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0068] Terms such as "first" or "second" may be used to describe various components, but these components are not limited by the terms described above. The terms described above are used to distinguish one component from another; for example, without departing from the scope of the concept according to this disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0069] Furthermore, "connected / linked" indicates that one component is directly electrically connected to another component or indirectly electrically connected through another component. Unless otherwise explicitly stated in the sentence, the singular form may include the plural form. Additionally, the terms "comprising / including" or "containing / including" as used in this specification indicate the presence or addition of one or more components, steps, operations, and elements. Specific structural or functional descriptions of examples of embodiments of the concepts disclosed in this specification are merely illustrative to describe examples of embodiments of the concepts, and examples of embodiments of the concepts can be implemented in various forms, but these descriptions are not limited to the examples of embodiments described in this specification.

[0070] Based on the concept, various modifications and changes can be applied to examples of embodiments, such that examples of embodiments will be illustrated in the accompanying drawings and described in the specification. However, examples of embodiments based on the concept are not limited to specific embodiments, but include all changes, equivalents, or substitutions included within the spirit and scope of this disclosure.

[0071] It should be understood that when describing an element as "connected" or "linked" to another element, the element may be directly connected or linked to the other element, or it may be connected or linked to the other element via a third element. Conversely, it should be understood that when an element is described as "directly connected to" or "directly linked to" another element, no other element is placed between them. Other expressions describing relationships between components (i.e., "between" and "directly between" or "adjacent to" and "directly adjacent to") need to be interpreted in the same way.

[0072] The terminology used in this specification is for the purpose of describing specific examples of implementations only and is not intended to limit this disclosure. The singular form may include the plural form unless there is an explicit contrary meaning in the context. It should be understood in this specification that the terms "comprising" or "having" indicate the presence of the features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof.

[0073] Unless otherwise defined, all terms used herein (including technical or scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. If a term is not clearly defined in a common dictionary in this specification, it shall be interpreted as having the same meaning as in the context of the relevant art, and not as an ideal or overly formal meaning.

[0074] Descriptions of known components and processing techniques may be omitted to avoid unnecessarily obscuring the embodiments of this disclosure.

[0075] Throughout this specification, the same reference numerals refer to the same elements. Therefore, even if a reference numeral is not mentioned or described with reference to one drawing, it may be mentioned or described with reference to another drawing. Furthermore, even if a reference numeral is not shown in one drawing, it may be mentioned or described with reference to another drawing.

[0076] Additionally, the logic level of a signal may be different from or opposite to the logic level described. For example, a signal described as having a logic "high" level may optionally have a logic "low" level, and a signal described as having a logic "low" level may optionally have a logic "high" level.

[0077] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0078] Please see Figure 1 , Figure 2 , Figure 1 This is a schematic diagram of a small-angle generation system based on magnetorheological fluid and a fine-tuning motor according to an embodiment of the present invention; Figure 2 This is a top view of the main structure of a small-angle generation system based on magnetorheological fluid and a fine-tuning motor according to an embodiment of the present invention. The present invention provides a small-angle generation system based on magnetorheological fluid and a fine-tuning motor, comprising: two capacitive angular displacement sensors 10 for measuring the relative rotation angle between an inner shaft 2 and an outer shaft 4; an angle sensor signal acquisition module 11 for acquiring the relative rotation angle measured by the two capacitive angular displacement sensors 10, subtracting the two relative rotation angles, and transmitting the angle difference value to a feedback controller 12; the feedback controller 12 for comparing the angle difference value with a preset target angle, calculating the angle error, and performing feedback control on a motor drive control unit 13; the motor drive control unit 13 for outputting a control signal for the angle error to a signal processing and analysis unit 15; the signal processing and analysis unit 15 for analyzing and processing the angle error through a closed-loop control strategy, so as to control the motor drive control unit 13 and the magnetic field control unit 16 according to the angle error, so that the relative rotation angle between the inner shaft 2 and the outer shaft 4 is stabilized within the target angle; and a computer 17 for displaying and outputting the relative rotation angle between the inner shaft 2 and the outer shaft 4.

[0079] Specifically, the small-angle generation system based on magnetorheological fluid and a fine-tuning motor further includes: a frustum 1 mounted on the upper part of the inner shaft 2, the frustum 1 being fixed to and rotating together with the inner shaft 2; an inner shaft base 3 mounted on the lower part of the inner shaft 2, the inner shaft base 3 being fixed to the outer shaft 4, the inner shaft 2 and the inner shaft base 3 rotating relative to each other; an outer shaft 4 disposed outside the inner shaft 2 and surrounding the inner shaft 2; a magnetic field generating unit 7 disposed outside the outer shaft 4, the bottom of the magnetic field generating unit 7 being disposed on a device base 8; a device base 8 mounted on the lower part of the inner shaft base 3, the inner shaft base 3 rotating relative to the device base 8; a device outer wall 9 fixedly mounted on the upper part of the device base 8, the device outer wall 9 being disposed outside the magnetic field generating unit 7, with a gap between the device outer wall 9 and the magnetic field generating unit 7; and a capacitive angular displacement sensor 10 mounted on the outer side of the upper edge of the frustum 1 and the outer shaft 4, and on the inner side of the device outer wall 9. Magnetorheological fluid 5 is disposed between the inner shaft 2 and the outer shaft 4.

[0080] In one embodiment of the present invention, a capacitive angular displacement sensor 10 is installed on the outer edge of the upper edge of the frustum 1 and the outer shaft 4, and on the inner side of the opposite outer wall 9 of the device. This allows for highly accurate measurement of the angle when the relative areas change. The frustum 1 is fixed to the inner shaft 2 and rotates together; the inner shaft base 3 is fixed to the outer shaft 4, and the device base 8 is fixed to the outer wall 9 of the device. The inner shaft 2 and the inner shaft base 3 can rotate relative to each other, and the inner shaft base 3 and the device base 8 can rotate relative to each other.

[0081] In one embodiment of the present invention, the annular space between the inner shaft 2 and the outer shaft 4 is filled with magnetorheological fluid 5, and high-precision capacitive angular displacement sensors 10 are respectively installed on the inner shaft 2 and the outer shaft 4. Multiple independently controllable magnetic field generating units 7 surround the outer shaft 4, the upper and lower surfaces of the frustum 1, and the upper and lower surfaces of the inner shaft base 3. These magnetic field generating units 7 can generate magnetic fields of different directions and intensities. The specific working principle is as follows: When there is no magnetic field, the magnetorheological fluid 5 is in a liquid state, and the inner shaft 2 and the outer shaft 4 can rotate freely relative to each other. When a small angle (±5°) is required, the magnetic field generating unit 7 is activated, generating a magnetic field inside the annular space. Under the action of the magnetic field, the magnetorheological fluid 5 rapidly changes its rheological properties, forming a localized high-viscosity region. Due to the change in friction between the inner shaft 2 and the outer shaft 4, the outer shaft 4 will have a slight tendency to rotate relative to the inner shaft 2. At this time, a fine-tuning motor 13 connected to the inner shaft 2 is used. The fine-tuning motor 13 is connected to the inner shaft 2 via a connecting rod on the fine-tuning motor, so as to precisely control the rotation of the inner shaft 2 with extremely small torque. The relative rotation angle between the inner and outer shafts can be accurately measured by a capacitive angular displacement sensor 10.

[0082] Specifically, the capacitive angular displacement sensor 10 includes a first capacitor plate 101, a second capacitor plate 102, a third capacitor plate 103, a fourth capacitor plate 104, a fifth capacitor plate 105, a sixth capacitor plate 106, a seventh capacitor plate 107, and an eighth capacitor plate 108. The first capacitor plate 101 and the second capacitor plate 102 are positioned opposite each other; the third capacitor plate 103 and the fourth capacitor plate 104 are positioned opposite each other; the fifth capacitor plate 105 and the sixth capacitor plate 106 are positioned opposite each other; and the seventh capacitor plate 107 and the eighth capacitor plate 108 are positioned opposite each other. The first capacitor plate 101 and the fifth capacitor plate 105 are mounted on... The third capacitor plate 103 and the seventh capacitor plate 107 are mounted on the side of the outer shaft 4; the second capacitor plate 102, the fourth capacitor plate 104, the sixth capacitor plate 106, and the eighth capacitor plate 108 are fixedly installed on the inner side of the outer wall 9 of the device. The first capacitor plate 101, the second capacitor plate 102, the fifth capacitor plate 105, and the sixth capacitor plate 106 are used to measure the rotation angle of the container 1 relative to the inner shaft 2; the third capacitor plate 103, the fourth capacitor plate 104, the seventh capacitor plate 107, and the eighth capacitor plate 108 are used to measure the rotation angle of the outer shaft 4 relative to the device base 8.

[0083] In one embodiment of the present invention, two pairs of angle sensors, namely the first capacitor plate 101 and the second capacitor plate 102, and the fifth capacitor plate 105 and the sixth capacitor plate 106, are used to measure the rotation angle of the frustum 1 relative to the inner shaft 2; two pairs of angle sensors, namely the third capacitor plate 103 and the fourth capacitor plate 104, and the seventh capacitor plate 107 and the eighth capacitor plate 108, are used to measure the rotation angle of the outer shaft 4 relative to the device base 8. The specific installation method is as follows: the first capacitor plate 101 and the fifth capacitor plate 105 are installed on the side of the frustum 1; the third capacitor plate 103 and the seventh capacitor plate 107 are installed on the side of the outer shaft 4; the second capacitor plate 102, the fourth capacitor plate 104, the sixth capacitor plate 106, and the eighth capacitor plate 108 are fixedly installed on the inner side of the outer wall 9 of the device. By cleverly controlling the position and intensity of the magnetic field and finely adjusting the torque of the motor, precise small angles can be generated. Using a dual-axis interference method allows for more flexible angle adjustment and achieves higher control precision.

[0084] The small-angle generation system based on magnetorheological fluid and a fine-tuning motor further includes: a magnetorheological fluid microsphere array 6, which is disposed at the lower part of the frustum 1 and on the upper surface of the outer shaft 4. The upper surface substrate of the outer shaft 4 is etched with a plurality of pit arrays, each pit array containing one magnetorheological fluid microsphere, collectively constituting the magnetorheological fluid microsphere array 6.

[0085] In one embodiment of the present invention, a magnetorheological fluid microsphere array 6 is used to assist in generating minute angular changes. A tiny array of pits is etched on the upper surface substrate of the outer shaft 4, with one magnetorheological fluid microsphere placed in each pit, collectively forming the magnetorheological fluid microsphere array 6. A frustum 1 is mounted on the upper surface substrate of the outer shaft 4, and the frustum 1 is fixedly connected to the inner shaft 2. The lower surface of the frustum 1 can rotate relative to the upper surface substrate of the outer shaft 4, and there is an extremely thin gap between the lower surface of the frustum 1 and the upper surface substrate of the outer shaft 4. The size of this gap is just enough to allow the magnetorheological fluid microspheres to contact the cover plate and generate friction under the action of a magnetic field.

[0086] Specifically, the magnetic field generating unit 7 includes: a first vertical electromagnetic coil 701, a second vertical electromagnetic coil 702, a third vertical electromagnetic coil 703, a fourth vertical electromagnetic coil 704, and a first horizontal electromagnetic coil 705; the first vertical electromagnetic coil 701 and the second vertical electromagnetic coil 702 are opposite each other and are respectively disposed on both sides of the magnetorheological fluid 5; the third vertical electromagnetic coil 703 and the fourth vertical electromagnetic coil 704 are opposite each other, and the third vertical electromagnetic coil 703 is disposed on the upper part of the frustum 1; the fourth vertical electromagnetic coil 704 is disposed on the lower part of the inner shaft base 3; the first horizontal electromagnetic coil 705 is disposed on the outer side of the outer shaft 4.

[0087] In one embodiment of the present invention, a first horizontal electromagnetic coil 705 is used, and the electromagnetic coils are arranged in a ring. The positional relationship of the electromagnetic coils is as follows: the first vertical electromagnetic coil 701 is opposite to the second vertical electromagnetic coil 702; the third vertical electromagnetic coil 703 is opposite to the fourth vertical electromagnetic coil 704. The specific working principle of the magnetorheological fluid microsphere array 6 is as follows: In the initial state, the magnetorheological fluid microsphere array 6 is in a natural state. When a small angle (±5°) is required, a magnetic field is generated in a specific area through the magnetic field generating unit 7. Under the action of the magnetic field, the rheological properties of the magnetorheological fluid microsphere array 6 change, and the microspheres expand and contact the lower surface of the frustum 1. Due to the increased friction between the microspheres and the lower surface of the frustum 1, when a small force is applied to the edge of the frustum 1, the frustum 1 will rotate at a small angle relative to the outer axis 4. By controlling the distribution and intensity of the magnetic field, the degree of expansion of the microspheres and the magnitude of the friction can be precisely controlled, thereby precisely controlling the small-angle rotation of the frustum 1.

[0088] In one embodiment of the present invention, the capacitive angular displacement sensor 10 measures the angle value and calculates the difference, transmitting the angle difference signal to the feedback controller 11. The feedback controller 11 performs feedback control on the motor drive control unit 12, comparing the angle signal measured by the capacitive angular displacement sensor 10 with the target angle set by the system, and calculating the angle error. Then, based on the error signal, a certain control strategy is used to adjust the rotation of the fine-tuning motor 13 and the magnetic field strength of the magnetic field control unit 15. Specifically, a closed-loop control strategy is adopted. After the signal processing and analysis unit 14 analyzes and processes the angle error signal, when the angle error is greater than a set threshold, the signal processing and analysis unit 14 transmits the error signal to the motor drive control unit 12. The motor drive control unit 12 adjusts the rotation speed of the fine-tuning motor 13 or increases the magnetic field strength to reduce the angle error signal as quickly as possible. When the angle error signal is small, the system fine-tunes the motor 13 and the magnetic field to stabilize the angle near the target value. Finally, the generated angle result is displayed and output by the computer 16.

[0089] Please see Figure 3 , Figure 3 This is a flowchart of a method for generating small angles based on magnetorheological fluid and a fine-tuning motor, according to an embodiment of the present invention. The present invention also provides a method for generating small angles based on magnetorheological fluid and a fine-tuning motor, including the aforementioned small angle generation system based on magnetorheological fluid and a fine-tuning motor, wherein the method for generating small angles based on magnetorheological fluid and a fine-tuning motor includes:

[0090] S1. The relative rotation angle between the inner shaft 2 and the outer shaft 4 is measured by two capacitive angular displacement sensors 10;

[0091] S2. The relative rotation angle measured by the two capacitive angular displacement sensors 10 is acquired by the angle sensor signal acquisition module 11, and the difference between the two relative rotation angles is transmitted to the feedback controller 12.

[0092] S3. The feedback controller 12 compares the angle difference with the preset target angle and calculates the angle error. The feedback controller 12 performs feedback control on the motor drive control unit 13.

[0093] S4. The motor drive control unit 13 outputs the control signal of the angle error to the signal processing and analysis unit 15;

[0094] S5, the signal processing and analysis unit 15 analyzes and processes the angle error through a closed-loop control strategy, so as to control the motor drive control unit 13 and the magnetic field control unit 16 according to the angle error, so that the relative rotation angle between the inner shaft 2 and the outer shaft 4 is stabilized within the target angle.

[0095] S6. The relative rotation angle between the inner shaft 2 and the outer shaft 4 is displayed and output by the computer 17.

[0096] In step S5, the signal processing and analysis unit 15 analyzes and processes the angle error using a closed-loop control strategy, and controls the motor drive control unit 13 and the magnetic field control unit 16 according to the angle error to stabilize the relative rotation angle between the inner shaft 2 and the outer shaft 4 within the target angle, including:

[0097] An area-type capacitive angular displacement sensor is installed on the upper edge of the outer shaft of a circular frustum, and on the inner side of the opposite outer edge of the device. High-accuracy angle measurement can be achieved when the area changes relative to the surface. Taking an area-type single-plate capacitor, i.e., the first capacitor plate 101, the second capacitor plate 102, the third capacitor plate 103, the fourth capacitor plate 104, the fifth capacitor plate 105, the sixth capacitor plate 106, the seventh capacitor plate 107, and the eighth capacitor plate 108, as an example, for a sector-shaped plate capacitive displacement sensor, assuming the initial overlapping area of ​​the plates is A0, the dielectric constant between the plates is ε, and the plate spacing is d, when the angle changes by Δθ, the change in the overlapping area of ​​the plates is ΔA. Then, the relationship between the capacitance change ΔC and the angle change Δθ can be approximated as:

[0098]

[0099] Assuming the radius of the sector-shaped plate is r, the overlapping area caused by the angle change is approximately:

[0100]

[0101] The change in angle Δθ can then be expressed as:

[0102]

[0103] This system operates in shear mode, in which the magnetorheological fluid is confined between two relatively rotating cylinders. In this mode, the shear rate ω (i.e., the derivative of the angle with respect to time) is... The expression for force F is as follows:

[0104]

[0105] The formula simplifies to:

[0106]

[0107] Among them, F 屈服 (H) is the static yield force related to the magnetic field, which is independent of the angle; It is the viscous damping coefficient; η is the angular velocity (i.e., the rate of change of angle); A is the shear area, r is the radius of rotation, d is the gap thickness (the gap thickness is the cross-sectional dimension of the magnetorheological fluid flow path), and η is the zero-field viscosity. In the shear mode, the magnetorheological fluid is located between two relatively moving cylinders. When a magnetic field is applied, the magnetorheological fluid generates shear stress, which is related to the shear rate (i.e., angular velocity). F in the formula is the force caused by the shear stress, which consists of two parts: static yield force (related to the magnetic field) and dynamic viscous force (related to the angular velocity). When subjected to an external torque (such as the torque generated by a fine-tuning motor), the resulting angle is divided into two modes: stable rotation (constant angular velocity) and dynamic response (including inertia term).

[0108] (1) Stable rotation (constant angular velocity)

[0109] Assume the system reaches steady state (no angular acceleration, i.e.) At this point, the external torque Text is balanced with the damping torque of the magnetorheological fluid, and the resulting steady-state angle change is:

[0110]

[0111] In the formula, θ0 is the initial angle value, and T ext The torque generated by the fine-tuning motor is given by t, which is the time for the angle change.

[0112] (2) Dynamic response (including inertial term)

[0113] Assuming the system undergoes a transient change, the obtained transient angle change is:

[0114]

[0115] In the formula, C1 and C2 are determined by the initial conditions, and l is the total length of the magnetorheological fluid flow path.

[0116] In summary, the present invention provides a small-angle generation system and method based on magnetorheological fluid and a fine-tuning motor. It utilizes the rapid solidification characteristics of magnetorheological fluid under a magnetic field (millisecond-level response) combined with the stepper drive of the fine-tuning motor to achieve instantaneous locking after angle adjustment, avoiding the lag and loosening of traditional mechanical locking. The invention employs a closed-loop adaptive algorithm, integrating motor encoder signals and magnetorheological fluid damping feedback to achieve dynamic compensation for angle fine-tuning. By combining the microstepping drive of the motor with the vibration suppression characteristics of magnetorheological fluid damping, it achieves highly accurate small-angle generation.

[0117] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A small-angle generation system based on magnetorheological fluid and a fine-tuning motor, characterized in that, include: Two capacitive angular displacement sensors (10) are used to measure the relative rotation angle between the inner shaft (2) and the outer shaft (4); Angle sensor signal acquisition module (11) is used to acquire the relative rotation angle measured by the two capacitive angular displacement sensors (10), and to calculate the difference between the two relative rotation angles and transmit the angle difference value to the feedback controller (12). The feedback controller (12) is used to compare the angle difference with the preset target angle and calculate the angle error. The feedback controller (12) is used to perform feedback control on the motor drive control unit (13). The motor drive control unit (13) is used to output the control signal of the angle error to the signal processing and analysis unit (15). The signal processing and analysis unit (15) is used to analyze and process the angle error through a closed-loop control strategy, so as to control the motor drive control unit (13) and the magnetic field control unit (16) according to the angle error, so that the relative rotation angle between the inner shaft (2) and the outer shaft (4) is stabilized within the preset target angle. Computer (17) is used to display and output the relative rotation angle between the inner shaft (2) and the outer shaft (4); A frustum (1) is mounted on the upper part of the inner shaft (2), and the frustum (1) is fixed to the inner shaft (2) and rotates together; An inner shaft base (3) is installed on the lower part of the inner shaft (2), and the inner shaft base (3) is fixed to the outer shaft (4). The inner shaft (2) and the inner shaft base (3) rotate relative to each other. An outer shaft (4) is disposed outside the inner shaft (2) and surrounds the inner shaft (2); A magnetic field generating unit (7) is disposed on the outside of the outer shaft (4), and the bottom of the magnetic field generating unit (7) is disposed on the device base (8); Device base (8), which is installed on the lower part of the inner shaft base (3), the inner shaft base (3) and the device base (8) rotate relative to each other; The outer wall (9) of the device is fixedly installed on the upper part of the device base (8), and the outer wall (9) of the device is located on the outside of the magnetic field generating unit (7), and there is a gap between it and the magnetic field generating unit (7). The capacitive angular displacement sensor (10) is installed on the outer side of the upper edge of the loading frustum (1) and the outer shaft (4) and on the inner side of the outer wall (9) of the device. Magnetorheological fluid (5) is disposed between the inner shaft (2) and the outer shaft (4); A magnetorheological fluid microsphere array (6) is disposed at the lower part of the frustum (1) and the magnetorheological fluid microsphere array (6) is disposed on the upper surface of the outer shaft (4); The upper surface substrate of the outer shaft (4) is etched with a plurality of pit arrays, and a magnetorheological fluid microsphere is placed in each pit array, which together constitute the magnetorheological fluid microsphere array (6).

2. The small-angle generation system based on magnetorheological fluid and a fine-tuning motor according to claim 1, characterized in that, The capacitive angular displacement sensor (10) includes a first capacitor plate (101), a second capacitor plate (102), a third capacitor plate (103), a fourth capacitor plate (104), a fifth capacitor plate (105), a sixth capacitor plate (106), a seventh capacitor plate (107), and an eighth capacitor plate (108). The first capacitor plate (101) and the second capacitor plate (102) are positioned opposite each other; the third capacitor plate (103) and the fourth capacitor plate (104) are positioned opposite each other; the fifth capacitor plate (105) and the sixth capacitor plate (106) are positioned opposite each other; and the seventh capacitor plate (107) and the eighth capacitor plate (108) are positioned opposite each other. The first capacitor plate (101) and the fifth capacitor plate (105) are mounted on the carrier. The object frustum (1) is mounted on the side; the third capacitor plate (103) and the seventh capacitor plate (107) are mounted on the side of the outer shaft (4); the second capacitor plate (102), the fourth capacitor plate (104), the sixth capacitor plate (106) and the eighth capacitor plate (108) are fixedly mounted on the inner side of the outer wall (9) of the device. The first capacitor plate (101) and the second capacitor plate (102), the fifth capacitor plate (105) and the sixth capacitor plate (106) are used to measure the rotation angle of the object frustum (1) relative to the inner shaft (2); the third capacitor plate (103) and the fourth capacitor plate (104), the seventh capacitor plate (107) and the eighth capacitor plate (108) are used to measure the rotation angle of the outer shaft (4) relative to the device base (8).

3. The small-angle generation system based on magnetorheological fluid and fine-tuning motor according to claim 2, characterized in that, The magnetic field generating unit (7) includes: a first vertical electromagnetic coil (701), a second vertical electromagnetic coil (702), a third vertical electromagnetic coil (703), a fourth vertical electromagnetic coil (704), and a first horizontal electromagnetic coil (705). The first vertical electromagnetic coil (701) and the second vertical electromagnetic coil (702) are opposite to each other and are respectively disposed on both sides of the magnetorheological fluid (5); The third vertical electromagnetic coil (703) is opposite to the fourth vertical electromagnetic coil (704). The third vertical electromagnetic coil (703) is located on the upper part of the frustum (1); the fourth vertical electromagnetic coil (704) is located on the lower part of the inner shaft base (3). The first horizontal electromagnetic coil (705) is disposed on the outside of the outer shaft (4).

4. A method for generating small angles based on magnetorheological fluid and a fine-tuning motor, characterized in that, The small-angle generation system based on magnetorheological fluid and fine-tuning motor as described in claim 3 includes: S1. The relative rotation angle between the inner shaft (2) and the outer shaft (4) is measured by two capacitive angular displacement sensors (10); S2. The relative rotation angle measured by the two capacitive angular displacement sensors (10) is acquired by the angle sensor signal acquisition module (11), and the difference between the two relative rotation angles is transmitted to the feedback controller (12). S3. The feedback controller (12) compares the angle difference with the preset target angle and calculates the angle error. The feedback controller (12) performs feedback control on the motor drive control unit (13). S4. The motor drive control unit (13) outputs the control signal of the angle error to the signal processing and analysis unit (15). S5. The signal processing and analysis unit (15) analyzes and processes the angle error through a closed-loop control strategy, so as to control the motor drive control unit (13) and the magnetic field control unit (16) according to the angle error, so that the relative rotation angle between the inner shaft (2) and the outer shaft (4) is stabilized within the preset target angle. S6. The relative rotation angle between the inner shaft (2) and the outer shaft (4) is displayed and output by computer (17).

5. The method for generating small angles based on magnetorheological fluid and a fine-tuning motor according to claim 4, characterized in that: The signal processing and analysis unit (15) in step S5 analyzes and processes the angle error using a closed-loop control strategy, and controls the motor drive control unit (13) and the magnetic field control unit (16) according to the angle error, so that the relative rotation angle between the inner shaft (2) and the outer shaft (4) is stabilized within a preset target angle, including: For the first capacitor plate (101), the second capacitor plate (102), the third capacitor plate (103), the fourth capacitor plate (104), the fifth capacitor plate (105), the sixth capacitor plate (106), the seventh capacitor plate (107), and the eighth capacitor plate (108), assuming the initial overlap area of ​​the plates is A0, the dielectric constant between the plates is ε, and the distance between the plates is d, when the angle changes... At time θ, the change in the overlap area of ​​the plates is: A, then the change in capacitance C and angle change The relationship of θ is approximately: （1） Assuming the radius of the sector-shaped plate is r, the overlapping area caused by the angle change is approximately: （2） Then the angle changes θ can be represented as: （3） The small-angle generating system operates in shear mode. In shear mode, the magnetorheological fluid (5) is confined between the inner shaft (2) and the outer shaft (4). At this time, the shear rate ω is related, and the expression for the force F is: （4） Formula (4) simplifies to: （5） in, This is a static yield force related to the magnetic field and independent of the angle. It is the viscous damping coefficient; ω is the angular velocity; A is the shear area; r is the radius of rotation; d is the gap thickness; η is the zero-field viscosity; F in the formula is the force caused by shear stress. When subjected to external torque, the resulting angle is divided into a stable rotation mode and a dynamic response mode.

6. The method for generating small angles based on magnetorheological fluid and a fine-tuning motor according to claim 5, characterized in that: The stable rotation mode: Assuming the small-angle generating system reaches a steady state, at which point the external torque and the damping torque of the magnetorheological fluid (5) are balanced, the resulting steady-state angle change is: （6） in, This is the initial angle value. The torque generated by the fine-tuning motor is given by t, which is the time of angle change. The dynamic response mode: Assuming the small angle generation system is a transient change, the obtained transient angle change is: （7） C1 and C2 are determined by the initial conditions, and l is the total length of the flow path of the magnetorheological fluid (5).

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